Switch analysis_server to language 2.12, so null safety, but opt-out files.

This should allow doing partial migration, specifically protocol files,
which are imported by other libraries, but are a small library cycle
that does not import much outside of it.

Change-Id: I904c05d6d5b444ee9a9dbd1f7ada12aabdcc5165
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/193583
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>
diff --git a/.dart_tool/package_config.json b/.dart_tool/package_config.json
index 056b654..3c57af1 100644
--- a/.dart_tool/package_config.json
+++ b/.dart_tool/package_config.json
@@ -70,7 +70,7 @@
       "name": "analysis_server",
       "rootUri": "../pkg/analysis_server",
       "packageUri": "lib/",
-      "languageVersion": "2.6"
+      "languageVersion": "2.12"
     },
     {
       "name": "analysis_server_client",
diff --git a/pkg/analysis_server/benchmark/benchmarks.dart b/pkg/analysis_server/benchmark/benchmarks.dart
index 1dd12cb..5276220 100644
--- a/pkg/analysis_server/benchmark/benchmarks.dart
+++ b/pkg/analysis_server/benchmark/benchmarks.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 import 'dart:io';
 import 'dart:math' as math;
diff --git a/pkg/analysis_server/benchmark/integration/driver.dart b/pkg/analysis_server/benchmark/integration/driver.dart
index 0bb18c1..6e831aa 100644
--- a/pkg/analysis_server/benchmark/integration/driver.dart
+++ b/pkg/analysis_server/benchmark/integration/driver.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:math' show max, sqrt;
 
diff --git a/pkg/analysis_server/benchmark/integration/input_converter.dart b/pkg/analysis_server/benchmark/integration/input_converter.dart
index 7f7ca06..e128456 100644
--- a/pkg/analysis_server/benchmark/integration/input_converter.dart
+++ b/pkg/analysis_server/benchmark/integration/input_converter.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
diff --git a/pkg/analysis_server/benchmark/integration/instrumentation_input_converter.dart b/pkg/analysis_server/benchmark/integration/instrumentation_input_converter.dart
index e2f01d3..2cd8783 100644
--- a/pkg/analysis_server/benchmark/integration/instrumentation_input_converter.dart
+++ b/pkg/analysis_server/benchmark/integration/instrumentation_input_converter.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 
 import 'package:analyzer/exception/exception.dart';
diff --git a/pkg/analysis_server/benchmark/integration/local_runner.dart b/pkg/analysis_server/benchmark/integration/local_runner.dart
index 857d422..e8353b2 100644
--- a/pkg/analysis_server/benchmark/integration/local_runner.dart
+++ b/pkg/analysis_server/benchmark/integration/local_runner.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io';
 
 import 'package:path/path.dart';
diff --git a/pkg/analysis_server/benchmark/integration/log_file_input_converter.dart b/pkg/analysis_server/benchmark/integration/log_file_input_converter.dart
index 6ec1a4f..238a1fa 100644
--- a/pkg/analysis_server/benchmark/integration/log_file_input_converter.dart
+++ b/pkg/analysis_server/benchmark/integration/log_file_input_converter.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 
 import 'package:analyzer/exception/exception.dart';
diff --git a/pkg/analysis_server/benchmark/integration/main.dart b/pkg/analysis_server/benchmark/integration/main.dart
index 8006da8..c1c9911 100644
--- a/pkg/analysis_server/benchmark/integration/main.dart
+++ b/pkg/analysis_server/benchmark/integration/main.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
diff --git a/pkg/analysis_server/benchmark/integration/operation.dart b/pkg/analysis_server/benchmark/integration/operation.dart
index 7532df2..eb70f44 100644
--- a/pkg/analysis_server/benchmark/integration/operation.dart
+++ b/pkg/analysis_server/benchmark/integration/operation.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/benchmark/perf/benchmarks_impl.dart b/pkg/analysis_server/benchmark/perf/benchmarks_impl.dart
index fab0850..1a59fa6 100644
--- a/pkg/analysis_server/benchmark/perf/benchmarks_impl.dart
+++ b/pkg/analysis_server/benchmark/perf/benchmarks_impl.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:io';
 
diff --git a/pkg/analysis_server/benchmark/perf/flutter_analyze_benchmark.dart b/pkg/analysis_server/benchmark/perf/flutter_analyze_benchmark.dart
index e0008e8..171aab6 100644
--- a/pkg/analysis_server/benchmark/perf/flutter_analyze_benchmark.dart
+++ b/pkg/analysis_server/benchmark/perf/flutter_analyze_benchmark.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 import 'dart:io';
 
diff --git a/pkg/analysis_server/benchmark/perf/memory_tests.dart b/pkg/analysis_server/benchmark/perf/memory_tests.dart
index c78c614..9a2c30c 100644
--- a/pkg/analysis_server/benchmark/perf/memory_tests.dart
+++ b/pkg/analysis_server/benchmark/perf/memory_tests.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:convert' show jsonDecode, jsonEncode;
 import 'dart:io';
diff --git a/pkg/analysis_server/bin/server.dart b/pkg/analysis_server/bin/server.dart
index 7810101..a873eb1 100644
--- a/pkg/analysis_server/bin/server.dart
+++ b/pkg/analysis_server/bin/server.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/starter.dart';
 
 /// Create and run an analysis server.
diff --git a/pkg/analysis_server/lib/lsp_protocol/protocol_custom_generated.dart b/pkg/analysis_server/lib/lsp_protocol/protocol_custom_generated.dart
index beaf3f5..53800de 100644
--- a/pkg/analysis_server/lib/lsp_protocol/protocol_custom_generated.dart
+++ b/pkg/analysis_server/lib/lsp_protocol/protocol_custom_generated.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 // This file has been automatically generated. Please do not edit it manually.
 // To regenerate the file, use the script
 // "pkg/analysis_server/tool/lsp_spec/generate_all.dart".
diff --git a/pkg/analysis_server/lib/lsp_protocol/protocol_generated.dart b/pkg/analysis_server/lib/lsp_protocol/protocol_generated.dart
index 03bb36c..ec98cde 100644
--- a/pkg/analysis_server/lib/lsp_protocol/protocol_generated.dart
+++ b/pkg/analysis_server/lib/lsp_protocol/protocol_generated.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 // This file has been automatically generated. Please do not edit it manually.
 // To regenerate the file, use the script
 // "pkg/analysis_server/tool/lsp_spec/generate_all.dart".
diff --git a/pkg/analysis_server/lib/lsp_protocol/protocol_special.dart b/pkg/analysis_server/lib/lsp_protocol/protocol_special.dart
index bd9b513..e1f4838 100644
--- a/pkg/analysis_server/lib/lsp_protocol/protocol_special.dart
+++ b/pkg/analysis_server/lib/lsp_protocol/protocol_special.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/lib/plugin/analysis/occurrences/occurrences_core.dart b/pkg/analysis_server/lib/plugin/analysis/occurrences/occurrences_core.dart
index 7483aa4..afc2f1a 100644
--- a/pkg/analysis_server/lib/plugin/analysis/occurrences/occurrences_core.dart
+++ b/pkg/analysis_server/lib/plugin/analysis/occurrences/occurrences_core.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/protocol/protocol_common.dart' show Occurrences;
 
 /// An object used to record occurrences into.
diff --git a/pkg/analysis_server/lib/plugin/edit/assist/assist_core.dart b/pkg/analysis_server/lib/plugin/edit/assist/assist_core.dart
index c4469ea..113cbcf 100644
--- a/pkg/analysis_server/lib/plugin/edit/assist/assist_core.dart
+++ b/pkg/analysis_server/lib/plugin/edit/assist/assist_core.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/protocol/protocol_common.dart'
     show SourceChange;
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
diff --git a/pkg/analysis_server/lib/plugin/edit/assist/assist_dart.dart b/pkg/analysis_server/lib/plugin/edit/assist/assist_dart.dart
index 3154306..b8a9946 100644
--- a/pkg/analysis_server/lib/plugin/edit/assist/assist_dart.dart
+++ b/pkg/analysis_server/lib/plugin/edit/assist/assist_dart.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/instrumentation/service.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_workspace.dart';
diff --git a/pkg/analysis_server/lib/plugin/edit/fix/fix_core.dart b/pkg/analysis_server/lib/plugin/edit/fix/fix_core.dart
index f3873dc..db3b1b8 100644
--- a/pkg/analysis_server/lib/plugin/edit/fix/fix_core.dart
+++ b/pkg/analysis_server/lib/plugin/edit/fix/fix_core.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart'
     show SourceChange;
diff --git a/pkg/analysis_server/lib/plugin/edit/fix/fix_dart.dart b/pkg/analysis_server/lib/plugin/edit/fix/fix_dart.dart
index 4792bed..50658b4 100644
--- a/pkg/analysis_server/lib/plugin/edit/fix/fix_dart.dart
+++ b/pkg/analysis_server/lib/plugin/edit/fix/fix_dart.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/plugin/edit/fix/fix_core.dart';
 import 'package:analysis_server/src/services/correction/fix/dart/top_level_declarations.dart';
 import 'package:analyzer/dart/analysis/results.dart';
diff --git a/pkg/analysis_server/lib/plugin/protocol/protocol_dart.dart b/pkg/analysis_server/lib/plugin/protocol/protocol_dart.dart
index 915d8b3..c456641 100644
--- a/pkg/analysis_server/lib/plugin/protocol/protocol_dart.dart
+++ b/pkg/analysis_server/lib/plugin/protocol/protocol_dart.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// Utilities for converting Dart entities into analysis server's protocol
 /// entities.
 import 'package:analysis_server/src/protocol_server.dart';
diff --git a/pkg/analysis_server/lib/protocol/protocol.dart b/pkg/analysis_server/lib/protocol/protocol.dart
index f995858..4f0437b 100644
--- a/pkg/analysis_server/lib/protocol/protocol.dart
+++ b/pkg/analysis_server/lib/protocol/protocol.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// Support for client code that needs to interact with the requests, responses
 /// and notifications that are part of the analysis server's wire protocol.
 import 'dart:convert' hide JsonDecoder;
diff --git a/pkg/analysis_server/lib/protocol/protocol_constants.dart b/pkg/analysis_server/lib/protocol/protocol_constants.dart
index 6772e9d..654d974 100644
--- a/pkg/analysis_server/lib/protocol/protocol_constants.dart
+++ b/pkg/analysis_server/lib/protocol/protocol_constants.dart
@@ -6,6 +6,8 @@
 // To regenerate the file, use the script
 // "pkg/analysis_server/tool/spec/generate_files".
 
+// @dart = 2.9
+
 const String PROTOCOL_VERSION = '1.32.5';
 
 const String ANALYSIS_NOTIFICATION_ANALYZED_FILES = 'analysis.analyzedFiles';
diff --git a/pkg/analysis_server/lib/protocol/protocol_generated.dart b/pkg/analysis_server/lib/protocol/protocol_generated.dart
index 1ae7337..6893238 100644
--- a/pkg/analysis_server/lib/protocol/protocol_generated.dart
+++ b/pkg/analysis_server/lib/protocol/protocol_generated.dart
@@ -6,6 +6,8 @@
 // To regenerate the file, use the script
 // "pkg/analysis_server/tool/spec/generate_files".
 
+// @dart = 2.9
+
 import 'dart:convert' hide JsonDecoder;
 
 import 'package:analyzer/src/generated/utilities_general.dart';
diff --git a/pkg/analysis_server/lib/src/analysis_server.dart b/pkg/analysis_server/lib/src/analysis_server.dart
index 3ac7ec6..77193b3 100644
--- a/pkg/analysis_server/lib/src/analysis_server.dart
+++ b/pkg/analysis_server/lib/src/analysis_server.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:collection';
 import 'dart:core';
diff --git a/pkg/analysis_server/lib/src/analysis_server_abstract.dart b/pkg/analysis_server/lib/src/analysis_server_abstract.dart
index 2d17fe4..3288d8b 100644
--- a/pkg/analysis_server/lib/src/analysis_server_abstract.dart
+++ b/pkg/analysis_server/lib/src/analysis_server_abstract.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:core';
 import 'dart:io' as io;
 import 'dart:io';
diff --git a/pkg/analysis_server/lib/src/channel/byte_stream_channel.dart b/pkg/analysis_server/lib/src/channel/byte_stream_channel.dart
index a6567e6..f9abadf 100644
--- a/pkg/analysis_server/lib/src/channel/byte_stream_channel.dart
+++ b/pkg/analysis_server/lib/src/channel/byte_stream_channel.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
diff --git a/pkg/analysis_server/lib/src/channel/channel.dart b/pkg/analysis_server/lib/src/channel/channel.dart
index f8807d2..627db8a 100644
--- a/pkg/analysis_server/lib/src/channel/channel.dart
+++ b/pkg/analysis_server/lib/src/channel/channel.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 
 import 'package:analysis_server/protocol/protocol.dart';
diff --git a/pkg/analysis_server/lib/src/cider/assists.dart b/pkg/analysis_server/lib/src/cider/assists.dart
index ba46cce..c927a9e 100644
--- a/pkg/analysis_server/lib/src/cider/assists.dart
+++ b/pkg/analysis_server/lib/src/cider/assists.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/plugin/edit/assist/assist_core.dart';
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/assist_internal.dart';
diff --git a/pkg/analysis_server/lib/src/cider/completion.dart b/pkg/analysis_server/lib/src/cider/completion.dart
index 8f1ec94..99eeec2 100644
--- a/pkg/analysis_server/lib/src/cider/completion.dart
+++ b/pkg/analysis_server/lib/src/cider/completion.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/services/completion/completion_core.dart';
 import 'package:analysis_server/src/services/completion/completion_performance.dart';
diff --git a/pkg/analysis_server/lib/src/cider/fixes.dart b/pkg/analysis_server/lib/src/cider/fixes.dart
index 3f3f087..ae971be 100644
--- a/pkg/analysis_server/lib/src/cider/fixes.dart
+++ b/pkg/analysis_server/lib/src/cider/fixes.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/plugin/edit/fix/fix_core.dart';
 import 'package:analysis_server/src/services/correction/change_workspace.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/collections.dart b/pkg/analysis_server/lib/src/collections.dart
index 38f971a..80a5a22 100644
--- a/pkg/analysis_server/lib/src/collections.dart
+++ b/pkg/analysis_server/lib/src/collections.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// Returns the given [list] if it is not empty, or `null` otherwise.
 List<E> nullIfEmpty<E>(List<E> list) {
   if (list == null) {
diff --git a/pkg/analysis_server/lib/src/computer/computer_closingLabels.dart b/pkg/analysis_server/lib/src/computer/computer_closingLabels.dart
index dd01e3f..6c4c5ed 100644
--- a/pkg/analysis_server/lib/src/computer/computer_closingLabels.dart
+++ b/pkg/analysis_server/lib/src/computer/computer_closingLabels.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
diff --git a/pkg/analysis_server/lib/src/computer/computer_folding.dart b/pkg/analysis_server/lib/src/computer/computer_folding.dart
index 2a8bc96..a279dfb 100644
--- a/pkg/analysis_server/lib/src/computer/computer_folding.dart
+++ b/pkg/analysis_server/lib/src/computer/computer_folding.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
diff --git a/pkg/analysis_server/lib/src/computer/computer_highlights.dart b/pkg/analysis_server/lib/src/computer/computer_highlights.dart
index 717c136..2a97366 100644
--- a/pkg/analysis_server/lib/src/computer/computer_highlights.dart
+++ b/pkg/analysis_server/lib/src/computer/computer_highlights.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart'
     show SemanticTokenTypes, SemanticTokenModifiers;
 import 'package:analysis_server/src/lsp/constants.dart'
diff --git a/pkg/analysis_server/lib/src/computer/computer_hover.dart b/pkg/analysis_server/lib/src/computer/computer_hover.dart
index 3207fbf..53ff8df 100644
--- a/pkg/analysis_server/lib/src/computer/computer_hover.dart
+++ b/pkg/analysis_server/lib/src/computer/computer_hover.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart'
     show HoverInformation;
 import 'package:analysis_server/src/computer/computer_overrides.dart';
diff --git a/pkg/analysis_server/lib/src/computer/computer_outline.dart b/pkg/analysis_server/lib/src/computer/computer_outline.dart
index c3fb5d8..20e3278 100644
--- a/pkg/analysis_server/lib/src/computer/computer_outline.dart
+++ b/pkg/analysis_server/lib/src/computer/computer_outline.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/collections.dart';
 import 'package:analysis_server/src/utilities/flutter.dart';
 import 'package:analyzer/dart/analysis/results.dart';
diff --git a/pkg/analysis_server/lib/src/computer/computer_overrides.dart b/pkg/analysis_server/lib/src/computer/computer_overrides.dart
index 9a27a6e..505abac 100644
--- a/pkg/analysis_server/lib/src/computer/computer_overrides.dart
+++ b/pkg/analysis_server/lib/src/computer/computer_overrides.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/collections.dart';
 import 'package:analysis_server/src/protocol_server.dart' as proto;
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/computer/computer_signature.dart b/pkg/analysis_server/lib/src/computer/computer_signature.dart
index bb26c6a..20bc565 100644
--- a/pkg/analysis_server/lib/src/computer/computer_signature.dart
+++ b/pkg/analysis_server/lib/src/computer/computer_signature.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/computer/computer_hover.dart';
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/computer/import_elements_computer.dart b/pkg/analysis_server/lib/src/computer/import_elements_computer.dart
index 2229f6f..59a251a 100644
--- a/pkg/analysis_server/lib/src/computer/import_elements_computer.dart
+++ b/pkg/analysis_server/lib/src/computer/import_elements_computer.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/computer/imported_elements_computer.dart b/pkg/analysis_server/lib/src/computer/imported_elements_computer.dart
index 8d2c2f4..a53a891 100644
--- a/pkg/analysis_server/lib/src/computer/imported_elements_computer.dart
+++ b/pkg/analysis_server/lib/src/computer/imported_elements_computer.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
diff --git a/pkg/analysis_server/lib/src/context_manager.dart b/pkg/analysis_server/lib/src/context_manager.dart
index 9f4fee7..108e4c63 100644
--- a/pkg/analysis_server/lib/src/context_manager.dart
+++ b/pkg/analysis_server/lib/src/context_manager.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:collection';
 import 'dart:core';
diff --git a/pkg/analysis_server/lib/src/domain_abstract.dart b/pkg/analysis_server/lib/src/domain_abstract.dart
index 3d168d5..e88d541 100644
--- a/pkg/analysis_server/lib/src/domain_abstract.dart
+++ b/pkg/analysis_server/lib/src/domain_abstract.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:convert';
 import 'dart:math' as math;
diff --git a/pkg/analysis_server/lib/src/domain_analysis.dart b/pkg/analysis_server/lib/src/domain_analysis.dart
index 9785016..a34a056 100644
--- a/pkg/analysis_server/lib/src/domain_analysis.dart
+++ b/pkg/analysis_server/lib/src/domain_analysis.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:core';
 
 import 'package:analysis_server/protocol/protocol_constants.dart';
diff --git a/pkg/analysis_server/lib/src/domain_analytics.dart b/pkg/analysis_server/lib/src/domain_analytics.dart
index af31ca1..9a8f1aa 100644
--- a/pkg/analysis_server/lib/src/domain_analytics.dart
+++ b/pkg/analysis_server/lib/src/domain_analytics.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:core';
 
 import 'package:analysis_server/protocol/protocol.dart';
diff --git a/pkg/analysis_server/lib/src/domain_completion.dart b/pkg/analysis_server/lib/src/domain_completion.dart
index ea54b61..8a9ff43 100644
--- a/pkg/analysis_server/lib/src/domain_completion.dart
+++ b/pkg/analysis_server/lib/src/domain_completion.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/protocol/protocol.dart';
diff --git a/pkg/analysis_server/lib/src/domain_diagnostic.dart b/pkg/analysis_server/lib/src/domain_diagnostic.dart
index 747fb93..6e7b6ab 100644
--- a/pkg/analysis_server/lib/src/domain_diagnostic.dart
+++ b/pkg/analysis_server/lib/src/domain_diagnostic.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:core';
 
 import 'package:analysis_server/protocol/protocol.dart';
diff --git a/pkg/analysis_server/lib/src/domain_execution.dart b/pkg/analysis_server/lib/src/domain_execution.dart
index db74f5f..f1fec6e 100644
--- a/pkg/analysis_server/lib/src/domain_execution.dart
+++ b/pkg/analysis_server/lib/src/domain_execution.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:collection';
 import 'dart:core';
 
diff --git a/pkg/analysis_server/lib/src/domain_kythe.dart b/pkg/analysis_server/lib/src/domain_kythe.dart
index 26e4788..14ac442 100644
--- a/pkg/analysis_server/lib/src/domain_kythe.dart
+++ b/pkg/analysis_server/lib/src/domain_kythe.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:core';
 
 import 'package:analysis_server/protocol/protocol.dart';
diff --git a/pkg/analysis_server/lib/src/domain_server.dart b/pkg/analysis_server/lib/src/domain_server.dart
index c0d4e69..44a8b4b 100644
--- a/pkg/analysis_server/lib/src/domain_server.dart
+++ b/pkg/analysis_server/lib/src/domain_server.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_constants.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/lib/src/domains/analysis/implemented_dart.dart b/pkg/analysis_server/lib/src/domains/analysis/implemented_dart.dart
index 0939d94..3058da5 100644
--- a/pkg/analysis_server/lib/src/domains/analysis/implemented_dart.dart
+++ b/pkg/analysis_server/lib/src/domains/analysis/implemented_dart.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart' as protocol;
 import 'package:analysis_server/src/services/search/search_engine.dart';
 import 'package:analyzer/dart/element/element.dart';
diff --git a/pkg/analysis_server/lib/src/domains/analysis/occurrences.dart b/pkg/analysis_server/lib/src/domains/analysis/occurrences.dart
index 295d92c..5a10351 100644
--- a/pkg/analysis_server/lib/src/domains/analysis/occurrences.dart
+++ b/pkg/analysis_server/lib/src/domains/analysis/occurrences.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/plugin/analysis/occurrences/occurrences_core.dart';
 import 'package:analysis_server/src/protocol_server.dart' as protocol;
 
diff --git a/pkg/analysis_server/lib/src/domains/analysis/occurrences_dart.dart b/pkg/analysis_server/lib/src/domains/analysis/occurrences_dart.dart
index f263e74..441e949 100644
--- a/pkg/analysis_server/lib/src/domains/analysis/occurrences_dart.dart
+++ b/pkg/analysis_server/lib/src/domains/analysis/occurrences_dart.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/plugin/analysis/occurrences/occurrences_core.dart';
 import 'package:analysis_server/src/protocol_server.dart' as protocol;
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/domains/completion/available_suggestions.dart b/pkg/analysis_server/lib/src/domains/completion/available_suggestions.dart
index d671c03..8440c7d 100644
--- a/pkg/analysis_server/lib/src/domains/completion/available_suggestions.dart
+++ b/pkg/analysis_server/lib/src/domains/completion/available_suggestions.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart' as protocol;
 import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/dart/element/element.dart';
diff --git a/pkg/analysis_server/lib/src/domains/execution/completion.dart b/pkg/analysis_server/lib/src/domains/execution/completion.dart
index faad3f9..26197cd 100644
--- a/pkg/analysis_server/lib/src/domains/execution/completion.dart
+++ b/pkg/analysis_server/lib/src/domains/execution/completion.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart'
     show
         CompletionSuggestion,
diff --git a/pkg/analysis_server/lib/src/edit/edit_dartfix.dart b/pkg/analysis_server/lib/src/edit/edit_dartfix.dart
index c36f2bb..2468615 100644
--- a/pkg/analysis_server/lib/src/edit/edit_dartfix.dart
+++ b/pkg/analysis_server/lib/src/edit/edit_dartfix.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/analysis_server.dart';
diff --git a/pkg/analysis_server/lib/src/edit/edit_domain.dart b/pkg/analysis_server/lib/src/edit/edit_domain.dart
index be204d63..93c8e3d 100644
--- a/pkg/analysis_server/lib/src/edit/edit_domain.dart
+++ b/pkg/analysis_server/lib/src/edit/edit_domain.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/plugin/edit/assist/assist_core.dart';
diff --git a/pkg/analysis_server/lib/src/edit/fix/dartfix_info.dart b/pkg/analysis_server/lib/src/edit/fix/dartfix_info.dart
index 0fe5aba..6335d65 100644
--- a/pkg/analysis_server/lib/src/edit/fix/dartfix_info.dart
+++ b/pkg/analysis_server/lib/src/edit/fix/dartfix_info.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart'
     show DartFix, EditDartfixParams;
 import 'package:analysis_server/src/edit/edit_dartfix.dart';
diff --git a/pkg/analysis_server/lib/src/edit/fix/dartfix_listener.dart b/pkg/analysis_server/lib/src/edit/fix/dartfix_listener.dart
index c9fd823..556cc38 100644
--- a/pkg/analysis_server/lib/src/edit/fix/dartfix_listener.dart
+++ b/pkg/analysis_server/lib/src/edit/fix/dartfix_listener.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analyzer/dart/analysis/results.dart';
diff --git a/pkg/analysis_server/lib/src/edit/fix/dartfix_registrar.dart b/pkg/analysis_server/lib/src/edit/fix/dartfix_registrar.dart
index 07652c0..f1c8b44 100644
--- a/pkg/analysis_server/lib/src/edit/fix/dartfix_registrar.dart
+++ b/pkg/analysis_server/lib/src/edit/fix/dartfix_registrar.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/edit/fix/dartfix_info.dart';
 import 'package:analysis_server/src/edit/fix/fix_code_task.dart';
 import 'package:analysis_server/src/edit/fix/fix_error_task.dart';
diff --git a/pkg/analysis_server/lib/src/edit/fix/fix_code_task.dart b/pkg/analysis_server/lib/src/edit/fix/fix_code_task.dart
index a4243a9..cca1834 100644
--- a/pkg/analysis_server/lib/src/edit/fix/fix_code_task.dart
+++ b/pkg/analysis_server/lib/src/edit/fix/fix_code_task.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:math' show max;
 
 import 'package:analysis_server/src/edit/edit_dartfix.dart';
diff --git a/pkg/analysis_server/lib/src/edit/fix/fix_error_task.dart b/pkg/analysis_server/lib/src/edit/fix/fix_error_task.dart
index 2896407..5f7ec39 100644
--- a/pkg/analysis_server/lib/src/edit/fix/fix_error_task.dart
+++ b/pkg/analysis_server/lib/src/edit/fix/fix_error_task.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/edit/edit_dartfix.dart';
 import 'package:analysis_server/src/edit/fix/dartfix_listener.dart';
diff --git a/pkg/analysis_server/lib/src/edit/fix/fix_lint_task.dart b/pkg/analysis_server/lib/src/edit/fix/fix_lint_task.dart
index 2aac75e..d7564a9 100644
--- a/pkg/analysis_server/lib/src/edit/fix/fix_lint_task.dart
+++ b/pkg/analysis_server/lib/src/edit/fix/fix_lint_task.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/edit/edit_dartfix.dart';
 import 'package:analysis_server/src/edit/fix/dartfix_listener.dart';
 import 'package:analysis_server/src/edit/fix/fix_error_task.dart';
diff --git a/pkg/analysis_server/lib/src/edit/fix/prefer_mixin_fix.dart b/pkg/analysis_server/lib/src/edit/fix/prefer_mixin_fix.dart
index 9797215..f9ef2a5 100644
--- a/pkg/analysis_server/lib/src/edit/fix/prefer_mixin_fix.dart
+++ b/pkg/analysis_server/lib/src/edit/fix/prefer_mixin_fix.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/edit/fix/dartfix_listener.dart';
 import 'package:analysis_server/src/edit/fix/dartfix_registrar.dart';
diff --git a/pkg/analysis_server/lib/src/flutter/flutter_domain.dart b/pkg/analysis_server/lib/src/flutter/flutter_domain.dart
index 1a5f819..6996ece 100644
--- a/pkg/analysis_server/lib/src/flutter/flutter_domain.dart
+++ b/pkg/analysis_server/lib/src/flutter/flutter_domain.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_constants.dart';
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/domain_abstract.dart';
diff --git a/pkg/analysis_server/lib/src/flutter/flutter_notifications.dart b/pkg/analysis_server/lib/src/flutter/flutter_notifications.dart
index 74085faa..a18cb7d 100644
--- a/pkg/analysis_server/lib/src/flutter/flutter_notifications.dart
+++ b/pkg/analysis_server/lib/src/flutter/flutter_notifications.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/flutter/flutter_outline_computer.dart';
 import 'package:analysis_server/src/protocol_server.dart' as protocol;
diff --git a/pkg/analysis_server/lib/src/flutter/flutter_outline_computer.dart b/pkg/analysis_server/lib/src/flutter/flutter_outline_computer.dart
index 3467add..5f79173 100644
--- a/pkg/analysis_server/lib/src/flutter/flutter_outline_computer.dart
+++ b/pkg/analysis_server/lib/src/flutter/flutter_outline_computer.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/computer/computer_outline.dart';
 import 'package:analysis_server/src/protocol_server.dart' as protocol;
 import 'package:analysis_server/src/utilities/flutter.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/channel/lsp_byte_stream_channel.dart b/pkg/analysis_server/lib/src/lsp/channel/lsp_byte_stream_channel.dart
index acd9c2e..993ab3a 100644
--- a/pkg/analysis_server/lib/src/lsp/channel/lsp_byte_stream_channel.dart
+++ b/pkg/analysis_server/lib/src/lsp/channel/lsp_byte_stream_channel.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
diff --git a/pkg/analysis_server/lib/src/lsp/channel/lsp_channel.dart b/pkg/analysis_server/lib/src/lsp/channel/lsp_channel.dart
index 8d488b6..5163e84 100644
--- a/pkg/analysis_server/lib/src/lsp/channel/lsp_channel.dart
+++ b/pkg/analysis_server/lib/src/lsp/channel/lsp_channel.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/src/lsp/lsp_analysis_server.dart';
 
diff --git a/pkg/analysis_server/lib/src/lsp/client_capabilities.dart b/pkg/analysis_server/lib/src/lsp/client_capabilities.dart
index 1047961..2a2039a 100644
--- a/pkg/analysis_server/lib/src/lsp/client_capabilities.dart
+++ b/pkg/analysis_server/lib/src/lsp/client_capabilities.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 
 /// Wraps the client (editor) capabilities to improve performance.
diff --git a/pkg/analysis_server/lib/src/lsp/client_configuration.dart b/pkg/analysis_server/lib/src/lsp/client_configuration.dart
index 26ad2d0..fb2fa13 100644
--- a/pkg/analysis_server/lib/src/lsp/client_configuration.dart
+++ b/pkg/analysis_server/lib/src/lsp/client_configuration.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// Wraps the client (editor) configuration to provide stronger typing and
 /// handling of default values where a setting has not been supplied.
 class LspClientConfiguration {
diff --git a/pkg/analysis_server/lib/src/lsp/constants.dart b/pkg/analysis_server/lib/src/lsp/constants.dart
index 952a5c5..d04c276 100644
--- a/pkg/analysis_server/lib/src/lsp/constants.dart
+++ b/pkg/analysis_server/lib/src/lsp/constants.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 
diff --git a/pkg/analysis_server/lib/src/lsp/dartdoc.dart b/pkg/analysis_server/lib/src/lsp/dartdoc.dart
index ee6d6c7..cc8f07f 100644
--- a/pkg/analysis_server/lib/src/lsp/dartdoc.dart
+++ b/pkg/analysis_server/lib/src/lsp/dartdoc.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 final _dartdocCodeBlockSections = RegExp(r'(```\w+) +\w+');
 final _dartdocDirectives =
     RegExp(r'(\n *{@.*?}$)|(^{@.*?}\n)', multiLine: true);
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/commands/organize_imports.dart b/pkg/analysis_server/lib/src/lsp/handlers/commands/organize_imports.dart
index c1c00de..998a39e 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/commands/organize_imports.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/commands/organize_imports.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/commands/perform_refactor.dart b/pkg/analysis_server/lib/src/lsp/handlers/commands/perform_refactor.dart
index 581c499..fccceba 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/commands/perform_refactor.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/commands/perform_refactor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/commands/send_workspace_edit.dart b/pkg/analysis_server/lib/src/lsp/handlers/commands/send_workspace_edit.dart
index c4eda52..1f81768 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/commands/send_workspace_edit.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/commands/send_workspace_edit.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/commands/simple_edit_handler.dart b/pkg/analysis_server/lib/src/lsp/handlers/commands/simple_edit_handler.dart
index c8fa759..0b3a4ef 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/commands/simple_edit_handler.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/commands/simple_edit_handler.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/commands/sort_members.dart b/pkg/analysis_server/lib/src/lsp/handlers/commands/sort_members.dart
index ca10fa4..dd7b2d0 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/commands/sort_members.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/commands/sort_members.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/custom/handler_diagnostic_server.dart b/pkg/analysis_server/lib/src/lsp/handlers/custom/handler_diagnostic_server.dart
index 66f95f6..8c8d812 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/custom/handler_diagnostic_server.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/custom/handler_diagnostic_server.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_custom_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/custom/handler_reanalyze.dart b/pkg/analysis_server/lib/src/lsp/handlers/custom/handler_reanalyze.dart
index 0c2cde4..cd62bcc 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/custom/handler_reanalyze.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/custom/handler_reanalyze.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/custom/handler_super.dart b/pkg/analysis_server/lib/src/lsp/handlers/custom/handler_super.dart
index 9ddba98..50f0c5d 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/custom/handler_super.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/custom/handler_super.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_cancel_request.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_cancel_request.dart
index 82008a9..1bdc3db 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_cancel_request.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_cancel_request.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/handlers/handlers.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_change_workspace_folders.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_change_workspace_folders.dart
index c25595d..857fcb3 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_change_workspace_folders.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_change_workspace_folders.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/handlers/handlers.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_code_actions.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_code_actions.dart
index f7afd25..219138b 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_code_actions.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_code_actions.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/plugin/edit/assist/assist_core.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_completion.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_completion.dart
index f6671c6..13a5890 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_completion.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_completion.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:math' as math;
 
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_completion_resolve.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_completion_resolve.dart
index cafa2b6..95e8259 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_completion_resolve.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_completion_resolve.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_custom_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_definition.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_definition.dart
index e3599b6e..5b52c33 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_definition.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_definition.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart'
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_document_highlights.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_document_highlights.dart
index 8044281..9573acc 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_document_highlights.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_document_highlights.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/domains/analysis/occurrences.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_document_symbols.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_document_symbols.dart
index f8ad0d6..b4b6f14 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_document_symbols.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_document_symbols.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/computer/computer_outline.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_execute_command.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_execute_command.dart
index 43d877e..40e0e03 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_execute_command.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_execute_command.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_exit.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_exit.dart
index 82b3f07..bb33c81 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_exit.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_exit.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io';
 
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_folding.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_folding.dart
index 988b719..cda2b35 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_folding.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_folding.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/computer/computer_folding.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_format_on_type.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_format_on_type.dart
index d34bcea..cc07266 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_format_on_type.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_format_on_type.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_format_range.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_format_range.dart
index 3c6183d..bc83804 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_format_range.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_format_range.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_formatting.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_formatting.dart
index 554ed01..eefcd07 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_formatting.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_formatting.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_hover.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_hover.dart
index 4e57b46..8c82497 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_hover.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_hover.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_implementation.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_implementation.dart
index 17a3b28..822398c 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_implementation.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_implementation.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_initialize.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_initialize.dart
index 9174fb8..091f1e0 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_initialize.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_initialize.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io';
 
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_initialized.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_initialized.dart
index b42d11f..462e933 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_initialized.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_initialized.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/handlers/handler_states.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_references.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_references.dart
index 4dc81df..31f5872 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_references.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_references.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/handlers/handlers.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_reject.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_reject.dart
index a1f42ff..e841a61 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_reject.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_reject.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/handlers/handlers.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_rename.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_rename.dart
index d1c3aca..20f59c0 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_rename.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_rename.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_semantic_tokens.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_semantic_tokens.dart
index ad40077..61e411e 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_semantic_tokens.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_semantic_tokens.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_shutdown.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_shutdown.dart
index d591480..9746f3a 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_shutdown.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_shutdown.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/handlers/handler_states.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_signature_help.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_signature_help.dart
index d01e33d..5d97030 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_signature_help.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_signature_help.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/computer/computer_signature.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_states.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_states.dart
index c1298e5..d1194ee 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_states.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_states.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_text_document_changes.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_text_document_changes.dart
index de9cb07..f703d18 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_text_document_changes.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_text_document_changes.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_will_rename_files.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_will_rename_files.dart
index 3d32e86..c256d6d 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_will_rename_files.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_will_rename_files.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/handlers/handlers.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_workspace_configuration.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_workspace_configuration.dart
index 8551a6d..3be46d8 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_workspace_configuration.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_workspace_configuration.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/handlers/handlers.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handler_workspace_symbols.dart b/pkg/analysis_server/lib/src/lsp/handlers/handler_workspace_symbols.dart
index ef781d1..37f455b 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_workspace_symbols.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_workspace_symbols.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/handlers/handlers.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/handlers/handlers.dart b/pkg/analysis_server/lib/src/lsp/handlers/handlers.dart
index 0835da5..3f5def6 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handlers.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handlers.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/json_parsing.dart b/pkg/analysis_server/lib/src/lsp/json_parsing.dart
index 148a9ca..412c96c 100644
--- a/pkg/analysis_server/lib/src/lsp/json_parsing.dart
+++ b/pkg/analysis_server/lib/src/lsp/json_parsing.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:collection';
 
 final nullLspJsonReporter = _NullLspJsonReporter();
diff --git a/pkg/analysis_server/lib/src/lsp/lsp_analysis_server.dart b/pkg/analysis_server/lib/src/lsp/lsp_analysis_server.dart
index e5e609d..afb577f 100644
--- a/pkg/analysis_server/lib/src/lsp/lsp_analysis_server.dart
+++ b/pkg/analysis_server/lib/src/lsp/lsp_analysis_server.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/lsp_protocol/protocol_custom_generated.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/lsp_packet_transformer.dart b/pkg/analysis_server/lib/src/lsp/lsp_packet_transformer.dart
index 8f5021f..b80e082 100644
--- a/pkg/analysis_server/lib/src/lsp/lsp_packet_transformer.dart
+++ b/pkg/analysis_server/lib/src/lsp/lsp_packet_transformer.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:convert';
 
diff --git a/pkg/analysis_server/lib/src/lsp/lsp_socket_server.dart b/pkg/analysis_server/lib/src/lsp/lsp_socket_server.dart
index 419fe43..d567d37 100644
--- a/pkg/analysis_server/lib/src/lsp/lsp_socket_server.dart
+++ b/pkg/analysis_server/lib/src/lsp/lsp_socket_server.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/analysis_server.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/mapping.dart b/pkg/analysis_server/lib/src/lsp/mapping.dart
index a409c06..1a75652 100644
--- a/pkg/analysis_server/lib/src/lsp/mapping.dart
+++ b/pkg/analysis_server/lib/src/lsp/mapping.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:math';
 
 import 'package:analysis_server/lsp_protocol/protocol_custom_generated.dart'
diff --git a/pkg/analysis_server/lib/src/lsp/notification_manager.dart b/pkg/analysis_server/lib/src/lsp/notification_manager.dart
index 7752a79..e6506bd 100644
--- a/pkg/analysis_server/lib/src/lsp/notification_manager.dart
+++ b/pkg/analysis_server/lib/src/lsp/notification_manager.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/channel/lsp_channel.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/progress.dart b/pkg/analysis_server/lib/src/lsp/progress.dart
index 45c040a..6b87f74 100644
--- a/pkg/analysis_server/lib/src/lsp/progress.dart
+++ b/pkg/analysis_server/lib/src/lsp/progress.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:math';
 
diff --git a/pkg/analysis_server/lib/src/lsp/semantic_tokens/encoder.dart b/pkg/analysis_server/lib/src/lsp/semantic_tokens/encoder.dart
index 4ee6f99..a3de7dd 100644
--- a/pkg/analysis_server/lib/src/lsp/semantic_tokens/encoder.dart
+++ b/pkg/analysis_server/lib/src/lsp/semantic_tokens/encoder.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:collection';
 import 'dart:math' as math;
 
diff --git a/pkg/analysis_server/lib/src/lsp/semantic_tokens/legend.dart b/pkg/analysis_server/lib/src/lsp/semantic_tokens/legend.dart
index ef2d8c4..2b7c3e4 100644
--- a/pkg/analysis_server/lib/src/lsp/semantic_tokens/legend.dart
+++ b/pkg/analysis_server/lib/src/lsp/semantic_tokens/legend.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:math' as math;
 
