Version 2.11.0-244.0.dev

Merge commit 'c8c87f40e58cb813420273930760878dc3cc1c23' into 'dev'
diff --git a/CHANGELOG.md b/CHANGELOG.md
index f0465af..28b2ea5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -29,6 +29,8 @@
 
 * New commands `pub add` and `pub remove` that adds and remove new dependencies
   to your `pubspec.yaml`.
+* New option `pub outdated mode=null-safety` that will analyze your dependencies
+  for null-safety.
 * `pub publish` will check your pubspec keys for likely typos.
 * `pub get` will print a warning if the resolution is mixed mode.
 
diff --git a/DEPS b/DEPS
index 8b6b6ce..ef5cb12 100644
--- a/DEPS
+++ b/DEPS
@@ -94,10 +94,10 @@
   #     and land the review.
   #
   # For more details, see https://github.com/dart-lang/sdk/issues/30164
-  "dart_style_tag": "1.3.7",  # Please see the note above before updating.
+  "dart_style_tag": "1.3.8",  # Please see the note above before updating.
 
   "chromedriver_tag": "83.0.4103.39",
-  "dartdoc_rev" : "8f5f30e58bbc0f11f104888ee87f11cbd6b82cc7",
+  "dartdoc_rev" : "39cec16700839847876849fef4f0769f8689b6c8",
   "ffi_rev": "a90bd424116fb6f416337db67425171f2dc4c98f",
   "fixnum_rev": "16d3890c6dc82ca629659da1934e412292508bba",
   "glob_rev": "e9f4e6b7ae8abe5071461cf8f47191bb19cf7ef6",
@@ -106,7 +106,7 @@
   "http_multi_server_rev" : "ea269f79321d659208402088f3297e8920a88ee6",
   "http_parser_rev": "5dd4d16693242049dfb43b5efa429fedbf932e98",
   "http_retry_tag": "0.1.1",
-  "http_rev": "20e3a594872ae1565249c7cfc8977f9a10ca9927",
+  "http_rev": "a8efbef05a58919dc7aa2dab42198334f2459ffb",
   "http_throttle_tag" : "1.0.2",
   "icu_rev" : "79326efe26e5440f530963704c3c0ff965b3a4ac",
   "idl_parser_rev": "5fb1ebf49d235b5a70c9f49047e83b0654031eb7",
@@ -128,7 +128,7 @@
   "ply_rev": "604b32590ffad5cbb82e4afef1d305512d06ae93",
   "pool_rev": "eedbd5fde84f9a1a8da643b475305a81841da599",
   "protobuf_rev": "3746c8fd3f2b0147623a8e3db89c3ff4330de760",
-  "pub_rev": "f0c7771b38155d3829a60d60b5dba2784b100811",
+  "pub_rev": "5b4df5a6f931c63622ac349602d6ef0367e8070f",
   "pub_semver_tag": "v1.4.4",
   "quiver-dart_tag": "246e754fe45cecb6aa5f3f13b4ed61037ff0d784",
   "resource_rev": "6b79867d0becf5395e5819a75720963b8298e9a7",
@@ -146,7 +146,7 @@
   "sse_tag": "e5cf68975e8e87171a3dc297577aa073454a91dc",
   "stack_trace_tag": "45319bfd2a6da228d8c32b06e1da02ad199373c7",
   "stagehand_tag": "v3.3.9",
-  "stream_channel_tag": "c446774fd077c9bdbd6235a7aadc661ef60a9727",
+  "stream_channel_tag": "d7251e61253ec389ee6e045ee1042311bced8f1d",
   "string_scanner_rev": "1b63e6e5db5933d7be0a45da6e1129fe00262734",
   "sync_http_rev": "a85d7ec764ea485cbbc49f3f3e7f1b43f87a1c74",
   "test_descriptor_tag": "1.1.1",
@@ -158,7 +158,7 @@
   "typed_data_tag": "f94fc57b8e8c0e4fe4ff6cfd8290b94af52d3719",
   "usage_tag": "3.4.0",
   "vector_math_rev": "0c9f5d68c047813a6dcdeb88ba7a42daddf25025",
-  "watcher_rev": "5df2e364b0c3ec12b9ed9cf2eedb71f9ddf8b7cd",
+  "watcher_rev": "64e254eba16f56d41f10d72c0b1cb24e130e1f8b",
   "webdriver_rev": "5a8d6805d9cf8a3cbb4fcd64849b538b7491e50e",
   "web_components_rev": "8f57dac273412a7172c8ade6f361b407e2e4ed02",
   "web_socket_channel_rev": "490061ef0e22d3c8460ad2802f9948219365ad6b",
diff --git a/docs/process/experimental-flags.md b/docs/process/experimental-flags.md
index 7512875..7f336ce 100644
--- a/docs/process/experimental-flags.md
+++ b/docs/process/experimental-flags.md
@@ -60,9 +60,9 @@
 comma-separated flags. Examples:
 
 ```
-dart --enable-experiment super-mixins
-dart --enable-experiment super-mixins,no-slow-checks,preview-dart3
-dart --enable-experiment super-mixins --enable-experiment no-slow-checks --enable-experiment preview-dart3
+dart --enable-experiment=super-mixins
+dart --enable-experiment=super-mixins,no-slow-checks,preview-dart3
+dart --enable-experiment=super-mixins --enable-experiment no-slow-checks --enable-experiment preview-dart3
 ```
 