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/semantic_tokens/mapping.dart b/pkg/analysis_server/lib/src/lsp/semantic_tokens/mapping.dart
index 7405b0e..34c7909 100644
--- a/pkg/analysis_server/lib/src/lsp/semantic_tokens/mapping.dart
+++ b/pkg/analysis_server/lib/src/lsp/semantic_tokens/mapping.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
 import 'package:analysis_server/src/lsp/semantic_tokens/legend.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/server_capabilities_computer.dart b/pkg/analysis_server/lib/src/lsp/server_capabilities_computer.dart
index 808446a..72b8dbc 100644
--- a/pkg/analysis_server/lib/src/lsp/server_capabilities_computer.dart
+++ b/pkg/analysis_server/lib/src/lsp/server_capabilities_computer.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/client_capabilities.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/source_edits.dart b/pkg/analysis_server/lib/src/lsp/source_edits.dart
index d97576f..a1004f1 100644
--- a/pkg/analysis_server/lib/src/lsp/source_edits.dart
+++ b/pkg/analysis_server/lib/src/lsp/source_edits.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/mapping.dart';
diff --git a/pkg/analysis_server/lib/src/operation/operation_analysis.dart b/pkg/analysis_server/lib/src/operation/operation_analysis.dart
index aa6443e..f612320 100644
--- a/pkg/analysis_server/lib/src/operation/operation_analysis.dart
+++ b/pkg/analysis_server/lib/src/operation/operation_analysis.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/computer/computer_closingLabels.dart';
 import 'package:analysis_server/src/computer/computer_folding.dart';
diff --git a/pkg/analysis_server/lib/src/plugin/notification_manager.dart b/pkg/analysis_server/lib/src/plugin/notification_manager.dart
index 5b3eef8..6ebbf40 100644
--- a/pkg/analysis_server/lib/src/plugin/notification_manager.dart
+++ b/pkg/analysis_server/lib/src/plugin/notification_manager.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:collection';
 
 import 'package:analysis_server/protocol/protocol_generated.dart' as server;
diff --git a/pkg/analysis_server/lib/src/plugin/plugin_locator.dart b/pkg/analysis_server/lib/src/plugin/plugin_locator.dart
index 0ff0268..58f8aa2 100644
--- a/pkg/analysis_server/lib/src/plugin/plugin_locator.dart
+++ b/pkg/analysis_server/lib/src/plugin/plugin_locator.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/file_system/file_system.dart';
 
 /// An object used to locate a plugin within a package.
diff --git a/pkg/analysis_server/lib/src/plugin/plugin_manager.dart b/pkg/analysis_server/lib/src/plugin/plugin_manager.dart
index 40d94a7..02c1294 100644
--- a/pkg/analysis_server/lib/src/plugin/plugin_manager.dart
+++ b/pkg/analysis_server/lib/src/plugin/plugin_manager.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:collection';
 import 'dart:convert';
diff --git a/pkg/analysis_server/lib/src/plugin/plugin_watcher.dart b/pkg/analysis_server/lib/src/plugin/plugin_watcher.dart
index 7eab2f2..6e9bb99 100644
--- a/pkg/analysis_server/lib/src/plugin/plugin_watcher.dart
+++ b/pkg/analysis_server/lib/src/plugin/plugin_watcher.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 
 import 'package:analysis_server/src/plugin/plugin_locator.dart';
diff --git a/pkg/analysis_server/lib/src/plugin/request_converter.dart b/pkg/analysis_server/lib/src/plugin/request_converter.dart
index 82b2bf4..0909ca1 100644
--- a/pkg/analysis_server/lib/src/plugin/request_converter.dart
+++ b/pkg/analysis_server/lib/src/plugin/request_converter.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart' as server;
 import 'package:analyzer_plugin/protocol/protocol_generated.dart' as plugin;
 
diff --git a/pkg/analysis_server/lib/src/plugin/result_collector.dart b/pkg/analysis_server/lib/src/plugin/result_collector.dart
index 9ce9ecc..a016ed1 100644
--- a/pkg/analysis_server/lib/src/plugin/result_collector.dart
+++ b/pkg/analysis_server/lib/src/plugin/result_collector.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// A function used to determine whether results should be collected for the
 /// file with the given [path].
 typedef ShouldCollectPredicate = bool Function(String path);
diff --git a/pkg/analysis_server/lib/src/plugin/result_converter.dart b/pkg/analysis_server/lib/src/plugin/result_converter.dart
index 3a0983b..a4cd788 100644
--- a/pkg/analysis_server/lib/src/plugin/result_converter.dart
+++ b/pkg/analysis_server/lib/src/plugin/result_converter.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart' as server;
 import 'package:analysis_server/src/protocol/protocol_internal.dart' as server;
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
diff --git a/pkg/analysis_server/lib/src/plugin/result_merger.dart b/pkg/analysis_server/lib/src/plugin/result_merger.dart
index 0336650b2..5194674 100644
--- a/pkg/analysis_server/lib/src/plugin/result_merger.dart
+++ b/pkg/analysis_server/lib/src/plugin/result_merger.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:collection';
 
 import 'package:analysis_server/protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/lib/src/protocol/protocol_internal.dart b/pkg/analysis_server/lib/src/protocol/protocol_internal.dart
index 17d4837..1b4f60e 100644
--- a/pkg/analysis_server/lib/src/protocol/protocol_internal.dart
+++ b/pkg/analysis_server/lib/src/protocol/protocol_internal.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:collection';
 import 'dart:convert' hide JsonDecoder;
 
diff --git a/pkg/analysis_server/lib/src/protocol_server.dart b/pkg/analysis_server/lib/src/protocol_server.dart
index b330f89..dda065c 100644
--- a/pkg/analysis_server/lib/src/protocol_server.dart
+++ b/pkg/analysis_server/lib/src/protocol_server.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/plugin/protocol/protocol_dart.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/provisional/completion/completion_core.dart b/pkg/analysis_server/lib/src/provisional/completion/completion_core.dart
index d252dd8..d072cad 100644
--- a/pkg/analysis_server/lib/src/provisional/completion/completion_core.dart
+++ b/pkg/analysis_server/lib/src/provisional/completion/completion_core.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/generated/source.dart';
diff --git a/pkg/analysis_server/lib/src/provisional/completion/dart/completion_dart.dart b/pkg/analysis_server/lib/src/provisional/completion/dart/completion_dart.dart
index 4177a84..de9c92b 100644
--- a/pkg/analysis_server/lib/src/provisional/completion/dart/completion_dart.dart
+++ b/pkg/analysis_server/lib/src/provisional/completion/dart/completion_dart.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/completion_core.dart';
 import 'package:analysis_server/src/services/completion/dart/feature_computer.dart';
 import 'package:analysis_server/src/services/completion/dart/suggestion_builder.dart';
diff --git a/pkg/analysis_server/lib/src/search/element_references.dart b/pkg/analysis_server/lib/src/search/element_references.dart
index dc07265..9cee80a 100644
--- a/pkg/analysis_server/lib/src/search/element_references.dart
+++ b/pkg/analysis_server/lib/src/search/element_references.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart'
     show SearchResult, newSearchResult_fromMatch;
 import 'package:analysis_server/src/services/search/hierarchy.dart';
diff --git a/pkg/analysis_server/lib/src/search/search_domain.dart b/pkg/analysis_server/lib/src/search/search_domain.dart
index 9dd70bf..80b84ce 100644
--- a/pkg/analysis_server/lib/src/search/search_domain.dart
+++ b/pkg/analysis_server/lib/src/search/search_domain.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_constants.dart';
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/protocol_server.dart' as protocol;
diff --git a/pkg/analysis_server/lib/src/search/type_hierarchy.dart b/pkg/analysis_server/lib/src/search/type_hierarchy.dart
index d5b1804..90c3866 100644
--- a/pkg/analysis_server/lib/src/search/type_hierarchy.dart
+++ b/pkg/analysis_server/lib/src/search/type_hierarchy.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:collection';
 
 import 'package:analysis_server/src/protocol_server.dart'
diff --git a/pkg/analysis_server/lib/src/search/workspace_symbols.dart b/pkg/analysis_server/lib/src/search/workspace_symbols.dart
index 63adfd4..a256782 100644
--- a/pkg/analysis_server/lib/src/search/workspace_symbols.dart
+++ b/pkg/analysis_server/lib/src/search/workspace_symbols.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:collection';
 
 import 'package:analyzer/source/line_info.dart';
diff --git a/pkg/analysis_server/lib/src/server/crash_reporting.dart b/pkg/analysis_server/lib/src/server/crash_reporting.dart
index 4849825..b5c775e 100644
--- a/pkg/analysis_server/lib/src/server/crash_reporting.dart
+++ b/pkg/analysis_server/lib/src/server/crash_reporting.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/exception/exception.dart';
 import 'package:analyzer/instrumentation/noop_service.dart';
 import 'package:analyzer/instrumentation/plugin_data.dart';
diff --git a/pkg/analysis_server/lib/src/server/crash_reporting_attachments.dart b/pkg/analysis_server/lib/src/server/crash_reporting_attachments.dart
index 0648968..790ccab 100644
--- a/pkg/analysis_server/lib/src/server/crash_reporting_attachments.dart
+++ b/pkg/analysis_server/lib/src/server/crash_reporting_attachments.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/instrumentation/service.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart' show ExceptionResult;
 
diff --git a/pkg/analysis_server/lib/src/server/detachable_filesystem_manager.dart b/pkg/analysis_server/lib/src/server/detachable_filesystem_manager.dart
index d32ca39..1bad242 100644
--- a/pkg/analysis_server/lib/src/server/detachable_filesystem_manager.dart
+++ b/pkg/analysis_server/lib/src/server/detachable_filesystem_manager.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/analysis_server.dart';
 
 /// A class that can be used to configure an analysis server instance to better
diff --git a/pkg/analysis_server/lib/src/server/dev_server.dart b/pkg/analysis_server/lib/src/server/dev_server.dart
index 0a1593d..f15d228 100644
--- a/pkg/analysis_server/lib/src/server/dev_server.dart
+++ b/pkg/analysis_server/lib/src/server/dev_server.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:io';
 
diff --git a/pkg/analysis_server/lib/src/server/diagnostic_server.dart b/pkg/analysis_server/lib/src/server/diagnostic_server.dart
index 4a0a27a0..7d5586a 100644
--- a/pkg/analysis_server/lib/src/server/diagnostic_server.dart
+++ b/pkg/analysis_server/lib/src/server/diagnostic_server.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// A handle to start, and return the current port of, a diagnostic server.
 abstract class DiagnosticServer {
   /// Return the port of the diagnostic web server. If the server is not running
diff --git a/pkg/analysis_server/lib/src/server/driver.dart b/pkg/analysis_server/lib/src/server/driver.dart
index 46b867d..0521a2a 100644
--- a/pkg/analysis_server/lib/src/server/driver.dart
+++ b/pkg/analysis_server/lib/src/server/driver.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:io';
 import 'dart:isolate';
diff --git a/pkg/analysis_server/lib/src/server/error_notifier.dart b/pkg/analysis_server/lib/src/server/error_notifier.dart
index a69f1f0..f329c92 100644
--- a/pkg/analysis_server/lib/src/server/error_notifier.dart
+++ b/pkg/analysis_server/lib/src/server/error_notifier.dart
@@ -1,3 +1,9 @@
+// Copyright (c) 2019, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// @dart = 2.9
+
 import 'package:analysis_server/src/analysis_server_abstract.dart';
 import 'package:analyzer/exception/exception.dart';
 import 'package:analyzer/instrumentation/instrumentation.dart';
diff --git a/pkg/analysis_server/lib/src/server/features.dart b/pkg/analysis_server/lib/src/server/features.dart
index fd02aa1..65668bd 100644
--- a/pkg/analysis_server/lib/src/server/features.dart
+++ b/pkg/analysis_server/lib/src/server/features.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// The set of features enabled in a server session.
 ///
 /// When some features are not enabled, the server might avoid doing work
diff --git a/pkg/analysis_server/lib/src/server/http_server.dart b/pkg/analysis_server/lib/src/server/http_server.dart
index 1083d5c..1e6fc74 100644
--- a/pkg/analysis_server/lib/src/server/http_server.dart
+++ b/pkg/analysis_server/lib/src/server/http_server.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io';
 
 import 'package:analysis_server/src/socket_server.dart';
diff --git a/pkg/analysis_server/lib/src/server/isolate_analysis_server.dart b/pkg/analysis_server/lib/src/server/isolate_analysis_server.dart
index 2ef30d3..aaf2ae3 100644
--- a/pkg/analysis_server/lib/src/server/isolate_analysis_server.dart
+++ b/pkg/analysis_server/lib/src/server/isolate_analysis_server.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io' show IOSink;
 import 'dart:isolate';
 
diff --git a/pkg/analysis_server/lib/src/server/lsp_stdio_server.dart b/pkg/analysis_server/lib/src/server/lsp_stdio_server.dart
index 2fa5b8a..e96bb9c 100644
--- a/pkg/analysis_server/lib/src/server/lsp_stdio_server.dart
+++ b/pkg/analysis_server/lib/src/server/lsp_stdio_server.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io';
 
 import 'package:analysis_server/src/lsp/channel/lsp_byte_stream_channel.dart';
diff --git a/pkg/analysis_server/lib/src/server/sdk_configuration.dart b/pkg/analysis_server/lib/src/server/sdk_configuration.dart
index c296772..b2ac8bf 100644
--- a/pkg/analysis_server/lib/src/server/sdk_configuration.dart
+++ b/pkg/analysis_server/lib/src/server/sdk_configuration.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 import 'dart:io';
 
diff --git a/pkg/analysis_server/lib/src/server/stdio_server.dart b/pkg/analysis_server/lib/src/server/stdio_server.dart
index 06c5030..337436e 100644
--- a/pkg/analysis_server/lib/src/server/stdio_server.dart
+++ b/pkg/analysis_server/lib/src/server/stdio_server.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io';
 
 import 'package:analysis_server/src/channel/byte_stream_channel.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/completion_core.dart b/pkg/analysis_server/lib/src/services/completion/completion_core.dart
index 4141b3b..e69c357 100644
--- a/pkg/analysis_server/lib/src/services/completion/completion_core.dart
+++ b/pkg/analysis_server/lib/src/services/completion/completion_core.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/completion_core.dart';
 import 'package:analysis_server/src/services/completion/completion_performance.dart';
 import 'package:analyzer/dart/analysis/results.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/completion_performance.dart b/pkg/analysis_server/lib/src/services/completion/completion_performance.dart
index e233d13..dd3480e 100644
--- a/pkg/analysis_server/lib/src/services/completion/completion_performance.dart
+++ b/pkg/analysis_server/lib/src/services/completion/completion_performance.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/src/util/performance/operation_performance.dart';
 
 /// Compute a string representing a code completion operation at the
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/arglist_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/arglist_contributor.dart
index 271b7fb..5274710 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/arglist_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/arglist_contributor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/completion_core.dart';
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/suggestion_builder.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/combinator_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/combinator_contributor.dart
index ebebb68..c774a4e 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/combinator_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/combinator_contributor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart'
     hide Element, ElementKind;
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/completion_manager.dart b/pkg/analysis_server/lib/src/services/completion/dart/completion_manager.dart
index 245abf6..578501a 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/completion_manager.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/completion_manager.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/provisional/completion/completion_core.dart';
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/extension_member_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/extension_member_contributor.dart
index d847127..e0232fb 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/extension_member_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/extension_member_contributor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/suggestion_builder.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/feature_computer.dart b/pkg/analysis_server/lib/src/services/completion/dart/feature_computer.dart
index ea06634..1b6eea7 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/feature_computer.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/feature_computer.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// Utility methods to compute the value of the features used for code
 /// completion.
 import 'dart:math' as math;
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/field_formal_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/field_formal_contributor.dart
index a24d5c4..b322111 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/field_formal_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/field_formal_contributor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/suggestion_builder.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/imported_reference_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/imported_reference_contributor.dart
index 4f560e3..dd993ba 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/imported_reference_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/imported_reference_contributor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/local_library_contributor.dart';
 import 'package:analysis_server/src/services/completion/dart/suggestion_builder.dart'
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/keyword_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/keyword_contributor.dart
index 4963edb..4b48766 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/keyword_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/keyword_contributor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/completion_manager.dart';
 import 'package:analysis_server/src/services/completion/dart/suggestion_builder.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/label_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/label_contributor.dart
index 9434271..e333940 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/label_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/label_contributor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/completion_manager.dart'
     show DartCompletionRequestImpl;
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/library_member_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/library_member_contributor.dart
index c9ff9c9..634cae3 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/library_member_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/library_member_contributor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart'
     show CompletionSuggestionKind;
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/library_prefix_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/library_prefix_contributor.dart
index 0fccab2..2ec7b23 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/library_prefix_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/library_prefix_contributor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/suggestion_builder.dart';
 
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/local_library_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/local_library_contributor.dart
index 7ed705f..279f4fb 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/local_library_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/local_library_contributor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart'
     show CompletionSuggestionKind;
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/local_reference_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/local_reference_contributor.dart
index d92cc04..546c236 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/local_reference_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/local_reference_contributor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart'
     show CompletionSuggestionKind;
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/named_constructor_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/named_constructor_contributor.dart
index 4c06dad..b31253f 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/named_constructor_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/named_constructor_contributor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/suggestion_builder.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/override_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/override_contributor.dart
index 178dc1d..c18f91d 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/override_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/override_contributor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/suggestion_builder.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/probability_range.dart b/pkg/analysis_server/lib/src/services/completion/dart/probability_range.dart
index d5167d9..2c5de16 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/probability_range.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/probability_range.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// A range of probabilities that a given event has occurred.
 class ProbabilityRange {
   /// The lower bound of the range.
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/relevance_tables.g.dart b/pkg/analysis_server/lib/src/services/completion/dart/relevance_tables.g.dart
index 25f3857..22f1ab7 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/relevance_tables.g.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/relevance_tables.g.dart
@@ -1,6 +1,8 @@
 // Copyright (c) 2020, the Dart project authors. Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
+
+// @dart = 2.9
 //
 // This file has been automatically generated. Please do not edit it manually.
 // To regenerate the file, use the script
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/static_member_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/static_member_contributor.dart
index 151d8d2..cfd2a34 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/static_member_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/static_member_contributor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/suggestion_builder.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/suggestion_builder.dart b/pkg/analysis_server/lib/src/services/completion/dart/suggestion_builder.dart
index 05338a0..43af352 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/suggestion_builder.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/suggestion_builder.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:collection';
 
 import 'package:_fe_analyzer_shared/src/base/syntactic_entity.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/type_member_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/type_member_contributor.dart
index 2ffa0b5..19510c7 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/type_member_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/type_member_contributor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:collection';
 
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/uri_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/uri_contributor.dart
index fed0ed7..33dbf47 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/uri_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/uri_contributor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:core';
 
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/utilities.dart b/pkg/analysis_server/lib/src/services/completion/dart/utilities.dart
index efead5f..75b43b9 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/utilities.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/utilities.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// A collection of utility methods used by completion contributors.
 import 'package:analysis_server/src/protocol_server.dart'
     show CompletionSuggestion, Location;
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/variable_name_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/variable_name_contributor.dart
index 1c4e0db..50e0fd16 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/variable_name_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/variable_name_contributor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/suggestion_builder.dart';
 import 'package:analysis_server/src/services/correction/name_suggestion.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/filtering/fuzzy_matcher.dart b/pkg/analysis_server/lib/src/services/completion/filtering/fuzzy_matcher.dart
index 7868f80..765c39a 100644
--- a/pkg/analysis_server/lib/src/services/completion/filtering/fuzzy_matcher.dart
+++ b/pkg/analysis_server/lib/src/services/completion/filtering/fuzzy_matcher.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:math' as math;
 
 /// Character role in a candidate string.
diff --git a/pkg/analysis_server/lib/src/services/completion/postfix/postfix_completion.dart b/pkg/analysis_server/lib/src/services/completion/postfix/postfix_completion.dart
index b648f7f..c88f85d 100644
--- a/pkg/analysis_server/lib/src/services/completion/postfix/postfix_completion.dart
+++ b/pkg/analysis_server/lib/src/services/completion/postfix/postfix_completion.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
 import 'package:analysis_server/src/services/correction/util.dart';
 import 'package:analyzer/dart/analysis/results.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/statement/statement_completion.dart b/pkg/analysis_server/lib/src/services/completion/statement/statement_completion.dart
index 830a57d..679b457 100644
--- a/pkg/analysis_server/lib/src/services/completion/statement/statement_completion.dart
+++ b/pkg/analysis_server/lib/src/services/completion/statement/statement_completion.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:math';
 
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
diff --git a/pkg/analysis_server/lib/src/services/completion/yaml/analysis_options_generator.dart b/pkg/analysis_server/lib/src/services/completion/yaml/analysis_options_generator.dart
index 7f60edd..7fd44bd 100644
--- a/pkg/analysis_server/lib/src/services/completion/yaml/analysis_options_generator.dart
+++ b/pkg/analysis_server/lib/src/services/completion/yaml/analysis_options_generator.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/services/completion/yaml/producer.dart';
 import 'package:analysis_server/src/services/completion/yaml/yaml_completion_generator.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/yaml/fix_data_generator.dart b/pkg/analysis_server/lib/src/services/completion/yaml/fix_data_generator.dart
index 15ef594..e1f1d55 100644
--- a/pkg/analysis_server/lib/src/services/completion/yaml/fix_data_generator.dart
+++ b/pkg/analysis_server/lib/src/services/completion/yaml/fix_data_generator.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/completion/yaml/producer.dart';
 import 'package:analysis_server/src/services/completion/yaml/yaml_completion_generator.dart';
 import 'package:analyzer/file_system/file_system.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/yaml/producer.dart b/pkg/analysis_server/lib/src/services/completion/yaml/producer.dart
index 06a5401..c56f9d2 100644
--- a/pkg/analysis_server/lib/src/services/completion/yaml/producer.dart
+++ b/pkg/analysis_server/lib/src/services/completion/yaml/producer.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/services/pub/pub_package_service.dart';
 import 'package:analyzer/file_system/file_system.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/yaml/pubspec_generator.dart b/pkg/analysis_server/lib/src/services/completion/yaml/pubspec_generator.dart
index d167c72..629db2a 100644
--- a/pkg/analysis_server/lib/src/services/completion/yaml/pubspec_generator.dart
+++ b/pkg/analysis_server/lib/src/services/completion/yaml/pubspec_generator.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/services/completion/yaml/producer.dart';
 import 'package:analysis_server/src/services/completion/yaml/yaml_completion_generator.dart';
diff --git a/pkg/analysis_server/lib/src/services/completion/yaml/yaml_completion_generator.dart b/pkg/analysis_server/lib/src/services/completion/yaml/yaml_completion_generator.dart
index e610849..b6bff4c 100644
--- a/pkg/analysis_server/lib/src/services/completion/yaml/yaml_completion_generator.dart
+++ b/pkg/analysis_server/lib/src/services/completion/yaml/yaml_completion_generator.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/services/completion/yaml/producer.dart';
 import 'package:analysis_server/src/services/pub/pub_package_service.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/assist.dart b/pkg/analysis_server/lib/src/services/correction/assist.dart
index 2929cc2..6b01848 100644
--- a/pkg/analysis_server/lib/src/services/correction/assist.dart
+++ b/pkg/analysis_server/lib/src/services/correction/assist.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/plugin/edit/assist/assist_dart.dart';
 import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/instrumentation/service.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/assist_internal.dart b/pkg/analysis_server/lib/src/services/correction/assist_internal.dart
index 2ea65b8..42230fe 100644
--- a/pkg/analysis_server/lib/src/services/correction/assist_internal.dart
+++ b/pkg/analysis_server/lib/src/services/correction/assist_internal.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/plugin/edit/assist/assist_core.dart';
 import 'package:analysis_server/plugin/edit/assist/assist_dart.dart';
 import 'package:analysis_server/src/services/correction/assist.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/base_processor.dart b/pkg/analysis_server/lib/src/services/correction/base_processor.dart
index 836467a..0750898 100644
--- a/pkg/analysis_server/lib/src/services/correction/base_processor.dart
+++ b/pkg/analysis_server/lib/src/services/correction/base_processor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/util.dart';
 import 'package:analysis_server/src/utilities/flutter.dart';
 import 'package:analyzer/dart/analysis/results.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/bulk_fix_processor.dart b/pkg/analysis_server/lib/src/services/correction/bulk_fix_processor.dart
index c719a1e..093355b 100644
--- a/pkg/analysis_server/lib/src/services/correction/bulk_fix_processor.dart
+++ b/pkg/analysis_server/lib/src/services/correction/bulk_fix_processor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:core';
 
 import 'package:analysis_server/plugin/edit/fix/fix_dart.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/change_workspace.dart b/pkg/analysis_server/lib/src/services/correction/change_workspace.dart
index c206924..579a614 100644
--- a/pkg/analysis_server/lib/src/services/correction/change_workspace.dart
+++ b/pkg/analysis_server/lib/src/services/correction/change_workspace.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/dart/analysis/session.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_workspace.dart';
 
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/abstract_producer.dart b/pkg/analysis_server/lib/src/services/correction/dart/abstract_producer.dart
index b7e0c1c..6bef12b 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/abstract_producer.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/abstract_producer.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:math' as math;
 
 import 'package:_fe_analyzer_shared/src/scanner/token.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/add_async.dart b/pkg/analysis_server/lib/src/services/correction/dart/add_async.dart
index 2e73adb..79c8f63 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/add_async.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/add_async.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/add_await.dart b/pkg/analysis_server/lib/src/services/correction/dart/add_await.dart
index 6e72eae..7acd73c 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/add_await.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/add_await.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/add_const.dart b/pkg/analysis_server/lib/src/services/correction/dart/add_const.dart
index c0e5abe..d4b2642 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/add_const.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/add_const.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/add_diagnostic_property_reference.dart b/pkg/analysis_server/lib/src/services/correction/dart/add_diagnostic_property_reference.dart
index 283dfb0..649cfbc 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/add_diagnostic_property_reference.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/add_diagnostic_property_reference.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/add_explicit_cast.dart b/pkg/analysis_server/lib/src/services/correction/dart/add_explicit_cast.dart
index f66b06f..aaaf687 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/add_explicit_cast.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/add_explicit_cast.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/utilities/extensions/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/add_field_formal_parameters.dart b/pkg/analysis_server/lib/src/services/correction/dart/add_field_formal_parameters.dart
index 6a23e04..e4ef282 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/add_field_formal_parameters.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/add_field_formal_parameters.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/add_late.dart b/pkg/analysis_server/lib/src/services/correction/dart/add_late.dart
index 56791c0..06bb9e0 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/add_late.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/add_late.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/add_missing_enum_case_clauses.dart b/pkg/analysis_server/lib/src/services/correction/dart/add_missing_enum_case_clauses.dart
index d4426a0..b4825c1 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/add_missing_enum_case_clauses.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/add_missing_enum_case_clauses.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/add_missing_parameter.dart b/pkg/analysis_server/lib/src/services/correction/dart/add_missing_parameter.dart
index 9b8f484..0d40bea 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/add_missing_parameter.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/add_missing_parameter.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/executable_parameters.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/add_missing_parameter_named.dart b/pkg/analysis_server/lib/src/services/correction/dart/add_missing_parameter_named.dart
index 93ab6ad..e06b063 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/add_missing_parameter_named.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/add_missing_parameter_named.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/executable_parameters.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/add_missing_required_argument.dart b/pkg/analysis_server/lib/src/services/correction/dart/add_missing_required_argument.dart
index 40e8f6f..d95722a 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/add_missing_required_argument.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/add_missing_required_argument.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:_fe_analyzer_shared/src/scanner/token.dart';
 import 'package:analysis_server/src/services/completion/dart/utilities.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/add_ne_null.dart b/pkg/analysis_server/lib/src/services/correction/dart/add_ne_null.dart
index dcaffb5..cd75a2b 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/add_ne_null.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/add_ne_null.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/analysis/features.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/add_not_null_assert.dart b/pkg/analysis_server/lib/src/services/correction/dart/add_not_null_assert.dart
index 20b8972..fe5c8f6 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/add_not_null_assert.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/add_not_null_assert.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:math';
 
 import 'package:_fe_analyzer_shared/src/scanner/token.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/add_null_check.dart b/pkg/analysis_server/lib/src/services/correction/dart/add_null_check.dart
index bc898f7..891afc1 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/add_null_check.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/add_null_check.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/analysis/features.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/add_override.dart b/pkg/analysis_server/lib/src/services/correction/dart/add_override.dart
index 92958f1..5f066c3 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/add_override.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/add_override.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:_fe_analyzer_shared/src/scanner/token.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/add_required.dart b/pkg/analysis_server/lib/src/services/correction/dart/add_required.dart
index 0a5d869..81a242b 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/add_required.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/add_required.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/add_required_keyword.dart b/pkg/analysis_server/lib/src/services/correction/dart/add_required_keyword.dart
index 8e20c54..4160520 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/add_required_keyword.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/add_required_keyword.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/add_return_type.dart b/pkg/analysis_server/lib/src/services/correction/dart/add_return_type.dart
index b4d5d8d..dbc3d8d 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/add_return_type.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/add_return_type.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/add_static.dart b/pkg/analysis_server/lib/src/services/correction/dart/add_static.dart
index 4ee5960..f165efc 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/add_static.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/add_static.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/add_super_constructor_invocation.dart b/pkg/analysis_server/lib/src/services/correction/dart/add_super_constructor_invocation.dart
index 3911cf4..cce07f3 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/add_super_constructor_invocation.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/add_super_constructor_invocation.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/add_type_annotation.dart b/pkg/analysis_server/lib/src/services/correction/dart/add_type_annotation.dart
index e2912b0..ef04b02 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/add_type_annotation.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/add_type_annotation.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:_fe_analyzer_shared/src/scanner/token.dart';
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/assign_to_local_variable.dart b/pkg/analysis_server/lib/src/services/correction/dart/assign_to_local_variable.dart
index 92fc7ad..54e77cf 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/assign_to_local_variable.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/assign_to_local_variable.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/change_argument_name.dart b/pkg/analysis_server/lib/src/services/correction/dart/change_argument_name.dart
index 34f81c7..32a7ec0 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/change_argument_name.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/change_argument_name.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/executable_parameters.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/change_to.dart b/pkg/analysis_server/lib/src/services/correction/dart/change_to.dart
index c62d89e..7ba2aa2 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/change_to.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/change_to.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/correction/levenshtein.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/change_to_nearest_precise_value.dart b/pkg/analysis_server/lib/src/services/correction/dart/change_to_nearest_precise_value.dart
index 5caea4e..ef2e3ba 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/change_to_nearest_precise_value.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/change_to_nearest_precise_value.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/change_to_static_access.dart b/pkg/analysis_server/lib/src/services/correction/dart/change_to_static_access.dart
index 02b291f..69aad4b 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/change_to_static_access.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/change_to_static_access.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/change_type_annotation.dart b/pkg/analysis_server/lib/src/services/correction/dart/change_type_annotation.dart
index 0dfea8a..9aef73e 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/change_type_annotation.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/change_type_annotation.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_add_all_to_spread.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_add_all_to_spread.dart
index 181ec8f..06de8b9 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_add_all_to_spread.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_add_all_to_spread.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:_fe_analyzer_shared/src/scanner/token.dart';
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_class_to_mixin.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_class_to_mixin.dart
index 00a5ef9..d54b755 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_class_to_mixin.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_class_to_mixin.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_conditional_expression_to_if_element.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_conditional_expression_to_if_element.dart
index 5f8cc29..64feabda 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_conditional_expression_to_if_element.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_conditional_expression_to_if_element.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_documentation_into_block.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_documentation_into_block.dart
index 7068e136..d3e57cf 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_documentation_into_block.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_documentation_into_block.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:_fe_analyzer_shared/src/scanner/token.dart';
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_documentation_into_line.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_documentation_into_line.dart
index f82eeca..5b7b37a 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_documentation_into_line.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_documentation_into_line.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:_fe_analyzer_shared/src/scanner/token.dart';
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_flutter_child.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_flutter_child.dart
index 3556de0..b767896 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_flutter_child.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_flutter_child.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_flutter_children.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_flutter_children.dart
index 29fd8d0..5e29768 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_flutter_children.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_flutter_children.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_into_async_body.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_into_async_body.dart
index 1ccaff4..5373777 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_into_async_body.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_into_async_body.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_into_block_body.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_into_block_body.dart
index 629db9d..20c3d7c 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_into_block_body.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_into_block_body.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_into_final_field.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_into_final_field.dart
index 9523790..0cd856c 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_into_final_field.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_into_final_field.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_into_for_index.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_into_for_index.dart
index eee7b51..39c4e84 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_into_for_index.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_into_for_index.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_into_getter.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_into_getter.dart
index 437bb0b..75b47ca 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_into_getter.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_into_getter.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_into_is_not.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_into_is_not.dart
index 114f8d8..d39a67d 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_into_is_not.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_into_is_not.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_into_is_not_empty.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_into_is_not_empty.dart
index 98edb9b..e236dea 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_into_is_not_empty.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_into_is_not_empty.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:_fe_analyzer_shared/src/scanner/token.dart';
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_map_from_iterable_to_for_literal.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_map_from_iterable_to_for_literal.dart
index 517a309..20985e4 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_map_from_iterable_to_for_literal.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_map_from_iterable_to_for_literal.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_part_of_to_uri.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_part_of_to_uri.dart
index 246a7e3..e532273 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_part_of_to_uri.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_part_of_to_uri.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_quotes.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_quotes.dart
index 0a90211..c853070 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_quotes.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_quotes.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_contains.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_contains.dart
index d1a5302..7665de9 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_contains.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_contains.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_expression_function_body.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_expression_function_body.dart
index 138adcc..fd38a12 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_expression_function_body.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_expression_function_body.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_field_parameter.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_field_parameter.dart
index 886c599..ef999da 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_field_parameter.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_field_parameter.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_generic_function_syntax.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_generic_function_syntax.dart
index 9b3906c..7b197a4 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_generic_function_syntax.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_generic_function_syntax.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_if_null.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_if_null.dart
index d8ca1d2..19e52d8 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_if_null.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_if_null.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_int_literal.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_int_literal.dart
index 6ccea99..ed675e7 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_int_literal.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_int_literal.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_list_literal.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_list_literal.dart
index 0f915cd..ba140fa 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_list_literal.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_list_literal.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_map_literal.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_map_literal.dart
index e1c555a..76221ea 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_map_literal.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_map_literal.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_multiline_string.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_multiline_string.dart
index e394659..0dd99aa 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_multiline_string.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_multiline_string.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_named_arguments.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_named_arguments.dart
index 5f62701..a4af1c4 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_named_arguments.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_named_arguments.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_normal_parameter.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_normal_parameter.dart
index 9e488f2..b220afd 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_normal_parameter.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_normal_parameter.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_null_aware.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_null_aware.dart
index 3a92192..5307774 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_null_aware.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_null_aware.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_null_aware_spread.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_null_aware_spread.dart
index 765178a..8f54f38 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_null_aware_spread.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_null_aware_spread.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_on_type.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_on_type.dart
index 470c614..ead067d 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_on_type.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_on_type.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_package_import.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_package_import.dart
index 08e3f39..074e90c 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_package_import.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_package_import.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_relative_import.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_relative_import.dart
index ee82eb3..a312a32 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_relative_import.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_relative_import.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_set_literal.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_set_literal.dart
index 4fcf3c9..fb2b42c 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_set_literal.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_set_literal.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_where_type.dart b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_where_type.dart
index 5fe1a84..eb508d4 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/convert_to_where_type.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/convert_to_where_type.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/create_class.dart b/pkg/analysis_server/lib/src/services/correction/dart/create_class.dart
index 90624ae..05d4f47 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/create_class.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/create_class.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/create_constructor.dart b/pkg/analysis_server/lib/src/services/correction/dart/create_constructor.dart
index aa2739b..6526f89 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/create_constructor.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/create_constructor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/create_constructor_for_final_fields.dart b/pkg/analysis_server/lib/src/services/correction/dart/create_constructor_for_final_fields.dart
index 2c879f1..62a920e 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/create_constructor_for_final_fields.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/create_constructor_for_final_fields.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/analysis/features.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/create_constructor_super.dart b/pkg/analysis_server/lib/src/services/correction/dart/create_constructor_super.dart
index 23223ba..212261b 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/create_constructor_super.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/create_constructor_super.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/create_field.dart b/pkg/analysis_server/lib/src/services/correction/dart/create_field.dart
index 1a72275..fa00de2 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/create_field.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/create_field.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/create_file.dart b/pkg/analysis_server/lib/src/services/correction/dart/create_file.dart
index e64471b..6dd55bf 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/create_file.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/create_file.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/create_function.dart b/pkg/analysis_server/lib/src/services/correction/dart/create_function.dart
index 05a71da..2351d57 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/create_function.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/create_function.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/create_getter.dart b/pkg/analysis_server/lib/src/services/correction/dart/create_getter.dart
index 5b38e57..3ca2941 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/create_getter.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/create_getter.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/create_local_variable.dart b/pkg/analysis_server/lib/src/services/correction/dart/create_local_variable.dart
index 08cb4f8..42ba1d7 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/create_local_variable.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/create_local_variable.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:_fe_analyzer_shared/src/scanner/token.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/create_method.dart b/pkg/analysis_server/lib/src/services/correction/dart/create_method.dart
index 9ded1dc..66397fc 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/create_method.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/create_method.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/create_method_or_function.dart b/pkg/analysis_server/lib/src/services/correction/dart/create_method_or_function.dart
index 166d447..c831928 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/create_method_or_function.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/create_method_or_function.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/create_missing_overrides.dart b/pkg/analysis_server/lib/src/services/correction/dart/create_missing_overrides.dart
index d0fac46..a1e5881 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/create_missing_overrides.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/create_missing_overrides.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/utilities/strings.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/create_mixin.dart b/pkg/analysis_server/lib/src/services/correction/dart/create_mixin.dart
index c4a8131..6f783b2 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/create_mixin.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/create_mixin.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/create_no_such_method.dart b/pkg/analysis_server/lib/src/services/correction/dart/create_no_such_method.dart
index aa62503..92af6ca 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/create_no_such_method.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/create_no_such_method.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/create_setter.dart b/pkg/analysis_server/lib/src/services/correction/dart/create_setter.dart
index c89701f..c6c7fc5 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/create_setter.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/create_setter.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/data_driven.dart b/pkg/analysis_server/lib/src/services/correction/dart/data_driven.dart
index e4c9bd3..1f2770b 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/data_driven.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/data_driven.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/code_template.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/encapsulate_field.dart b/pkg/analysis_server/lib/src/services/correction/dart/encapsulate_field.dart
index 23d6686..d5aa8b9 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/encapsulate_field.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/encapsulate_field.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/exchange_operands.dart b/pkg/analysis_server/lib/src/services/correction/dart/exchange_operands.dart
index 54bbe13..bb6b9de 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/exchange_operands.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/exchange_operands.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/extend_class_for_mixin.dart b/pkg/analysis_server/lib/src/services/correction/dart/extend_class_for_mixin.dart
index a2233818..e9eab92 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/extend_class_for_mixin.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/extend_class_for_mixin.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/flutter_convert_to_children.dart b/pkg/analysis_server/lib/src/services/correction/dart/flutter_convert_to_children.dart
index 5bcc3fc..01cc86a 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/flutter_convert_to_children.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/flutter_convert_to_children.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/flutter_convert_to_stateful_widget.dart b/pkg/analysis_server/lib/src/services/correction/dart/flutter_convert_to_stateful_widget.dart
index 80aa9ae..48cf327 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/flutter_convert_to_stateful_widget.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/flutter_convert_to_stateful_widget.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:_fe_analyzer_shared/src/scanner/token.dart';
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/flutter_move_down.dart b/pkg/analysis_server/lib/src/services/correction/dart/flutter_move_down.dart
index 1e2fa0f..740afed 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/flutter_move_down.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/flutter_move_down.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/flutter_move_up.dart b/pkg/analysis_server/lib/src/services/correction/dart/flutter_move_up.dart
index 8513af7..ec29164 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/flutter_move_up.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/flutter_move_up.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/flutter_remove_widget.dart b/pkg/analysis_server/lib/src/services/correction/dart/flutter_remove_widget.dart
index c260fac..0158fbc 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/flutter_remove_widget.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/flutter_remove_widget.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/flutter_swap_with_child.dart b/pkg/analysis_server/lib/src/services/correction/dart/flutter_swap_with_child.dart
index c5442e8..c1c46e5 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/flutter_swap_with_child.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/flutter_swap_with_child.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/flutter_swap_with_parent.dart b/pkg/analysis_server/lib/src/services/correction/dart/flutter_swap_with_parent.dart
index cfb62b0..a8b9f8b 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/flutter_swap_with_parent.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/flutter_swap_with_parent.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/flutter_swap_with_child.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/flutter_wrap.dart b/pkg/analysis_server/lib/src/services/correction/dart/flutter_wrap.dart
index b2d6d98..a6400d8 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/flutter_wrap.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/flutter_wrap.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/selection_analyzer.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/flutter_wrap_generic.dart b/pkg/analysis_server/lib/src/services/correction/dart/flutter_wrap_generic.dart
index 5fcd235..4938af4 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/flutter_wrap_generic.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/flutter_wrap_generic.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/flutter_wrap_stream_builder.dart b/pkg/analysis_server/lib/src/services/correction/dart/flutter_wrap_stream_builder.dart
index 4e5535a..50f11bb 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/flutter_wrap_stream_builder.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/flutter_wrap_stream_builder.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/import_add_show.dart b/pkg/analysis_server/lib/src/services/correction/dart/import_add_show.dart
index 2b53b99..19ee675 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/import_add_show.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/import_add_show.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:collection';
 
 import 'package:analysis_server/src/services/correction/assist.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/import_library.dart b/pkg/analysis_server/lib/src/services/correction/dart/import_library.dart
index da36857..872fd34 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/import_library.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/import_library.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:collection';
 
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/inline_invocation.dart b/pkg/analysis_server/lib/src/services/correction/dart/inline_invocation.dart
index de2dac5..eb35756 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/inline_invocation.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/inline_invocation.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/inline_typedef.dart b/pkg/analysis_server/lib/src/services/correction/dart/inline_typedef.dart
index 6cc3abd..6790500 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/inline_typedef.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/inline_typedef.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:_fe_analyzer_shared/src/scanner/token.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/insert_semicolon.dart b/pkg/analysis_server/lib/src/services/correction/dart/insert_semicolon.dart
index 04ba0b4..8c837c1 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/insert_semicolon.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/insert_semicolon.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/introduce_local_cast_type.dart b/pkg/analysis_server/lib/src/services/correction/dart/introduce_local_cast_type.dart
index af8eb02..c696b43 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/introduce_local_cast_type.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/introduce_local_cast_type.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/name_suggestion.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/invert_if_statement.dart b/pkg/analysis_server/lib/src/services/correction/dart/invert_if_statement.dart
index 38e35f2..2fa703ac 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/invert_if_statement.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/invert_if_statement.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/join_if_with_inner.dart b/pkg/analysis_server/lib/src/services/correction/dart/join_if_with_inner.dart
index 0c55e56..00337c6 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/join_if_with_inner.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/join_if_with_inner.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/join_if_with_outer.dart b/pkg/analysis_server/lib/src/services/correction/dart/join_if_with_outer.dart
index 1e5ca88..22761fe 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/join_if_with_outer.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/join_if_with_outer.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/join_variable_declaration.dart b/pkg/analysis_server/lib/src/services/correction/dart/join_variable_declaration.dart
index dfa9305..c7713a2 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/join_variable_declaration.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/join_variable_declaration.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:_fe_analyzer_shared/src/scanner/token.dart';
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/make_class_abstract.dart b/pkg/analysis_server/lib/src/services/correction/dart/make_class_abstract.dart
index c585b2e..416e4fa 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/make_class_abstract.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/make_class_abstract.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/make_field_not_final.dart b/pkg/analysis_server/lib/src/services/correction/dart/make_field_not_final.dart
index b8db161..ab137eb 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/make_field_not_final.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/make_field_not_final.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/make_final.dart b/pkg/analysis_server/lib/src/services/correction/dart/make_final.dart
index 3ae0f99a..f3063c1 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/make_final.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/make_final.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/make_return_type_nullable.dart b/pkg/analysis_server/lib/src/services/correction/dart/make_return_type_nullable.dart
index fa90e5f..bdc633e 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/make_return_type_nullable.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/make_return_type_nullable.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/analysis/features.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/make_variable_not_final.dart b/pkg/analysis_server/lib/src/services/correction/dart/make_variable_not_final.dart
index 276549b..4eb043f 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/make_variable_not_final.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/make_variable_not_final.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:_fe_analyzer_shared/src/scanner/token.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/make_variable_nullable.dart b/pkg/analysis_server/lib/src/services/correction/dart/make_variable_nullable.dart
index fcc42fd..62f8696 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/make_variable_nullable.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/make_variable_nullable.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/analysis/features.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/move_type_arguments_to_class.dart b/pkg/analysis_server/lib/src/services/correction/dart/move_type_arguments_to_class.dart
index 8381a75..95503c8 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/move_type_arguments_to_class.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/move_type_arguments_to_class.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/organize_imports.dart b/pkg/analysis_server/lib/src/services/correction/dart/organize_imports.dart
index 4c17e69..fc2aa60 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/organize_imports.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/organize_imports.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/correction/organize_imports.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/qualify_reference.dart b/pkg/analysis_server/lib/src/services/correction/dart/qualify_reference.dart
index fd81e75..968562b 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/qualify_reference.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/qualify_reference.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_annotation.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_annotation.dart
index 6a6d159..1ab65d1 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_annotation.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_annotation.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_argument.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_argument.dart
index e864bb9..d7a3eda 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_argument.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_argument.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_await.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_await.dart
index b5671b2..c25a7ae 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_await.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_await.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_comparison.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_comparison.dart
index 8802226..617d8e9 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_comparison.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_comparison.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_const.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_const.dart
index 485e7da..c540cec 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_const.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_const.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_dead_code.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_dead_code.dart
index bf9b3f1..3fadc64 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_dead_code.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_dead_code.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_dead_if_null.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_dead_if_null.dart
index 17e9a2d..cff4eb2 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_dead_if_null.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_dead_if_null.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_duplicate_case.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_duplicate_case.dart
index 88e3bfd..d6146ef 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_duplicate_case.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_duplicate_case.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_empty_catch.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_empty_catch.dart
index c2ac9e5..394ee32 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_empty_catch.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_empty_catch.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_empty_constructor_body.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_empty_constructor_body.dart
index 07e6a47..b72c2f2 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_empty_constructor_body.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_empty_constructor_body.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_empty_else.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_empty_else.dart
index 3c07e57..aab2666 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_empty_else.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_empty_else.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_empty_statement.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_empty_statement.dart
index e45057a..ecd86e3 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_empty_statement.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_empty_statement.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_if_null_operator.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_if_null_operator.dart
index 5d75e08..9397912 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_if_null_operator.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_if_null_operator.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_initializer.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_initializer.dart
index a927201..c1b1080 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_initializer.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_initializer.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_interpolation_braces.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_interpolation_braces.dart
index 03ceb42..8d2a673 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_interpolation_braces.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_interpolation_braces.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_method_declaration.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_method_declaration.dart
index db3ac40..d9c0e81 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_method_declaration.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_method_declaration.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_name_from_combinator.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_name_from_combinator.dart
index e0cde53..107f650 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_name_from_combinator.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_name_from_combinator.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_non_null_assertion.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_non_null_assertion.dart
index ff01bf5..79c8910 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_non_null_assertion.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_non_null_assertion.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_operator.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_operator.dart
index 1b44daf..ddbfc3b 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_operator.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_operator.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_parameters_in_getter_declaration.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_parameters_in_getter_declaration.dart
index 281e9a6..0d9cd83 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_parameters_in_getter_declaration.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_parameters_in_getter_declaration.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_parentheses_in_getter_invocation.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_parentheses_in_getter_invocation.dart
index 97e5d0f8..cd52486 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_parentheses_in_getter_invocation.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_parentheses_in_getter_invocation.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_question_mark.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_question_mark.dart
index 378c883..cadd199 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_question_mark.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_question_mark.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_this_expression.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_this_expression.dart
index 0f41278..30fd8a4 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_this_expression.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_this_expression.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_type_annotation.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_type_annotation.dart
index e58c795..997c1ee 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_type_annotation.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_type_annotation.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_type_arguments.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_type_arguments.dart
index 815154e..9423b86 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_type_arguments.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_type_arguments.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_unnecessary_cast.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_unnecessary_cast.dart
index 1cf53bb..a087d1d 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_unnecessary_cast.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_unnecessary_cast.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_unnecessary_new.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_unnecessary_new.dart
index a613dfd..86e1bf9 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_unnecessary_new.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_unnecessary_new.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_unnecessary_parentheses.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_unnecessary_parentheses.dart
index 7baa9e0..39d7d8c 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_unnecessary_parentheses.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_unnecessary_parentheses.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_unnecessary_string_interpolation.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_unnecessary_string_interpolation.dart
index 6651bf4..a6cf0b9 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_unnecessary_string_interpolation.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_unnecessary_string_interpolation.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_unused.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_unused.dart
index 156be05..700bf1a 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_unused.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_unused.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_catch_clause.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_catch_clause.dart
index 078124e..5981330 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_catch_clause.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_catch_clause.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_catch_stack.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_catch_stack.dart
index a757788..f03e3c7 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_catch_stack.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_catch_stack.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_import.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_import.dart
index 3fa7457..d5336a0 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_import.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_import.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_label.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_label.dart
index 86e508c..9939f3f 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_label.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_label.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_local_variable.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_local_variable.dart
index e3b5cf2..9fe3616 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_local_variable.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_local_variable.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_parameter.dart b/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_parameter.dart
index 62037ee..2700eb1 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_parameter.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/remove_unused_parameter.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/rename_to_camel_case.dart b/pkg/analysis_server/lib/src/services/correction/dart/rename_to_camel_case.dart
index 4130747..7e61a0e 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/rename_to_camel_case.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/rename_to_camel_case.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_boolean_with_bool.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_boolean_with_bool.dart
index 0105fed..5039e9b 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_boolean_with_bool.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_boolean_with_bool.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_cascade_with_dot.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_cascade_with_dot.dart
index eba59da..00d41c3 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_cascade_with_dot.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_cascade_with_dot.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_colon_with_equals.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_colon_with_equals.dart
index 70f6134..4f9b235 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_colon_with_equals.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_colon_with_equals.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_conditional_with_if_else.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_conditional_with_if_else.dart
index 197ec2a..adb16a8 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_conditional_with_if_else.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_conditional_with_if_else.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:_fe_analyzer_shared/src/scanner/token.dart';
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_final_with_const.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_final_with_const.dart
index c644020..3a77351 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_final_with_const.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_final_with_const.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_final_with_var.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_final_with_var.dart
index 4766290..58a4a76 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_final_with_var.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_final_with_var.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_if_else_with_conditional.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_if_else_with_conditional.dart
index 85e9599..9224921 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_if_else_with_conditional.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_if_else_with_conditional.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:_fe_analyzer_shared/src/scanner/token.dart';
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_new_with_const.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_new_with_const.dart
index 85c1ae0..9a9cd77 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_new_with_const.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_new_with_const.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_null_with_closure.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_null_with_closure.dart
index 0744780..39aabc2 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_null_with_closure.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_null_with_closure.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_return_type_future.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_return_type_future.dart
index 6af3d1f..3d0000a 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_return_type_future.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_return_type_future.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_var_with_dynamic.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_var_with_dynamic.dart
index d0176ed..3da975f 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_var_with_dynamic.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_var_with_dynamic.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_brackets.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_brackets.dart
index eb4fc02..83f4caf 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_brackets.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_brackets.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_conditional_assignment.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_conditional_assignment.dart
index 0d81cddf..e7dfbd2 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_conditional_assignment.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_conditional_assignment.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_eight_digit_hex.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_eight_digit_hex.dart
index 65db348..d0c7229 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_eight_digit_hex.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_eight_digit_hex.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_extension_name.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_extension_name.dart
index 5ebc324..ed7fa48 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_extension_name.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_extension_name.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_filled.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_filled.dart
index 860e620..fc40853 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_filled.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_filled.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_identifier.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_identifier.dart
index 9b30817..33d0b66 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_identifier.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_identifier.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_interpolation.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_interpolation.dart
index aaafcb8..77aa027 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_interpolation.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_interpolation.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_is_empty.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_is_empty.dart
index 4238767..9c02fda 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_is_empty.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_is_empty.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_not_null_aware.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_not_null_aware.dart
index 75d20bcb..4cc14c0 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_not_null_aware.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_not_null_aware.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_null_aware.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_null_aware.dart
index 20aeeb9..0f36a39 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_null_aware.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_null_aware.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_tear_off.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_tear_off.dart
index 6d6434f..44df3ff 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_tear_off.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_tear_off.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_var.dart b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_var.dart
index 64a2f1d..dcdee93 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/replace_with_var.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/replace_with_var.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/shadow_field.dart b/pkg/analysis_server/lib/src/services/correction/dart/shadow_field.dart
index 2f96ebb..8f4de40 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/shadow_field.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/shadow_field.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/sort_child_property_last.dart b/pkg/analysis_server/lib/src/services/correction/dart/sort_child_property_last.dart
index d478b33..6f0d392 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/sort_child_property_last.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/sort_child_property_last.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/split_and_condition.dart b/pkg/analysis_server/lib/src/services/correction/dart/split_and_condition.dart
index 1f38c26..f358b4e8 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/split_and_condition.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/split_and_condition.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/split_variable_declaration.dart b/pkg/analysis_server/lib/src/services/correction/dart/split_variable_declaration.dart
index faac0be..c5b109e 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/split_variable_declaration.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/split_variable_declaration.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:_fe_analyzer_shared/src/scanner/token.dart';
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/surround_with.dart b/pkg/analysis_server/lib/src/services/correction/dart/surround_with.dart
index be324d4..e2868bb 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/surround_with.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/surround_with.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/statement_analyzer.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/update_sdk_constraints.dart b/pkg/analysis_server/lib/src/services/correction/dart/update_sdk_constraints.dart
index f25d116..dddf351 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/update_sdk_constraints.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/update_sdk_constraints.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/file_system/file_system.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/use_const.dart b/pkg/analysis_server/lib/src/services/correction/dart/use_const.dart
index 4ac0dfc..1c9d823 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/use_const.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/use_const.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/use_curly_braces.dart b/pkg/analysis_server/lib/src/services/correction/dart/use_curly_braces.dart
index fc35192..f76e561 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/use_curly_braces.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/use_curly_braces.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/use_effective_integer_division.dart b/pkg/analysis_server/lib/src/services/correction/dart/use_effective_integer_division.dart
index 7c086e3..babab16 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/use_effective_integer_division.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/use_effective_integer_division.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/use_eq_eq_null.dart b/pkg/analysis_server/lib/src/services/correction/dart/use_eq_eq_null.dart
index 86ad614..ce4e1f4 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/use_eq_eq_null.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/use_eq_eq_null.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/use_is_not_empty.dart b/pkg/analysis_server/lib/src/services/correction/dart/use_is_not_empty.dart
index 665dc9c..ca10cbf 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/use_is_not_empty.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/use_is_not_empty.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/use_not_eq_null.dart b/pkg/analysis_server/lib/src/services/correction/dart/use_not_eq_null.dart
index e53bc02..120e87d 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/use_not_eq_null.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/use_not_eq_null.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/use_rethrow.dart b/pkg/analysis_server/lib/src/services/correction/dart/use_rethrow.dart
index 8c31100..dc55220 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/use_rethrow.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/use_rethrow.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/wrap_in_future.dart b/pkg/analysis_server/lib/src/services/correction/dart/wrap_in_future.dart
index 1ccd887..794bb72 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/wrap_in_future.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/wrap_in_future.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/dart/wrap_in_text.dart b/pkg/analysis_server/lib/src/services/correction/dart/wrap_in_text.dart
index 53776c3..bfd97f5 100644
--- a/pkg/analysis_server/lib/src/services/correction/dart/wrap_in_text.dart
+++ b/pkg/analysis_server/lib/src/services/correction/dart/wrap_in_text.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/executable_parameters.dart b/pkg/analysis_server/lib/src/services/correction/executable_parameters.dart
index 6f66ef2..7fc7558 100644
--- a/pkg/analysis_server/lib/src/services/correction/executable_parameters.dart
+++ b/pkg/analysis_server/lib/src/services/correction/executable_parameters.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:core';
 
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/fix.dart b/pkg/analysis_server/lib/src/services/correction/fix.dart
index 01063f4..f0f4dcb 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/plugin/edit/fix/fix_dart.dart';
 import 'package:analysis_server/src/services/correction/fix/dart/top_level_declarations.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/analysis_options/fix_generator.dart b/pkg/analysis_server/lib/src/services/correction/fix/analysis_options/fix_generator.dart
index 241673e..31034bf 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/analysis_options/fix_generator.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/analysis_options/fix_generator.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:math' as math;
 
 import 'package:analysis_server/plugin/edit/fix/fix_core.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/dart/top_level_declarations.dart b/pkg/analysis_server/lib/src/services/correction/fix/dart/top_level_declarations.dart
index 5c51d43..ecfca96 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/dart/top_level_declarations.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/dart/top_level_declarations.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/dart/analysis/analysis_context.dart';
 import 'package:analyzer/src/services/available_declarations.dart';
 
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/accessor.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/accessor.dart
index 765e120..bbfdd2a 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/accessor.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/accessor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/parameter_reference.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/add_type_parameter.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/add_type_parameter.dart
index 1dc11da..c75c1dc 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/add_type_parameter.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/add_type_parameter.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/data_driven.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/change.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/code_template.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/change.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/change.dart
index f73f6ae..2966d55 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/change.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/change.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/data_driven.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_dart.dart';
 
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/changes_selector.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/changes_selector.dart
index c441575..e8e7a33 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/changes_selector.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/changes_selector.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/change.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/code_template.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/expression.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/code_fragment_parser.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/code_fragment_parser.dart
index 27dd4cb..bebdc17 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/code_fragment_parser.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/code_fragment_parser.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/accessor.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/expression.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/parameter_reference.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/code_template.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/code_template.dart
index 4fc44c5..3a89d93 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/code_template.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/code_template.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/expression.dart'
     as data_driven;
 import 'package:analysis_server/src/services/correction/fix/data_driven/value_generator.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/element_descriptor.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/element_descriptor.dart
index ae3f501..9eeedf3 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/element_descriptor.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/element_descriptor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/element_kind.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart' show ClassElement;
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/element_kind.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/element_kind.dart
index c0233f7..be3d61e 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/element_kind.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/element_kind.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// An indication of the kind of an element.
 enum ElementKind {
   classKind,
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/element_matcher.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/element_matcher.dart
index d07b075..fe8ba62 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/element_matcher.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/element_matcher.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/element_descriptor.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/element_kind.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/expression.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/expression.dart
index 9f56ae1..3a554d3 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/expression.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/expression.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/code_template.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/value_generator.dart';
 
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/modify_parameters.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/modify_parameters.dart
index 04c7d6e..76ec8f6 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/modify_parameters.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/modify_parameters.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/data_driven.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/change.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/code_template.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/parameter_reference.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/parameter_reference.dart
index d2fc364..662a953 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/parameter_reference.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/parameter_reference.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/dart/ast/ast.dart';
 
 /// A reference to a named parameter.
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/rename.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/rename.dart
index 58eb217..b7958ad9 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/rename.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/rename.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/data_driven.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/change.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/rename_parameter.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/rename_parameter.dart
index 97065b7..7f9dbac 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/rename_parameter.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/rename_parameter.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/data_driven.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/change.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform.dart
index 0a60dd7..cc03b29 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/changes_selector.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/element_descriptor.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/element_matcher.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_override.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_override.dart
index abb7246..b873aba 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_override.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_override.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:meta/meta.dart';
 
 /// A description of a set of changes to a single transform.
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_override_set.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_override_set.dart
index 597efde..9b18a0f 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_override_set.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_override_set.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_override.dart';
 
 /// A description of a set of transform overrides.
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_override_set_parser.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_override_set_parser.dart
index 29e814f..30c3995 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_override_set_parser.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_override_set_parser.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_override.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_override_set.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_error_code.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_set.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_set.dart
index de1b7dd..5ef1a7a 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_set.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_set.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/element_matcher.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_override_set.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_set_error_code.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_set_error_code.dart
index 508635c..10a8af9 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_set_error_code.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_set_error_code.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 // ignore_for_file: prefer_single_quotes, slash_for_doc_comments
 import 'package:analyzer/error/error.dart';
 
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_set_manager.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_set_manager.dart
index 23ad911..38f3aa0 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_set_manager.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_set_manager.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_parser.dart';
 import 'package:analyzer/dart/element/element.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_set_parser.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_set_parser.dart
index 21e7d1d..eb162b3 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_set_parser.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/transform_set_parser.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/add_type_parameter.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/change.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/changes_selector.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/value_generator.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/value_generator.dart
index 16c8388..fc9b2fb 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/value_generator.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/value_generator.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/accessor.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/code_template.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/variable_scope.dart b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/variable_scope.dart
index 0ae0c27..6137a32 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/data_driven/variable_scope.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/data_driven/variable_scope.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/value_generator.dart';
 
 /// A scope in which the generators associated with variables can be looked up.
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/manifest/fix_generator.dart b/pkg/analysis_server/lib/src/services/correction/fix/manifest/fix_generator.dart
index ebc7431..b2d0854 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/manifest/fix_generator.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/manifest/fix_generator.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:math' as math;
 
 import 'package:analysis_server/plugin/edit/fix/fix_core.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/fix/pubspec/fix_generator.dart b/pkg/analysis_server/lib/src/services/correction/fix/pubspec/fix_generator.dart
index d82b128..62130a9 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix/pubspec/fix_generator.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix/pubspec/fix_generator.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:math' as math;
 
 import 'package:analysis_server/plugin/edit/fix/fix_core.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/fix_internal.dart b/pkg/analysis_server/lib/src/services/correction/fix_internal.dart
index a040273..dfc9b79 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix_internal.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix_internal.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:core';
 
 import 'package:analysis_server/plugin/edit/fix/fix_core.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/levenshtein.dart b/pkg/analysis_server/lib/src/services/correction/levenshtein.dart
index 42f8cda..7146b2d 100644
--- a/pkg/analysis_server/lib/src/services/correction/levenshtein.dart
+++ b/pkg/analysis_server/lib/src/services/correction/levenshtein.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:math' as math;
 
 /// The value returned by [levenshtein] if the distance is determined
diff --git a/pkg/analysis_server/lib/src/services/correction/name_suggestion.dart b/pkg/analysis_server/lib/src/services/correction/name_suggestion.dart
index a06b069..b52a410 100644
--- a/pkg/analysis_server/lib/src/services/correction/name_suggestion.dart
+++ b/pkg/analysis_server/lib/src/services/correction/name_suggestion.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/utilities/strings.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/namespace.dart b/pkg/analysis_server/lib/src/services/correction/namespace.dart
index 30c5494..98423a2 100644
--- a/pkg/analysis_server/lib/src/services/correction/namespace.dart
+++ b/pkg/analysis_server/lib/src/services/correction/namespace.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/dart/resolver/scope.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/organize_imports.dart b/pkg/analysis_server/lib/src/services/correction/organize_imports.dart
index 22e440b..d051fa9 100644
--- a/pkg/analysis_server/lib/src/services/correction/organize_imports.dart
+++ b/pkg/analysis_server/lib/src/services/correction/organize_imports.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/utilities/strings.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/selection_analyzer.dart b/pkg/analysis_server/lib/src/services/correction/selection_analyzer.dart
index deac73d..d71a7e1 100644
--- a/pkg/analysis_server/lib/src/services/correction/selection_analyzer.dart
+++ b/pkg/analysis_server/lib/src/services/correction/selection_analyzer.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/src/generated/source.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/sort_members.dart b/pkg/analysis_server/lib/src/services/correction/sort_members.dart
index cf3db41..34fb091 100644
--- a/pkg/analysis_server/lib/src/services/correction/sort_members.dart
+++ b/pkg/analysis_server/lib/src/services/correction/sort_members.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/organize_imports.dart';
 import 'package:analysis_server/src/utilities/strings.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/source_buffer.dart b/pkg/analysis_server/lib/src/services/correction/source_buffer.dart
index 323c721..55dcdc00 100644
--- a/pkg/analysis_server/lib/src/services/correction/source_buffer.dart
+++ b/pkg/analysis_server/lib/src/services/correction/source_buffer.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// Helper for building Dart source with linked positions.
 class SourceBuilder {
   final String file;
diff --git a/pkg/analysis_server/lib/src/services/correction/statement_analyzer.dart b/pkg/analysis_server/lib/src/services/correction/statement_analyzer.dart
index 96e8e89..3f62794 100644
--- a/pkg/analysis_server/lib/src/services/correction/statement_analyzer.dart
+++ b/pkg/analysis_server/lib/src/services/correction/statement_analyzer.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/services/correction/selection_analyzer.dart';
 import 'package:analysis_server/src/services/correction/status.dart';
diff --git a/pkg/analysis_server/lib/src/services/correction/status.dart b/pkg/analysis_server/lib/src/services/correction/status.dart
index 20c2268..d552874 100644
--- a/pkg/analysis_server/lib/src/services/correction/status.dart
+++ b/pkg/analysis_server/lib/src/services/correction/status.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 
 /// An outcome of a condition checking operation.
diff --git a/pkg/analysis_server/lib/src/services/correction/util.dart b/pkg/analysis_server/lib/src/services/correction/util.dart
index 9914359..903f88f 100644
--- a/pkg/analysis_server/lib/src/services/correction/util.dart
+++ b/pkg/analysis_server/lib/src/services/correction/util.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:math';
 
 import 'package:analysis_server/src/protocol_server.dart'
diff --git a/pkg/analysis_server/lib/src/services/flutter/class_description.dart b/pkg/analysis_server/lib/src/services/flutter/class_description.dart
index f3b8a83..b8caaf2 100644
--- a/pkg/analysis_server/lib/src/services/flutter/class_description.dart
+++ b/pkg/analysis_server/lib/src/services/flutter/class_description.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
diff --git a/pkg/analysis_server/lib/src/services/flutter/property.dart b/pkg/analysis_server/lib/src/services/flutter/property.dart
index 25f01ab..d7dce19 100644
--- a/pkg/analysis_server/lib/src/services/flutter/property.dart
+++ b/pkg/analysis_server/lib/src/services/flutter/property.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart' as protocol;
 import 'package:analysis_server/src/services/flutter/class_description.dart';
 import 'package:analysis_server/src/utilities/flutter.dart';
diff --git a/pkg/analysis_server/lib/src/services/flutter/widget_descriptions.dart b/pkg/analysis_server/lib/src/services/flutter/widget_descriptions.dart
index e24d8d5..b33557d 100644
--- a/pkg/analysis_server/lib/src/services/flutter/widget_descriptions.dart
+++ b/pkg/analysis_server/lib/src/services/flutter/widget_descriptions.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart' as protocol;
 import 'package:analysis_server/src/services/flutter/class_description.dart';
 import 'package:analysis_server/src/services/flutter/property.dart';
diff --git a/pkg/analysis_server/lib/src/services/kythe/kythe_visitors.dart b/pkg/analysis_server/lib/src/services/kythe/kythe_visitors.dart
index f2f430f..57085d1 100644
--- a/pkg/analysis_server/lib/src/services/kythe/kythe_visitors.dart
+++ b/pkg/analysis_server/lib/src/services/kythe/kythe_visitors.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/lib/src/services/kythe/schema.dart b/pkg/analysis_server/lib/src/services/kythe/schema.dart
index 3016742..dfd091e 100644
--- a/pkg/analysis_server/lib/src/services/kythe/schema.dart
+++ b/pkg/analysis_server/lib/src/services/kythe/schema.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// This file gathers constant strings from the Kythe Schema:
 /// kythe.io/docs/schema/
 
diff --git a/pkg/analysis_server/lib/src/services/linter/lint_names.dart b/pkg/analysis_server/lib/src/services/linter/lint_names.dart
index cc4823f..cfaf553 100644
--- a/pkg/analysis_server/lib/src/services/linter/lint_names.dart
+++ b/pkg/analysis_server/lib/src/services/linter/lint_names.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// An enumeration of lint names.
 class LintNames {
   static const String always_declare_return_types =
diff --git a/pkg/analysis_server/lib/src/services/pub/pub_api.dart b/pkg/analysis_server/lib/src/services/pub/pub_api.dart
index 7f43aa0..a9e504a 100644
--- a/pkg/analysis_server/lib/src/services/pub/pub_api.dart
+++ b/pkg/analysis_server/lib/src/services/pub/pub_api.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
diff --git a/pkg/analysis_server/lib/src/services/pub/pub_package_service.dart b/pkg/analysis_server/lib/src/services/pub/pub_package_service.dart
index aca37e4..09d0c80 100644
--- a/pkg/analysis_server/lib/src/services/pub/pub_package_service.dart
+++ b/pkg/analysis_server/lib/src/services/pub/pub_package_service.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:convert';
 
diff --git a/pkg/analysis_server/lib/src/services/refactoring/convert_getter_to_method.dart b/pkg/analysis_server/lib/src/services/refactoring/convert_getter_to_method.dart
index 5c1e88a..b2f9f13 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/convert_getter_to_method.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/convert_getter_to_method.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
 import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
diff --git a/pkg/analysis_server/lib/src/services/refactoring/convert_method_to_getter.dart b/pkg/analysis_server/lib/src/services/refactoring/convert_method_to_getter.dart
index c1d584c..7fb6210 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/convert_method_to_getter.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/convert_method_to_getter.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
 import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
diff --git a/pkg/analysis_server/lib/src/services/refactoring/extract_local.dart b/pkg/analysis_server/lib/src/services/refactoring/extract_local.dart
index 792e05e..e6ffa45 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/extract_local.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/extract_local.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:collection';
 
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
diff --git a/pkg/analysis_server/lib/src/services/refactoring/extract_method.dart b/pkg/analysis_server/lib/src/services/refactoring/extract_method.dart
index 81e08f1..d9c1a15 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/extract_method.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/extract_method.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
 import 'package:analysis_server/src/services/correction/name_suggestion.dart';
 import 'package:analysis_server/src/services/correction/selection_analyzer.dart';
diff --git a/pkg/analysis_server/lib/src/services/refactoring/extract_widget.dart b/pkg/analysis_server/lib/src/services/refactoring/extract_widget.dart
index 9570680..f7f67c7 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/extract_widget.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/extract_widget.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
 import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
diff --git a/pkg/analysis_server/lib/src/services/refactoring/inline_local.dart b/pkg/analysis_server/lib/src/services/refactoring/inline_local.dart
index 0710a92..bbfccb9 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/inline_local.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/inline_local.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
 import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
diff --git a/pkg/analysis_server/lib/src/services/refactoring/inline_method.dart b/pkg/analysis_server/lib/src/services/refactoring/inline_method.dart
index 1489cd7..0b6f4a2 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/inline_method.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/inline_method.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
 import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
diff --git a/pkg/analysis_server/lib/src/services/refactoring/move_file.dart b/pkg/analysis_server/lib/src/services/refactoring/move_file.dart
index 94d8faf..2c92945 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/move_file.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/move_file.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:core';
 
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
diff --git a/pkg/analysis_server/lib/src/services/refactoring/naming_conventions.dart b/pkg/analysis_server/lib/src/services/refactoring/naming_conventions.dart
index 3cd4fe3..735bed9 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/naming_conventions.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/naming_conventions.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:_fe_analyzer_shared/src/scanner/token.dart' show Keyword;
 import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/utilities/strings.dart';
diff --git a/pkg/analysis_server/lib/src/services/refactoring/refactoring.dart b/pkg/analysis_server/lib/src/services/refactoring/refactoring.dart
index 9d2e00f..fbd4d3b 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/refactoring.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/refactoring.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/services/refactoring/convert_getter_to_method.dart';
 import 'package:analysis_server/src/services/refactoring/convert_method_to_getter.dart';
diff --git a/pkg/analysis_server/lib/src/services/refactoring/refactoring_internal.dart b/pkg/analysis_server/lib/src/services/refactoring/refactoring_internal.dart
index 1677bb8..dd05a9b 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/refactoring_internal.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/refactoring_internal.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:collection';
 
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
diff --git a/pkg/analysis_server/lib/src/services/refactoring/rename.dart b/pkg/analysis_server/lib/src/services/refactoring/rename.dart
index 6c25dd6..35d547b 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/rename.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/rename.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
 import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
diff --git a/pkg/analysis_server/lib/src/services/refactoring/rename_class_member.dart b/pkg/analysis_server/lib/src/services/refactoring/rename_class_member.dart
index 7f96d3a..eb2ab3c 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/rename_class_member.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/rename_class_member.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart'
     hide Element, ElementKind;
 import 'package:analysis_server/src/services/correction/status.dart';
diff --git a/pkg/analysis_server/lib/src/services/refactoring/rename_constructor.dart b/pkg/analysis_server/lib/src/services/refactoring/rename_constructor.dart
index 1009de9..3d6edf8 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/rename_constructor.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/rename_constructor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
 import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
diff --git a/pkg/analysis_server/lib/src/services/refactoring/rename_extension_member.dart b/pkg/analysis_server/lib/src/services/refactoring/rename_extension_member.dart
index 6187abe..2665ac7 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/rename_extension_member.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/rename_extension_member.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart'
     hide Element, ElementKind;
 import 'package:analysis_server/src/services/correction/status.dart';
diff --git a/pkg/analysis_server/lib/src/services/refactoring/rename_import.dart b/pkg/analysis_server/lib/src/services/refactoring/rename_import.dart
index 0dfbac5..04eeea2 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/rename_import.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/rename_import.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/services/refactoring/naming_conventions.dart';
diff --git a/pkg/analysis_server/lib/src/services/refactoring/rename_label.dart b/pkg/analysis_server/lib/src/services/refactoring/rename_label.dart
index d32922a..86873b0 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/rename_label.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/rename_label.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/services/refactoring/naming_conventions.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
diff --git a/pkg/analysis_server/lib/src/services/refactoring/rename_library.dart b/pkg/analysis_server/lib/src/services/refactoring/rename_library.dart
index 68b8849..1338bbc 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/rename_library.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/rename_library.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/services/refactoring/naming_conventions.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
diff --git a/pkg/analysis_server/lib/src/services/refactoring/rename_local.dart b/pkg/analysis_server/lib/src/services/refactoring/rename_local.dart
index 3b3d492..04fa336 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/rename_local.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/rename_local.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart'
     hide Element, ElementKind;
 import 'package:analysis_server/src/services/correction/status.dart';
diff --git a/pkg/analysis_server/lib/src/services/refactoring/rename_unit_member.dart b/pkg/analysis_server/lib/src/services/refactoring/rename_unit_member.dart
index 05cf609..2afbf50 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/rename_unit_member.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/rename_unit_member.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart'
     show newLocation_fromElement, newLocation_fromMatch;
 import 'package:analysis_server/src/services/correction/status.dart';
diff --git a/pkg/analysis_server/lib/src/services/refactoring/visible_ranges_computer.dart b/pkg/analysis_server/lib/src/services/refactoring/visible_ranges_computer.dart
index 4d15c8e..4eaa39c 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/visible_ranges_computer.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/visible_ranges_computer.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element.dart';
diff --git a/pkg/analysis_server/lib/src/services/search/element_visitors.dart b/pkg/analysis_server/lib/src/services/search/element_visitors.dart
index d3e11ae..de03c6f 100644
--- a/pkg/analysis_server/lib/src/services/search/element_visitors.dart
+++ b/pkg/analysis_server/lib/src/services/search/element_visitors.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/visitor.dart';
 
diff --git a/pkg/analysis_server/lib/src/services/search/hierarchy.dart b/pkg/analysis_server/lib/src/services/search/hierarchy.dart
index 7a3f90e..6d30c6b 100644
--- a/pkg/analysis_server/lib/src/services/search/hierarchy.dart
+++ b/pkg/analysis_server/lib/src/services/search/hierarchy.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:collection';
 
 import 'package:analysis_server/src/services/search/element_visitors.dart';
diff --git a/pkg/analysis_server/lib/src/services/search/search_engine.dart b/pkg/analysis_server/lib/src/services/search/search_engine.dart
index 95b74ec..8addf0a 100644
--- a/pkg/analysis_server/lib/src/services/search/search_engine.dart
+++ b/pkg/analysis_server/lib/src/services/search/search_engine.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/generated/source.dart';
 
diff --git a/pkg/analysis_server/lib/src/services/search/search_engine_internal.dart b/pkg/analysis_server/lib/src/services/search/search_engine_internal.dart
index ddc1c22..3f5cd22 100644
--- a/pkg/analysis_server/lib/src/services/search/search_engine_internal.dart
+++ b/pkg/analysis_server/lib/src/services/search/search_engine_internal.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/search/search_engine.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart';
diff --git a/pkg/analysis_server/lib/src/socket_server.dart b/pkg/analysis_server/lib/src/socket_server.dart
index a72d97b..df0d3e2 100644
--- a/pkg/analysis_server/lib/src/socket_server.dart
+++ b/pkg/analysis_server/lib/src/socket_server.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/analysis_server.dart';
diff --git a/pkg/analysis_server/lib/src/status/ast_writer.dart b/pkg/analysis_server/lib/src/status/ast_writer.dart
index 29a96b8..ef6cc8e 100644
--- a/pkg/analysis_server/lib/src/status/ast_writer.dart
+++ b/pkg/analysis_server/lib/src/status/ast_writer.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:collection';
 
 import 'package:analysis_server/src/status/tree_writer.dart';
diff --git a/pkg/analysis_server/lib/src/status/diagnostics.dart b/pkg/analysis_server/lib/src/status/diagnostics.dart
index 7818392..bfb39c7 100644
--- a/pkg/analysis_server/lib/src/status/diagnostics.dart
+++ b/pkg/analysis_server/lib/src/status/diagnostics.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:developer' as developer;
 import 'dart:io';
 
diff --git a/pkg/analysis_server/lib/src/status/element_writer.dart b/pkg/analysis_server/lib/src/status/element_writer.dart
index 20e2720..e75777c 100644
--- a/pkg/analysis_server/lib/src/status/element_writer.dart
+++ b/pkg/analysis_server/lib/src/status/element_writer.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:collection';
 import 'dart:convert';
 
diff --git a/pkg/analysis_server/lib/src/status/pages.dart b/pkg/analysis_server/lib/src/status/pages.dart
index 177f04f..2edec799 100644
--- a/pkg/analysis_server/lib/src/status/pages.dart
+++ b/pkg/analysis_server/lib/src/status/pages.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 import 'dart:io';
 
diff --git a/pkg/analysis_server/lib/src/status/tree_writer.dart b/pkg/analysis_server/lib/src/status/tree_writer.dart
index 4ed9ad0..25bd024 100644
--- a/pkg/analysis_server/lib/src/status/tree_writer.dart
+++ b/pkg/analysis_server/lib/src/status/tree_writer.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 
 import 'package:analyzer/exception/exception.dart';
diff --git a/pkg/analysis_server/lib/src/utilities/extensions/ast.dart b/pkg/analysis_server/lib/src/utilities/extensions/ast.dart
index 1287b2e..d7eaa90 100644
--- a/pkg/analysis_server/lib/src/utilities/extensions/ast.dart
+++ b/pkg/analysis_server/lib/src/utilities/extensions/ast.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/utilities/extensions/element.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
diff --git a/pkg/analysis_server/lib/src/utilities/extensions/element.dart b/pkg/analysis_server/lib/src/utilities/extensions/element.dart
index 1d6b14c..b9f85ed 100644
--- a/pkg/analysis_server/lib/src/utilities/extensions/element.dart
+++ b/pkg/analysis_server/lib/src/utilities/extensions/element.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/dart/element/element.dart';
 
 extension ClassElementExtensions on ClassElement {
diff --git a/pkg/analysis_server/lib/src/utilities/extensions/numeric.dart b/pkg/analysis_server/lib/src/utilities/extensions/numeric.dart
index 005763f..b4f7f78 100644
--- a/pkg/analysis_server/lib/src/utilities/extensions/numeric.dart
+++ b/pkg/analysis_server/lib/src/utilities/extensions/numeric.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 extension DoubleExtensions on double {
   /// Return `true` if this value is between the [lower] and [upper] bound,
   /// inclusive.
diff --git a/pkg/analysis_server/lib/src/utilities/extensions/yaml.dart b/pkg/analysis_server/lib/src/utilities/extensions/yaml.dart
index 1199a2f..d3bf132 100644
--- a/pkg/analysis_server/lib/src/utilities/extensions/yaml.dart
+++ b/pkg/analysis_server/lib/src/utilities/extensions/yaml.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:yaml/yaml.dart';
 
 extension YamlNodeExtensions on YamlNode {
diff --git a/pkg/analysis_server/lib/src/utilities/file_string_sink.dart b/pkg/analysis_server/lib/src/utilities/file_string_sink.dart
index 9486dfa..a81ef8f 100644
--- a/pkg/analysis_server/lib/src/utilities/file_string_sink.dart
+++ b/pkg/analysis_server/lib/src/utilities/file_string_sink.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io';
 