 If the user passes a flag that is not recognized (for example, when the flag is
diff --git a/pkg/_fe_analyzer_shared/analysis_options_no_lints.yaml b/pkg/_fe_analyzer_shared/analysis_options_no_lints.yaml
index 583344a..bba3f74 100644
--- a/pkg/_fe_analyzer_shared/analysis_options_no_lints.yaml
+++ b/pkg/_fe_analyzer_shared/analysis_options_no_lints.yaml
@@ -8,6 +8,7 @@
     todo: ignore
   exclude:
     - test/constants/data/**
+    - test/constants/data_2/**
     - test/flow_analysis/assigned_variables/data/**
     - test/flow_analysis/definite_assignment/data/**
     - test/flow_analysis/definite_unassignment/data/**
diff --git a/pkg/_fe_analyzer_shared/lib/src/messages/codes_generated.dart b/pkg/_fe_analyzer_shared/lib/src/messages/codes_generated.dart
index 98448cc..c288f21 100644
--- a/pkg/_fe_analyzer_shared/lib/src/messages/codes_generated.dart
+++ b/pkg/_fe_analyzer_shared/lib/src/messages/codes_generated.dart
@@ -3092,6 +3092,60 @@
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
 const Template<
     Message Function(
+        String
+            string)> templateExperimentDisabled = const Template<
+        Message Function(String string)>(
+    messageTemplate:
+        r"""This requires the '#string' language feature to be enabled.""",
+    tipTemplate:
+        r"""The feature is on by default but is currently disabled, maybe because the '--enable-experiment=no-#string' command line option is passed.""",
+    withArguments: _withArgumentsExperimentDisabled);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Message Function(String string)> codeExperimentDisabled =
+    const Code<Message Function(String string)>(
+        "ExperimentDisabled", templateExperimentDisabled,
+        analyzerCodes: <String>["ParserErrorCode.EXPERIMENT_NOT_ENABLED"]);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsExperimentDisabled(String string) {
+  if (string.isEmpty) throw 'No string provided';
+  return new Message(codeExperimentDisabled,
+      message:
+          """This requires the '${string}' language feature to be enabled.""",
+      tip:
+          """The feature is on by default but is currently disabled, maybe because the '--enable-experiment=no-${string}' command line option is passed.""",
+      arguments: {'string': string});
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<Message Function(String string2)>
+    templateExperimentDisabledInvalidLanguageVersion =
+    const Template<Message Function(String string2)>(
+        messageTemplate:
+            r"""This requires the null safety language feature, which requires language version of #string2 or higher.""",
+        withArguments: _withArgumentsExperimentDisabledInvalidLanguageVersion);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Message Function(String string2)>
+    codeExperimentDisabledInvalidLanguageVersion =
+    const Code<Message Function(String string2)>(
+        "ExperimentDisabledInvalidLanguageVersion",
+        templateExperimentDisabledInvalidLanguageVersion,
+        analyzerCodes: <String>["ParserErrorCode.EXPERIMENT_NOT_ENABLED"]);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsExperimentDisabledInvalidLanguageVersion(String string2) {
+  if (string2.isEmpty) throw 'No string provided';
+  return new Message(codeExperimentDisabledInvalidLanguageVersion,
+      message:
+          """This requires the null safety language feature, which requires language version of ${string2} or higher.""",
+      arguments: {'string2': string2});
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<
+    Message Function(
         String string,
         String
             string2)> templateExperimentNotEnabled = const Template<
diff --git a/pkg/analysis_server/lib/plugin/protocol/protocol_dart.dart b/pkg/analysis_server/lib/plugin/protocol/protocol_dart.dart
index 3e44f4c..f62b233 100644
--- a/pkg/analysis_server/lib/plugin/protocol/protocol_dart.dart
+++ b/pkg/analysis_server/lib/plugin/protocol/protocol_dart.dart
@@ -6,7 +6,6 @@
 /// entities.
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analyzer/dart/element/element.dart' as engine;
-import 'package:analyzer/src/generated/utilities_dart.dart' as engine;
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:path/path.dart' as pathos;
 