 /// A string sink that write into a file.
diff --git a/pkg/analysis_server/lib/src/utilities/flutter.dart b/pkg/analysis_server/lib/src/utilities/flutter.dart
index 9243a189..11c4fdd 100644
--- a/pkg/analysis_server/lib/src/utilities/flutter.dart
+++ b/pkg/analysis_server/lib/src/utilities/flutter.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/utilities/strings.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
diff --git a/pkg/analysis_server/lib/src/utilities/mocks.dart b/pkg/analysis_server/lib/src/utilities/mocks.dart
index 9775fee..6c4134a 100644
--- a/pkg/analysis_server/lib/src/utilities/mocks.dart
+++ b/pkg/analysis_server/lib/src/utilities/mocks.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/protocol/protocol.dart';
diff --git a/pkg/analysis_server/lib/src/utilities/null_string_sink.dart b/pkg/analysis_server/lib/src/utilities/null_string_sink.dart
index 3f6b29e..9fb109c 100644
--- a/pkg/analysis_server/lib/src/utilities/null_string_sink.dart
+++ b/pkg/analysis_server/lib/src/utilities/null_string_sink.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// A string sink that ignores everything written to it.
 class NullStringSink implements StringSink {
   @override
diff --git a/pkg/analysis_server/lib/src/utilities/profiling.dart b/pkg/analysis_server/lib/src/utilities/profiling.dart
index 1d18313..b426b39 100644
--- a/pkg/analysis_server/lib/src/utilities/profiling.dart
+++ b/pkg/analysis_server/lib/src/utilities/profiling.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io';
 
 /// A class that can return memory and cpu usage information for a given
diff --git a/pkg/analysis_server/lib/src/utilities/request_statistics.dart b/pkg/analysis_server/lib/src/utilities/request_statistics.dart
index 828dd36..044be84 100644
--- a/pkg/analysis_server/lib/src/utilities/request_statistics.dart
+++ b/pkg/analysis_server/lib/src/utilities/request_statistics.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 import 'dart:io';
 
diff --git a/pkg/analysis_server/lib/src/utilities/strings.dart b/pkg/analysis_server/lib/src/utilities/strings.dart
index 42155b9..d323ee8 100644
--- a/pkg/analysis_server/lib/src/utilities/strings.dart
+++ b/pkg/analysis_server/lib/src/utilities/strings.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:math';
 
 import 'package:analyzer_plugin/src/utilities/string_utilities.dart';
diff --git a/pkg/analysis_server/lib/src/utilities/tee_string_sink.dart b/pkg/analysis_server/lib/src/utilities/tee_string_sink.dart
index 978c4ed..bb3be93 100644
--- a/pkg/analysis_server/lib/src/utilities/tee_string_sink.dart
+++ b/pkg/analysis_server/lib/src/utilities/tee_string_sink.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// A [StringSink] that writes into two other [StringSink]s.
 class TeeStringSink implements StringSink {
   final StringSink sink1;
diff --git a/pkg/analysis_server/lib/src/utilities/yaml_node_locator.dart b/pkg/analysis_server/lib/src/utilities/yaml_node_locator.dart
index 809748f..b34ef9c 100644
--- a/pkg/analysis_server/lib/src/utilities/yaml_node_locator.dart
+++ b/pkg/analysis_server/lib/src/utilities/yaml_node_locator.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:meta/meta.dart';
 import 'package:yaml/yaml.dart';
 
diff --git a/pkg/analysis_server/lib/starter.dart b/pkg/analysis_server/lib/starter.dart
index 78fb773..a8d4451 100644
--- a/pkg/analysis_server/lib/starter.dart
+++ b/pkg/analysis_server/lib/starter.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:isolate';
 
 import 'package:analysis_server/src/server/crash_reporting_attachments.dart';
diff --git a/pkg/analysis_server/pubspec.yaml b/pkg/analysis_server/pubspec.yaml
index c968f5b..5629eb1 100644
--- a/pkg/analysis_server/pubspec.yaml
+++ b/pkg/analysis_server/pubspec.yaml
@@ -3,7 +3,7 @@
 publish_to: none
 
 environment:
-  sdk: '>=2.6.0 <3.0.0'
+  sdk: '>=2.12.0 <3.0.0'
 
 dependencies:
   _fe_analyzer_shared:
diff --git a/pkg/analysis_server/test/abstract_context.dart b/pkg/analysis_server/test/abstract_context.dart
index 6e069d0..a5ac7d5 100644
--- a/pkg/analysis_server/test/abstract_context.dart
+++ b/pkg/analysis_server/test/abstract_context.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/dart/analysis/analysis_context.dart';
 import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/dart/analysis/session.dart';
diff --git a/pkg/analysis_server/test/abstract_single_unit.dart b/pkg/analysis_server/test/abstract_single_unit.dart
index 1a04502..96e5da9 100644
--- a/pkg/analysis_server/test/abstract_single_unit.dart
+++ b/pkg/analysis_server/test/abstract_single_unit.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
diff --git a/pkg/analysis_server/test/analysis/get_errors_test.dart b/pkg/analysis_server/test/analysis/get_errors_test.dart
index 5707925..145a3a5 100644
--- a/pkg/analysis_server/test/analysis/get_errors_test.dart
+++ b/pkg/analysis_server/test/analysis/get_errors_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/domain_analysis.dart';
diff --git a/pkg/analysis_server/test/analysis/get_hover_test.dart b/pkg/analysis_server/test/analysis/get_hover_test.dart
index d1133a8..fb78fb5 100644
--- a/pkg/analysis_server/test/analysis/get_hover_test.dart
+++ b/pkg/analysis_server/test/analysis/get_hover_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:meta/meta.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/analysis/get_navigation_test.dart b/pkg/analysis_server/test/analysis/get_navigation_test.dart
index 9e2b5d6..99943b9 100644
--- a/pkg/analysis_server/test/analysis/get_navigation_test.dart
+++ b/pkg/analysis_server/test/analysis/get_navigation_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/domain_analysis.dart';
diff --git a/pkg/analysis_server/test/analysis/get_signature_test.dart b/pkg/analysis_server/test/analysis/get_signature_test.dart
index 3eb51ae..5d4e202 100644
--- a/pkg/analysis_server/test/analysis/get_signature_test.dart
+++ b/pkg/analysis_server/test/analysis/get_signature_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/analysis/notification_analysis_options_test.dart b/pkg/analysis_server/test/analysis/notification_analysis_options_test.dart
index d9b3a95..55924d9 100644
--- a/pkg/analysis_server/test/analysis/notification_analysis_options_test.dart
+++ b/pkg/analysis_server/test/analysis/notification_analysis_options_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_constants.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart'
diff --git a/pkg/analysis_server/test/analysis/notification_analyzed_files_test.dart b/pkg/analysis_server/test/analysis/notification_analyzed_files_test.dart
index c574991..9561c95 100644
--- a/pkg/analysis_server/test/analysis/notification_analyzed_files_test.dart
+++ b/pkg/analysis_server/test/analysis/notification_analyzed_files_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_constants.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/test/analysis/notification_closing_labels_test.dart b/pkg/analysis_server/test/analysis/notification_closing_labels_test.dart
index e3873d3..da4b925 100644
--- a/pkg/analysis_server/test/analysis/notification_closing_labels_test.dart
+++ b/pkg/analysis_server/test/analysis/notification_closing_labels_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/protocol/protocol.dart';
diff --git a/pkg/analysis_server/test/analysis/notification_errors_test.dart b/pkg/analysis_server/test/analysis/notification_errors_test.dart
index 4bbe367..04dba84 100644
--- a/pkg/analysis_server/test/analysis/notification_errors_test.dart
+++ b/pkg/analysis_server/test/analysis/notification_errors_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_constants.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/test/analysis/notification_folding_test.dart b/pkg/analysis_server/test/analysis/notification_folding_test.dart
index 09a78a5..d00446f 100644
--- a/pkg/analysis_server/test/analysis/notification_folding_test.dart
+++ b/pkg/analysis_server/test/analysis/notification_folding_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/protocol/protocol_constants.dart';
diff --git a/pkg/analysis_server/test/analysis/notification_highlights2_test.dart b/pkg/analysis_server/test/analysis/notification_highlights2_test.dart
index 92777a1..8650731 100644
--- a/pkg/analysis_server/test/analysis/notification_highlights2_test.dart
+++ b/pkg/analysis_server/test/analysis/notification_highlights2_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/protocol/protocol.dart';
diff --git a/pkg/analysis_server/test/analysis/notification_implemented_test.dart b/pkg/analysis_server/test/analysis/notification_implemented_test.dart
index 43a5a24..cc1b1c8 100644
--- a/pkg/analysis_server/test/analysis/notification_implemented_test.dart
+++ b/pkg/analysis_server/test/analysis/notification_implemented_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_constants.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/test/analysis/notification_navigation_test.dart b/pkg/analysis_server/test/analysis/notification_navigation_test.dart
index 8f42b24..8e52073 100644
--- a/pkg/analysis_server/test/analysis/notification_navigation_test.dart
+++ b/pkg/analysis_server/test/analysis/notification_navigation_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/protocol/protocol.dart';
diff --git a/pkg/analysis_server/test/analysis/notification_occurrences_test.dart b/pkg/analysis_server/test/analysis/notification_occurrences_test.dart
index 31fe525..bf46653 100644
--- a/pkg/analysis_server/test/analysis/notification_occurrences_test.dart
+++ b/pkg/analysis_server/test/analysis/notification_occurrences_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/protocol/protocol.dart';
diff --git a/pkg/analysis_server/test/analysis/notification_outline_test.dart b/pkg/analysis_server/test/analysis/notification_outline_test.dart
index d43aeb2..f372764 100644
--- a/pkg/analysis_server/test/analysis/notification_outline_test.dart
+++ b/pkg/analysis_server/test/analysis/notification_outline_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/protocol/protocol.dart';
diff --git a/pkg/analysis_server/test/analysis/notification_overrides_test.dart b/pkg/analysis_server/test/analysis/notification_overrides_test.dart
index 8ac4dd2..14f5294 100644
--- a/pkg/analysis_server/test/analysis/notification_overrides_test.dart
+++ b/pkg/analysis_server/test/analysis/notification_overrides_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/protocol/protocol.dart';
diff --git a/pkg/analysis_server/test/analysis/reanalyze_test.dart b/pkg/analysis_server/test/analysis/reanalyze_test.dart
index 358df55..934e6cc 100644
--- a/pkg/analysis_server/test/analysis/reanalyze_test.dart
+++ b/pkg/analysis_server/test/analysis/reanalyze_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_constants.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/test/analysis/set_priority_files_test.dart b/pkg/analysis_server/test/analysis/set_priority_files_test.dart
index 46d189d..8554189 100644
--- a/pkg/analysis_server/test/analysis/set_priority_files_test.dart
+++ b/pkg/analysis_server/test/analysis/set_priority_files_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/domain_analysis.dart';
diff --git a/pkg/analysis_server/test/analysis/test_all.dart b/pkg/analysis_server/test/analysis/test_all.dart
index 1187065..8954813 100644
--- a/pkg/analysis_server/test/analysis/test_all.dart
+++ b/pkg/analysis_server/test/analysis/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'get_errors_test.dart' as get_errors;
diff --git a/pkg/analysis_server/test/analysis/update_content_test.dart b/pkg/analysis_server/test/analysis/update_content_test.dart
index b817956..9051b35 100644
--- a/pkg/analysis_server/test/analysis/update_content_test.dart
+++ b/pkg/analysis_server/test/analysis/update_content_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_constants.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/test/analysis_abstract.dart b/pkg/analysis_server/test/analysis_abstract.dart
index 08ac90a..f2f5cf8 100644
--- a/pkg/analysis_server/test/analysis_abstract.dart
+++ b/pkg/analysis_server/test/analysis_abstract.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_constants.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart'
diff --git a/pkg/analysis_server/test/analysis_server_test.dart b/pkg/analysis_server/test/analysis_server_test.dart
index f99570b..50d0459 100644
--- a/pkg/analysis_server/test/analysis_server_test.dart
+++ b/pkg/analysis_server/test/analysis_server_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_constants.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/test/channel/byte_stream_channel_test.dart b/pkg/analysis_server/test/channel/byte_stream_channel_test.dart
index 717b50b..5d80b9b 100644
--- a/pkg/analysis_server/test/channel/byte_stream_channel_test.dart
+++ b/pkg/analysis_server/test/channel/byte_stream_channel_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
diff --git a/pkg/analysis_server/test/channel/test_all.dart b/pkg/analysis_server/test/channel/test_all.dart
index b712e00..689c931 100644
--- a/pkg/analysis_server/test/channel/test_all.dart
+++ b/pkg/analysis_server/test/channel/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 
 import 'byte_stream_channel_test.dart' as byte_stream_channel_test;
diff --git a/pkg/analysis_server/test/client/completion_driver_test.dart b/pkg/analysis_server/test/client/completion_driver_test.dart
index ace6ad3..4d6ee60 100644
--- a/pkg/analysis_server/test/client/completion_driver_test.dart
+++ b/pkg/analysis_server/test/client/completion_driver_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/services/completion/dart/utilities.dart';
 import 'package:analyzer/src/test_utilities/resource_provider_mixin.dart';
diff --git a/pkg/analysis_server/test/client/impl/abstract_client.dart b/pkg/analysis_server/test/client/impl/abstract_client.dart
index a8613f8..44e67e3 100644
--- a/pkg/analysis_server/test/client/impl/abstract_client.dart
+++ b/pkg/analysis_server/test/client/impl/abstract_client.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart'
     hide AnalysisOptions;
diff --git a/pkg/analysis_server/test/client/impl/completion_driver.dart b/pkg/analysis_server/test/client/impl/completion_driver.dart
index 3eabfb6..a4569aa 100644
--- a/pkg/analysis_server/test/client/impl/completion_driver.dart
+++ b/pkg/analysis_server/test/client/impl/completion_driver.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:math' as math;
 
diff --git a/pkg/analysis_server/test/client/impl/expect_mixin.dart b/pkg/analysis_server/test/client/impl/expect_mixin.dart
index 803a6858..7f8444e 100644
--- a/pkg/analysis_server/test/client/impl/expect_mixin.dart
+++ b/pkg/analysis_server/test/client/impl/expect_mixin.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:matcher/matcher.dart';
 
 typedef _Predicate<T> = bool Function(T value);
diff --git a/pkg/analysis_server/test/client/test_all.dart b/pkg/analysis_server/test/client/test_all.dart
index 417c4d3..7887a9d 100644
--- a/pkg/analysis_server/test/client/test_all.dart
+++ b/pkg/analysis_server/test/client/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'completion_driver_test.dart' as completion_driver;
diff --git a/pkg/analysis_server/test/completion_test.dart b/pkg/analysis_server/test/completion_test.dart
index 6a3b7d3..4cefdef 100644
--- a/pkg/analysis_server/test/completion_test.dart
+++ b/pkg/analysis_server/test/completion_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:collection';
 
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/completion_test_support.dart b/pkg/analysis_server/test/completion_test_support.dart
index 191aad3..83a70c8 100644
--- a/pkg/analysis_server/test/completion_test_support.dart
+++ b/pkg/analysis_server/test/completion_test_support.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:collection';
 
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
diff --git a/pkg/analysis_server/test/constants.dart b/pkg/analysis_server/test/constants.dart
index 8c6d848..274bdb5 100644
--- a/pkg/analysis_server/test/constants.dart
+++ b/pkg/analysis_server/test/constants.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 const String CODE = 'code';
 const String COMPLETION_RESULTS = 'completion.results';
 const String CONTEXT_MESSAGES = 'contextMessages';
diff --git a/pkg/analysis_server/test/domain_analysis_test.dart b/pkg/analysis_server/test/domain_analysis_test.dart
index 2138863..b05effd 100644
--- a/pkg/analysis_server/test/domain_analysis_test.dart
+++ b/pkg/analysis_server/test/domain_analysis_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/protocol/protocol.dart';
diff --git a/pkg/analysis_server/test/domain_completion_test.dart b/pkg/analysis_server/test/domain_completion_test.dart
index bfb2c73..e31fc32 100644
--- a/pkg/analysis_server/test/domain_completion_test.dart
+++ b/pkg/analysis_server/test/domain_completion_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/plugin/plugin_manager.dart';
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
diff --git a/pkg/analysis_server/test/domain_completion_util.dart b/pkg/analysis_server/test/domain_completion_util.dart
index 6d93dcf..1d2720a 100644
--- a/pkg/analysis_server/test/domain_completion_util.dart
+++ b/pkg/analysis_server/test/domain_completion_util.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/protocol/protocol.dart';
diff --git a/pkg/analysis_server/test/domain_diagnostic_test.dart b/pkg/analysis_server/test/domain_diagnostic_test.dart
index f6a615c..4f6860e 100644
--- a/pkg/analysis_server/test/domain_diagnostic_test.dart
+++ b/pkg/analysis_server/test/domain_diagnostic_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/domain_diagnostic.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/domain_edit_dartfix_test.dart b/pkg/analysis_server/test/domain_edit_dartfix_test.dart
index 0d639ac..a3b114c 100644
--- a/pkg/analysis_server/test/domain_edit_dartfix_test.dart
+++ b/pkg/analysis_server/test/domain_edit_dartfix_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/edit/edit_dartfix.dart';
diff --git a/pkg/analysis_server/test/domain_execution_test.dart b/pkg/analysis_server/test/domain_execution_test.dart
index b7b387c..ad5fb97 100644
--- a/pkg/analysis_server/test/domain_execution_test.dart
+++ b/pkg/analysis_server/test/domain_execution_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/domain_execution.dart';
diff --git a/pkg/analysis_server/test/domain_server_test.dart b/pkg/analysis_server/test/domain_server_test.dart
index 1ac94cc..9af7c95 100644
--- a/pkg/analysis_server/test/domain_server_test.dart
+++ b/pkg/analysis_server/test/domain_server_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_constants.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/test/edit/assists_test.dart b/pkg/analysis_server/test/edit/assists_test.dart
index 3ab55f3..93a35f0 100644
--- a/pkg/analysis_server/test/edit/assists_test.dart
+++ b/pkg/analysis_server/test/edit/assists_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/edit/edit_domain.dart';
 import 'package:analysis_server/src/plugin/plugin_manager.dart';
diff --git a/pkg/analysis_server/test/edit/bulk_fixes_test.dart b/pkg/analysis_server/test/edit/bulk_fixes_test.dart
index 1c9b46b..5d88990 100644
--- a/pkg/analysis_server/test/edit/bulk_fixes_test.dart
+++ b/pkg/analysis_server/test/edit/bulk_fixes_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io';
 
 import 'package:analysis_server/protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/test/edit/fixes_test.dart b/pkg/analysis_server/test/edit/fixes_test.dart
index db742d8..d037309 100644
--- a/pkg/analysis_server/test/edit/fixes_test.dart
+++ b/pkg/analysis_server/test/edit/fixes_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/edit/edit_domain.dart';
 import 'package:analysis_server/src/plugin/plugin_manager.dart';
diff --git a/pkg/analysis_server/test/edit/format_test.dart b/pkg/analysis_server/test/edit/format_test.dart
index ac5b566..bcab9d1 100644
--- a/pkg/analysis_server/test/edit/format_test.dart
+++ b/pkg/analysis_server/test/edit/format_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/edit/edit_domain.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/edit/organize_directives_test.dart b/pkg/analysis_server/test/edit/organize_directives_test.dart
index 4a775db..e81ca0e 100644
--- a/pkg/analysis_server/test/edit/organize_directives_test.dart
+++ b/pkg/analysis_server/test/edit/organize_directives_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/edit/edit_domain.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
diff --git a/pkg/analysis_server/test/edit/postfix_completion_test.dart b/pkg/analysis_server/test/edit/postfix_completion_test.dart
index 9f55b0f..7cbe83f 100644
--- a/pkg/analysis_server/test/edit/postfix_completion_test.dart
+++ b/pkg/analysis_server/test/edit/postfix_completion_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/edit/edit_domain.dart';
diff --git a/pkg/analysis_server/test/edit/refactoring_test.dart b/pkg/analysis_server/test/edit/refactoring_test.dart
index 015b081..24d8e02 100644
--- a/pkg/analysis_server/test/edit/refactoring_test.dart
+++ b/pkg/analysis_server/test/edit/refactoring_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/edit/edit_domain.dart';
diff --git a/pkg/analysis_server/test/edit/sort_members_test.dart b/pkg/analysis_server/test/edit/sort_members_test.dart
index bd226a2..083b834 100644
--- a/pkg/analysis_server/test/edit/sort_members_test.dart
+++ b/pkg/analysis_server/test/edit/sort_members_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/edit/edit_domain.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
diff --git a/pkg/analysis_server/test/edit/statement_completion_test.dart b/pkg/analysis_server/test/edit/statement_completion_test.dart
index db31cac..c442c9c 100644
--- a/pkg/analysis_server/test/edit/statement_completion_test.dart
+++ b/pkg/analysis_server/test/edit/statement_completion_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/edit/edit_domain.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
diff --git a/pkg/analysis_server/test/edit/test_all.dart b/pkg/analysis_server/test/edit/test_all.dart
index 21cf0bc..e1d5aec 100644
--- a/pkg/analysis_server/test/edit/test_all.dart
+++ b/pkg/analysis_server/test/edit/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'assists_test.dart' as assists;
diff --git a/pkg/analysis_server/test/integration/analysis/analysis_options_test.dart b/pkg/analysis_server/test/integration/analysis/analysis_options_test.dart
index 0324041..d0afbc3 100644
--- a/pkg/analysis_server/test/integration/analysis/analysis_options_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/analysis_options_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/src/util/file_paths.dart' as file_paths;
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/integration/analysis/error_test.dart b/pkg/analysis_server/test/integration/analysis/error_test.dart
index 9d503a2..b5d5fb7 100644
--- a/pkg/analysis_server/test/integration/analysis/error_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/error_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/integration/analysis/get_errors_non_standard_sdk_test.dart b/pkg/analysis_server/test/integration/analysis/get_errors_non_standard_sdk_test.dart
index e80f671..1b0de2d 100644
--- a/pkg/analysis_server/test/integration/analysis/get_errors_non_standard_sdk_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/get_errors_non_standard_sdk_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io';
 
 import 'package:path/path.dart' as path;
diff --git a/pkg/analysis_server/test/integration/analysis/get_errors_test.dart b/pkg/analysis_server/test/integration/analysis/get_errors_test.dart
index 260cb6c..61d8b52 100644
--- a/pkg/analysis_server/test/integration/analysis/get_errors_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/get_errors_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/analysis/get_hover_test.dart b/pkg/analysis_server/test/integration/analysis/get_hover_test.dart
index 385d923..6da5c92 100644
--- a/pkg/analysis_server/test/integration/analysis/get_hover_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/get_hover_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:path/path.dart' as path;
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/integration/analysis/get_imported_elements_test.dart b/pkg/analysis_server/test/integration/analysis/get_imported_elements_test.dart
index 436da25..6aac49a 100644
--- a/pkg/analysis_server/test/integration/analysis/get_imported_elements_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/get_imported_elements_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/domain_analysis.dart';
 import 'package:path/path.dart' as path;
diff --git a/pkg/analysis_server/test/integration/analysis/get_library_dependencies_test.dart b/pkg/analysis_server/test/integration/analysis/get_library_dependencies_test.dart
index 568b151..ff3fd0f 100644
--- a/pkg/analysis_server/test/integration/analysis/get_library_dependencies_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/get_library_dependencies_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/analysis/get_navigation_test.dart b/pkg/analysis_server/test/integration/analysis/get_navigation_test.dart
index 1288adb..fc0a57b 100644
--- a/pkg/analysis_server/test/integration/analysis/get_navigation_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/get_navigation_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/integration/analysis/get_reachable_sources_test.dart b/pkg/analysis_server/test/integration/analysis/get_reachable_sources_test.dart
index 0073bde..15309a6 100644
--- a/pkg/analysis_server/test/integration/analysis/get_reachable_sources_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/get_reachable_sources_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io';
 
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/integration/analysis/highlights_test.dart b/pkg/analysis_server/test/integration/analysis/highlights_test.dart
index 9dfcaf7..c4c8fe2 100644
--- a/pkg/analysis_server/test/integration/analysis/highlights_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/highlights_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/integration/analysis/hint_sdk_version_async_exported_from_core_test.dart b/pkg/analysis_server/test/integration/analysis/hint_sdk_version_async_exported_from_core_test.dart
index 38428ff..5398abf 100644
--- a/pkg/analysis_server/test/integration/analysis/hint_sdk_version_async_exported_from_core_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/hint_sdk_version_async_exported_from_core_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/analysis/lint_test.dart b/pkg/analysis_server/test/integration/analysis/lint_test.dart
index ffc3d8b..5b11ea0 100644
--- a/pkg/analysis_server/test/integration/analysis/lint_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/lint_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/src/util/file_paths.dart' as file_paths;
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/integration/analysis/navigation_test.dart b/pkg/analysis_server/test/integration/analysis/navigation_test.dart
index b913d75..763097e 100644
--- a/pkg/analysis_server/test/integration/analysis/navigation_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/navigation_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/integration/analysis/occurrences_test.dart b/pkg/analysis_server/test/integration/analysis/occurrences_test.dart
index 112445a..0332e23 100644
--- a/pkg/analysis_server/test/integration/analysis/occurrences_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/occurrences_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/integration/analysis/outline_test.dart b/pkg/analysis_server/test/integration/analysis/outline_test.dart
index 7271ce6..bc498f8 100644
--- a/pkg/analysis_server/test/integration/analysis/outline_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/outline_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/integration/analysis/overrides_test.dart b/pkg/analysis_server/test/integration/analysis/overrides_test.dart
index dc3167f..912ac03 100644
--- a/pkg/analysis_server/test/integration/analysis/overrides_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/overrides_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/integration/analysis/package_root_test.dart b/pkg/analysis_server/test/integration/analysis/package_root_test.dart
index 3bb2096..6c7801b 100644
--- a/pkg/analysis_server/test/integration/analysis/package_root_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/package_root_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:path/path.dart' as path;
diff --git a/pkg/analysis_server/test/integration/analysis/reanalyze_concurrent_test.dart b/pkg/analysis_server/test/integration/analysis/reanalyze_concurrent_test.dart
index 1a42362..7cf4371 100644
--- a/pkg/analysis_server/test/integration/analysis/reanalyze_concurrent_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/reanalyze_concurrent_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// This test verifies that if reanalysis is performed while reanalysis is in
 /// progress, no problems occur.
 ///
diff --git a/pkg/analysis_server/test/integration/analysis/reanalyze_test.dart b/pkg/analysis_server/test/integration/analysis/reanalyze_test.dart
index 064d578..ddfd145 100644
--- a/pkg/analysis_server/test/integration/analysis/reanalyze_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/reanalyze_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/integration/analysis/set_analysis_roots_test.dart b/pkg/analysis_server/test/integration/analysis/set_analysis_roots_test.dart
index c8b991d..2ef9e06 100644
--- a/pkg/analysis_server/test/integration/analysis/set_analysis_roots_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/set_analysis_roots_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/analysis/set_general_subscriptions_test.dart b/pkg/analysis_server/test/integration/analysis/set_general_subscriptions_test.dart
index 18cc929..3523f2a 100644
--- a/pkg/analysis_server/test/integration/analysis/set_general_subscriptions_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/set_general_subscriptions_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:path/path.dart' show join;
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/integration/analysis/set_priority_files_test.dart b/pkg/analysis_server/test/integration/analysis/set_priority_files_test.dart
index a7151cf..01898a7 100644
--- a/pkg/analysis_server/test/integration/analysis/set_priority_files_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/set_priority_files_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/analysis/set_subscriptions_test.dart b/pkg/analysis_server/test/integration/analysis/set_subscriptions_test.dart
index d9d22d0..bfb9365 100644
--- a/pkg/analysis_server/test/integration/analysis/set_subscriptions_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/set_subscriptions_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/analysis/test_all.dart b/pkg/analysis_server/test/integration/analysis/test_all.dart
index 2e463f0..7bb5fd1 100644
--- a/pkg/analysis_server/test/integration/analysis/test_all.dart
+++ b/pkg/analysis_server/test/integration/analysis/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'analysis_options_test.dart' as analysis_options_test;
diff --git a/pkg/analysis_server/test/integration/analysis/update_content_list_test.dart b/pkg/analysis_server/test/integration/analysis/update_content_list_test.dart
index 40c015c..adb66f3 100644
--- a/pkg/analysis_server/test/integration/analysis/update_content_list_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/update_content_list_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/integration/analysis/update_content_test.dart b/pkg/analysis_server/test/integration/analysis/update_content_test.dart
index 9ab0807..5760287 100644
--- a/pkg/analysis_server/test/integration/analysis/update_content_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/update_content_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/integration/analysis/update_options_test.dart b/pkg/analysis_server/test/integration/analysis/update_options_test.dart
index 4864f2c..cd18c90 100644
--- a/pkg/analysis_server/test/integration/analysis/update_options_test.dart
+++ b/pkg/analysis_server/test/integration/analysis/update_options_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/integration/analytics/enable_test.dart b/pkg/analysis_server/test/integration/analytics/enable_test.dart
index 780810e..0a7b44a 100644
--- a/pkg/analysis_server/test/integration/analytics/enable_test.dart
+++ b/pkg/analysis_server/test/integration/analytics/enable_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/analytics/is_enabled_test.dart b/pkg/analysis_server/test/integration/analytics/is_enabled_test.dart
index 0f86bfe..721a495 100644
--- a/pkg/analysis_server/test/integration/analytics/is_enabled_test.dart
+++ b/pkg/analysis_server/test/integration/analytics/is_enabled_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/analytics/send_event_test.dart b/pkg/analysis_server/test/integration/analytics/send_event_test.dart
index 5f5aefe..edf7c38 100644
--- a/pkg/analysis_server/test/integration/analytics/send_event_test.dart
+++ b/pkg/analysis_server/test/integration/analytics/send_event_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import '../support/integration_tests.dart';
diff --git a/pkg/analysis_server/test/integration/analytics/send_timing_test.dart b/pkg/analysis_server/test/integration/analytics/send_timing_test.dart
index 8e74028..6154b53 100644
--- a/pkg/analysis_server/test/integration/analytics/send_timing_test.dart
+++ b/pkg/analysis_server/test/integration/analytics/send_timing_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import '../support/integration_tests.dart';
diff --git a/pkg/analysis_server/test/integration/analytics/test_all.dart b/pkg/analysis_server/test/integration/analytics/test_all.dart
index 4781bad..3699d0c 100644
--- a/pkg/analysis_server/test/integration/analytics/test_all.dart
+++ b/pkg/analysis_server/test/integration/analytics/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'enable_test.dart' as enable_test;
diff --git a/pkg/analysis_server/test/integration/completion/get_suggestions_test.dart b/pkg/analysis_server/test/integration/completion/get_suggestions_test.dart
index 1dd38a1..8c982b5 100644
--- a/pkg/analysis_server/test/integration/completion/get_suggestions_test.dart
+++ b/pkg/analysis_server/test/integration/completion/get_suggestions_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/integration/completion/test_all.dart b/pkg/analysis_server/test/integration/completion/test_all.dart
index 857202f..54aa987 100644
--- a/pkg/analysis_server/test/integration/completion/test_all.dart
+++ b/pkg/analysis_server/test/integration/completion/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'get_suggestions_test.dart' as get_suggestions;
diff --git a/pkg/analysis_server/test/integration/coverage_test.dart b/pkg/analysis_server/test/integration/coverage_test.dart
index 73caa7a..db49f18 100644
--- a/pkg/analysis_server/test/integration/coverage_test.dart
+++ b/pkg/analysis_server/test/integration/coverage_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io';
 
 import 'package:analyzer_plugin/src/utilities/string_utilities.dart';
diff --git a/pkg/analysis_server/test/integration/diagnostic/get_diagnostics_test.dart b/pkg/analysis_server/test/integration/diagnostic/get_diagnostics_test.dart
index 84b84ae..8b6fb64 100644
--- a/pkg/analysis_server/test/integration/diagnostic/get_diagnostics_test.dart
+++ b/pkg/analysis_server/test/integration/diagnostic/get_diagnostics_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/diagnostic/get_server_port_test.dart b/pkg/analysis_server/test/integration/diagnostic/get_server_port_test.dart
index 42541e2..8efd679 100644
--- a/pkg/analysis_server/test/integration/diagnostic/get_server_port_test.dart
+++ b/pkg/analysis_server/test/integration/diagnostic/get_server_port_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 import 'dart:io';
 
diff --git a/pkg/analysis_server/test/integration/diagnostic/test_all.dart b/pkg/analysis_server/test/integration/diagnostic/test_all.dart
index 50293e2..0b76085 100644
--- a/pkg/analysis_server/test/integration/diagnostic/test_all.dart
+++ b/pkg/analysis_server/test/integration/diagnostic/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'get_diagnostics_test.dart' as get_diagnostics_test;
diff --git a/pkg/analysis_server/test/integration/edit/bulk_fixes_test.dart b/pkg/analysis_server/test/integration/edit/bulk_fixes_test.dart
index 4c4d82d..0a9f574 100644
--- a/pkg/analysis_server/test/integration/edit/bulk_fixes_test.dart
+++ b/pkg/analysis_server/test/integration/edit/bulk_fixes_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/src/util/file_paths.dart' as file_paths;
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/integration/edit/dartfix_test.dart b/pkg/analysis_server/test/integration/edit/dartfix_test.dart
index 7029973..1422a4c 100644
--- a/pkg/analysis_server/test/integration/edit/dartfix_test.dart
+++ b/pkg/analysis_server/test/integration/edit/dartfix_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/edit/format_test.dart b/pkg/analysis_server/test/integration/edit/format_test.dart
index 081d9fc..25975e3 100644
--- a/pkg/analysis_server/test/integration/edit/format_test.dart
+++ b/pkg/analysis_server/test/integration/edit/format_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/edit/get_assists_test.dart b/pkg/analysis_server/test/integration/edit/get_assists_test.dart
index 015a385..de4bb79 100644
--- a/pkg/analysis_server/test/integration/edit/get_assists_test.dart
+++ b/pkg/analysis_server/test/integration/edit/get_assists_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/integration/edit/get_available_refactorings_test.dart b/pkg/analysis_server/test/integration/edit/get_available_refactorings_test.dart
index 79b7389..08d3275 100644
--- a/pkg/analysis_server/test/integration/edit/get_available_refactorings_test.dart
+++ b/pkg/analysis_server/test/integration/edit/get_available_refactorings_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/edit/get_dartfix_info_test.dart b/pkg/analysis_server/test/integration/edit/get_dartfix_info_test.dart
index 3d3bf9f..a924cc3 100644
--- a/pkg/analysis_server/test/integration/edit/get_dartfix_info_test.dart
+++ b/pkg/analysis_server/test/integration/edit/get_dartfix_info_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/edit/get_fixes_test.dart b/pkg/analysis_server/test/integration/edit/get_fixes_test.dart
index 6610ea2..f6ef4e9 100644
--- a/pkg/analysis_server/test/integration/edit/get_fixes_test.dart
+++ b/pkg/analysis_server/test/integration/edit/get_fixes_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/integration/edit/get_postfix_completion_test.dart b/pkg/analysis_server/test/integration/edit/get_postfix_completion_test.dart
index db032ec..356a4e6 100644
--- a/pkg/analysis_server/test/integration/edit/get_postfix_completion_test.dart
+++ b/pkg/analysis_server/test/integration/edit/get_postfix_completion_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/integration/edit/get_refactoring_test.dart b/pkg/analysis_server/test/integration/edit/get_refactoring_test.dart
index 81b5e22..a96db43 100644
--- a/pkg/analysis_server/test/integration/edit/get_refactoring_test.dart
+++ b/pkg/analysis_server/test/integration/edit/get_refactoring_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/integration/edit/get_statement_completion_test.dart b/pkg/analysis_server/test/integration/edit/get_statement_completion_test.dart
index 5c3ce3e..9f4465f 100644
--- a/pkg/analysis_server/test/integration/edit/get_statement_completion_test.dart
+++ b/pkg/analysis_server/test/integration/edit/get_statement_completion_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/integration/edit/import_elements_test.dart b/pkg/analysis_server/test/integration/edit/import_elements_test.dart
index 06ab05f..f55d0ac 100644
--- a/pkg/analysis_server/test/integration/edit/import_elements_test.dart
+++ b/pkg/analysis_server/test/integration/edit/import_elements_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analyzer/file_system/physical_file_system.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
diff --git a/pkg/analysis_server/test/integration/edit/is_postfix_completion_applicable_test.dart b/pkg/analysis_server/test/integration/edit/is_postfix_completion_applicable_test.dart
index af423d1..5a4620b 100644
--- a/pkg/analysis_server/test/integration/edit/is_postfix_completion_applicable_test.dart
+++ b/pkg/analysis_server/test/integration/edit/is_postfix_completion_applicable_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/edit/list_postfix_completion_templates_test.dart b/pkg/analysis_server/test/integration/edit/list_postfix_completion_templates_test.dart
index 21f950d..1af3946 100644
--- a/pkg/analysis_server/test/integration/edit/list_postfix_completion_templates_test.dart
+++ b/pkg/analysis_server/test/integration/edit/list_postfix_completion_templates_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/integration/edit/organize_directives_test.dart b/pkg/analysis_server/test/integration/edit/organize_directives_test.dart
index 2bf4c1f..c43c5ee 100644
--- a/pkg/analysis_server/test/integration/edit/organize_directives_test.dart
+++ b/pkg/analysis_server/test/integration/edit/organize_directives_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/edit/sort_members_test.dart b/pkg/analysis_server/test/integration/edit/sort_members_test.dart
index a49aca3..bba0bc6 100644
--- a/pkg/analysis_server/test/integration/edit/sort_members_test.dart
+++ b/pkg/analysis_server/test/integration/edit/sort_members_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/edit/test_all.dart b/pkg/analysis_server/test/integration/edit/test_all.dart
index 5c3a653..e61e3b7 100644
--- a/pkg/analysis_server/test/integration/edit/test_all.dart
+++ b/pkg/analysis_server/test/integration/edit/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'bulk_fixes_test.dart' as bulk_fixes_test;
diff --git a/pkg/analysis_server/test/integration/execution/create_context_test.dart b/pkg/analysis_server/test/integration/execution/create_context_test.dart
index 563e405..3a938cd 100644
--- a/pkg/analysis_server/test/integration/execution/create_context_test.dart
+++ b/pkg/analysis_server/test/integration/execution/create_context_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/execution/delete_context_test.dart b/pkg/analysis_server/test/integration/execution/delete_context_test.dart
index 4087c06..0e84d3e 100644
--- a/pkg/analysis_server/test/integration/execution/delete_context_test.dart
+++ b/pkg/analysis_server/test/integration/execution/delete_context_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/execution/map_uri_test.dart b/pkg/analysis_server/test/integration/execution/map_uri_test.dart
index 98f9e7e..1efe500 100644
--- a/pkg/analysis_server/test/integration/execution/map_uri_test.dart
+++ b/pkg/analysis_server/test/integration/execution/map_uri_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/execution/set_subscriptions_test.dart b/pkg/analysis_server/test/integration/execution/set_subscriptions_test.dart
index 340ded4..3e328f2 100644
--- a/pkg/analysis_server/test/integration/execution/set_subscriptions_test.dart
+++ b/pkg/analysis_server/test/integration/execution/set_subscriptions_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/execution/test_all.dart b/pkg/analysis_server/test/integration/execution/test_all.dart
index 76aa11d..9214e0d 100644
--- a/pkg/analysis_server/test/integration/execution/test_all.dart
+++ b/pkg/analysis_server/test/integration/execution/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'create_context_test.dart' as create_context_test;
diff --git a/pkg/analysis_server/test/integration/kythe/get_kythe_entries_test.dart b/pkg/analysis_server/test/integration/kythe/get_kythe_entries_test.dart
index 00719b3..a4a3a5f 100644
--- a/pkg/analysis_server/test/integration/kythe/get_kythe_entries_test.dart
+++ b/pkg/analysis_server/test/integration/kythe/get_kythe_entries_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/kythe/test_all.dart b/pkg/analysis_server/test/integration/kythe/test_all.dart
index c50b940..f63a340 100644
--- a/pkg/analysis_server/test/integration/kythe/test_all.dart
+++ b/pkg/analysis_server/test/integration/kythe/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'get_kythe_entries_test.dart' as get_kythe_entries_test;
diff --git a/pkg/analysis_server/test/integration/linter/lint_names_test.dart b/pkg/analysis_server/test/integration/linter/lint_names_test.dart
index f36937a..cc57c3d 100644
--- a/pkg/analysis_server/test/integration/linter/lint_names_test.dart
+++ b/pkg/analysis_server/test/integration/linter/lint_names_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io';
 
 import 'package:analyzer/dart/analysis/features.dart';
diff --git a/pkg/analysis_server/test/integration/linter/test_all.dart b/pkg/analysis_server/test/integration/linter/test_all.dart
index addcf98..833b9ae 100644
--- a/pkg/analysis_server/test/integration/linter/test_all.dart
+++ b/pkg/analysis_server/test/integration/linter/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'lint_names_test.dart' as lint_names;
diff --git a/pkg/analysis_server/test/integration/lsp_server/analyzer_status_test.dart b/pkg/analysis_server/test/integration/lsp_server/analyzer_status_test.dart
index 0184100..94f3328 100644
--- a/pkg/analysis_server/test/integration/lsp_server/analyzer_status_test.dart
+++ b/pkg/analysis_server/test/integration/lsp_server/analyzer_status_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/lsp_server/diagnostic_test.dart b/pkg/analysis_server/test/integration/lsp_server/diagnostic_test.dart
index 0763cda..7f9a527 100644
--- a/pkg/analysis_server/test/integration/lsp_server/diagnostic_test.dart
+++ b/pkg/analysis_server/test/integration/lsp_server/diagnostic_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/lsp_server/initialization_test.dart b/pkg/analysis_server/test/integration/lsp_server/initialization_test.dart
index 1759e58..422086a 100644
--- a/pkg/analysis_server/test/integration/lsp_server/initialization_test.dart
+++ b/pkg/analysis_server/test/integration/lsp_server/initialization_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/integration/lsp_server/integration_tests.dart b/pkg/analysis_server/test/integration/lsp_server/integration_tests.dart
index bd8a64f..fa871ff 100644
--- a/pkg/analysis_server/test/integration/lsp_server/integration_tests.dart
+++ b/pkg/analysis_server/test/integration/lsp_server/integration_tests.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:io';
 
diff --git a/pkg/analysis_server/test/integration/lsp_server/server_test.dart b/pkg/analysis_server/test/integration/lsp_server/server_test.dart
index 8ceb281..2771564 100644
--- a/pkg/analysis_server/test/integration/lsp_server/server_test.dart
+++ b/pkg/analysis_server/test/integration/lsp_server/server_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 import 'dart:io';
 
diff --git a/pkg/analysis_server/test/integration/lsp_server/test_all.dart b/pkg/analysis_server/test/integration/lsp_server/test_all.dart
index 3c85a81..2a5741e 100644
--- a/pkg/analysis_server/test/integration/lsp_server/test_all.dart
+++ b/pkg/analysis_server/test/integration/lsp_server/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'analyzer_status_test.dart' as analyzer_status;
diff --git a/pkg/analysis_server/test/integration/search/find_element_references_test.dart b/pkg/analysis_server/test/integration/search/find_element_references_test.dart
index c0d758a..f74346b 100644
--- a/pkg/analysis_server/test/integration/search/find_element_references_test.dart
+++ b/pkg/analysis_server/test/integration/search/find_element_references_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/integration/search/find_member_declarations_test.dart b/pkg/analysis_server/test/integration/search/find_member_declarations_test.dart
index 74fab07..71d4557 100644
--- a/pkg/analysis_server/test/integration/search/find_member_declarations_test.dart
+++ b/pkg/analysis_server/test/integration/search/find_member_declarations_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/integration/search/find_member_references_test.dart b/pkg/analysis_server/test/integration/search/find_member_references_test.dart
index 249a3ba..209c1ec 100644
--- a/pkg/analysis_server/test/integration/search/find_member_references_test.dart
+++ b/pkg/analysis_server/test/integration/search/find_member_references_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/integration/search/find_top_level_declarations_test.dart b/pkg/analysis_server/test/integration/search/find_top_level_declarations_test.dart
index 79d3eb8..8185e1a 100644
--- a/pkg/analysis_server/test/integration/search/find_top_level_declarations_test.dart
+++ b/pkg/analysis_server/test/integration/search/find_top_level_declarations_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/integration/search/get_type_hierarchy_test.dart b/pkg/analysis_server/test/integration/search/get_type_hierarchy_test.dart
index 0003214..5c5c6d5 100644
--- a/pkg/analysis_server/test/integration/search/get_type_hierarchy_test.dart
+++ b/pkg/analysis_server/test/integration/search/get_type_hierarchy_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/integration/search/test_all.dart b/pkg/analysis_server/test/integration/search/test_all.dart
index b39f490..e95e3f5 100644
--- a/pkg/analysis_server/test/integration/search/test_all.dart
+++ b/pkg/analysis_server/test/integration/search/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'find_element_references_test.dart' as find_element_references_test;
diff --git a/pkg/analysis_server/test/integration/server/bazel_changes_test.dart b/pkg/analysis_server/test/integration/server/bazel_changes_test.dart
index eadac35..9b64519 100644
--- a/pkg/analysis_server/test/integration/server/bazel_changes_test.dart
+++ b/pkg/analysis_server/test/integration/server/bazel_changes_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:io';
 
diff --git a/pkg/analysis_server/test/integration/server/get_version_test.dart b/pkg/analysis_server/test/integration/server/get_version_test.dart
index a82ea75..d1c3428 100644
--- a/pkg/analysis_server/test/integration/server/get_version_test.dart
+++ b/pkg/analysis_server/test/integration/server/get_version_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import '../support/integration_tests.dart';
diff --git a/pkg/analysis_server/test/integration/server/set_subscriptions_invalid_service_test.dart b/pkg/analysis_server/test/integration/server/set_subscriptions_invalid_service_test.dart
index afb3195..f25b46c 100644
--- a/pkg/analysis_server/test/integration/server/set_subscriptions_invalid_service_test.dart
+++ b/pkg/analysis_server/test/integration/server/set_subscriptions_invalid_service_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/server/set_subscriptions_test.dart b/pkg/analysis_server/test/integration/server/set_subscriptions_test.dart
index 9a7078b..2ea390e 100644
--- a/pkg/analysis_server/test/integration/server/set_subscriptions_test.dart
+++ b/pkg/analysis_server/test/integration/server/set_subscriptions_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/test/integration/server/shutdown_test.dart b/pkg/analysis_server/test/integration/server/shutdown_test.dart
index a14e573..cee3a55 100644
--- a/pkg/analysis_server/test/integration/server/shutdown_test.dart
+++ b/pkg/analysis_server/test/integration/server/shutdown_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/integration/server/status_test.dart b/pkg/analysis_server/test/integration/server/status_test.dart
index 1fdf46b..020b6b64 100644
--- a/pkg/analysis_server/test/integration/server/status_test.dart
+++ b/pkg/analysis_server/test/integration/server/status_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/test/integration/server/test_all.dart b/pkg/analysis_server/test/integration/server/test_all.dart
index 92ae2b1..cc55441 100644
--- a/pkg/analysis_server/test/integration/server/test_all.dart
+++ b/pkg/analysis_server/test/integration/server/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'bazel_changes_test.dart' as bazel_changes_test;
diff --git a/pkg/analysis_server/test/integration/support/integration_test_methods.dart b/pkg/analysis_server/test/integration/support/integration_test_methods.dart
index b086276c4..5a1688c 100644
--- a/pkg/analysis_server/test/integration/support/integration_test_methods.dart
+++ b/pkg/analysis_server/test/integration/support/integration_test_methods.dart
@@ -6,6 +6,8 @@
 // To regenerate the file, use the script
 // "pkg/analysis_server/tool/spec/generate_files".
 
+// @dart = 2.9
+
 /// Convenience methods for running integration tests.
 import 'dart:async';
 
diff --git a/pkg/analysis_server/test/integration/support/integration_tests.dart b/pkg/analysis_server/test/integration/support/integration_tests.dart
index 69a4804..fa6d958 100644
--- a/pkg/analysis_server/test/integration/support/integration_tests.dart
+++ b/pkg/analysis_server/test/integration/support/integration_tests.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:collection';
 import 'dart:convert';
diff --git a/pkg/analysis_server/test/integration/support/protocol_matchers.dart b/pkg/analysis_server/test/integration/support/protocol_matchers.dart
index 4a8e453..2d11af9 100644
--- a/pkg/analysis_server/test/integration/support/protocol_matchers.dart
+++ b/pkg/analysis_server/test/integration/support/protocol_matchers.dart
@@ -6,6 +6,8 @@
 // To regenerate the file, use the script
 // "pkg/analysis_server/tool/spec/generate_files".
 
+// @dart = 2.9
+
 /// Matchers for data types defined in the analysis server API.
 import 'package:test/test.dart';
 
diff --git a/pkg/analysis_server/test/integration/test_all.dart b/pkg/analysis_server/test/integration/test_all.dart
index 9ef661b..5ed27bc1 100644
--- a/pkg/analysis_server/test/integration/test_all.dart
+++ b/pkg/analysis_server/test/integration/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'analysis/test_all.dart' as analysis;
diff --git a/pkg/analysis_server/test/lsp/analyzer_status_test.dart b/pkg/analysis_server/test/lsp/analyzer_status_test.dart
index 40cb5e4..8d1492a 100644
--- a/pkg/analysis_server/test/lsp/analyzer_status_test.dart
+++ b/pkg/analysis_server/test/lsp/analyzer_status_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/lsp/cancel_request_test.dart b/pkg/analysis_server/test/lsp/cancel_request_test.dart
index f39dff9..6780145 100644
--- a/pkg/analysis_server/test/lsp/cancel_request_test.dart
+++ b/pkg/analysis_server/test/lsp/cancel_request_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/lsp/change_workspace_folders_test.dart b/pkg/analysis_server/test/lsp/change_workspace_folders_test.dart
index 414c52d..9bec4ca 100644
--- a/pkg/analysis_server/test/lsp/change_workspace_folders_test.dart
+++ b/pkg/analysis_server/test/lsp/change_workspace_folders_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/lsp/closing_labels_test.dart b/pkg/analysis_server/test/lsp/closing_labels_test.dart
index 4a671a6..3a400e1 100644
--- a/pkg/analysis_server/test/lsp/closing_labels_test.dart
+++ b/pkg/analysis_server/test/lsp/closing_labels_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/lsp/code_actions_abstract.dart b/pkg/analysis_server/test/lsp/code_actions_abstract.dart
index 67d220b..ee4ca4d 100644
--- a/pkg/analysis_server/test/lsp/code_actions_abstract.dart
+++ b/pkg/analysis_server/test/lsp/code_actions_abstract.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/lsp/code_actions_assists_test.dart b/pkg/analysis_server/test/lsp/code_actions_assists_test.dart
index b70a2c2..69e627b 100644
--- a/pkg/analysis_server/test/lsp/code_actions_assists_test.dart
+++ b/pkg/analysis_server/test/lsp/code_actions_assists_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_custom_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
diff --git a/pkg/analysis_server/test/lsp/code_actions_fixes_test.dart b/pkg/analysis_server/test/lsp/code_actions_fixes_test.dart
index abc67e7..8e6ba91 100644
--- a/pkg/analysis_server/test/lsp/code_actions_fixes_test.dart
+++ b/pkg/analysis_server/test/lsp/code_actions_fixes_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:linter/src/rules.dart';
 import 'package:path/path.dart' as path;
diff --git a/pkg/analysis_server/test/lsp/code_actions_refactor_test.dart b/pkg/analysis_server/test/lsp/code_actions_refactor_test.dart
index e6d10cc..1301230 100644
--- a/pkg/analysis_server/test/lsp/code_actions_refactor_test.dart
+++ b/pkg/analysis_server/test/lsp/code_actions_refactor_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/test/lsp/code_actions_source_test.dart b/pkg/analysis_server/test/lsp/code_actions_source_test.dart
index 9a75e7e..0d0ca6e 100644
--- a/pkg/analysis_server/test/lsp/code_actions_source_test.dart
+++ b/pkg/analysis_server/test/lsp/code_actions_source_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/lsp/completion.dart b/pkg/analysis_server/test/lsp/completion.dart
index f1f5b9a..2e1e1e2 100644
--- a/pkg/analysis_server/test/lsp/completion.dart
+++ b/pkg/analysis_server/test/lsp/completion.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:test/test.dart';
 
diff --git a/pkg/analysis_server/test/lsp/completion_dart_test.dart b/pkg/analysis_server/test/lsp/completion_dart_test.dart
index 4ad9170..07e00ed 100644
--- a/pkg/analysis_server/test/lsp/completion_dart_test.dart
+++ b/pkg/analysis_server/test/lsp/completion_dart_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart' as plugin;
diff --git a/pkg/analysis_server/test/lsp/completion_yaml_test.dart b/pkg/analysis_server/test/lsp/completion_yaml_test.dart
index 9a9da49..a00dce5 100644
--- a/pkg/analysis_server/test/lsp/completion_yaml_test.dart
+++ b/pkg/analysis_server/test/lsp/completion_yaml_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/pub/pub_api.dart';
 import 'package:http/http.dart';
 import 'package:linter/src/rules.dart';
diff --git a/pkg/analysis_server/test/lsp/configuration_test.dart b/pkg/analysis_server/test/lsp/configuration_test.dart
index 2c91650..980af42 100644
--- a/pkg/analysis_server/test/lsp/configuration_test.dart
+++ b/pkg/analysis_server/test/lsp/configuration_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/lsp/definition_test.dart b/pkg/analysis_server/test/lsp/definition_test.dart
index d64412c..f78d059 100644
--- a/pkg/analysis_server/test/lsp/definition_test.dart
+++ b/pkg/analysis_server/test/lsp/definition_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart' as lsp;
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:analyzer_plugin/protocol/protocol_generated.dart' as plugin;
diff --git a/pkg/analysis_server/test/lsp/diagnostic_test.dart b/pkg/analysis_server/test/lsp/diagnostic_test.dart
index 741c410..46ace8a 100644
--- a/pkg/analysis_server/test/lsp/diagnostic_test.dart
+++ b/pkg/analysis_server/test/lsp/diagnostic_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart' as plugin;
diff --git a/pkg/analysis_server/test/lsp/document_changes_test.dart b/pkg/analysis_server/test/lsp/document_changes_test.dart
index a674b75..0c8f181 100644
--- a/pkg/analysis_server/test/lsp/document_changes_test.dart
+++ b/pkg/analysis_server/test/lsp/document_changes_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/test/lsp/document_highlights_test.dart b/pkg/analysis_server/test/lsp/document_highlights_test.dart
index 68b147d..1812f86 100644
--- a/pkg/analysis_server/test/lsp/document_highlights_test.dart
+++ b/pkg/analysis_server/test/lsp/document_highlights_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/lsp/document_symbols_test.dart b/pkg/analysis_server/test/lsp/document_symbols_test.dart
index fa1e3e0..1883728 100644
--- a/pkg/analysis_server/test/lsp/document_symbols_test.dart
+++ b/pkg/analysis_server/test/lsp/document_symbols_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/lsp/file_modification_test.dart b/pkg/analysis_server/test/lsp/file_modification_test.dart
index 3c9dac5..5f5e747 100644
--- a/pkg/analysis_server/test/lsp/file_modification_test.dart
+++ b/pkg/analysis_server/test/lsp/file_modification_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/lsp/flutter_outline_test.dart b/pkg/analysis_server/test/lsp/flutter_outline_test.dart
index 5ece2b69..60bb110 100644
--- a/pkg/analysis_server/test/lsp/flutter_outline_test.dart
+++ b/pkg/analysis_server/test/lsp/flutter_outline_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/lsp/folding_test.dart b/pkg/analysis_server/test/lsp/folding_test.dart
index 8b4e389..bea190d 100644
--- a/pkg/analysis_server/test/lsp/folding_test.dart
+++ b/pkg/analysis_server/test/lsp/folding_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart' as plugin;
 import 'package:analyzer_plugin/protocol/protocol_generated.dart' as plugin;
diff --git a/pkg/analysis_server/test/lsp/format_test.dart b/pkg/analysis_server/test/lsp/format_test.dart
index e629a4d..ad5bb9c 100644
--- a/pkg/analysis_server/test/lsp/format_test.dart
+++ b/pkg/analysis_server/test/lsp/format_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/lsp/hover_test.dart b/pkg/analysis_server/test/lsp/hover_test.dart
index de40613..0be55c5 100644
--- a/pkg/analysis_server/test/lsp/hover_test.dart
+++ b/pkg/analysis_server/test/lsp/hover_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/lsp/implementation_test.dart b/pkg/analysis_server/test/lsp/implementation_test.dart
index 195b46b..63cc7f8 100644
--- a/pkg/analysis_server/test/lsp/implementation_test.dart
+++ b/pkg/analysis_server/test/lsp/implementation_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/lsp/initialization_test.dart b/pkg/analysis_server/test/lsp/initialization_test.dart
index f864ea6..032df8d 100644
--- a/pkg/analysis_server/test/lsp/initialization_test.dart
+++ b/pkg/analysis_server/test/lsp/initialization_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
diff --git a/pkg/analysis_server/test/lsp/mapping_test.dart b/pkg/analysis_server/test/lsp/mapping_test.dart
index ce08941..6c89580 100644
--- a/pkg/analysis_server/test/lsp/mapping_test.dart
+++ b/pkg/analysis_server/test/lsp/mapping_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart' as lsp;
 import 'package:analysis_server/src/lsp/mapping.dart' as lsp;
 import 'package:analysis_server/src/protocol_server.dart' as server;
diff --git a/pkg/analysis_server/test/lsp/outline_test.dart b/pkg/analysis_server/test/lsp/outline_test.dart
index 8ab0aa3..1c04b0c 100644
--- a/pkg/analysis_server/test/lsp/outline_test.dart
+++ b/pkg/analysis_server/test/lsp/outline_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/lsp/priority_files_test.dart b/pkg/analysis_server/test/lsp/priority_files_test.dart
index 028f903..8d5107c 100644
--- a/pkg/analysis_server/test/lsp/priority_files_test.dart
+++ b/pkg/analysis_server/test/lsp/priority_files_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/lsp/pub_package_service_test.dart b/pkg/analysis_server/test/lsp/pub_package_service_test.dart
index f76aaa9..f40f50a 100644
--- a/pkg/analysis_server/test/lsp/pub_package_service_test.dart
+++ b/pkg/analysis_server/test/lsp/pub_package_service_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/pub/pub_api.dart';
 import 'package:analysis_server/src/services/pub/pub_package_service.dart';
 import 'package:analyzer/instrumentation/service.dart';
diff --git a/pkg/analysis_server/test/lsp/reanalyze_test.dart b/pkg/analysis_server/test/lsp/reanalyze_test.dart
index 69afce8..150c8a0 100644
--- a/pkg/analysis_server/test/lsp/reanalyze_test.dart
+++ b/pkg/analysis_server/test/lsp/reanalyze_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/lsp/references_test.dart b/pkg/analysis_server/test/lsp/references_test.dart
index 350de59..9af7eef 100644
--- a/pkg/analysis_server/test/lsp/references_test.dart
+++ b/pkg/analysis_server/test/lsp/references_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/lsp/rename_test.dart b/pkg/analysis_server/test/lsp/rename_test.dart
index 6c14e48..a65a4ef 100644
--- a/pkg/analysis_server/test/lsp/rename_test.dart
+++ b/pkg/analysis_server/test/lsp/rename_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
 import 'package:meta/meta.dart';
diff --git a/pkg/analysis_server/test/lsp/semantic_tokens_test.dart b/pkg/analysis_server/test/lsp/semantic_tokens_test.dart
index dfd4324..b97795e 100644
--- a/pkg/analysis_server/test/lsp/semantic_tokens_test.dart
+++ b/pkg/analysis_server/test/lsp/semantic_tokens_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/src/lsp/constants.dart';
 import 'package:analysis_server/src/lsp/semantic_tokens/legend.dart';
diff --git a/pkg/analysis_server/test/lsp/server_abstract.dart b/pkg/analysis_server/test/lsp/server_abstract.dart
index dd35465..663687b 100644
--- a/pkg/analysis_server/test/lsp/server_abstract.dart
+++ b/pkg/analysis_server/test/lsp/server_abstract.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/lsp_protocol/protocol_custom_generated.dart';
diff --git a/pkg/analysis_server/test/lsp/server_test.dart b/pkg/analysis_server/test/lsp/server_test.dart
index 8b0bd596..07858b3 100644
--- a/pkg/analysis_server/test/lsp/server_test.dart
+++ b/pkg/analysis_server/test/lsp/server_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/lsp/signature_help_test.dart b/pkg/analysis_server/test/lsp/signature_help_test.dart
index 9bee6e4..13432a9 100644
--- a/pkg/analysis_server/test/lsp/signature_help_test.dart
+++ b/pkg/analysis_server/test/lsp/signature_help_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/lsp/super_test.dart b/pkg/analysis_server/test/lsp/super_test.dart
index b9192d9..29eec48 100644
--- a/pkg/analysis_server/test/lsp/super_test.dart
+++ b/pkg/analysis_server/test/lsp/super_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/lsp/test_all.dart b/pkg/analysis_server/test/lsp/test_all.dart
index dd27eb3..4972696 100644
--- a/pkg/analysis_server/test/lsp/test_all.dart
+++ b/pkg/analysis_server/test/lsp/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import '../src/lsp/lsp_packet_transformer_test.dart' as lsp_packet_transformer;
diff --git a/pkg/analysis_server/test/lsp/will_rename_files_test.dart b/pkg/analysis_server/test/lsp/will_rename_files_test.dart
index e9b6fee..124671d 100644
--- a/pkg/analysis_server/test/lsp/will_rename_files_test.dart
+++ b/pkg/analysis_server/test/lsp/will_rename_files_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/test/lsp/workspace_symbols_test.dart b/pkg/analysis_server/test/lsp/workspace_symbols_test.dart
index 4c53c44..d20b42e 100644
--- a/pkg/analysis_server/test/lsp/workspace_symbols_test.dart
+++ b/pkg/analysis_server/test/lsp/workspace_symbols_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/mocks.dart b/pkg/analysis_server/test/mocks.dart
index d8c9e0a..f0ca226 100644
--- a/pkg/analysis_server/test/mocks.dart
+++ b/pkg/analysis_server/test/mocks.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:convert';
 
diff --git a/pkg/analysis_server/test/plugin/protocol_dart_test.dart b/pkg/analysis_server/test/plugin/protocol_dart_test.dart
index 91ab49f..da9514d 100644
--- a/pkg/analysis_server/test/plugin/protocol_dart_test.dart
+++ b/pkg/analysis_server/test/plugin/protocol_dart_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/plugin/protocol/protocol_dart.dart';
 import 'package:analyzer/dart/element/element.dart' as engine;
 import 'package:analyzer/src/dart/element/element.dart' as engine;
diff --git a/pkg/analysis_server/test/plugin/test_all.dart b/pkg/analysis_server/test/plugin/test_all.dart
index 56ce709..66ab7e3 100644
--- a/pkg/analysis_server/test/plugin/test_all.dart
+++ b/pkg/analysis_server/test/plugin/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'protocol_dart_test.dart' as protocol_dart_test;
diff --git a/pkg/analysis_server/test/protocol_server_test.dart b/pkg/analysis_server/test/protocol_server_test.dart
index 4b290ce..65df4b5 100644
--- a/pkg/analysis_server/test/protocol_server_test.dart
+++ b/pkg/analysis_server/test/protocol_server_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:mirrors';
 
 import 'package:analysis_server/src/protocol_server.dart'
diff --git a/pkg/analysis_server/test/protocol_test.dart b/pkg/analysis_server/test/protocol_test.dart
index 7f534a2..e4edae0 100644
--- a/pkg/analysis_server/test/protocol_test.dart
+++ b/pkg/analysis_server/test/protocol_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 
 import 'package:analysis_server/protocol/protocol.dart';
diff --git a/pkg/analysis_server/test/search/abstract_search_domain.dart b/pkg/analysis_server/test/search/abstract_search_domain.dart
index 1e5b0d1..50021f6 100644
--- a/pkg/analysis_server/test/search/abstract_search_domain.dart
+++ b/pkg/analysis_server/test/search/abstract_search_domain.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_constants.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/test/search/declarations_test.dart b/pkg/analysis_server/test/search/declarations_test.dart
index cb79730..349085d 100644
--- a/pkg/analysis_server/test/search/declarations_test.dart
+++ b/pkg/analysis_server/test/search/declarations_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/search/element_references_test.dart b/pkg/analysis_server/test/search/element_references_test.dart
index 5b7d558..fba332c 100644
--- a/pkg/analysis_server/test/search/element_references_test.dart
+++ b/pkg/analysis_server/test/search/element_references_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/search/member_declarations_test.dart b/pkg/analysis_server/test/search/member_declarations_test.dart
index 5e02cc2..46e9a46 100644
--- a/pkg/analysis_server/test/search/member_declarations_test.dart
+++ b/pkg/analysis_server/test/search/member_declarations_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/search/member_references_test.dart b/pkg/analysis_server/test/search/member_references_test.dart
index a2c7b18..ca74c67 100644
--- a/pkg/analysis_server/test/search/member_references_test.dart
+++ b/pkg/analysis_server/test/search/member_references_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/search/search_result_test.dart b/pkg/analysis_server/test/search/search_result_test.dart
index 02c82a6..978f0ec 100644
--- a/pkg/analysis_server/test/search/search_result_test.dart
+++ b/pkg/analysis_server/test/search/search_result_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/search/test_all.dart b/pkg/analysis_server/test/search/test_all.dart
index 403be90..b4e4f8c 100644
--- a/pkg/analysis_server/test/search/test_all.dart
+++ b/pkg/analysis_server/test/search/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'declarations_test.dart' as declarations_test;
diff --git a/pkg/analysis_server/test/search/top_level_declarations_test.dart b/pkg/analysis_server/test/search/top_level_declarations_test.dart
index 84735c2..7cda6cf 100644
--- a/pkg/analysis_server/test/search/top_level_declarations_test.dart
+++ b/pkg/analysis_server/test/search/top_level_declarations_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/search/type_hierarchy_test.dart b/pkg/analysis_server/test/search/type_hierarchy_test.dart
index 2c0f034..4b11bba 100644
--- a/pkg/analysis_server/test/search/type_hierarchy_test.dart
+++ b/pkg/analysis_server/test/search/type_hierarchy_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/search/search_domain.dart';
diff --git a/pkg/analysis_server/test/services/completion/dart/arglist_contributor_test.dart b/pkg/analysis_server/test/services/completion/dart/arglist_contributor_test.dart
index 1004b9b..dc5be49 100644
--- a/pkg/analysis_server/test/services/completion/dart/arglist_contributor_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/arglist_contributor_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/arglist_contributor.dart';
 import 'package:analyzer/src/dart/analysis/experiments.dart';
diff --git a/pkg/analysis_server/test/services/completion/dart/combinator_contributor_test.dart b/pkg/analysis_server/test/services/completion/dart/combinator_contributor_test.dart
index ea96470..952c66a 100644
--- a/pkg/analysis_server/test/services/completion/dart/combinator_contributor_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/combinator_contributor_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/combinator_contributor.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
diff --git a/pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart b/pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart
index 07e6752..d0bb800 100644
--- a/pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart
+++ b/pkg/analysis_server/test/services/completion/dart/completion_contributor_util.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
diff --git a/pkg/analysis_server/test/services/completion/dart/completion_manager_test.dart b/pkg/analysis_server/test/services/completion/dart/completion_manager_test.dart
index cd8e243..ab89e1b 100644
--- a/pkg/analysis_server/test/services/completion/dart/completion_manager_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/completion_manager_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
diff --git a/pkg/analysis_server/test/services/completion/dart/extension_member_contributor_test.dart b/pkg/analysis_server/test/services/completion/dart/extension_member_contributor_test.dart
index 12a2cad..2d51dba 100644
--- a/pkg/analysis_server/test/services/completion/dart/extension_member_contributor_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/extension_member_contributor_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/extension_member_contributor.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/services/completion/dart/field_formal_contributor_test.dart b/pkg/analysis_server/test/services/completion/dart/field_formal_contributor_test.dart
index d28095f..58ed66b 100644
--- a/pkg/analysis_server/test/services/completion/dart/field_formal_contributor_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/field_formal_contributor_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/field_formal_contributor.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/services/completion/dart/imported_reference_contributor_test.dart b/pkg/analysis_server/test/services/completion/dart/imported_reference_contributor_test.dart
index f8b642b..c1e03c4 100644
--- a/pkg/analysis_server/test/services/completion/dart/imported_reference_contributor_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/imported_reference_contributor_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/imported_reference_contributor.dart';
diff --git a/pkg/analysis_server/test/services/completion/dart/keyword_contributor_test.dart b/pkg/analysis_server/test/services/completion/dart/keyword_contributor_test.dart
index 84b0ba8..4abe258 100644
--- a/pkg/analysis_server/test/services/completion/dart/keyword_contributor_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/keyword_contributor_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/keyword_contributor.dart';
 import 'package:analyzer/dart/analysis/features.dart';
diff --git a/pkg/analysis_server/test/services/completion/dart/label_contributor_test.dart b/pkg/analysis_server/test/services/completion/dart/label_contributor_test.dart
index 6e8832b..b4223ba 100644
--- a/pkg/analysis_server/test/services/completion/dart/label_contributor_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/label_contributor_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/label_contributor.dart';
diff --git a/pkg/analysis_server/test/services/completion/dart/library_member_contributor_test.dart b/pkg/analysis_server/test/services/completion/dart/library_member_contributor_test.dart
index 023cef5..3ed1036 100644
--- a/pkg/analysis_server/test/services/completion/dart/library_member_contributor_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/library_member_contributor_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/library_member_contributor.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/services/completion/dart/library_prefix_contributor_test.dart b/pkg/analysis_server/test/services/completion/dart/library_prefix_contributor_test.dart
index e6e9ec2..e717c1d 100644
--- a/pkg/analysis_server/test/services/completion/dart/library_prefix_contributor_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/library_prefix_contributor_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/library_prefix_contributor.dart';
diff --git a/pkg/analysis_server/test/services/completion/dart/local_library_contributor_test.dart b/pkg/analysis_server/test/services/completion/dart/local_library_contributor_test.dart
index 6417557..3cabd97 100644
--- a/pkg/analysis_server/test/services/completion/dart/local_library_contributor_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/local_library_contributor_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/local_library_contributor.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/services/completion/dart/local_reference_contributor_test.dart b/pkg/analysis_server/test/services/completion/dart/local_reference_contributor_test.dart
index 7fbc2bf..4f97ee4 100644
--- a/pkg/analysis_server/test/services/completion/dart/local_reference_contributor_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/local_reference_contributor_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/local_reference_contributor.dart';
diff --git a/pkg/analysis_server/test/services/completion/dart/named_constructor_contributor_test.dart b/pkg/analysis_server/test/services/completion/dart/named_constructor_contributor_test.dart
index 68a9878..c058de6 100644
--- a/pkg/analysis_server/test/services/completion/dart/named_constructor_contributor_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/named_constructor_contributor_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/named_constructor_contributor.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
diff --git a/pkg/analysis_server/test/services/completion/dart/override_contributor_test.dart b/pkg/analysis_server/test/services/completion/dart/override_contributor_test.dart
index 34832e9..55cad3f 100644
--- a/pkg/analysis_server/test/services/completion/dart/override_contributor_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/override_contributor_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/override_contributor.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
diff --git a/pkg/analysis_server/test/services/completion/dart/relevance/bool_assignment_test.dart b/pkg/analysis_server/test/services/completion/dart/relevance/bool_assignment_test.dart
index 039c915..701f7c5 100644
--- a/pkg/analysis_server/test/services/completion/dart/relevance/bool_assignment_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/relevance/bool_assignment_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/services/completion/dart/relevance/completion_relevance.dart b/pkg/analysis_server/test/services/completion/dart/relevance/completion_relevance.dart
index 81532df..8a2fcd3b 100644
--- a/pkg/analysis_server/test/services/completion/dart/relevance/completion_relevance.dart
+++ b/pkg/analysis_server/test/services/completion/dart/relevance/completion_relevance.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
 