diff --git a/pkg/analysis_server/lib/src/analysis_server.dart b/pkg/analysis_server/lib/src/analysis_server.dart
index 2c9e1e4..ea398ea 100644
--- a/pkg/analysis_server/lib/src/analysis_server.dart
+++ b/pkg/analysis_server/lib/src/analysis_server.dart
@@ -51,7 +51,6 @@
 import 'package:analyzer/src/context/builder.dart';
 import 'package:analyzer/src/context/context_root.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart' as nd;
-import 'package:analyzer/src/dart/analysis/file_state.dart' as nd;
 import 'package:analyzer/src/dart/analysis/status.dart' as nd;
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/sdk.dart';
diff --git a/pkg/analysis_server/lib/src/analysis_server_abstract.dart b/pkg/analysis_server/lib/src/analysis_server_abstract.dart
index e18292c..bb545e4 100644
--- a/pkg/analysis_server/lib/src/analysis_server_abstract.dart
+++ b/pkg/analysis_server/lib/src/analysis_server_abstract.dart
@@ -38,9 +38,7 @@
     as analyzer_features;
 import 'package:analyzer/src/dart/analysis/file_byte_store.dart'
     show EvictingFileByteStore;
-import 'package:analyzer/src/dart/analysis/file_state.dart' as nd;
 import 'package:analyzer/src/dart/analysis/performance_logger.dart';
-import 'package:analyzer/src/dart/analysis/status.dart' as nd;
 import 'package:analyzer/src/dart/ast/element_locator.dart';
 import 'package:analyzer/src/dart/ast/utilities.dart';
 import 'package:analyzer/src/dartdoc/dartdoc_directive_info.dart';
diff --git a/pkg/analysis_server/lib/src/computer/computer_outline.dart b/pkg/analysis_server/lib/src/computer/computer_outline.dart
index b1abe78..e36aed7 100644
--- a/pkg/analysis_server/lib/src/computer/computer_outline.dart
+++ b/pkg/analysis_server/lib/src/computer/computer_outline.dart
@@ -8,7 +8,6 @@
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element.dart' as engine;
-import 'package:analyzer/dart/element/type.dart' as engine;
 import 'package:analyzer/source/line_info.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 
diff --git a/pkg/analysis_server/lib/src/domain_abstract.dart b/pkg/analysis_server/lib/src/domain_abstract.dart
index a2c28e2..3d168d5 100644
--- a/pkg/analysis_server/lib/src/domain_abstract.dart
+++ b/pkg/analysis_server/lib/src/domain_abstract.dart
@@ -11,8 +11,6 @@
 import 'package:analysis_server/src/plugin/plugin_manager.dart';
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
 import 'package:analyzer_plugin/protocol/protocol.dart' as plugin;
-import 'package:analyzer_plugin/protocol/protocol_constants.dart' as plugin;
-import 'package:analyzer_plugin/protocol/protocol_generated.dart' as plugin;
 import 'package:analyzer_plugin/src/protocol/protocol_internal.dart' as plugin;
 