diff --git a/pkg/analysis_server/test/services/completion/dart/relevance/deprecated_member_test.dart b/pkg/analysis_server/test/services/completion/dart/relevance/deprecated_member_test.dart
index 44d0f92..fe82af1 100644
--- a/pkg/analysis_server/test/services/completion/dart/relevance/deprecated_member_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/relevance/deprecated_member_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/services/completion/dart/relevance/instance_member_test.dart b/pkg/analysis_server/test/services/completion/dart/relevance/instance_member_test.dart
index de08d73..5faa5df 100644
--- a/pkg/analysis_server/test/services/completion/dart/relevance/instance_member_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/relevance/instance_member_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'completion_relevance.dart';
diff --git a/pkg/analysis_server/test/services/completion/dart/relevance/is_no_such_method_test.dart b/pkg/analysis_server/test/services/completion/dart/relevance/is_no_such_method_test.dart
index 388a377..52327e6 100644
--- a/pkg/analysis_server/test/services/completion/dart/relevance/is_no_such_method_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/relevance/is_no_such_method_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/services/completion/dart/relevance/local_variable_test.dart b/pkg/analysis_server/test/services/completion/dart/relevance/local_variable_test.dart
index c1481fb..284020f 100644
--- a/pkg/analysis_server/test/services/completion/dart/relevance/local_variable_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/relevance/local_variable_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/services/completion/dart/relevance/named_argument_test.dart b/pkg/analysis_server/test/services/completion/dart/relevance/named_argument_test.dart
index ff02ed2..b9c200d 100644
--- a/pkg/analysis_server/test/services/completion/dart/relevance/named_argument_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/relevance/named_argument_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import '../../../../src/utilities/mock_packages.dart';
diff --git a/pkg/analysis_server/test/services/completion/dart/relevance/non_type_member_test.dart b/pkg/analysis_server/test/services/completion/dart/relevance/non_type_member_test.dart
index 084c91c..27f3789 100644
--- a/pkg/analysis_server/test/services/completion/dart/relevance/non_type_member_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/relevance/non_type_member_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/services/completion/dart/relevance/static_member_test.dart b/pkg/analysis_server/test/services/completion/dart/relevance/static_member_test.dart
index 314b1e0..7042169 100644
--- a/pkg/analysis_server/test/services/completion/dart/relevance/static_member_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/relevance/static_member_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'completion_relevance.dart';
diff --git a/pkg/analysis_server/test/services/completion/dart/relevance/test_all.dart b/pkg/analysis_server/test/services/completion/dart/relevance/test_all.dart
index d6679e5..d6bf383 100644
--- a/pkg/analysis_server/test/services/completion/dart/relevance/test_all.dart
+++ b/pkg/analysis_server/test/services/completion/dart/relevance/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'bool_assignment_test.dart' as bool_assignments;
diff --git a/pkg/analysis_server/test/services/completion/dart/static_member_contributor_test.dart b/pkg/analysis_server/test/services/completion/dart/static_member_contributor_test.dart
index 7253f49..72f6bb8 100644
--- a/pkg/analysis_server/test/services/completion/dart/static_member_contributor_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/static_member_contributor_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/static_member_contributor.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/services/completion/dart/test_all.dart b/pkg/analysis_server/test/services/completion/dart/test_all.dart
index c8ccce6..7e3c13c 100644
--- a/pkg/analysis_server/test/services/completion/dart/test_all.dart
+++ b/pkg/analysis_server/test/services/completion/dart/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'arglist_contributor_test.dart' as arglist_test;
diff --git a/pkg/analysis_server/test/services/completion/dart/type_member_contributor_test.dart b/pkg/analysis_server/test/services/completion/dart/type_member_contributor_test.dart
index 982f671..9ff66d1 100644
--- a/pkg/analysis_server/test/services/completion/dart/type_member_contributor_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/type_member_contributor_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/type_member_contributor.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
diff --git a/pkg/analysis_server/test/services/completion/dart/uri_contributor_test.dart b/pkg/analysis_server/test/services/completion/dart/uri_contributor_test.dart
index e19ca34..ab0b151 100644
--- a/pkg/analysis_server/test/services/completion/dart/uri_contributor_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/uri_contributor_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/uri_contributor.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
diff --git a/pkg/analysis_server/test/services/completion/dart/variable_name_contributor_test.dart b/pkg/analysis_server/test/services/completion/dart/variable_name_contributor_test.dart
index 3b75a53..5f252da 100644
--- a/pkg/analysis_server/test/services/completion/dart/variable_name_contributor_test.dart
+++ b/pkg/analysis_server/test/services/completion/dart/variable_name_contributor_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/provisional/completion/dart/completion_dart.dart';
 import 'package:analysis_server/src/services/completion/dart/variable_name_contributor.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/services/completion/postfix/postfix_completion_test.dart b/pkg/analysis_server/test/services/completion/postfix/postfix_completion_test.dart
index fe4bbb1..a88af5a 100644
--- a/pkg/analysis_server/test/services/completion/postfix/postfix_completion_test.dart
+++ b/pkg/analysis_server/test/services/completion/postfix/postfix_completion_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/services/completion/postfix/postfix_completion.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/services/completion/postfix/test_all.dart b/pkg/analysis_server/test/services/completion/postfix/test_all.dart
index 36604fe..958d06b 100644
--- a/pkg/analysis_server/test/services/completion/postfix/test_all.dart
+++ b/pkg/analysis_server/test/services/completion/postfix/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'postfix_completion_test.dart' as postfix_completion_test;
diff --git a/pkg/analysis_server/test/services/completion/statement/statement_completion_test.dart b/pkg/analysis_server/test/services/completion/statement/statement_completion_test.dart
index 5d99721..6d787d6 100644
--- a/pkg/analysis_server/test/services/completion/statement/statement_completion_test.dart
+++ b/pkg/analysis_server/test/services/completion/statement/statement_completion_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/services/completion/statement/statement_completion.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/services/completion/statement/test_all.dart b/pkg/analysis_server/test/services/completion/statement/test_all.dart
index 6d4d86e..8edd7fe 100644
--- a/pkg/analysis_server/test/services/completion/statement/test_all.dart
+++ b/pkg/analysis_server/test/services/completion/statement/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'statement_completion_test.dart' as statement_completion_test;
diff --git a/pkg/analysis_server/test/services/completion/test_all.dart b/pkg/analysis_server/test/services/completion/test_all.dart
index 533fb7a..4aaa784 100644
--- a/pkg/analysis_server/test/services/completion/test_all.dart
+++ b/pkg/analysis_server/test/services/completion/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'dart/test_all.dart' as dart_all;
diff --git a/pkg/analysis_server/test/services/correction/change_test.dart b/pkg/analysis_server/test/services/correction/change_test.dart
index 90b2dd9..8616a2c 100644
--- a/pkg/analysis_server/test/services/correction/change_test.dart
+++ b/pkg/analysis_server/test/services/correction/change_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/services/correction/levenshtein_test.dart b/pkg/analysis_server/test/services/correction/levenshtein_test.dart
index dc320bd..24826fd 100644
--- a/pkg/analysis_server/test/services/correction/levenshtein_test.dart
+++ b/pkg/analysis_server/test/services/correction/levenshtein_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/levenshtein.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/services/correction/name_suggestion_test.dart b/pkg/analysis_server/test/services/correction/name_suggestion_test.dart
index 243fd9b..7216dcd 100644
--- a/pkg/analysis_server/test/services/correction/name_suggestion_test.dart
+++ b/pkg/analysis_server/test/services/correction/name_suggestion_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/name_suggestion.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/services/correction/organize_directives_test.dart b/pkg/analysis_server/test/services/correction/organize_directives_test.dart
index 4b8aa22..1bebd49 100644
--- a/pkg/analysis_server/test/services/correction/organize_directives_test.dart
+++ b/pkg/analysis_server/test/services/correction/organize_directives_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/organize_imports.dart';
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart'
diff --git a/pkg/analysis_server/test/services/correction/sort_members_test.dart b/pkg/analysis_server/test/services/correction/sort_members_test.dart
index 88cc25d..c6e55cf 100644
--- a/pkg/analysis_server/test/services/correction/sort_members_test.dart
+++ b/pkg/analysis_server/test/services/correction/sort_members_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/sort_members.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/services/correction/status_test.dart b/pkg/analysis_server/test/services/correction/status_test.dart
index 0e00b19..3bcc7a9 100644
--- a/pkg/analysis_server/test/services/correction/status_test.dart
+++ b/pkg/analysis_server/test/services/correction/status_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
 import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart';
diff --git a/pkg/analysis_server/test/services/correction/test_all.dart b/pkg/analysis_server/test/services/correction/test_all.dart
index 0b289d9..de358b6 100644
--- a/pkg/analysis_server/test/services/correction/test_all.dart
+++ b/pkg/analysis_server/test/services/correction/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'change_test.dart' as change_test;
diff --git a/pkg/analysis_server/test/services/correction/util_test.dart b/pkg/analysis_server/test/services/correction/util_test.dart
index cba88ef..203ccf9 100644
--- a/pkg/analysis_server/test/services/correction/util_test.dart
+++ b/pkg/analysis_server/test/services/correction/util_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/util.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
diff --git a/pkg/analysis_server/test/services/linter/linter_test.dart b/pkg/analysis_server/test/services/linter/linter_test.dart
index ec60e13..031509a 100644
--- a/pkg/analysis_server/test/services/linter/linter_test.dart
+++ b/pkg/analysis_server/test/services/linter/linter_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer/error/listener.dart';
 import 'package:analyzer/src/analysis_options/analysis_options_provider.dart';
diff --git a/pkg/analysis_server/test/services/linter/test_all.dart b/pkg/analysis_server/test/services/linter/test_all.dart
index bfc8186..b9d816c 100644
--- a/pkg/analysis_server/test/services/linter/test_all.dart
+++ b/pkg/analysis_server/test/services/linter/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'linter_test.dart' as linter_test;
diff --git a/pkg/analysis_server/test/services/refactoring/abstract_refactoring.dart b/pkg/analysis_server/test/services/refactoring/abstract_refactoring.dart
index 82eca0f..7e982701 100644
--- a/pkg/analysis_server/test/services/refactoring/abstract_refactoring.dart
+++ b/pkg/analysis_server/test/services/refactoring/abstract_refactoring.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart';
diff --git a/pkg/analysis_server/test/services/refactoring/abstract_rename.dart b/pkg/analysis_server/test/services/refactoring/abstract_rename.dart
index 3a3c7aa..1437541 100644
--- a/pkg/analysis_server/test/services/refactoring/abstract_rename.dart
+++ b/pkg/analysis_server/test/services/refactoring/abstract_rename.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/namespace.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
 import 'package:analyzer/dart/ast/ast.dart';
diff --git a/pkg/analysis_server/test/services/refactoring/convert_getter_to_method_test.dart b/pkg/analysis_server/test/services/refactoring/convert_getter_to_method_test.dart
index 17c7103..ff2de57 100644
--- a/pkg/analysis_server/test/services/refactoring/convert_getter_to_method_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/convert_getter_to_method_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart' hide ElementKind;
diff --git a/pkg/analysis_server/test/services/refactoring/convert_method_to_getter_test.dart b/pkg/analysis_server/test/services/refactoring/convert_method_to_getter_test.dart
index 7afbb5d..d743439 100644
--- a/pkg/analysis_server/test/services/refactoring/convert_method_to_getter_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/convert_method_to_getter_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart'
diff --git a/pkg/analysis_server/test/services/refactoring/extract_local_test.dart b/pkg/analysis_server/test/services/refactoring/extract_local_test.dart
index 4d5d5bf..215745e 100644
--- a/pkg/analysis_server/test/services/refactoring/extract_local_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/extract_local_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 
 import 'package:analysis_server/src/services/linter/lint_names.dart';
diff --git a/pkg/analysis_server/test/services/refactoring/extract_method_test.dart b/pkg/analysis_server/test/services/refactoring/extract_method_test.dart
index 71155fe..06b2131 100644
--- a/pkg/analysis_server/test/services/refactoring/extract_method_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/extract_method_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/refactoring/extract_method.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
diff --git a/pkg/analysis_server/test/services/refactoring/extract_widget_test.dart b/pkg/analysis_server/test/services/refactoring/extract_widget_test.dart
index 23d0d92..8ceaf78 100644
--- a/pkg/analysis_server/test/services/refactoring/extract_widget_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/extract_widget_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/refactoring/extract_widget.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
diff --git a/pkg/analysis_server/test/services/refactoring/inline_local_test.dart b/pkg/analysis_server/test/services/refactoring/inline_local_test.dart
index 6409980..80920b8 100644
--- a/pkg/analysis_server/test/services/refactoring/inline_local_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/inline_local_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/services/refactoring/inline_local.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
diff --git a/pkg/analysis_server/test/services/refactoring/inline_method_test.dart b/pkg/analysis_server/test/services/refactoring/inline_method_test.dart
index 0f5d160..204df5c 100644
--- a/pkg/analysis_server/test/services/refactoring/inline_method_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/inline_method_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/refactoring/inline_method.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
 import 'package:analyzer/src/generated/source.dart';
diff --git a/pkg/analysis_server/test/services/refactoring/move_file_test.dart b/pkg/analysis_server/test/services/refactoring/move_file_test.dart
index e83a314..adab84f 100644
--- a/pkg/analysis_server/test/services/refactoring/move_file_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/move_file_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/services/refactoring/naming_conventions_test.dart b/pkg/analysis_server/test/services/refactoring/naming_conventions_test.dart
index ea21e44..810ec9b 100644
--- a/pkg/analysis_server/test/services/refactoring/naming_conventions_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/naming_conventions_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/services/refactoring/naming_conventions.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
diff --git a/pkg/analysis_server/test/services/refactoring/rename_class_member_test.dart b/pkg/analysis_server/test/services/refactoring/rename_class_member_test.dart
index 24223d8..47a6c12 100644
--- a/pkg/analysis_server/test/services/refactoring/rename_class_member_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/rename_class_member_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/services/refactoring/rename_constructor_test.dart b/pkg/analysis_server/test/services/refactoring/rename_constructor_test.dart
index 50f73a3..2cb9270 100644
--- a/pkg/analysis_server/test/services/refactoring/rename_constructor_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/rename_constructor_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/services/refactoring/rename_extension_member_test.dart b/pkg/analysis_server/test/services/refactoring/rename_extension_member_test.dart
index 8490802..36f2bc3 100644
--- a/pkg/analysis_server/test/services/refactoring/rename_extension_member_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/rename_extension_member_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/services/refactoring/rename_import_test.dart b/pkg/analysis_server/test/services/refactoring/rename_import_test.dart
index b0305ee..0e90484 100644
--- a/pkg/analysis_server/test/services/refactoring/rename_import_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/rename_import_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/services/refactoring/rename_label_test.dart b/pkg/analysis_server/test/services/refactoring/rename_label_test.dart
index 6ca432e..98f5cb9 100644
--- a/pkg/analysis_server/test/services/refactoring/rename_label_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/rename_label_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/services/refactoring/rename_library_test.dart b/pkg/analysis_server/test/services/refactoring/rename_library_test.dart
index 38c315a..3b22091 100644
--- a/pkg/analysis_server/test/services/refactoring/rename_library_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/rename_library_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/services/refactoring/rename_local_test.dart b/pkg/analysis_server/test/services/refactoring/rename_local_test.dart
index 533456b..c620f97 100644
--- a/pkg/analysis_server/test/services/refactoring/rename_local_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/rename_local_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/services/refactoring/rename_unit_member_test.dart b/pkg/analysis_server/test/services/refactoring/rename_unit_member_test.dart
index c2afbdc..84b916e 100644
--- a/pkg/analysis_server/test/services/refactoring/rename_unit_member_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/rename_unit_member_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/services/refactoring/test_all.dart b/pkg/analysis_server/test/services/refactoring/test_all.dart
index d48e879..9dc8a8e 100644
--- a/pkg/analysis_server/test/services/refactoring/test_all.dart
+++ b/pkg/analysis_server/test/services/refactoring/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'convert_getter_to_method_test.dart' as convert_getter_to_method_test;
diff --git a/pkg/analysis_server/test/services/search/element_visitors_test.dart b/pkg/analysis_server/test/services/search/element_visitors_test.dart
index be601d3..3f2b9e4 100644
--- a/pkg/analysis_server/test/services/search/element_visitors_test.dart
+++ b/pkg/analysis_server/test/services/search/element_visitors_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/search/element_visitors.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/services/search/hierarchy_test.dart b/pkg/analysis_server/test/services/search/hierarchy_test.dart
index e576ae2..fc72aa4 100644
--- a/pkg/analysis_server/test/services/search/hierarchy_test.dart
+++ b/pkg/analysis_server/test/services/search/hierarchy_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/search/hierarchy.dart';
 import 'package:analysis_server/src/services/search/search_engine_internal.dart';
 import 'package:analyzer/dart/element/element.dart';
diff --git a/pkg/analysis_server/test/services/search/search_engine_test.dart b/pkg/analysis_server/test/services/search/search_engine_test.dart
index 9e59c61..593f483 100644
--- a/pkg/analysis_server/test/services/search/search_engine_test.dart
+++ b/pkg/analysis_server/test/services/search/search_engine_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/search/search_engine.dart';
 import 'package:analysis_server/src/services/search/search_engine_internal.dart';
 import 'package:analyzer/dart/analysis/results.dart';
diff --git a/pkg/analysis_server/test/services/search/test_all.dart b/pkg/analysis_server/test/services/search/test_all.dart
index c3f8f91..123f0cf 100644
--- a/pkg/analysis_server/test/services/search/test_all.dart
+++ b/pkg/analysis_server/test/services/search/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'element_visitors_test.dart' as element_visitors;
diff --git a/pkg/analysis_server/test/services/test_all.dart b/pkg/analysis_server/test/services/test_all.dart
index 954023d..85f29c1 100644
--- a/pkg/analysis_server/test/services/test_all.dart
+++ b/pkg/analysis_server/test/services/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'completion/test_all.dart' as completion_all;
diff --git a/pkg/analysis_server/test/socket_server_test.dart b/pkg/analysis_server/test/socket_server_test.dart
index d62ab2e..b7877f9 100644
--- a/pkg/analysis_server/test/socket_server_test.dart
+++ b/pkg/analysis_server/test/socket_server_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_constants.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/test/src/cider/assists_test.dart b/pkg/analysis_server/test/src/cider/assists_test.dart
index db0e616b2..defbb80 100644
--- a/pkg/analysis_server/test/src/cider/assists_test.dart
+++ b/pkg/analysis_server/test/src/cider/assists_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/plugin/edit/assist/assist_core.dart';
 import 'package:analysis_server/src/cider/assists.dart';
 import 'package:analysis_server/src/services/correction/assist.dart';
diff --git a/pkg/analysis_server/test/src/cider/cider_service.dart b/pkg/analysis_server/test/src/cider/cider_service.dart
index a1a0f10..cbbc876 100644
--- a/pkg/analysis_server/test/src/cider/cider_service.dart
+++ b/pkg/analysis_server/test/src/cider/cider_service.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 
 import 'package:analyzer/src/dart/analysis/byte_store.dart';
diff --git a/pkg/analysis_server/test/src/cider/completion_test.dart b/pkg/analysis_server/test/src/cider/completion_test.dart
index cc3ed2d..b64e585 100644
--- a/pkg/analysis_server/test/src/cider/completion_test.dart
+++ b/pkg/analysis_server/test/src/cider/completion_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/cider/completion.dart';
 import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/source/line_info.dart';
diff --git a/pkg/analysis_server/test/src/cider/fixes_test.dart b/pkg/analysis_server/test/src/cider/fixes_test.dart
index 8b8d691..590ae33 100644
--- a/pkg/analysis_server/test/src/cider/fixes_test.dart
+++ b/pkg/analysis_server/test/src/cider/fixes_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/plugin/edit/fix/fix_core.dart';
 import 'package:analysis_server/src/cider/fixes.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/test/src/cider/test_all.dart b/pkg/analysis_server/test/src/cider/test_all.dart
index 524383b..05483ca 100644
--- a/pkg/analysis_server/test/src/cider/test_all.dart
+++ b/pkg/analysis_server/test/src/cider/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'assists_test.dart' as assists;
diff --git a/pkg/analysis_server/test/src/computer/closing_labels_computer_test.dart b/pkg/analysis_server/test/src/computer/closing_labels_computer_test.dart
index 85369d1..47c1a01 100644
--- a/pkg/analysis_server/test/src/computer/closing_labels_computer_test.dart
+++ b/pkg/analysis_server/test/src/computer/closing_labels_computer_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/computer/computer_closingLabels.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/src/computer/folding_computer_test.dart b/pkg/analysis_server/test/src/computer/folding_computer_test.dart
index 03534e7..6f1df02 100644
--- a/pkg/analysis_server/test/src/computer/folding_computer_test.dart
+++ b/pkg/analysis_server/test/src/computer/folding_computer_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/computer/computer_folding.dart';
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/src/computer/highlights_computer_test.dart b/pkg/analysis_server/test/src/computer/highlights_computer_test.dart
index 5880e68..3b3aacb 100644
--- a/pkg/analysis_server/test/src/computer/highlights_computer_test.dart
+++ b/pkg/analysis_server/test/src/computer/highlights_computer_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/computer/computer_highlights.dart';
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/src/computer/import_elements_computer_test.dart b/pkg/analysis_server/test/src/computer/import_elements_computer_test.dart
index 8b0f30c..cc30a93 100644
--- a/pkg/analysis_server/test/src/computer/import_elements_computer_test.dart
+++ b/pkg/analysis_server/test/src/computer/import_elements_computer_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/computer/import_elements_computer.dart';
 import 'package:analyzer/src/test_utilities/package_config_file_builder.dart';
diff --git a/pkg/analysis_server/test/src/computer/imported_elements_computer_test.dart b/pkg/analysis_server/test/src/computer/imported_elements_computer_test.dart
index 171d627..9f55abb 100644
--- a/pkg/analysis_server/test/src/computer/imported_elements_computer_test.dart
+++ b/pkg/analysis_server/test/src/computer/imported_elements_computer_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/computer/imported_elements_computer.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/src/computer/outline_computer_test.dart b/pkg/analysis_server/test/src/computer/outline_computer_test.dart
index 7c3ca64..191bade 100644
--- a/pkg/analysis_server/test/src/computer/outline_computer_test.dart
+++ b/pkg/analysis_server/test/src/computer/outline_computer_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/computer/computer_outline.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:meta/meta.dart';
diff --git a/pkg/analysis_server/test/src/computer/test_all.dart b/pkg/analysis_server/test/src/computer/test_all.dart
index 1a04173..a1243b2 100644
--- a/pkg/analysis_server/test/src/computer/test_all.dart
+++ b/pkg/analysis_server/test/src/computer/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'closing_labels_computer_test.dart' as closing_labels_computer;
diff --git a/pkg/analysis_server/test/src/domain_abstract_test.dart b/pkg/analysis_server/test/src/domain_abstract_test.dart
index 46c9aa6..73c72eb 100644
--- a/pkg/analysis_server/test/src/domain_abstract_test.dart
+++ b/pkg/analysis_server/test/src/domain_abstract_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/domain_abstract.dart';
 import 'package:analysis_server/src/plugin/plugin_manager.dart';
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
diff --git a/pkg/analysis_server/test/src/domains/completion/available_suggestion_sets_test.dart b/pkg/analysis_server/test/src/domains/completion/available_suggestion_sets_test.dart
index 5f6c972..32f0198 100644
--- a/pkg/analysis_server/test/src/domains/completion/available_suggestion_sets_test.dart
+++ b/pkg/analysis_server/test/src/domains/completion/available_suggestion_sets_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/domains/completion/available_suggestions_base.dart b/pkg/analysis_server/test/src/domains/completion/available_suggestions_base.dart
index 1f4317b..76e3d5c 100644
--- a/pkg/analysis_server/test/src/domains/completion/available_suggestions_base.dart
+++ b/pkg/analysis_server/test/src/domains/completion/available_suggestions_base.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 
 import 'package:analysis_server/protocol/protocol_constants.dart';
diff --git a/pkg/analysis_server/test/src/domains/completion/get_suggestion_details_test.dart b/pkg/analysis_server/test/src/domains/completion/get_suggestion_details_test.dart
index 7876489..9b4d38a 100644
--- a/pkg/analysis_server/test/src/domains/completion/get_suggestion_details_test.dart
+++ b/pkg/analysis_server/test/src/domains/completion/get_suggestion_details_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:meta/meta.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/src/domains/completion/get_suggestions_available_test.dart b/pkg/analysis_server/test/src/domains/completion/get_suggestions_available_test.dart
index fe4524b..9ec1326 100644
--- a/pkg/analysis_server/test/src/domains/completion/get_suggestions_available_test.dart
+++ b/pkg/analysis_server/test/src/domains/completion/get_suggestions_available_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/domains/completion/test_all.dart b/pkg/analysis_server/test/src/domains/completion/test_all.dart
index 1452e21..dc4bd6b 100644
--- a/pkg/analysis_server/test/src/domains/completion/test_all.dart
+++ b/pkg/analysis_server/test/src/domains/completion/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'available_suggestion_sets_test.dart' as available_suggestion_sets;
diff --git a/pkg/analysis_server/test/src/domains/execution/completion_test.dart b/pkg/analysis_server/test/src/domains/execution/completion_test.dart
index b70a9bb..92e3282 100644
--- a/pkg/analysis_server/test/src/domains/execution/completion_test.dart
+++ b/pkg/analysis_server/test/src/domains/execution/completion_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/domains/execution/completion.dart';
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analyzer/file_system/overlay_file_system.dart';
diff --git a/pkg/analysis_server/test/src/domains/execution/test_all.dart b/pkg/analysis_server/test/src/domains/execution/test_all.dart
index 1cbd9d3..88b3d88 100644
--- a/pkg/analysis_server/test/src/domains/execution/test_all.dart
+++ b/pkg/analysis_server/test/src/domains/execution/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'completion_test.dart' as completion_test;
diff --git a/pkg/analysis_server/test/src/domains/flutter/base.dart b/pkg/analysis_server/test/src/domains/flutter/base.dart
index 2cadf8b..88d9c9d 100644
--- a/pkg/analysis_server/test/src/domains/flutter/base.dart
+++ b/pkg/analysis_server/test/src/domains/flutter/base.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/flutter/flutter_domain.dart';
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/src/domains/flutter/get_widget_description_test.dart b/pkg/analysis_server/test/src/domains/flutter/get_widget_description_test.dart
index 45affaa..fe6b73a 100644
--- a/pkg/analysis_server/test/src/domains/flutter/get_widget_description_test.dart
+++ b/pkg/analysis_server/test/src/domains/flutter/get_widget_description_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/domains/flutter/set_property_value_test.dart b/pkg/analysis_server/test/src/domains/flutter/set_property_value_test.dart
index 6475882..10c2eb9 100644
--- a/pkg/analysis_server/test/src/domains/flutter/set_property_value_test.dart
+++ b/pkg/analysis_server/test/src/domains/flutter/set_property_value_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/domains/flutter/test_all.dart b/pkg/analysis_server/test/src/domains/flutter/test_all.dart
index 2030531..97e2c81 100644
--- a/pkg/analysis_server/test/src/domains/flutter/test_all.dart
+++ b/pkg/analysis_server/test/src/domains/flutter/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'get_widget_description_test.dart' as get_widget_description;
diff --git a/pkg/analysis_server/test/src/domains/test_all.dart b/pkg/analysis_server/test/src/domains/test_all.dart
index dac4cfe..dc9a595 100644
--- a/pkg/analysis_server/test/src/domains/test_all.dart
+++ b/pkg/analysis_server/test/src/domains/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'completion/test_all.dart' as completion;
diff --git a/pkg/analysis_server/test/src/flutter/flutter_outline_computer_test.dart b/pkg/analysis_server/test/src/flutter/flutter_outline_computer_test.dart
index 969b238..da859cb 100644
--- a/pkg/analysis_server/test/src/flutter/flutter_outline_computer_test.dart
+++ b/pkg/analysis_server/test/src/flutter/flutter_outline_computer_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/flutter/flutter_outline_computer.dart';
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analyzer/dart/analysis/results.dart';
diff --git a/pkg/analysis_server/test/src/flutter/flutter_outline_notification_test.dart b/pkg/analysis_server/test/src/flutter/flutter_outline_notification_test.dart
index 67fec6f..7096a77 100644
--- a/pkg/analysis_server/test/src/flutter/flutter_outline_notification_test.dart
+++ b/pkg/analysis_server/test/src/flutter/flutter_outline_notification_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/protocol/protocol.dart';
diff --git a/pkg/analysis_server/test/src/flutter/test_all.dart b/pkg/analysis_server/test/src/flutter/test_all.dart
index 48db007..54e575a 100644
--- a/pkg/analysis_server/test/src/flutter/test_all.dart
+++ b/pkg/analysis_server/test/src/flutter/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'flutter_outline_computer_test.dart' as outline_computer;
diff --git a/pkg/analysis_server/test/src/lsp/lsp_packet_transformer_test.dart b/pkg/analysis_server/test/src/lsp/lsp_packet_transformer_test.dart
index 614fe4f..bb8927a 100644
--- a/pkg/analysis_server/test/src/lsp/lsp_packet_transformer_test.dart
+++ b/pkg/analysis_server/test/src/lsp/lsp_packet_transformer_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 
 import 'package:analysis_server/src/lsp/lsp_packet_transformer.dart';
diff --git a/pkg/analysis_server/test/src/lsp/test_all.dart b/pkg/analysis_server/test/src/lsp/test_all.dart
index 5f61e61..e51799f 100644
--- a/pkg/analysis_server/test/src/lsp/test_all.dart
+++ b/pkg/analysis_server/test/src/lsp/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'lsp_packet_transformer_test.dart' as lsp_packet_transformer;
diff --git a/pkg/analysis_server/test/src/plugin/notification_manager_test.dart b/pkg/analysis_server/test/src/plugin/notification_manager_test.dart
index 3157c0c..25f5615 100644
--- a/pkg/analysis_server/test/src/plugin/notification_manager_test.dart
+++ b/pkg/analysis_server/test/src/plugin/notification_manager_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol.dart' as server;
 import 'package:analysis_server/protocol/protocol_generated.dart' as server;
 import 'package:analysis_server/src/channel/channel.dart';
diff --git a/pkg/analysis_server/test/src/plugin/plugin_locator_test.dart b/pkg/analysis_server/test/src/plugin/plugin_locator_test.dart
index 4e4cbda..5b71ce6 100644
--- a/pkg/analysis_server/test/src/plugin/plugin_locator_test.dart
+++ b/pkg/analysis_server/test/src/plugin/plugin_locator_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/plugin/plugin_locator.dart';
 import 'package:analyzer/src/test_utilities/resource_provider_mixin.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/src/plugin/plugin_manager_test.dart b/pkg/analysis_server/test/src/plugin/plugin_manager_test.dart
index d9bea42..ae1ba51 100644
--- a/pkg/analysis_server/test/src/plugin/plugin_manager_test.dart
+++ b/pkg/analysis_server/test/src/plugin/plugin_manager_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io' as io;
 
 import 'package:analysis_server/src/plugin/notification_manager.dart';
diff --git a/pkg/analysis_server/test/src/plugin/plugin_watcher_test.dart b/pkg/analysis_server/test/src/plugin/plugin_watcher_test.dart
index 361cd03..7906315 100644
--- a/pkg/analysis_server/test/src/plugin/plugin_watcher_test.dart
+++ b/pkg/analysis_server/test/src/plugin/plugin_watcher_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 
 import 'package:analysis_server/src/plugin/plugin_locator.dart';
diff --git a/pkg/analysis_server/test/src/plugin/protocol_test_utilities.dart b/pkg/analysis_server/test/src/plugin/protocol_test_utilities.dart
index 3d84f35..a91d352 100644
--- a/pkg/analysis_server/test/src/plugin/protocol_test_utilities.dart
+++ b/pkg/analysis_server/test/src/plugin/protocol_test_utilities.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart' as server;
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:analyzer_plugin/protocol/protocol_generated.dart' as plugin;
diff --git a/pkg/analysis_server/test/src/plugin/request_converter_test.dart b/pkg/analysis_server/test/src/plugin/request_converter_test.dart
index 7ba3049..42125bb 100644
--- a/pkg/analysis_server/test/src/plugin/request_converter_test.dart
+++ b/pkg/analysis_server/test/src/plugin/request_converter_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart' as server;
 import 'package:analysis_server/src/plugin/request_converter.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
diff --git a/pkg/analysis_server/test/src/plugin/result_collector_test.dart b/pkg/analysis_server/test/src/plugin/result_collector_test.dart
index 39a4486..a8892b5 100644
--- a/pkg/analysis_server/test/src/plugin/result_collector_test.dart
+++ b/pkg/analysis_server/test/src/plugin/result_collector_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/plugin/result_collector.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/plugin/result_converter_test.dart b/pkg/analysis_server/test/src/plugin/result_converter_test.dart
index 220ca9a..7eaaa6e 100644
--- a/pkg/analysis_server/test/src/plugin/result_converter_test.dart
+++ b/pkg/analysis_server/test/src/plugin/result_converter_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart' as server;
 import 'package:analysis_server/src/plugin/result_converter.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
diff --git a/pkg/analysis_server/test/src/plugin/result_merger_test.dart b/pkg/analysis_server/test/src/plugin/result_merger_test.dart
index 934e335..0116e27 100644
--- a/pkg/analysis_server/test/src/plugin/result_merger_test.dart
+++ b/pkg/analysis_server/test/src/plugin/result_merger_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/plugin/result_merger.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
diff --git a/pkg/analysis_server/test/src/plugin/test_all.dart b/pkg/analysis_server/test/src/plugin/test_all.dart
index 9240a5d..70d0fd0 100644
--- a/pkg/analysis_server/test/src/plugin/test_all.dart
+++ b/pkg/analysis_server/test/src/plugin/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'notification_manager_test.dart' as notification_manager_test;
diff --git a/pkg/analysis_server/test/src/server/sdk_configuration_test.dart b/pkg/analysis_server/test/src/server/sdk_configuration_test.dart
index b007d66..e0a6525 100644
--- a/pkg/analysis_server/test/src/server/sdk_configuration_test.dart
+++ b/pkg/analysis_server/test/src/server/sdk_configuration_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io';
 
 import 'package:analysis_server/src/server/sdk_configuration.dart';
diff --git a/pkg/analysis_server/test/src/server/test_all.dart b/pkg/analysis_server/test/src/server/test_all.dart
index cf5da10..4dcbb2a 100644
--- a/pkg/analysis_server/test/src/server/test_all.dart
+++ b/pkg/analysis_server/test/src/server/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'sdk_configuration_test.dart' as sdk_configuration;
 
 void main() {
diff --git a/pkg/analysis_server/test/src/services/completion/dart/completion_test.dart b/pkg/analysis_server/test/src/services/completion/dart/completion_test.dart
index 004e07b..c9c355e 100644
--- a/pkg/analysis_server/test/src/services/completion/dart/completion_test.dart
+++ b/pkg/analysis_server/test/src/services/completion/dart/completion_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/completion/dart/feature_computer_test.dart b/pkg/analysis_server/test/src/services/completion/dart/feature_computer_test.dart
index c2a5bb6..4dbb904 100644
--- a/pkg/analysis_server/test/src/services/completion/dart/feature_computer_test.dart
+++ b/pkg/analysis_server/test/src/services/completion/dart/feature_computer_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/completion/dart/feature_computer.dart';
 import 'package:analyzer_plugin/src/utilities/completion/completion_target.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/src/services/completion/dart/test_all.dart b/pkg/analysis_server/test/src/services/completion/dart/test_all.dart
index ab0ad81..06a051a 100644
--- a/pkg/analysis_server/test/src/services/completion/dart/test_all.dart
+++ b/pkg/analysis_server/test/src/services/completion/dart/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'completion_test.dart' as completion;
diff --git a/pkg/analysis_server/test/src/services/completion/filtering/fuzzy_matcher_test.dart b/pkg/analysis_server/test/src/services/completion/filtering/fuzzy_matcher_test.dart
index 3bc5d7a..b607031 100644
--- a/pkg/analysis_server/test/src/services/completion/filtering/fuzzy_matcher_test.dart
+++ b/pkg/analysis_server/test/src/services/completion/filtering/fuzzy_matcher_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/completion/filtering/fuzzy_matcher.dart';
 import 'package:meta/meta.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/src/services/completion/filtering/test_all.dart b/pkg/analysis_server/test/src/services/completion/filtering/test_all.dart
index ffc9b80..77a55cd 100644
--- a/pkg/analysis_server/test/src/services/completion/filtering/test_all.dart
+++ b/pkg/analysis_server/test/src/services/completion/filtering/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'fuzzy_matcher_test.dart' as fuzzy_matcher;
diff --git a/pkg/analysis_server/test/src/services/completion/test_all.dart b/pkg/analysis_server/test/src/services/completion/test_all.dart
index 19d31b3..75303aa 100644
--- a/pkg/analysis_server/test/src/services/completion/test_all.dart
+++ b/pkg/analysis_server/test/src/services/completion/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'dart/test_all.dart' as dart;
diff --git a/pkg/analysis_server/test/src/services/completion/yaml/analysis_options_generator_test.dart b/pkg/analysis_server/test/src/services/completion/yaml/analysis_options_generator_test.dart
index c86dc28..c9e33de 100644
--- a/pkg/analysis_server/test/src/services/completion/yaml/analysis_options_generator_test.dart
+++ b/pkg/analysis_server/test/src/services/completion/yaml/analysis_options_generator_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/completion/yaml/analysis_options_generator.dart';
 import 'package:analyzer/src/task/options.dart';
 import 'package:linter/src/rules.dart';
diff --git a/pkg/analysis_server/test/src/services/completion/yaml/fix_data_generator_test.dart b/pkg/analysis_server/test/src/services/completion/yaml/fix_data_generator_test.dart
index 4634360..3ded781 100644
--- a/pkg/analysis_server/test/src/services/completion/yaml/fix_data_generator_test.dart
+++ b/pkg/analysis_server/test/src/services/completion/yaml/fix_data_generator_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/completion/yaml/fix_data_generator.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/completion/yaml/pubspec_generator_test.dart b/pkg/analysis_server/test/src/services/completion/yaml/pubspec_generator_test.dart
index acfead8..07d2bb7 100644
--- a/pkg/analysis_server/test/src/services/completion/yaml/pubspec_generator_test.dart
+++ b/pkg/analysis_server/test/src/services/completion/yaml/pubspec_generator_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/completion/yaml/pubspec_generator.dart';
 import 'package:analysis_server/src/services/pub/pub_api.dart';
 import 'package:analysis_server/src/services/pub/pub_package_service.dart';
diff --git a/pkg/analysis_server/test/src/services/completion/yaml/test_all.dart b/pkg/analysis_server/test/src/services/completion/yaml/test_all.dart
index 0d82611..e793c59 100644
--- a/pkg/analysis_server/test/src/services/completion/yaml/test_all.dart
+++ b/pkg/analysis_server/test/src/services/completion/yaml/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'analysis_options_generator_test.dart' as analysis_options_generator;
diff --git a/pkg/analysis_server/test/src/services/completion/yaml/yaml_generator_test_support.dart b/pkg/analysis_server/test/src/services/completion/yaml/yaml_generator_test_support.dart
index 3baebe1..254a855 100644
--- a/pkg/analysis_server/test/src/services/completion/yaml/yaml_generator_test_support.dart
+++ b/pkg/analysis_server/test/src/services/completion/yaml/yaml_generator_test_support.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/services/completion/yaml/yaml_completion_generator.dart';
 import 'package:analyzer/src/test_utilities/resource_provider_mixin.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/add_diagnostic_property_reference_test.dart b/pkg/analysis_server/test/src/services/correction/assist/add_diagnostic_property_reference_test.dart
index f9b684c..6a79a03 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/add_diagnostic_property_reference_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/add_diagnostic_property_reference_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/add_not_null_assert_test.dart b/pkg/analysis_server/test/src/services/correction/assist/add_not_null_assert_test.dart
index d100c48..ac70f98 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/add_not_null_assert_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/add_not_null_assert_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/add_return_type_test.dart b/pkg/analysis_server/test/src/services/correction/assist/add_return_type_test.dart
index c288dd0..3224af1 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/add_return_type_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/add_return_type_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/add_type_annotation_test.dart b/pkg/analysis_server/test/src/services/correction/assist/add_type_annotation_test.dart
index 06724fb..e897474 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/add_type_annotation_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/add_type_annotation_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/assign_to_local_variable_test.dart b/pkg/analysis_server/test/src/services/correction/assist/assign_to_local_variable_test.dart
index 3fa857a..9630000 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/assign_to_local_variable_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/assign_to_local_variable_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/assist_processor.dart b/pkg/analysis_server/test/src/services/correction/assist/assist_processor.dart
index 1435f6c..ae5b9a6 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/assist_processor.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/assist_processor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/plugin/edit/assist/assist_core.dart';
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/assist_internal.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_class_to_mixin_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_class_to_mixin_test.dart
index 9ccf27d..20b116b 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_class_to_mixin_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_class_to_mixin_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_documentation_into_block_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_documentation_into_block_test.dart
index 9fe4f87..b7b2a62 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_documentation_into_block_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_documentation_into_block_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_documentation_into_line_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_documentation_into_line_test.dart
index 92a8449..660e128 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_documentation_into_line_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_documentation_into_line_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_into_async_body_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_into_async_body_test.dart
index 0120636..353acef 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_into_async_body_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_into_async_body_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_into_block_body_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_into_block_body_test.dart
index db04588..869228d 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_into_block_body_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_into_block_body_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_into_expression_body_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_into_expression_body_test.dart
index 6e8152d..612ddfb 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_into_expression_body_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_into_expression_body_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_into_final_field_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_into_final_field_test.dart
index 345eda1..5e2aaba 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_into_final_field_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_into_final_field_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_into_for_index_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_into_for_index_test.dart
index d6aca70..6fc9393 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_into_for_index_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_into_for_index_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_into_generic_function_syntax_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_into_generic_function_syntax_test.dart
index cb80726..90c02e0 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_into_generic_function_syntax_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_into_generic_function_syntax_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_into_getter_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_into_getter_test.dart
index ffc7664..d806251 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_into_getter_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_into_getter_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_into_is_not_empty_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_into_is_not_empty_test.dart
index ce777b0..c34ba7e 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_into_is_not_empty_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_into_is_not_empty_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_into_is_not_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_into_is_not_test.dart
index 5a68942..e66f540 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_into_is_not_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_into_is_not_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_part_of_to_uri_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_part_of_to_uri_test.dart
index 4f99ef9..e9f455e 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_part_of_to_uri_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_part_of_to_uri_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_to_double_quoted_string_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_to_double_quoted_string_test.dart
index 813e4bc..16bd7b3 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_to_double_quoted_string_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_to_double_quoted_string_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_to_field_parameter_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_to_field_parameter_test.dart
index f616eab..acb1577 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_to_field_parameter_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_to_field_parameter_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_to_for_element_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_to_for_element_test.dart
index 80cd6c1..e9b0024 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_to_for_element_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_to_for_element_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_to_if_element_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_to_if_element_test.dart
index b277e60..274f6d4 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_to_if_element_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_to_if_element_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_to_int_literal_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_to_int_literal_test.dart
index 919ab32..7ebfdae 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_to_int_literal_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_to_int_literal_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_to_list_literal_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_to_list_literal_test.dart
index 880a6f1..68a565d 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_to_list_literal_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_to_list_literal_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_to_map_literal_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_to_map_literal_test.dart
index 9b6b24b..f2d4e19 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_to_map_literal_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_to_map_literal_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_to_multiline_string_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_to_multiline_string_test.dart
index 1e52915..1f3291a 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_to_multiline_string_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_to_multiline_string_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_to_normal_parameter_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_to_normal_parameter_test.dart
index 90973a6..c26c19b 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_to_normal_parameter_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_to_normal_parameter_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_to_null_aware_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_to_null_aware_test.dart
index 7d6b659..67d578c 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_to_null_aware_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_to_null_aware_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_to_package_import_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_to_package_import_test.dart
index 1fe3d84..417fdcc 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_to_package_import_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_to_package_import_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_to_set_literal_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_to_set_literal_test.dart
index 76079f7..20eeb8c 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_to_set_literal_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_to_set_literal_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_to_single_quoted_string_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_to_single_quoted_string_test.dart
index 4214de8..8515b73 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_to_single_quoted_string_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_to_single_quoted_string_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/convert_to_spread_test.dart b/pkg/analysis_server/test/src/services/correction/assist/convert_to_spread_test.dart
index dc43575..22cf5e0 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/convert_to_spread_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/convert_to_spread_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/encapsulate_field_test.dart b/pkg/analysis_server/test/src/services/correction/assist/encapsulate_field_test.dart
index 5817ae2..f359ea9 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/encapsulate_field_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/encapsulate_field_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/exchange_operands_test.dart b/pkg/analysis_server/test/src/services/correction/assist/exchange_operands_test.dart
index c5921f3..5ea4c1f 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/exchange_operands_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/exchange_operands_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/flutter_convert_to_children_test.dart b/pkg/analysis_server/test/src/services/correction/assist/flutter_convert_to_children_test.dart
index 1bac364..6241079 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/flutter_convert_to_children_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/flutter_convert_to_children_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/flutter_convert_to_stateful_widget_test.dart b/pkg/analysis_server/test/src/services/correction/assist/flutter_convert_to_stateful_widget_test.dart
index 426fa2b..16088e8 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/flutter_convert_to_stateful_widget_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/flutter_convert_to_stateful_widget_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/flutter_move_down_test.dart b/pkg/analysis_server/test/src/services/correction/assist/flutter_move_down_test.dart
index 3ed98b5..ecab131 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/flutter_move_down_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/flutter_move_down_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/flutter_move_up_test.dart b/pkg/analysis_server/test/src/services/correction/assist/flutter_move_up_test.dart
index 905d316..e713017 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/flutter_move_up_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/flutter_move_up_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/flutter_remove_widget_test.dart b/pkg/analysis_server/test/src/services/correction/assist/flutter_remove_widget_test.dart
index f6ed88f..0cd56e9 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/flutter_remove_widget_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/flutter_remove_widget_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/flutter_surround_with_set_state_test.dart b/pkg/analysis_server/test/src/services/correction/assist/flutter_surround_with_set_state_test.dart
index d13bb22..7462d46 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/flutter_surround_with_set_state_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/flutter_surround_with_set_state_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/flutter_swap_with_child_test.dart b/pkg/analysis_server/test/src/services/correction/assist/flutter_swap_with_child_test.dart
index babc107..2cd225e 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/flutter_swap_with_child_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/flutter_swap_with_child_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/flutter_swap_with_parent_test.dart b/pkg/analysis_server/test/src/services/correction/assist/flutter_swap_with_parent_test.dart
index 197470b..e9e36b5 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/flutter_swap_with_parent_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/flutter_swap_with_parent_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_center_test.dart b/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_center_test.dart
index 877ffb7..d34de66 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_center_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_center_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_column_test.dart b/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_column_test.dart
index fc79cb7..4b960dd 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_column_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_column_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_container_test.dart b/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_container_test.dart
index 04702fa..62aca16 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_container_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_container_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_generic_test.dart b/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_generic_test.dart
index e8df73f..5bc12d6 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_generic_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_generic_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_padding_test.dart b/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_padding_test.dart
index 685b2df..6e4e119 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_padding_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_padding_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_row_test.dart b/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_row_test.dart
index a9e6554..fd16ea4 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_row_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_row_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_sized_box_test.dart b/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_sized_box_test.dart
index 74c6918..8f7b42b 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_sized_box_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_sized_box_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_stream_builder_test.dart b/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_stream_builder_test.dart
index 4c32342..abb6e96 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_stream_builder_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/flutter_wrap_stream_builder_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/import_add_show_test.dart b/pkg/analysis_server/test/src/services/correction/assist/import_add_show_test.dart
index e00ee78..66bf905 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/import_add_show_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/import_add_show_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/inline_invocation_test.dart b/pkg/analysis_server/test/src/services/correction/assist/inline_invocation_test.dart
index 23749ff..41352e8 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/inline_invocation_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/inline_invocation_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/introduce_local_cast_type_test.dart b/pkg/analysis_server/test/src/services/correction/assist/introduce_local_cast_type_test.dart
index 784efb9..29f7c3e 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/introduce_local_cast_type_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/introduce_local_cast_type_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/invert_if_statement_test.dart b/pkg/analysis_server/test/src/services/correction/assist/invert_if_statement_test.dart
index b86a190..503faef 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/invert_if_statement_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/invert_if_statement_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/join_if_with_inner_test.dart b/pkg/analysis_server/test/src/services/correction/assist/join_if_with_inner_test.dart
index 3c19528..c4e4a9a 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/join_if_with_inner_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/join_if_with_inner_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/join_if_with_outer_test.dart b/pkg/analysis_server/test/src/services/correction/assist/join_if_with_outer_test.dart
index a31c29e..56a6a4a 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/join_if_with_outer_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/join_if_with_outer_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/join_variable_declaration_test.dart b/pkg/analysis_server/test/src/services/correction/assist/join_variable_declaration_test.dart
index 8b885c8..f22173d 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/join_variable_declaration_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/join_variable_declaration_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/remove_type_annotation_test.dart b/pkg/analysis_server/test/src/services/correction/assist/remove_type_annotation_test.dart
index a1efc00..62bfeca 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/remove_type_annotation_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/remove_type_annotation_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/replace_conditional_with_if_else_test.dart b/pkg/analysis_server/test/src/services/correction/assist/replace_conditional_with_if_else_test.dart
index e5f1923..7be0adc 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/replace_conditional_with_if_else_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/replace_conditional_with_if_else_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/replace_if_else_with_conditional_test.dart b/pkg/analysis_server/test/src/services/correction/assist/replace_if_else_with_conditional_test.dart
index 7641070..cbbf880 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/replace_if_else_with_conditional_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/replace_if_else_with_conditional_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/replace_with_var_test.dart b/pkg/analysis_server/test/src/services/correction/assist/replace_with_var_test.dart
index 6ab4ad8..d0ab5ce 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/replace_with_var_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/replace_with_var_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/shadow_field_test.dart b/pkg/analysis_server/test/src/services/correction/assist/shadow_field_test.dart
index f13b966..ba8a0e3 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/shadow_field_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/shadow_field_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/sort_child_property_last_test.dart b/pkg/analysis_server/test/src/services/correction/assist/sort_child_property_last_test.dart
index b407482..96c39a9 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/sort_child_property_last_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/sort_child_property_last_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/split_and_condition_test.dart b/pkg/analysis_server/test/src/services/correction/assist/split_and_condition_test.dart
index 2e96ea7..5845e92 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/split_and_condition_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/split_and_condition_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/split_variable_declaration_test.dart b/pkg/analysis_server/test/src/services/correction/assist/split_variable_declaration_test.dart
index 255f6e5..c9e5eb4 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/split_variable_declaration_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/split_variable_declaration_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/surround_with_block_test.dart b/pkg/analysis_server/test/src/services/correction/assist/surround_with_block_test.dart
index 54ef449..085fec0 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/surround_with_block_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/surround_with_block_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/surround_with_do_while_test.dart b/pkg/analysis_server/test/src/services/correction/assist/surround_with_do_while_test.dart
index d6ad18f..ff7ca9c 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/surround_with_do_while_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/surround_with_do_while_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/surround_with_for_in_test.dart b/pkg/analysis_server/test/src/services/correction/assist/surround_with_for_in_test.dart
index 6b7ca74..ecd4297 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/surround_with_for_in_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/surround_with_for_in_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/surround_with_for_test.dart b/pkg/analysis_server/test/src/services/correction/assist/surround_with_for_test.dart
index ca39826..3ae3580 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/surround_with_for_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/surround_with_for_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/surround_with_if_test.dart b/pkg/analysis_server/test/src/services/correction/assist/surround_with_if_test.dart
index 91ed08c..6b77b2c 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/surround_with_if_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/surround_with_if_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/surround_with_try_catch_test.dart b/pkg/analysis_server/test/src/services/correction/assist/surround_with_try_catch_test.dart
index 3fa1377..823ec7a 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/surround_with_try_catch_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/surround_with_try_catch_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/surround_with_try_finally_test.dart b/pkg/analysis_server/test/src/services/correction/assist/surround_with_try_finally_test.dart
index e6d5010..81a75c4 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/surround_with_try_finally_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/surround_with_try_finally_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/surround_with_while_test.dart b/pkg/analysis_server/test/src/services/correction/assist/surround_with_while_test.dart
index 24eb591..c989ffd 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/surround_with_while_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/surround_with_while_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/assist/test_all.dart b/pkg/analysis_server/test/src/services/correction/assist/test_all.dart
index 9a0192e..fef565f5 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/test_all.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'add_diagnostic_property_reference_test.dart' as add_diagnostic_property;
diff --git a/pkg/analysis_server/test/src/services/correction/assist/use_curly_braces_test.dart b/pkg/analysis_server/test/src/services/correction/assist/use_curly_braces_test.dart
index 93d28d6..df54292 100644
--- a/pkg/analysis_server/test/src/services/correction/assist/use_curly_braces_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/assist/use_curly_braces_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/assist/assist.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/add_async_test.dart b/pkg/analysis_server/test/src/services/correction/fix/add_async_test.dart
index bb382ff..dad6767 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/add_async_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/add_async_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer/src/error/codes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/add_await_test.dart b/pkg/analysis_server/test/src/services/correction/fix/add_await_test.dart
index 31ce0c6..45dbde2 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/add_await_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/add_await_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/add_const_test.dart b/pkg/analysis_server/test/src/services/correction/fix/add_const_test.dart
index bcb2893..c38b96f 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/add_const_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/add_const_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/add_curly_braces_test.dart b/pkg/analysis_server/test/src/services/correction/fix/add_curly_braces_test.dart
index 18da15e..8bf57b5 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/add_curly_braces_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/add_curly_braces_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/add_diagnostic_property_reference_test.dart b/pkg/analysis_server/test/src/services/correction/fix/add_diagnostic_property_reference_test.dart
index 7df0970..671d48f 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/add_diagnostic_property_reference_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/add_diagnostic_property_reference_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer/src/error/codes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/add_explicit_cast_test.dart b/pkg/analysis_server/test/src/services/correction/fix/add_explicit_cast_test.dart
index 797f097..e15b3c6 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/add_explicit_cast_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/add_explicit_cast_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/add_field_formal_parameters_test.dart b/pkg/analysis_server/test/src/services/correction/fix/add_field_formal_parameters_test.dart
index b8dbde7..6c53168 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/add_field_formal_parameters_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/add_field_formal_parameters_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/add_late_test.dart b/pkg/analysis_server/test/src/services/correction/fix/add_late_test.dart
index 039dd8d..4600c2d 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/add_late_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/add_late_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/add_missing_enum_case_clauses_test.dart b/pkg/analysis_server/test/src/services/correction/fix/add_missing_enum_case_clauses_test.dart
index f23da1c..7bdcdb5 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/add_missing_enum_case_clauses_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/add_missing_enum_case_clauses_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer/src/error/codes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/add_missing_parameter_named_test.dart b/pkg/analysis_server/test/src/services/correction/fix/add_missing_parameter_named_test.dart
index d1572d6..b870f80 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/add_missing_parameter_named_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/add_missing_parameter_named_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/add_missing_parameter_positional_test.dart b/pkg/analysis_server/test/src/services/correction/fix/add_missing_parameter_positional_test.dart
index 532f7a1..9176d52 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/add_missing_parameter_positional_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/add_missing_parameter_positional_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/add_missing_parameter_required_test.dart b/pkg/analysis_server/test/src/services/correction/fix/add_missing_parameter_required_test.dart
index b073812..7649cf2 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/add_missing_parameter_required_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/add_missing_parameter_required_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/change_workspace.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_workspace.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/add_missing_required_argument_test.dart b/pkg/analysis_server/test/src/services/correction/fix/add_missing_required_argument_test.dart
index 593c68c..d0c172f 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/add_missing_required_argument_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/add_missing_required_argument_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/add_ne_null_test.dart b/pkg/analysis_server/test/src/services/correction/fix/add_ne_null_test.dart
index 0d52849..38912fd 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/add_ne_null_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/add_ne_null_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/add_null_check_test.dart b/pkg/analysis_server/test/src/services/correction/fix/add_null_check_test.dart
index 84fb89a..eaeb488 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/add_null_check_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/add_null_check_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer/src/error/codes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/add_override_test.dart b/pkg/analysis_server/test/src/services/correction/fix/add_override_test.dart
index 7a33711..54e6983 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/add_override_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/add_override_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/add_required_test.dart b/pkg/analysis_server/test/src/services/correction/fix/add_required_test.dart
index d5b03dc..237f0e0 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/add_required_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/add_required_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/add_return_type_test.dart b/pkg/analysis_server/test/src/services/correction/fix/add_return_type_test.dart
index 75a8383..33a21c1 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/add_return_type_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/add_return_type_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/add_static_test.dart b/pkg/analysis_server/test/src/services/correction/fix/add_static_test.dart
index 7fd378a..1c18f09 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/add_static_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/add_static_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/add_super_constructor_invocation_test.dart b/pkg/analysis_server/test/src/services/correction/fix/add_super_constructor_invocation_test.dart
index ce129cc..73348d8 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/add_super_constructor_invocation_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/add_super_constructor_invocation_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/add_type_annotation_test.dart b/pkg/analysis_server/test/src/services/correction/fix/add_type_annotation_test.dart
index dd375be..338af4b 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/add_type_annotation_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/add_type_annotation_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/analysis_options/remove_lint_test.dart b/pkg/analysis_server/test/src/services/correction/fix/analysis_options/remove_lint_test.dart
index deb6eb4..f099050 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/analysis_options/remove_lint_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/analysis_options/remove_lint_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:linter/src/rules.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/analysis_options/remove_setting_test.dart b/pkg/analysis_server/test/src/services/correction/fix/analysis_options/remove_setting_test.dart
index c378884..87870a2 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/analysis_options/remove_setting_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/analysis_options/remove_setting_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'test_support.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/analysis_options/test_all.dart b/pkg/analysis_server/test/src/services/correction/fix/analysis_options/test_all.dart
index 6d61c19..68e1ceb 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/analysis_options/test_all.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/analysis_options/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'remove_lint_test.dart' as remove_lint;
diff --git a/pkg/analysis_server/test/src/services/correction/fix/analysis_options/test_support.dart b/pkg/analysis_server/test/src/services/correction/fix/analysis_options/test_support.dart
index 4d1d0a8..8762e93 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/analysis_options/test_support.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/analysis_options/test_support.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/plugin/edit/fix/fix_core.dart';
 import 'package:analysis_server/src/protocol_server.dart' show SourceEdit;
 import 'package:analysis_server/src/services/correction/fix/analysis_options/fix_generator.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/add_await_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/add_await_test.dart
index dc61da4..66f6bdc 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/add_await_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/add_await_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/add_const_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/add_const_test.dart
index d20eaf8..0801465 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/add_const_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/add_const_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/add_diagnostic_property_reference_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/add_diagnostic_property_reference_test.dart
index 0fead9f..c0e7ad4 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/add_diagnostic_property_reference_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/add_diagnostic_property_reference_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/add_override_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/add_override_test.dart
index b62d97e..bbd1463 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/add_override_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/add_override_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/add_required_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/add_required_test.dart
index 0be6d18..ba1b000 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/add_required_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/add_required_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/bulk_fix_processor.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/bulk_fix_processor.dart
index 59ae8b8..82b04e2 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/bulk_fix_processor.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/bulk_fix_processor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/bulk_fix_processor.dart';
 import 'package:analysis_server/src/services/correction/change_workspace.dart';
 import 'package:analyzer/src/dart/analysis/byte_store.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/bulk_fix_processor_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/bulk_fix_processor_test.dart
index 2e36f14..991651f 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/bulk_fix_processor_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/bulk_fix_processor_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_documentation_into_line_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_documentation_into_line_test.dart
index 2094c37..7773740 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_documentation_into_line_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_documentation_into_line_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_map_from_iterable_to_for_literal_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_map_from_iterable_to_for_literal_test.dart
index d9e3834..51d99c2 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_map_from_iterable_to_for_literal_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_map_from_iterable_to_for_literal_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_contains_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_contains_test.dart
index eacb1cc..65b9139 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_contains_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_contains_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_generic_function_syntax_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_generic_function_syntax_test.dart
index e279e12..dccf8b9 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_generic_function_syntax_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_generic_function_syntax_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_if_element_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_if_element_test.dart
index e965e54..64cfc42 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_if_element_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_if_element_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_if_null_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_if_null_test.dart
index 5bca56c..8c7b83f 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_if_null_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_if_null_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_int_literal_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_int_literal_test.dart
index 32b17ce..b154097 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_int_literal_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_int_literal_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_is_not_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_is_not_test.dart
index 42a907d..3fe2ff6 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_is_not_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_is_not_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_list_literal_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_list_literal_test.dart
index af7f3cb..c130c0b 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_list_literal_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_list_literal_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_map_literal_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_map_literal_test.dart
index cb02894..b018ce0 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_map_literal_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_map_literal_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_null_aware_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_null_aware_test.dart
index e30e7d7..45b117a 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_null_aware_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_null_aware_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_package_import_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_package_import_test.dart
index 3c8cf2b..8bec06f 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_package_import_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_package_import_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_relative_import_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_relative_import_test.dart
index 40b022f..78f50bf 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_relative_import_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_relative_import_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_set_literal_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_set_literal_test.dart
index bfcaf1c..0ee4a40 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_set_literal_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_set_literal_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_single_quoted_strings_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_single_quoted_strings_test.dart
index 68a54c0..92d1d10 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_single_quoted_strings_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_single_quoted_strings_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_spread_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_spread_test.dart
index ddbdc0a..6219446 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_spread_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_spread_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_where_type_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_where_type_test.dart
index 62788ef..c0a382f2 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_where_type_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/convert_to_where_type_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/create_method_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/create_method_test.dart
index cf17881..c111c46 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/create_method_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/create_method_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/data_driven_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/data_driven_test.dart
index 09a3433..0c50eda 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/data_driven_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/data_driven_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/bulk_fix_processor.dart';
 import 'package:analysis_server/src/services/correction/dart/data_driven.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_manager.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/inline_invocation_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/inline_invocation_test.dart
index b34d124..8ec7bb0 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/inline_invocation_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/inline_invocation_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/inline_typedef_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/inline_typedef_test.dart
index c2612f9..0673ac0 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/inline_typedef_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/inline_typedef_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/make_final_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/make_final_test.dart
index 21724f2..4af5171 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/make_final_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/make_final_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_argument_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_argument_test.dart
index 7d87ea4..613c373 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_argument_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_argument_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_await_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_await_test.dart
index b1c9f97..85c8868 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_await_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_await_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_duplicate_case_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_duplicate_case_test.dart
index 76d7a914..350c861 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_duplicate_case_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_duplicate_case_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_empty_catch_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_empty_catch_test.dart
index a6a0897d..c23610f 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_empty_catch_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_empty_catch_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_empty_constructor_body_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_empty_constructor_body_test.dart
index 9469973..b1def09 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_empty_constructor_body_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_empty_constructor_body_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_empty_else_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_empty_else_test.dart
index 5c967e2..e184a79 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_empty_else_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_empty_else_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_empty_statement_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_empty_statement_test.dart
index fbf7b39..87bf05a 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_empty_statement_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_empty_statement_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_if_null_operator_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_if_null_operator_test.dart
index 0003079..b73ecb5 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_if_null_operator_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_if_null_operator_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_initializer_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_initializer_test.dart
index c95ede1..a8c3614 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_initializer_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_initializer_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_interpolation_braces_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_interpolation_braces_test.dart
index a291bf1..51fb561 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_interpolation_braces_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_interpolation_braces_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_method_declaration_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_method_declaration_test.dart
index 65f79185..e6b5a9b 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_method_declaration_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_method_declaration_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_non_null_assertion_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_non_null_assertion_test.dart
index eeacfbc..46e164e 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_non_null_assertion_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_non_null_assertion_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import '../../../../../abstract_context.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_operator_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_operator_test.dart
index f876196..a80779a 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_operator_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_operator_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_question_mark_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_question_mark_test.dart
index 48706e9..a87d83c 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_question_mark_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_question_mark_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_this_expression_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_this_expression_test.dart
index eb9eb5c..fd30b02 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_this_expression_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_this_expression_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_type_annotation_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_type_annotation_test.dart
index 600d12d..018fd3d 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_type_annotation_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_type_annotation_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_unnecessary_const_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_unnecessary_const_test.dart
index eb112f7..2bbcf70 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_unnecessary_const_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_unnecessary_const_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_unnecessary_new_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_unnecessary_new_test.dart
index 88670c3..39d2110 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_unnecessary_new_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_unnecessary_new_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_unnecessary_string_interpolation_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_unnecessary_string_interpolation_test.dart
index 1ae3d1d..bd639ad 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_unnecessary_string_interpolation_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/remove_unnecessary_string_interpolation_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/rename_to_camel_case_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/rename_to_camel_case_test.dart
index 5248e32..9c35121 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/rename_to_camel_case_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/rename_to_camel_case_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_colon_with_equals_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_colon_with_equals_test.dart
index f057c74..b74ba21 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_colon_with_equals_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_colon_with_equals_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_final_with_const_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_final_with_const_test.dart
index d886f78..d5d91f3 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_final_with_const_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_final_with_const_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_new_with_const_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_new_with_const_test.dart
index f8ba7bd..982c596 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_new_with_const_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_new_with_const_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_null_with_closure_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_null_with_closure_test.dart
index 9a686bf..a82c882 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_null_with_closure_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_null_with_closure_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_with_conditional_assignment_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_with_conditional_assignment_test.dart
index 77c9615..bab21ca 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_with_conditional_assignment_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_with_conditional_assignment_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_with_is_empty_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_with_is_empty_test.dart
index b61ffd7..13b9776 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_with_is_empty_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_with_is_empty_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_with_tear_off_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_with_tear_off_test.dart
index eef575b..777ac6e 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_with_tear_off_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_with_tear_off_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_with_var_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_with_var_test.dart
index 27367dc..ac0bf55 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_with_var_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/replace_with_var_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/sort_child_properties_last_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/sort_child_properties_last_test.dart
index 3cc5338..89b30db 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/sort_child_properties_last_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/sort_child_properties_last_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/test_all.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/test_all.dart
index 6b8bb68..33acd38 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/test_all.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'add_await_test.dart' as add_await;
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/use_curly_braces_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/use_curly_braces_test.dart
index 8e1f19a..9bbbeea 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/use_curly_braces_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/use_curly_braces_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/use_is_not_empty_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/use_is_not_empty_test.dart
index 1f337b8..1d1268b 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/use_is_not_empty_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/use_is_not_empty_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/bulk/use_rethrow_test.dart b/pkg/analysis_server/test/src/services/correction/fix/bulk/use_rethrow_test.dart
index 9d4678b..cdd797d 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/bulk/use_rethrow_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/bulk/use_rethrow_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/change_argument_name_test.dart b/pkg/analysis_server/test/src/services/correction/fix/change_argument_name_test.dart
index 5bb073d..3fbed10 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/change_argument_name_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/change_argument_name_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/change_to_nearest_precise_value_test.dart b/pkg/analysis_server/test/src/services/correction/fix/change_to_nearest_precise_value_test.dart
index 419a6c1..c4bf81b 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/change_to_nearest_precise_value_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/change_to_nearest_precise_value_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/change_to_static_access_test.dart b/pkg/analysis_server/test/src/services/correction/fix/change_to_static_access_test.dart
index dd985bb..a6720bf 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/change_to_static_access_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/change_to_static_access_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/change_to_test.dart b/pkg/analysis_server/test/src/services/correction/fix/change_to_test.dart
index da9231f..0131fcd 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/change_to_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/change_to_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/change_type_annotation_test.dart b/pkg/analysis_server/test/src/services/correction/fix/change_type_annotation_test.dart
index c848914..3d07b71 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/change_type_annotation_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/change_type_annotation_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/convert_documentation_into_line_test.dart b/pkg/analysis_server/test/src/services/correction/fix/convert_documentation_into_line_test.dart
index e68869f..51be47f 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/convert_documentation_into_line_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/convert_documentation_into_line_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/convert_flutter_child_test.dart b/pkg/analysis_server/test/src/services/correction/fix/convert_flutter_child_test.dart
index 7afc732..c4602e4 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/convert_flutter_child_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/convert_flutter_child_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/convert_flutter_children_test.dart b/pkg/analysis_server/test/src/services/correction/fix/convert_flutter_children_test.dart
index 0d5ae48..46797c9 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/convert_flutter_children_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/convert_flutter_children_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/convert_into_expression_body_test.dart b/pkg/analysis_server/test/src/services/correction/fix/convert_into_expression_body_test.dart
index 5bcdd3e..70c20334 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/convert_into_expression_body_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/convert_into_expression_body_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/convert_to_contains_test.dart b/pkg/analysis_server/test/src/services/correction/fix/convert_to_contains_test.dart
index f0edd0b..6602062 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/convert_to_contains_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/convert_to_contains_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/convert_to_for_element_test.dart b/pkg/analysis_server/test/src/services/correction/fix/convert_to_for_element_test.dart
index fafbb6e..1c35ea9 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/convert_to_for_element_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/convert_to_for_element_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/convert_to_generic_function_syntax_test.dart b/pkg/analysis_server/test/src/services/correction/fix/convert_to_generic_function_syntax_test.dart
index 6d1ed6b..634617b 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/convert_to_generic_function_syntax_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/convert_to_generic_function_syntax_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/convert_to_if_element_test.dart b/pkg/analysis_server/test/src/services/correction/fix/convert_to_if_element_test.dart
index ed2c3aa..677f515 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/convert_to_if_element_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/convert_to_if_element_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/convert_to_if_null_test.dart b/pkg/analysis_server/test/src/services/correction/fix/convert_to_if_null_test.dart
index 1a641e7..749807a 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/convert_to_if_null_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/convert_to_if_null_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer/src/dart/error/lint_codes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/convert_to_int_literal_test.dart b/pkg/analysis_server/test/src/services/correction/fix/convert_to_int_literal_test.dart
index 154e215..c70252a 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/convert_to_int_literal_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/convert_to_int_literal_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/convert_to_list_literal_test.dart b/pkg/analysis_server/test/src/services/correction/fix/convert_to_list_literal_test.dart
index 160c5f4..c77702a 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/convert_to_list_literal_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/convert_to_list_literal_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/convert_to_map_literal_test.dart b/pkg/analysis_server/test/src/services/correction/fix/convert_to_map_literal_test.dart
index 3407683..4f1a80f 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/convert_to_map_literal_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/convert_to_map_literal_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/convert_to_named_arguments_test.dart b/pkg/analysis_server/test/src/services/correction/fix/convert_to_named_arguments_test.dart
index cf35cc7..18f9934 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/convert_to_named_arguments_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/convert_to_named_arguments_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/convert_to_null_aware_spread_test.dart b/pkg/analysis_server/test/src/services/correction/fix/convert_to_null_aware_spread_test.dart
index 8cdcb25..4901a63 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/convert_to_null_aware_spread_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/convert_to_null_aware_spread_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/convert_to_null_aware_test.dart b/pkg/analysis_server/test/src/services/correction/fix/convert_to_null_aware_test.dart
index 52e07bf..4331faa 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/convert_to_null_aware_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/convert_to_null_aware_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/convert_to_on_type_test.dart b/pkg/analysis_server/test/src/services/correction/fix/convert_to_on_type_test.dart
index f14cf3c..9d765ab 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/convert_to_on_type_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/convert_to_on_type_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/convert_to_package_import_test.dart b/pkg/analysis_server/test/src/services/correction/fix/convert_to_package_import_test.dart
index e991423..3cc1704 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/convert_to_package_import_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/convert_to_package_import_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/convert_to_relative_import_test.dart b/pkg/analysis_server/test/src/services/correction/fix/convert_to_relative_import_test.dart
index 8e59b5f..b8bc8af 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/convert_to_relative_import_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/convert_to_relative_import_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer/src/error/codes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/convert_to_set_literal_test.dart b/pkg/analysis_server/test/src/services/correction/fix/convert_to_set_literal_test.dart
index 28674cb..ef21709 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/convert_to_set_literal_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/convert_to_set_literal_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/convert_to_single_quoted_string_test.dart b/pkg/analysis_server/test/src/services/correction/fix/convert_to_single_quoted_string_test.dart
index 12f8212..d615eb6 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/convert_to_single_quoted_string_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/convert_to_single_quoted_string_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/convert_to_spread_test.dart b/pkg/analysis_server/test/src/services/correction/fix/convert_to_spread_test.dart
index bb9b5c8..a85080b 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/convert_to_spread_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/convert_to_spread_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/convert_to_where_type_test.dart b/pkg/analysis_server/test/src/services/correction/fix/convert_to_where_type_test.dart
index 7768534..891dec0 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/convert_to_where_type_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/convert_to_where_type_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/create_class_test.dart b/pkg/analysis_server/test/src/services/correction/fix/create_class_test.dart
index b81a200..69df2df 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/create_class_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/create_class_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/create_constructor_for_final_fields_test.dart b/pkg/analysis_server/test/src/services/correction/fix/create_constructor_for_final_fields_test.dart
index 32efaed..3e1e664 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/create_constructor_for_final_fields_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/create_constructor_for_final_fields_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/create_constructor_super_test.dart b/pkg/analysis_server/test/src/services/correction/fix/create_constructor_super_test.dart
index 19af80e..efb4913 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/create_constructor_super_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/create_constructor_super_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/create_constructor_test.dart b/pkg/analysis_server/test/src/services/correction/fix/create_constructor_test.dart
index 233fa51..62ef51fa 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/create_constructor_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/create_constructor_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/create_field_test.dart b/pkg/analysis_server/test/src/services/correction/fix/create_field_test.dart
index 869bda5..bcd22c6 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/create_field_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/create_field_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/create_file_test.dart b/pkg/analysis_server/test/src/services/correction/fix/create_file_test.dart
index 0c156d3..7eef88f 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/create_file_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/create_file_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/create_function_test.dart b/pkg/analysis_server/test/src/services/correction/fix/create_function_test.dart
index fd2fea7..42f5940 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/create_function_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/create_function_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/create_getter_test.dart b/pkg/analysis_server/test/src/services/correction/fix/create_getter_test.dart
index af7db0e..dc573f5 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/create_getter_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/create_getter_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/create_local_variable_test.dart b/pkg/analysis_server/test/src/services/correction/fix/create_local_variable_test.dart
index 2c1d827..78960df 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/create_local_variable_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/create_local_variable_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/create_method_test.dart b/pkg/analysis_server/test/src/services/correction/fix/create_method_test.dart
index 4549b21..52fec47 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/create_method_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/create_method_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/create_missing_overrides_test.dart b/pkg/analysis_server/test/src/services/correction/fix/create_missing_overrides_test.dart
index 300d9aa..e45d973 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/create_missing_overrides_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/create_missing_overrides_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/create_mixin_test.dart b/pkg/analysis_server/test/src/services/correction/fix/create_mixin_test.dart
index 024eab8..0efaa4c 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/create_mixin_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/create_mixin_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/create_no_such_method_test.dart b/pkg/analysis_server/test/src/services/correction/fix/create_no_such_method_test.dart
index 19bfb81..09e733a 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/create_no_such_method_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/create_no_such_method_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/create_setter_test.dart b/pkg/analysis_server/test/src/services/correction/fix/create_setter_test.dart
index 610f7dc..0c93281 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/create_setter_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/create_setter_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/add_type_parameter_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/add_type_parameter_test.dart
index dcda4bc..1cb910e 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/add_type_parameter_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/add_type_parameter_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/add_type_parameter.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/changes_selector.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/element_descriptor.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/code_fragment_parser_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/code_fragment_parser_test.dart
index 9a8fdc2..5117185 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/code_fragment_parser_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/code_fragment_parser_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:_fe_analyzer_shared/src/base/errors.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/accessor.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/code_fragment_parser.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/code_template_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/code_template_test.dart
index f6ccc74..6a20dd1 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/code_template_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/code_template_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/accessor.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/code_template.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/parameter_reference.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/data_driven_test_support.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/data_driven_test_support.dart
index e26e0061..6149d77 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/data_driven_test_support.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/data_driven_test_support.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/dart/data_driven.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/code_template.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/conflicting_key_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/conflicting_key_test.dart
index 77d6de7..876aec3 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/conflicting_key_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/conflicting_key_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_error_code.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/expected_primary_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/expected_primary_test.dart
index 38c7e43..f9100e7 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/expected_primary_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/expected_primary_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_error_code.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_character_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_character_test.dart
index ab3ece6..1050f96 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_character_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_character_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_error_code.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_key_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_key_test.dart
index 0a7c158..ed9a783 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_key_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_key_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_error_code.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_parameter_style_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_parameter_style_test.dart
index 0fe38db..f2869c9 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_parameter_style_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_parameter_style_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_error_code.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_required_if_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_required_if_test.dart
index 5037a80..4f48576 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_required_if_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_required_if_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_error_code.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_value_one_of_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_value_one_of_test.dart
index fa9beb5..fd960eb 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_value_one_of_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_value_one_of_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_error_code.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_value_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_value_test.dart
index 1bd6446..4fe611d 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_value_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/invalid_value_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_error_code.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/missing_key_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/missing_key_test.dart
index c4a2e75..3efdb34 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/missing_key_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/missing_key_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_error_code.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/missing_one_of_multiple_keys_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/missing_one_of_multiple_keys_test.dart
index 002f2f5..9a2ef98 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/missing_one_of_multiple_keys_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/missing_one_of_multiple_keys_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_error_code.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/missing_template_end_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/missing_template_end_test.dart
index 0301220..f9ed776 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/missing_template_end_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/missing_template_end_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_error_code.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/missing_token_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/missing_token_test.dart
index c1ee9bd..549eac8 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/missing_token_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/missing_token_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_error_code.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/missing_uri_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/missing_uri_test.dart
index ac21bfc..8efa08b 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/missing_uri_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/missing_uri_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_error_code.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/test_all.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/test_all.dart
index bb2464ae..8a67f05 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/test_all.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'conflicting_key_test.dart' as conflicting_key;
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/undefined_variable_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/undefined_variable_test.dart
index db854a5..5014984 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/undefined_variable_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/undefined_variable_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_error_code.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/unexpected_token_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/unexpected_token_test.dart
index 9f6213c..f96685d 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/unexpected_token_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/unexpected_token_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_error_code.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/unknown_accessor_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/unknown_accessor_test.dart
index 205ad42..c877690 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/unknown_accessor_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/unknown_accessor_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_error_code.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/unsupported_key_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/unsupported_key_test.dart
index 64d724e..8e6df60 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/unsupported_key_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/unsupported_key_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_error_code.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/unsupported_version_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/unsupported_version_test.dart
index 606341f..7bd3c13 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/unsupported_version_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/unsupported_version_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_error_code.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_parser.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/wrong_token_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/wrong_token_test.dart
index ed35ea9..9548a68 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/wrong_token_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/wrong_token_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_error_code.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/yaml_syntax_error_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/yaml_syntax_error_test.dart
index dfa3444..a74c9d2 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/yaml_syntax_error_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/diagnostics/yaml_syntax_error_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_error_code.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/element_matcher_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/element_matcher_test.dart
index f462b36..aa9695e 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/element_matcher_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/element_matcher_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/element_kind.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/element_matcher.dart';
 import 'package:analyzer/src/test_utilities/package_config_file_builder.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/end_to_end_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/end_to_end_test.dart
index eb13dcf..dbabac1 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/end_to_end_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/end_to_end_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'data_driven_test_support.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/flutter_use_case_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/flutter_use_case_test.dart
index e8d6d1b..327fe3a 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/flutter_use_case_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/flutter_use_case_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'data_driven_test_support.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/modify_parameters_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/modify_parameters_test.dart
index 5791e25..bec1da6 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/modify_parameters_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/modify_parameters_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/changes_selector.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/element_descriptor.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/element_kind.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/rename_parameter_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/rename_parameter_test.dart
index 3a189c0..856d4e0 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/rename_parameter_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/rename_parameter_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/changes_selector.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/element_descriptor.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/element_kind.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/rename_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/rename_test.dart
index 6e0ce4a..0affe38 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/rename_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/rename_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/changes_selector.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/element_descriptor.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/element_kind.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/sdk_fix_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/sdk_fix_test.dart
index a154782..2dfa7b4 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/sdk_fix_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/sdk_fix_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_manager.dart';
 import 'package:analyzer/src/test_utilities/mock_sdk.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/test_all.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/test_all.dart
index a21ba3c..f393c9b 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/test_all.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'add_type_parameter_test.dart' as add_type_parameter;
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/transform_override_set_parser_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/transform_override_set_parser_test.dart
index 5aa8721..a219dbc 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/transform_override_set_parser_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/transform_override_set_parser_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:_fe_analyzer_shared/src/base/errors.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_override_set.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_override_set_parser.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/transform_set_manager_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/transform_set_manager_test.dart
index c0f59db..e845848 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/transform_set_manager_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/transform_set_manager_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_manager.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/transform_set_parser_test.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/transform_set_parser_test.dart
index d2789c8..73ce508 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/transform_set_parser_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/transform_set_parser_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/accessor.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/add_type_parameter.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/change.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/data_driven/transform_set_parser_test_support.dart b/pkg/analysis_server/test/src/services/correction/fix/data_driven/transform_set_parser_test_support.dart
index af3b094..a18e9be 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/data_driven/transform_set_parser_test_support.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/data_driven/transform_set_parser_test_support.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set.dart';
 import 'package:analysis_server/src/services/correction/fix/data_driven/transform_set_parser.dart';
 import 'package:analyzer/error/error.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/extend_class_for_mixin_test.dart b/pkg/analysis_server/test/src/services/correction/fix/extend_class_for_mixin_test.dart
index 1624c7f..e534c03 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/extend_class_for_mixin_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/extend_class_for_mixin_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/fix_in_file_test.dart b/pkg/analysis_server/test/src/services/correction/fix/fix_in_file_test.dart
index 52438b8..7545858 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/fix_in_file_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/fix_in_file_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix_internal.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/fix_processor.dart b/pkg/analysis_server/test/src/services/correction/fix/fix_processor.dart
index 7ca8451..4c8fc08 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/fix_processor.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/fix_processor.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/plugin/edit/fix/fix_core.dart';
 import 'package:analysis_server/src/services/correction/change_workspace.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/fix_test.dart b/pkg/analysis_server/test/src/services/correction/fix/fix_test.dart
index b66fd12f..c457918 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/fix_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/fix_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/import_async_test.dart b/pkg/analysis_server/test/src/services/correction/fix/import_async_test.dart
index 5fa217e..519e973 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/import_async_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/import_async_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/import_library_prefix_test.dart b/pkg/analysis_server/test/src/services/correction/fix/import_library_prefix_test.dart
index c1ffcce..821600b 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/import_library_prefix_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/import_library_prefix_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/import_library_project_test.dart b/pkg/analysis_server/test/src/services/correction/fix/import_library_project_test.dart
index fcfed31..709dd4c 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/import_library_project_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/import_library_project_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/import_library_sdk_test.dart b/pkg/analysis_server/test/src/services/correction/fix/import_library_sdk_test.dart
index 8b0b7e5..54edaa4 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/import_library_sdk_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/import_library_sdk_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/import_library_show_test.dart b/pkg/analysis_server/test/src/services/correction/fix/import_library_show_test.dart
index e54adba..57b95ad 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/import_library_show_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/import_library_show_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/inline_invocation_test.dart b/pkg/analysis_server/test/src/services/correction/fix/inline_invocation_test.dart
index bb8dc37..c1562ba 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/inline_invocation_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/inline_invocation_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/inline_typedef_test.dart b/pkg/analysis_server/test/src/services/correction/fix/inline_typedef_test.dart
index 39d4fdb..ff11196 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/inline_typedef_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/inline_typedef_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/insert_semicolon_test.dart b/pkg/analysis_server/test/src/services/correction/fix/insert_semicolon_test.dart
index 937ff59..1425260 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/insert_semicolon_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/insert_semicolon_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/make_class_abstract_test.dart b/pkg/analysis_server/test/src/services/correction/fix/make_class_abstract_test.dart
index f5927f9..a9d04c6 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/make_class_abstract_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/make_class_abstract_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/make_field_not_final_test.dart b/pkg/analysis_server/test/src/services/correction/fix/make_field_not_final_test.dart
index 941643a..c36b65d 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/make_field_not_final_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/make_field_not_final_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/make_final_test.dart b/pkg/analysis_server/test/src/services/correction/fix/make_final_test.dart
index fbee41d..d035112 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/make_final_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/make_final_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/make_return_type_nullable_test.dart b/pkg/analysis_server/test/src/services/correction/fix/make_return_type_nullable_test.dart
index 7e976e7..1e9cb8f 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/make_return_type_nullable_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/make_return_type_nullable_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/make_variable_not_final_test.dart b/pkg/analysis_server/test/src/services/correction/fix/make_variable_not_final_test.dart
index c87fde3..cf9a788 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/make_variable_not_final_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/make_variable_not_final_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/make_variable_nullable_test.dart b/pkg/analysis_server/test/src/services/correction/fix/make_variable_nullable_test.dart
index f619f67..488331c 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/make_variable_nullable_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/make_variable_nullable_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/move_type_arguments_to_class_test.dart b/pkg/analysis_server/test/src/services/correction/fix/move_type_arguments_to_class_test.dart
index c3b99ff..6ff66ba 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/move_type_arguments_to_class_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/move_type_arguments_to_class_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/organize_imports_test.dart b/pkg/analysis_server/test/src/services/correction/fix/organize_imports_test.dart
index 941bdf4..125a5d5 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/organize_imports_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/organize_imports_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/qualify_reference_test.dart b/pkg/analysis_server/test/src/services/correction/fix/qualify_reference_test.dart
index 5c92c08..e44250d 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/qualify_reference_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/qualify_reference_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_annotation_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_annotation_test.dart
index b693ead..36be9f6 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_annotation_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_annotation_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_argument_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_argument_test.dart
index cb1dc00..c528f5b 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_argument_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_argument_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_await_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_await_test.dart
index 97d8bf8..29c0674 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_await_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_await_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_comparison_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_comparison_test.dart
index 5494406..97608943 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_comparison_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_comparison_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_const_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_const_test.dart
index 3f347cc3..7b6b001 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_const_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_const_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_dead_code_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_dead_code_test.dart
index 3fd394e..dd0e173 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_dead_code_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_dead_code_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_duplicate_case_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_duplicate_case_test.dart
index 0d8a6b1..c6243fd 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_duplicate_case_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_duplicate_case_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_empty_catch_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_empty_catch_test.dart
index ff75a69..2321c20 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_empty_catch_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_empty_catch_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_empty_constructor_body_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_empty_constructor_body_test.dart
index 3f93785..51b93c3 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_empty_constructor_body_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_empty_constructor_body_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer/error/error.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_empty_else_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_empty_else_test.dart
index b7521b3..db6fb4b 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_empty_else_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_empty_else_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_empty_statement_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_empty_statement_test.dart
index 0b28f0f..1622bea 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_empty_statement_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_empty_statement_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_if_null_operator_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_if_null_operator_test.dart
index 3f86e17..c92d731 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_if_null_operator_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_if_null_operator_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_initializer_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_initializer_test.dart
index 7127fbd..151ac34 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_initializer_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_initializer_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_interpolation_braces_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_interpolation_braces_test.dart
index eaf6bc0..76179a9 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_interpolation_braces_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_interpolation_braces_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_method_declaration_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_method_declaration_test.dart
index d7d5d74..40b63e0 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_method_declaration_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_method_declaration_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer/src/dart/analysis/experiments.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_name_from_combinator_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_name_from_combinator_test.dart
index e833910..9280896 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_name_from_combinator_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_name_from_combinator_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_non_null_assertion_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_non_null_assertion_test.dart
index d66f1b8..643425b 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_non_null_assertion_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_non_null_assertion_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_operator_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_operator_test.dart
index 22aa7e5..b71c545 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_operator_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_operator_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_parameters_in_getter_declaration_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_parameters_in_getter_declaration_test.dart
index 8b96c684..b4c7466 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_parameters_in_getter_declaration_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_parameters_in_getter_declaration_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_parentheses_in_getter_invocation_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_parentheses_in_getter_invocation_test.dart
index 5f0d7e3..203eae4 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_parentheses_in_getter_invocation_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_parentheses_in_getter_invocation_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_question_mark_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_question_mark_test.dart
index 286b5d3..3fcd7f9 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_question_mark_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_question_mark_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_this_expression_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_this_expression_test.dart
index aa1a132..6efe653 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_this_expression_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_this_expression_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_type_annotation_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_type_annotation_test.dart
index d4c97ab..c26fe04 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_type_annotation_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_type_annotation_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_type_arguments_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_type_arguments_test.dart
index 62bf7e6..e13eb07 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_type_arguments_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_type_arguments_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_unnecessary_cast_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_unnecessary_cast_test.dart
index 57bfd6c..ea8217b 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_unnecessary_cast_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_unnecessary_cast_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_unnecessary_const_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_unnecessary_const_test.dart
index 1f1e6f2..1969f3e 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_unnecessary_const_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_unnecessary_const_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_unnecessary_new_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_unnecessary_new_test.dart
index dc6b443..ee1a000 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_unnecessary_new_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_unnecessary_new_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_unnecessary_parentheses_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_unnecessary_parentheses_test.dart
index 166007e..f482d47 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_unnecessary_parentheses_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_unnecessary_parentheses_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_unnecessary_string_interpolation_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_unnecessary_string_interpolation_test.dart
index cd6a3c4..d849c0e 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_unnecessary_string_interpolation_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_unnecessary_string_interpolation_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_unused_catch_clause_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_unused_catch_clause_test.dart
index d18763d..97e20b7 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_unused_catch_clause_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_unused_catch_clause_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_unused_catch_stack_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_unused_catch_stack_test.dart
index 730f44e..4d484d6 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_unused_catch_stack_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_unused_catch_stack_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_unused_element_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_unused_element_test.dart
index 154a433..9faaa3a 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_unused_element_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_unused_element_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer/src/error/codes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_unused_field_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_unused_field_test.dart
index 8bf054c..e8419fd 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_unused_field_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_unused_field_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_unused_import_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_unused_import_test.dart
index 020945a..44953fc 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_unused_import_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_unused_import_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_unused_label_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_unused_label_test.dart
index df57ba1..e5525f38 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_unused_label_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_unused_label_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_unused_local_variable_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_unused_local_variable_test.dart
index dac33f8..45e17e3 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_unused_local_variable_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_unused_local_variable_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/remove_unused_parameter_test.dart b/pkg/analysis_server/test/src/services/correction/fix/remove_unused_parameter_test.dart
index d32eb88..d8e42b3 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/remove_unused_parameter_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/remove_unused_parameter_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/rename_to_camel_case_test.dart b/pkg/analysis_server/test/src/services/correction/fix/rename_to_camel_case_test.dart
index 9ae1f64..7fe7132 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/rename_to_camel_case_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/rename_to_camel_case_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_boolean_with_bool_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_boolean_with_bool_test.dart
index 2d35370..6931abc 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_boolean_with_bool_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_boolean_with_bool_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_cascade_with_dot_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_cascade_with_dot_test.dart
index 8cf92ad..26a4c84 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_cascade_with_dot_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_cascade_with_dot_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_colon_with_equals_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_colon_with_equals_test.dart
index 852892b..006166c 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_colon_with_equals_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_colon_with_equals_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_final_with_const_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_final_with_const_test.dart
index e1ffdad..4855265 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_final_with_const_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_final_with_const_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_final_with_var_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_final_with_var_test.dart
index e13d52a..142e6a2 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_final_with_var_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_final_with_var_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_new_with_const_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_new_with_const_test.dart
index a1607e5..5c1dd65 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_new_with_const_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_new_with_const_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_null_with_closure_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_null_with_closure_test.dart
index 8c6d3b3..0588184 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_null_with_closure_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_null_with_closure_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_return_type_future_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_return_type_future_test.dart
index 0c42514..273fff5 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_return_type_future_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_return_type_future_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_var_with_dynamic_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_var_with_dynamic_test.dart
index 02b4eae..444cd2d 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_var_with_dynamic_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_var_with_dynamic_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/dart/error/syntactic_errors.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_with_brackets_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_with_brackets_test.dart
index 21075fa..63fed72 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_with_brackets_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_with_brackets_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_with_conditional_assignment_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_with_conditional_assignment_test.dart
index 8964e95..7a1dbb4 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_with_conditional_assignment_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_with_conditional_assignment_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_with_eight_digit_hex_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_with_eight_digit_hex_test.dart
index bd4e2e1..9ec3529 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_with_eight_digit_hex_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_with_eight_digit_hex_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_with_extension_name_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_with_extension_name_test.dart
index 0bf4a84..8d70db9 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_with_extension_name_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_with_extension_name_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_with_filled_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_with_filled_test.dart
index cdfb2bc..d719d36 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_with_filled_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_with_filled_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_with_identifier_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_with_identifier_test.dart
index ce9487a..99f9758 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_with_identifier_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_with_identifier_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_with_interpolation_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_with_interpolation_test.dart
index 0a2539b..4a552ee 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_with_interpolation_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_with_interpolation_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_with_is_empty_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_with_is_empty_test.dart
index ebff731..345ba29 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_with_is_empty_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_with_is_empty_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_with_is_not_empty_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_with_is_not_empty_test.dart
index b7bdd71..57827f3 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_with_is_not_empty_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_with_is_not_empty_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_with_not_null_aware_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_with_not_null_aware_test.dart
index ccbc1cf..cdce1b0 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_with_not_null_aware_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_with_not_null_aware_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_with_null_aware_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_with_null_aware_test.dart
index 226c4f7..05c60ac 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_with_null_aware_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_with_null_aware_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_with_tear_off_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_with_tear_off_test.dart
index 772ecd7..793d625 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_with_tear_off_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_with_tear_off_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/replace_with_var_test.dart b/pkg/analysis_server/test/src/services/correction/fix/replace_with_var_test.dart
index 422034e..3b57554 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/replace_with_var_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/replace_with_var_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/sort_child_property_last_test.dart b/pkg/analysis_server/test/src/services/correction/fix/sort_child_property_last_test.dart
index 686d8f2..7c46f06 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/sort_child_property_last_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/sort_child_property_last_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/test_all.dart b/pkg/analysis_server/test/src/services/correction/fix/test_all.dart
index 570d7a8..8d78b42 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/test_all.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'add_async_test.dart' as add_async;
diff --git a/pkg/analysis_server/test/src/services/correction/fix/update_sdk_constraints_test.dart b/pkg/analysis_server/test/src/services/correction/fix/update_sdk_constraints_test.dart
index d6f6cf6..416be56 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/update_sdk_constraints_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/update_sdk_constraints_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/dart/analysis/experiments.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/use_const_test.dart b/pkg/analysis_server/test/src/services/correction/fix/use_const_test.dart
index 62e0701..3476b67 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/use_const_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/use_const_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/use_effective_integer_division_test.dart b/pkg/analysis_server/test/src/services/correction/fix/use_effective_integer_division_test.dart
index d8a6c78..5a861d5 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/use_effective_integer_division_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/use_effective_integer_division_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/use_eq_eq_null_test.dart b/pkg/analysis_server/test/src/services/correction/fix/use_eq_eq_null_test.dart
index 2e53d54..9173967 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/use_eq_eq_null_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/use_eq_eq_null_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/use_is_not_empty_test.dart b/pkg/analysis_server/test/src/services/correction/fix/use_is_not_empty_test.dart
index 04a82ac..7142b2f 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/use_is_not_empty_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/use_is_not_empty_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/use_not_eq_null_test.dart b/pkg/analysis_server/test/src/services/correction/fix/use_not_eq_null_test.dart
index fdd7d12..768232f 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/use_not_eq_null_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/use_not_eq_null_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/use_rethrow_test.dart b/pkg/analysis_server/test/src/services/correction/fix/use_rethrow_test.dart
index 6d78eb0..1741227 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/use_rethrow_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/use_rethrow_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/wrap_in_future_test.dart b/pkg/analysis_server/test/src/services/correction/fix/wrap_in_future_test.dart
index b86e482..f7ff631 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/wrap_in_future_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/wrap_in_future_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/fix/wrap_in_text_test.dart b/pkg/analysis_server/test/src/services/correction/fix/wrap_in_text_test.dart
index bca0c26..60f9b0d 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/wrap_in_text_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/wrap_in_text_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/correction/test_all.dart b/pkg/analysis_server/test/src/services/correction/test_all.dart
index abc5ddb..96c3fa6 100644
--- a/pkg/analysis_server/test/src/services/correction/test_all.dart
+++ b/pkg/analysis_server/test/src/services/correction/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'assist/test_all.dart' as assist_all;
diff --git a/pkg/analysis_server/test/src/services/flutter/constants.dart b/pkg/analysis_server/test/src/services/flutter/constants.dart
index 3bf64d2..1f38fd5 100644
--- a/pkg/analysis_server/test/src/services/flutter/constants.dart
+++ b/pkg/analysis_server/test/src/services/flutter/constants.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 final alignmentEditor = '''
 "editor": {
     "kind": "ENUM_LIKE",
diff --git a/pkg/analysis_server/test/src/services/flutter/container_properties_test.dart b/pkg/analysis_server/test/src/services/flutter/container_properties_test.dart
index a546043..28903bc 100644
--- a/pkg/analysis_server/test/src/services/flutter/container_properties_test.dart
+++ b/pkg/analysis_server/test/src/services/flutter/container_properties_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart' as protocol;
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/flutter/test_all.dart b/pkg/analysis_server/test/src/services/flutter/test_all.dart
index c35d704..e45512e 100644
--- a/pkg/analysis_server/test/src/services/flutter/test_all.dart
+++ b/pkg/analysis_server/test/src/services/flutter/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'container_properties_test.dart' as container_properties;
diff --git a/pkg/analysis_server/test/src/services/flutter/widget_description.dart b/pkg/analysis_server/test/src/services/flutter/widget_description.dart
index 012b925..c4042ef 100644
--- a/pkg/analysis_server/test/src/services/flutter/widget_description.dart
+++ b/pkg/analysis_server/test/src/services/flutter/widget_description.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 
 import 'package:analysis_server/protocol/protocol_generated.dart' as protocol;
diff --git a/pkg/analysis_server/test/src/services/flutter/widget_descriptions_test.dart b/pkg/analysis_server/test/src/services/flutter/widget_descriptions_test.dart
index a29b993..daf6593 100644
--- a/pkg/analysis_server/test/src/services/flutter/widget_descriptions_test.dart
+++ b/pkg/analysis_server/test/src/services/flutter/widget_descriptions_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/protocol/protocol_generated.dart' as protocol;
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/services/test_all.dart b/pkg/analysis_server/test/src/services/test_all.dart
index e5d8aa0..2c3be26 100644
--- a/pkg/analysis_server/test/src/services/test_all.dart
+++ b/pkg/analysis_server/test/src/services/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'completion/test_all.dart' as completion;
diff --git a/pkg/analysis_server/test/src/test_all.dart b/pkg/analysis_server/test/src/test_all.dart
index 0cb76aa..ce38f77 100644
--- a/pkg/analysis_server/test/src/test_all.dart
+++ b/pkg/analysis_server/test/src/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'cider/test_all.dart' as cider;
diff --git a/pkg/analysis_server/test/src/utilities/flutter_test.dart b/pkg/analysis_server/test/src/utilities/flutter_test.dart
index cce042e..6f8b986 100644
--- a/pkg/analysis_server/test/src/utilities/flutter_test.dart
+++ b/pkg/analysis_server/test/src/utilities/flutter_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/utilities/flutter.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/src/utilities/mock_packages.dart b/pkg/analysis_server/test/src/utilities/mock_packages.dart
index e789d2e..714c50c 100644
--- a/pkg/analysis_server/test/src/utilities/mock_packages.dart
+++ b/pkg/analysis_server/test/src/utilities/mock_packages.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
 import 'package:analyzer/file_system/physical_file_system.dart';
diff --git a/pkg/analysis_server/test/src/utilities/profiling_test.dart b/pkg/analysis_server/test/src/utilities/profiling_test.dart
index 0485511..51d515d8 100644
--- a/pkg/analysis_server/test/src/utilities/profiling_test.dart
+++ b/pkg/analysis_server/test/src/utilities/profiling_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io';
 