 /// An abstract implementation of a request handler.
diff --git a/pkg/analysis_server/lib/src/domain_analysis.dart b/pkg/analysis_server/lib/src/domain_analysis.dart
index 35f6911..9d90b64 100644
--- a/pkg/analysis_server/lib/src/domain_analysis.dart
+++ b/pkg/analysis_server/lib/src/domain_analysis.dart
@@ -15,11 +15,8 @@
 import 'package:analysis_server/src/protocol/protocol_internal.dart';
 import 'package:analysis_server/src/protocol_server.dart';
 import 'package:analyzer/dart/analysis/results.dart';
-import 'package:analyzer/error/error.dart' as engine;
 import 'package:analyzer/src/generated/engine.dart' as engine;
-import 'package:analyzer_plugin/protocol/protocol.dart' as plugin;
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
-import 'package:analyzer_plugin/protocol/protocol_constants.dart' as plugin;
 import 'package:analyzer_plugin/protocol/protocol_generated.dart' as plugin;
 import 'package:analyzer_plugin/src/utilities/navigation/navigation.dart';
 import 'package:analyzer_plugin/utilities/navigation/navigation_dart.dart';
diff --git a/pkg/analysis_server/lib/src/domain_completion.dart b/pkg/analysis_server/lib/src/domain_completion.dart
index 2d0f0b1..7ba35cd 100644
--- a/pkg/analysis_server/lib/src/domain_completion.dart
+++ b/pkg/analysis_server/lib/src/domain_completion.dart
@@ -24,7 +24,6 @@
 import 'package:analyzer/src/util/performance/operation_performance.dart';
 import 'package:analyzer_plugin/protocol/protocol.dart' as plugin;
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
-import 'package:analyzer_plugin/protocol/protocol_constants.dart' as plugin;
 import 'package:analyzer_plugin/protocol/protocol_generated.dart' as plugin;
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
 
diff --git a/pkg/analysis_server/lib/src/domain_kythe.dart b/pkg/analysis_server/lib/src/domain_kythe.dart
index 565c6cd..a67e02a 100644
--- a/pkg/analysis_server/lib/src/domain_kythe.dart
+++ b/pkg/analysis_server/lib/src/domain_kythe.dart
@@ -13,9 +13,7 @@
 import 'package:analysis_server/src/services/kythe/kythe_visitors.dart';
 import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/src/dart/element/inheritance_manager3.dart';
-import 'package:analyzer_plugin/protocol/protocol.dart' as plugin;
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
-import 'package:analyzer_plugin/protocol/protocol_constants.dart' as plugin;
 import 'package:analyzer_plugin/protocol/protocol_generated.dart' as plugin;
 