 import 'package:analysis_server/src/utilities/profiling.dart';
diff --git a/pkg/analysis_server/test/src/utilities/strings_test.dart b/pkg/analysis_server/test/src/utilities/strings_test.dart
index 6f068d4..37a424b 100644
--- a/pkg/analysis_server/test/src/utilities/strings_test.dart
+++ b/pkg/analysis_server/test/src/utilities/strings_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/utilities/strings.dart';
 import 'package:test/test.dart' hide isEmpty;
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/analysis_server/test/src/utilities/test_all.dart b/pkg/analysis_server/test/src/utilities/test_all.dart
index a9cd96e..5916dac 100644
--- a/pkg/analysis_server/test/src/utilities/test_all.dart
+++ b/pkg/analysis_server/test/src/utilities/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'flutter_test.dart' as flutter_test;
diff --git a/pkg/analysis_server/test/stress/completion/completion.dart b/pkg/analysis_server/test/stress/completion/completion.dart
index b2b30f5..2f5fee0 100644
--- a/pkg/analysis_server/test/stress/completion/completion.dart
+++ b/pkg/analysis_server/test/stress/completion/completion.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io';
 
 import 'package:args/args.dart';
diff --git a/pkg/analysis_server/test/stress/completion/completion_runner.dart b/pkg/analysis_server/test/stress/completion/completion_runner.dart
index 7a1d675..0de5088 100644
--- a/pkg/analysis_server/test/stress/completion/completion_runner.dart
+++ b/pkg/analysis_server/test/stress/completion/completion_runner.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/completion/completion_core.dart';
 import 'package:analysis_server/src/services/completion/completion_performance.dart';
 import 'package:analysis_server/src/services/completion/dart/completion_manager.dart';
diff --git a/pkg/analysis_server/test/stress/replay/operation.dart b/pkg/analysis_server/test/stress/replay/operation.dart
index a83d8b8..8684ddc 100644
--- a/pkg/analysis_server/test/stress/replay/operation.dart
+++ b/pkg/analysis_server/test/stress/replay/operation.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// Operations to be performed during the simulation.
 import '../utilities/server.dart';
 
diff --git a/pkg/analysis_server/test/stress/replay/replay.dart b/pkg/analysis_server/test/stress/replay/replay.dart
index cc487bb..b4ef02f8 100644
--- a/pkg/analysis_server/test/stress/replay/replay.dart
+++ b/pkg/analysis_server/test/stress/replay/replay.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// A stress test for the analysis server.
 import 'dart:io';
 import 'dart:math' as math;
diff --git a/pkg/analysis_server/test/stress/utilities/git.dart b/pkg/analysis_server/test/stress/utilities/git.dart
index 7993e44..9386e05 100644
--- a/pkg/analysis_server/test/stress/utilities/git.dart
+++ b/pkg/analysis_server/test/stress/utilities/git.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// Support for interacting with a git repository.
 import 'dart:convert';
 import 'dart:io';
diff --git a/pkg/analysis_server/test/stress/utilities/logger.dart b/pkg/analysis_server/test/stress/utilities/logger.dart
index 00d99fb..5bb6e0e 100644
--- a/pkg/analysis_server/test/stress/utilities/logger.dart
+++ b/pkg/analysis_server/test/stress/utilities/logger.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// A utility class used to write logging information during a test.
 class Logger {
   /// The width of the field in which labels are printed.
diff --git a/pkg/analysis_server/test/stress/utilities/server.dart b/pkg/analysis_server/test/stress/utilities/server.dart
index 5e652d2..635fb81 100644
--- a/pkg/analysis_server/test/stress/utilities/server.dart
+++ b/pkg/analysis_server/test/stress/utilities/server.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// Support for interacting with an analysis server that is running in a
 /// separate process.
 import 'dart:async';
diff --git a/pkg/analysis_server/test/test_all.dart b/pkg/analysis_server/test/test_all.dart
index eca22e0..a042a4f 100644
--- a/pkg/analysis_server/test/test_all.dart
+++ b/pkg/analysis_server/test/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import '../tool/spec/check_all_test.dart' as check_spec;
diff --git a/pkg/analysis_server/test/timing/completion/completion_simple.dart b/pkg/analysis_server/test/timing/completion/completion_simple.dart
index 1c7b41d..c2ec8fd 100644
--- a/pkg/analysis_server/test/timing/completion/completion_simple.dart
+++ b/pkg/analysis_server/test/timing/completion/completion_simple.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:io';
 
diff --git a/pkg/analysis_server/test/timing/timing_framework.dart b/pkg/analysis_server/test/timing/timing_framework.dart
index f7d6da1..712257c 100644
--- a/pkg/analysis_server/test/timing/timing_framework.dart
+++ b/pkg/analysis_server/test/timing/timing_framework.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:async';
 import 'dart:io';
 import 'dart:math';
diff --git a/pkg/analysis_server/test/tool/completion_metrics/metrics_util_test.dart b/pkg/analysis_server/test/tool/completion_metrics/metrics_util_test.dart
index 5da637c..9b0865d 100644
--- a/pkg/analysis_server/test/tool/completion_metrics/metrics_util_test.dart
+++ b/pkg/analysis_server/test/tool/completion_metrics/metrics_util_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 
 import '../../../tool/code_completion/metrics_util.dart';
diff --git a/pkg/analysis_server/test/tool/completion_metrics/test_all.dart b/pkg/analysis_server/test/tool/completion_metrics/test_all.dart
index 8ca30d9..2a7e8b3 100644
--- a/pkg/analysis_server/test/tool/completion_metrics/test_all.dart
+++ b/pkg/analysis_server/test/tool/completion_metrics/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'metrics_util_test.dart' as metrics_util_test;
diff --git a/pkg/analysis_server/test/tool/lsp_spec/dart_test.dart b/pkg/analysis_server/test/tool/lsp_spec/dart_test.dart
index 7ead849..ea05eed 100644
--- a/pkg/analysis_server/test/tool/lsp_spec/dart_test.dart
+++ b/pkg/analysis_server/test/tool/lsp_spec/dart_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 
 import '../../../tool/lsp_spec/typescript_parser.dart' as ast;
diff --git a/pkg/analysis_server/test/tool/lsp_spec/generated_classes_test.dart b/pkg/analysis_server/test/tool/lsp_spec/generated_classes_test.dart
index a506de9..3b034df 100644
--- a/pkg/analysis_server/test/tool/lsp_spec/generated_classes_test.dart
+++ b/pkg/analysis_server/test/tool/lsp_spec/generated_classes_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:analysis_server/lsp_protocol/protocol_special.dart';
 import 'package:test/test.dart';
diff --git a/pkg/analysis_server/test/tool/lsp_spec/json_test.dart b/pkg/analysis_server/test/tool/lsp_spec/json_test.dart
index 4e32945..e0b9720 100644
--- a/pkg/analysis_server/test/tool/lsp_spec/json_test.dart
+++ b/pkg/analysis_server/test/tool/lsp_spec/json_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
diff --git a/pkg/analysis_server/test/tool/lsp_spec/markdown_test.dart b/pkg/analysis_server/test/tool/lsp_spec/markdown_test.dart
index bf968e7..6589b50 100644
--- a/pkg/analysis_server/test/tool/lsp_spec/markdown_test.dart
+++ b/pkg/analysis_server/test/tool/lsp_spec/markdown_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 
 import '../../../tool/lsp_spec/markdown.dart';
diff --git a/pkg/analysis_server/test/tool/lsp_spec/matchers.dart b/pkg/analysis_server/test/tool/lsp_spec/matchers.dart
index e5ed507..8fa3f4f 100644
--- a/pkg/analysis_server/test/tool/lsp_spec/matchers.dart
+++ b/pkg/analysis_server/test/tool/lsp_spec/matchers.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/lsp_protocol/protocol_generated.dart';
 import 'package:matcher/matcher.dart';
 
diff --git a/pkg/analysis_server/test/tool/lsp_spec/test_all.dart b/pkg/analysis_server/test/tool/lsp_spec/test_all.dart
index 07a4247..0b98b69 100644
--- a/pkg/analysis_server/test/tool/lsp_spec/test_all.dart
+++ b/pkg/analysis_server/test/tool/lsp_spec/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'dart_test.dart' as dart_test;
diff --git a/pkg/analysis_server/test/tool/lsp_spec/typescript_test.dart b/pkg/analysis_server/test/tool/lsp_spec/typescript_test.dart
index b439e68..3c69370 100644
--- a/pkg/analysis_server/test/tool/lsp_spec/typescript_test.dart
+++ b/pkg/analysis_server/test/tool/lsp_spec/typescript_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test/test.dart';
 
 import '../../../tool/lsp_spec/typescript_parser.dart';
diff --git a/pkg/analysis_server/test/tool/test_all.dart b/pkg/analysis_server/test/tool/test_all.dart
index 8d2910e..4852a64 100644
--- a/pkg/analysis_server/test/tool/test_all.dart
+++ b/pkg/analysis_server/test/tool/test_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'completion_metrics/test_all.dart' as completion_metrics;
diff --git a/pkg/analysis_server/test/utils/test_instrumentation_service.dart b/pkg/analysis_server/test/utils/test_instrumentation_service.dart
index f271860..5e8ed3e 100644
--- a/pkg/analysis_server/test/utils/test_instrumentation_service.dart
+++ b/pkg/analysis_server/test/utils/test_instrumentation_service.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/exception/exception.dart';
 import 'package:analyzer/instrumentation/service.dart';
 
diff --git a/pkg/analysis_server/test/utils/test_support.dart b/pkg/analysis_server/test/utils/test_support.dart
index 811d8ce..eafda82 100644
--- a/pkg/analysis_server/test/utils/test_support.dart
+++ b/pkg/analysis_server/test/utils/test_support.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// These classes were copied from `analyzer`. They should be moved into the
 /// `analyzer/lib/src/test_utilities` directory so that they can be shared.
 /// (This version has been converted to a more modern style.)
diff --git a/pkg/analysis_server/test/verify_sorted_test.dart b/pkg/analysis_server/test/verify_sorted_test.dart
index 869d702..40dfb32 100644
--- a/pkg/analysis_server/test/verify_sorted_test.dart
+++ b/pkg/analysis_server/test/verify_sorted_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/sort_members.dart';
 import 'package:analyzer/dart/analysis/analysis_context_collection.dart';
 import 'package:analyzer/dart/analysis/results.dart';
diff --git a/pkg/analysis_server/test/verify_tests_test.dart b/pkg/analysis_server/test/verify_tests_test.dart
index 4b07a76..5f62bd8 100644
--- a/pkg/analysis_server/test/verify_tests_test.dart
+++ b/pkg/analysis_server/test/verify_tests_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/physical_file_system.dart';
 import 'package:analyzer_utilities/package_root.dart' as package_root;
diff --git a/pkg/analysis_server/tool/bulk_fix/supported_lints.dart b/pkg/analysis_server/tool/bulk_fix/supported_lints.dart
index a9d4064..85a6eae 100644
--- a/pkg/analysis_server/tool/bulk_fix/supported_lints.dart
+++ b/pkg/analysis_server/tool/bulk_fix/supported_lints.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/services/correction/fix_internal.dart';
 
 /// Print lints that are bulk-fixable in a format that can be included in
diff --git a/pkg/analysis_server/tool/code_completion/code_metrics.dart b/pkg/analysis_server/tool/code_completion/code_metrics.dart
index 97510ff..43bf25b5 100644
--- a/pkg/analysis_server/tool/code_completion/code_metrics.dart
+++ b/pkg/analysis_server/tool/code_completion/code_metrics.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io' as io;
 
 import 'package:analyzer/dart/analysis/analysis_context_collection.dart';
diff --git a/pkg/analysis_server/tool/code_completion/completion_metrics.dart b/pkg/analysis_server/tool/code_completion/completion_metrics.dart
index 1479595..d5b2d61 100644
--- a/pkg/analysis_server/tool/code_completion/completion_metrics.dart
+++ b/pkg/analysis_server/tool/code_completion/completion_metrics.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 import 'dart:io' as io;
 import 'dart:math' as math;
diff --git a/pkg/analysis_server/tool/code_completion/corpus.dart b/pkg/analysis_server/tool/code_completion/corpus.dart
index 8f711d2..c8651ce 100644
--- a/pkg/analysis_server/tool/code_completion/corpus.dart
+++ b/pkg/analysis_server/tool/code_completion/corpus.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 import 'dart:io';
 
diff --git a/pkg/analysis_server/tool/code_completion/flutter_metrics.dart b/pkg/analysis_server/tool/code_completion/flutter_metrics.dart
index 74cc153..fb211d0 100644
--- a/pkg/analysis_server/tool/code_completion/flutter_metrics.dart
+++ b/pkg/analysis_server/tool/code_completion/flutter_metrics.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io' as io;
 
 import 'package:analysis_server/src/utilities/flutter.dart';
diff --git a/pkg/analysis_server/tool/code_completion/implicit_type_declarations.dart b/pkg/analysis_server/tool/code_completion/implicit_type_declarations.dart
index 056ff2e..3204eeb 100644
--- a/pkg/analysis_server/tool/code_completion/implicit_type_declarations.dart
+++ b/pkg/analysis_server/tool/code_completion/implicit_type_declarations.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io' as io;
 
 import 'package:analysis_server/src/status/pages.dart';
diff --git a/pkg/analysis_server/tool/code_completion/metrics_util.dart b/pkg/analysis_server/tool/code_completion/metrics_util.dart
index f5c385e1..47671f0 100644
--- a/pkg/analysis_server/tool/code_completion/metrics_util.dart
+++ b/pkg/analysis_server/tool/code_completion/metrics_util.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/status/pages.dart';
 import 'package:analyzer/src/generated/utilities_general.dart';
 
diff --git a/pkg/analysis_server/tool/code_completion/output_utilities.dart b/pkg/analysis_server/tool/code_completion/output_utilities.dart
index 8f7e096..483ba38 100644
--- a/pkg/analysis_server/tool/code_completion/output_utilities.dart
+++ b/pkg/analysis_server/tool/code_completion/output_utilities.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:math' as math;
 
 /// Print the given [table].
diff --git a/pkg/analysis_server/tool/code_completion/relevance_metrics.dart b/pkg/analysis_server/tool/code_completion/relevance_metrics.dart
index c4a6398..547bea6 100644
--- a/pkg/analysis_server/tool/code_completion/relevance_metrics.dart
+++ b/pkg/analysis_server/tool/code_completion/relevance_metrics.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io' as io;
 import 'dart:math' as math;
 
diff --git a/pkg/analysis_server/tool/code_completion/relevance_table_generator.dart b/pkg/analysis_server/tool/code_completion/relevance_table_generator.dart
index 60a3f5b..856594d 100644
--- a/pkg/analysis_server/tool/code_completion/relevance_table_generator.dart
+++ b/pkg/analysis_server/tool/code_completion/relevance_table_generator.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 import 'dart:io' as io;
 
@@ -1592,6 +1594,8 @@
 // Copyright (c) 2020, the Dart project authors. Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
+
+// @dart = 2.9
 //
 // This file has been automatically generated. Please do not edit it manually.
 // To regenerate the file, use the script
diff --git a/pkg/analysis_server/tool/code_completion/visitors.dart b/pkg/analysis_server/tool/code_completion/visitors.dart
index 69d68eb..a4abe60 100644
--- a/pkg/analysis_server/tool/code_completion/visitors.dart
+++ b/pkg/analysis_server/tool/code_completion/visitors.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analysis_server/src/protocol/protocol_internal.dart';
 import 'package:analysis_server/src/protocol_server.dart' as protocol;
 import 'package:analysis_server/src/services/completion/dart/keyword_contributor.dart';
diff --git a/pkg/analysis_server/tool/instrumentation/log/log.dart b/pkg/analysis_server/tool/instrumentation/log/log.dart
index f5663a0..ea4968d 100644
--- a/pkg/analysis_server/tool/instrumentation/log/log.dart
+++ b/pkg/analysis_server/tool/instrumentation/log/log.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// A representation of the contents of an instrumentation log.
 import 'dart:convert';
 import 'dart:math' as math;
diff --git a/pkg/analysis_server/tool/instrumentation/log_viewer.dart b/pkg/analysis_server/tool/instrumentation/log_viewer.dart
index aab0190..722f148 100644
--- a/pkg/analysis_server/tool/instrumentation/log_viewer.dart
+++ b/pkg/analysis_server/tool/instrumentation/log_viewer.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io' as io;
 
 import 'package:args/args.dart';
diff --git a/pkg/analysis_server/tool/instrumentation/page/log_page.dart b/pkg/analysis_server/tool/instrumentation/page/log_page.dart
index 27a6b65..67c7ded 100644
--- a/pkg/analysis_server/tool/instrumentation/page/log_page.dart
+++ b/pkg/analysis_server/tool/instrumentation/page/log_page.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:math' as math;
 
 import '../log/log.dart';
diff --git a/pkg/analysis_server/tool/instrumentation/page/page_writer.dart b/pkg/analysis_server/tool/instrumentation/page/page_writer.dart
index c70e0be..17658dc 100644
--- a/pkg/analysis_server/tool/instrumentation/page/page_writer.dart
+++ b/pkg/analysis_server/tool/instrumentation/page/page_writer.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 
 import '../log/log.dart';
diff --git a/pkg/analysis_server/tool/instrumentation/page/stats_page.dart b/pkg/analysis_server/tool/instrumentation/page/stats_page.dart
index e218583..7ad8f5b 100644
--- a/pkg/analysis_server/tool/instrumentation/page/stats_page.dart
+++ b/pkg/analysis_server/tool/instrumentation/page/stats_page.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import '../log/log.dart';
 import 'page_writer.dart';
 
diff --git a/pkg/analysis_server/tool/instrumentation/server.dart b/pkg/analysis_server/tool/instrumentation/server.dart
index 150eb9e..72757cc 100644
--- a/pkg/analysis_server/tool/instrumentation/server.dart
+++ b/pkg/analysis_server/tool/instrumentation/server.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:collection';
 import 'dart:io';
 
diff --git a/pkg/analysis_server/tool/lsp_spec/codegen_dart.dart b/pkg/analysis_server/tool/lsp_spec/codegen_dart.dart
index d697810..9c7e2b3 100644
--- a/pkg/analysis_server/tool/lsp_spec/codegen_dart.dart
+++ b/pkg/analysis_server/tool/lsp_spec/codegen_dart.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:dart_style/dart_style.dart';
 import 'package:meta/meta.dart';
 
diff --git a/pkg/analysis_server/tool/lsp_spec/generate_all.dart b/pkg/analysis_server/tool/lsp_spec/generate_all.dart
index a45cba0..24084c8 100644
--- a/pkg/analysis_server/tool/lsp_spec/generate_all.dart
+++ b/pkg/analysis_server/tool/lsp_spec/generate_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io';
 
 import 'package:analysis_server/src/utilities/strings.dart';
@@ -155,6 +157,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 // This file has been automatically generated. Please do not edit it manually.
 // To regenerate the file, use the script
 // "pkg/analysis_server/tool/lsp_spec/generate_all.dart".
diff --git a/pkg/analysis_server/tool/lsp_spec/markdown.dart b/pkg/analysis_server/tool/lsp_spec/markdown.dart
index fa9d47b..70582e0 100644
--- a/pkg/analysis_server/tool/lsp_spec/markdown.dart
+++ b/pkg/analysis_server/tool/lsp_spec/markdown.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 final _methodNamesPattern = RegExp(
     r'''_(?:Notification|Request):?_:?(?:\r?\n)+\* method: ['`](.*?)[`'],?\r?\n''',
     multiLine: true);
diff --git a/pkg/analysis_server/tool/lsp_spec/typescript.dart b/pkg/analysis_server/tool/lsp_spec/typescript.dart
index 801b093..da58944 100644
--- a/pkg/analysis_server/tool/lsp_spec/typescript.dart
+++ b/pkg/analysis_server/tool/lsp_spec/typescript.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'typescript_parser.dart';
 
 /// Removes types that are in the spec that we don't want in other signatures.
diff --git a/pkg/analysis_server/tool/lsp_spec/typescript_parser.dart b/pkg/analysis_server/tool/lsp_spec/typescript_parser.dart
index c657cab..b18b819 100644
--- a/pkg/analysis_server/tool/lsp_spec/typescript_parser.dart
+++ b/pkg/analysis_server/tool/lsp_spec/typescript_parser.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:math';
 
 import 'package:analysis_server/src/utilities/strings.dart' show capitalize;
diff --git a/pkg/analysis_server/tool/migration_runner.dart b/pkg/analysis_server/tool/migration_runner.dart
index 1edcefa..355040f 100644
--- a/pkg/analysis_server/tool/migration_runner.dart
+++ b/pkg/analysis_server/tool/migration_runner.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// This executable provides the ability to run the migration tool in process
 /// on a single package.  It should be invoked with two command-line arguments:
 /// a path to a configuration file and the name of a package to migrate.
diff --git a/pkg/analysis_server/tool/spec/api.dart b/pkg/analysis_server/tool/spec/api.dart
index 9619513..fd40a3b 100644
--- a/pkg/analysis_server/tool/spec/api.dart
+++ b/pkg/analysis_server/tool/spec/api.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// Data structures representing an API definition, and visitor base classes
 /// for visiting those data structures.
 import 'dart:collection';
diff --git a/pkg/analysis_server/tool/spec/check_all_test.dart b/pkg/analysis_server/tool/spec/check_all_test.dart
index 3be8ed7..14ede1c 100644
--- a/pkg/analysis_server/tool/spec/check_all_test.dart
+++ b/pkg/analysis_server/tool/spec/check_all_test.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io';
 
 import 'package:analyzer_utilities/tools.dart';
diff --git a/pkg/analysis_server/tool/spec/codegen_analysis_server.dart b/pkg/analysis_server/tool/spec/codegen_analysis_server.dart
index 9e19fb6..a41e9ad 100644
--- a/pkg/analysis_server/tool/spec/codegen_analysis_server.dart
+++ b/pkg/analysis_server/tool/spec/codegen_analysis_server.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// Code generation for the file "AnalysisServer.java".
 import 'package:analyzer_utilities/tools.dart';
 
diff --git a/pkg/analysis_server/tool/spec/codegen_dart.dart b/pkg/analysis_server/tool/spec/codegen_dart.dart
index 9dacf99..bc6eecc 100644
--- a/pkg/analysis_server/tool/spec/codegen_dart.dart
+++ b/pkg/analysis_server/tool/spec/codegen_dart.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'api.dart';
 
 /// Visitor specialized for generating Dart code.
diff --git a/pkg/analysis_server/tool/spec/codegen_dart_notification_handler.dart b/pkg/analysis_server/tool/spec/codegen_dart_notification_handler.dart
index 65515ef..ab39e33 100644
--- a/pkg/analysis_server/tool/spec/codegen_dart_notification_handler.dart
+++ b/pkg/analysis_server/tool/spec/codegen_dart_notification_handler.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_utilities/tools.dart';
 import 'package:html/dom.dart';
 
@@ -110,6 +112,8 @@
   void visitApi() {
     outputHeader(year: '2018');
     writeln();
+    writeln('// @dart = 2.9');
+    writeln();
     emitImports();
     emitNotificationHandler();
   }
diff --git a/pkg/analysis_server/tool/spec/codegen_dart_protocol.dart b/pkg/analysis_server/tool/spec/codegen_dart_protocol.dart
index 2acef57..3232082 100644
--- a/pkg/analysis_server/tool/spec/codegen_dart_protocol.dart
+++ b/pkg/analysis_server/tool/spec/codegen_dart_protocol.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:convert';
 
 import 'package:analyzer_utilities/tools.dart';
@@ -1120,6 +1122,8 @@
   void visitApi() {
     outputHeader(year: '2017');
     writeln();
+    writeln('// @dart = 2.9');
+    writeln();
     emitImports();
     emitClasses(getClassesToEmit());
   }
diff --git a/pkg/analysis_server/tool/spec/codegen_inttest_methods.dart b/pkg/analysis_server/tool/spec/codegen_inttest_methods.dart
index 208e0a0..56d4405 100644
--- a/pkg/analysis_server/tool/spec/codegen_inttest_methods.dart
+++ b/pkg/analysis_server/tool/spec/codegen_inttest_methods.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// Code generation for the file "integration_test_methods.dart".
 import 'package:analyzer_utilities/tools.dart';
 import 'package:path/path.dart' as path;
@@ -84,6 +86,8 @@
   void visitApi() {
     outputHeader(year: '2017');
     writeln();
+    writeln('// @dart = 2.9');
+    writeln();
     writeln('/// Convenience methods for running integration tests.');
     writeln("import 'dart:async';");
     writeln();
diff --git a/pkg/analysis_server/tool/spec/codegen_java.dart b/pkg/analysis_server/tool/spec/codegen_java.dart
index 341e4e1..ea62d4a 100644
--- a/pkg/analysis_server/tool/spec/codegen_java.dart
+++ b/pkg/analysis_server/tool/spec/codegen_java.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// Tools for Java code generation.
 import 'package:analyzer_utilities/tools.dart';
 import 'package:html/dom.dart' as dom;
diff --git a/pkg/analysis_server/tool/spec/codegen_java_types.dart b/pkg/analysis_server/tool/spec/codegen_java_types.dart
index a59a788..8b2d471 100644
--- a/pkg/analysis_server/tool/spec/codegen_java_types.dart
+++ b/pkg/analysis_server/tool/spec/codegen_java_types.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// Code generation for the file "AnalysisServer.java".
 import 'package:analyzer_utilities/tools.dart';
 import 'package:html/dom.dart' as dom;
diff --git a/pkg/analysis_server/tool/spec/codegen_matchers.dart b/pkg/analysis_server/tool/spec/codegen_matchers.dart
index 2e53975..9d7afb0 100644
--- a/pkg/analysis_server/tool/spec/codegen_matchers.dart
+++ b/pkg/analysis_server/tool/spec/codegen_matchers.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// Code generation for the file "matchers.dart".
 import 'package:analyzer_utilities/tools.dart';
 
@@ -89,6 +91,8 @@
   void visitApi() {
     outputHeader(year: '2017');
     writeln();
+    writeln('// @dart = 2.9');
+    writeln();
     writeln('/// Matchers for data types defined in the analysis server API.');
     writeln("import 'package:test/test.dart';");
     writeln();
diff --git a/pkg/analysis_server/tool/spec/codegen_protocol_constants.dart b/pkg/analysis_server/tool/spec/codegen_protocol_constants.dart
index 511f260..023562b 100644
--- a/pkg/analysis_server/tool/spec/codegen_protocol_constants.dart
+++ b/pkg/analysis_server/tool/spec/codegen_protocol_constants.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'package:analyzer_utilities/tools.dart';
 
 import 'api.dart';
@@ -88,6 +90,8 @@
   void visitApi() {
     outputHeader(year: '2017');
     writeln();
+    writeln('// @dart = 2.9');
+    writeln();
     generateConstants();
   }
 }
diff --git a/pkg/analysis_server/tool/spec/from_html.dart b/pkg/analysis_server/tool/spec/from_html.dart
index 237a6a7..de97dc7 100644
--- a/pkg/analysis_server/tool/spec/from_html.dart
+++ b/pkg/analysis_server/tool/spec/from_html.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// Code for reading an HTML API description.
 import 'dart:io';
 
diff --git a/pkg/analysis_server/tool/spec/generate_all.dart b/pkg/analysis_server/tool/spec/generate_all.dart
index 20840ce..30fb5f3 100644
--- a/pkg/analysis_server/tool/spec/generate_all.dart
+++ b/pkg/analysis_server/tool/spec/generate_all.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 import 'dart:io';
 
 import 'package:analyzer_utilities/tools.dart';
diff --git a/pkg/analysis_server/tool/spec/implied_types.dart b/pkg/analysis_server/tool/spec/implied_types.dart
index fb67058..521485c 100644
--- a/pkg/analysis_server/tool/spec/implied_types.dart
+++ b/pkg/analysis_server/tool/spec/implied_types.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// Code for enumerating the set of types implied by the API.
 import 'package:analyzer_utilities/tools.dart';
 
diff --git a/pkg/analysis_server/tool/spec/to_html.dart b/pkg/analysis_server/tool/spec/to_html.dart
index 35768e6..3d13b63 100644
--- a/pkg/analysis_server/tool/spec/to_html.dart
+++ b/pkg/analysis_server/tool/spec/to_html.dart
@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+// @dart = 2.9
+
 /// Code for displaying the API as HTML.  This is used both for generating a
 /// full description of the API as a web page, and for generating doc comments
 /// in generated code.
diff --git a/pkg/analysis_server_client/lib/handler/notification_handler.dart b/pkg/analysis_server_client/lib/handler/notification_handler.dart
index 2d8715a..c91a78c 100644
--- a/pkg/analysis_server_client/lib/handler/notification_handler.dart
+++ b/pkg/analysis_server_client/lib/handler/notification_handler.dart
@@ -6,6 +6,8 @@
 // To regenerate the file, use the script
 // "pkg/analysis_server/tool/spec/generate_files".
 
+// @dart = 2.9
+
 import 'package:analysis_server_client/protocol.dart';
 
 /// [NotificationHandler] processes analysis server notifications
diff --git a/pkg/analysis_server_client/lib/src/protocol/protocol_constants.dart b/pkg/analysis_server_client/lib/src/protocol/protocol_constants.dart
index 6772e9d..654d974 100644
--- a/pkg/analysis_server_client/lib/src/protocol/protocol_constants.dart
+++ b/pkg/analysis_server_client/lib/src/protocol/protocol_constants.dart
@@ -6,6 +6,8 @@
 // To regenerate the file, use the script
 // "pkg/analysis_server/tool/spec/generate_files".
 
+// @dart = 2.9
+
 const String PROTOCOL_VERSION = '1.32.5';
 
 const String ANALYSIS_NOTIFICATION_ANALYZED_FILES = 'analysis.analyzedFiles';
diff --git a/pkg/analysis_server_client/lib/src/protocol/protocol_generated.dart b/pkg/analysis_server_client/lib/src/protocol/protocol_generated.dart
index e5dd041..5b5a5ef 100644
--- a/pkg/analysis_server_client/lib/src/protocol/protocol_generated.dart
+++ b/pkg/analysis_server_client/lib/src/protocol/protocol_generated.dart
@@ -6,6 +6,8 @@
 // To regenerate the file, use the script
 // "pkg/analysis_server/tool/spec/generate_files".
 
+// @dart = 2.9
+
 import 'dart:convert' hide JsonDecoder;
 
 import 'package:analysis_server_client/src/protocol/protocol_base.dart';