 /// Instances of the class [KytheDomainHandler] implement a [RequestHandler]
diff --git a/pkg/analysis_server/lib/src/edit/edit_domain.dart b/pkg/analysis_server/lib/src/edit/edit_domain.dart
index b702179..e2fc729 100644
--- a/pkg/analysis_server/lib/src/edit/edit_domain.dart
+++ b/pkg/analysis_server/lib/src/edit/edit_domain.dart
@@ -47,7 +47,6 @@
 import 'package:analyzer/src/dart/ast/utilities.dart';
 import 'package:analyzer/src/dart/scanner/scanner.dart' as engine;
 import 'package:analyzer/src/dart/sdk/sdk.dart';
-import 'package:analyzer/src/error/codes.dart' as engine;
 import 'package:analyzer/src/exception/exception.dart';
 import 'package:analyzer/src/generated/engine.dart' as engine;
 import 'package:analyzer/src/generated/engine.dart';
@@ -58,7 +57,6 @@
 import 'package:analyzer/src/pubspec/pubspec_validator.dart';
 import 'package:analyzer/src/task/options.dart';
 import 'package:analyzer_plugin/protocol/protocol.dart' as plugin;
-import 'package:analyzer_plugin/protocol/protocol_constants.dart' as plugin;
 import 'package:analyzer_plugin/protocol/protocol_generated.dart' as plugin;
 import 'package:dart_style/dart_style.dart';
 import 'package:html/parser.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 1dd999b..559c54e 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
@@ -12,8 +12,6 @@
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/error/error.dart' as engine;
 import 'package:analyzer/src/dart/scanner/scanner.dart' as engine;
-import 'package:analyzer/src/error/codes.dart' as engine;
-import 'package:analyzer/src/generated/engine.dart' as engine;
 import 'package:analyzer/src/generated/parser.dart' as engine;
 import 'package:analyzer_plugin/protocol/protocol_common.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 8d75c98..430489a 100644
--- a/pkg/analysis_server/lib/src/lsp/handlers/handler_completion.dart
+++ b/pkg/analysis_server/lib/src/lsp/handlers/handler_completion.dart
@@ -231,6 +231,14 @@
                 item,
                 completionRequest.replacementOffset,
                 completionRequest.replacementLength,
+                // TODO(dantup): Including commit characters in every completion
+                // increases the payload size. The LSP spec is ambigious
+                // about how this should be handled (and VS Code requires it) but
+                // this should be removed (or made conditional based on a capability)
+                // depending on how the spec is updated.
+                // https://github.com/microsoft/vscode-languageserver-node/issues/673
+                includeCommitCharacters:
+                    server.clientConfiguration.previewCommitCharacters,
               ),
             )
             .toList();
@@ -315,6 +323,14 @@
                     item,
                     completionRequest.replacementOffset,
                     completionRequest.replacementLength,
+                    // TODO(dantup): Including commit characters in every completion
+                    // increases the payload size. The LSP spec is ambigious
+                    // about how this should be handled (and VS Code requires it) but
+                    // this should be removed (or made conditional based on a capability)
+                    // depending on how the spec is updated.
+                    // https://github.com/microsoft/vscode-languageserver-node/issues/673
+                    includeCommitCharacters:
+                        server.clientConfiguration.previewCommitCharacters,
                   ));
           results.addAll(setResults);
         });
@@ -352,6 +368,10 @@
           item,
           result.replacementOffset,
           result.replacementLength,
+          // Plugins cannot currently contribute commit characters and we should
+          // not assume that the Dart ones would be correct for all of their
+          // completions.
+          includeCommitCharacters: false,
         ),
       );
     });
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 a2c0d16..4e53670 100644
--- a/pkg/analysis_server/lib/src/lsp/lsp_analysis_server.dart
+++ b/pkg/analysis_server/lib/src/lsp/lsp_analysis_server.dart
@@ -42,7 +42,6 @@
 import 'package:analyzer/src/context/builder.dart';
 import 'package:analyzer/src/context/context_root.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart' as nd;
-import 'package:analyzer/src/dart/analysis/file_state.dart' as nd;
 import 'package:analyzer/src/dart/analysis/status.dart' as nd;
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/sdk.dart';
diff --git a/pkg/analysis_server/lib/src/lsp/mapping.dart b/pkg/analysis_server/lib/src/lsp/mapping.dart
index f710272..717b6cd 100644
--- a/pkg/analysis_server/lib/src/lsp/mapping.dart
+++ b/pkg/analysis_server/lib/src/lsp/mapping.dart
@@ -17,6 +17,7 @@
     show ErrorOr, Either2, Either4;
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/lsp/constants.dart' as lsp;
+import 'package:analysis_server/src/lsp/constants.dart';
 import 'package:analysis_server/src/lsp/dartdoc.dart';
 import 'package:analysis_server/src/lsp/lsp_analysis_server.dart' as lsp;
 import 'package:analysis_server/src/lsp/source_edits.dart';
@@ -33,9 +34,6 @@
 import 'package:analyzer/src/services/available_declarations.dart';
 import 'package:analyzer/src/services/available_declarations.dart' as dec;
 import 'package:analyzer_plugin/protocol/protocol_common.dart' as plugin;
-import 'package:analyzer_plugin/src/utilities/navigation/navigation.dart'
-    as server;
-import 'package:analyzer_plugin/utilities/fixes/fixes.dart' as server;
 import 'package:meta/meta.dart';
 
 const diagnosticTagsForErrorCode = <server.ErrorCode, List<lsp.DiagnosticTag>>{
@@ -201,8 +199,9 @@
   server.LineInfo lineInfo,
   dec.Declaration declaration,
   int replacementOffset,
-  int replacementLength,
-) {
+  int replacementLength, {
+  @required bool includeCommitCharacters,
+}) {
   // Build display labels and text to insert. insertText and filterText may
   // differ from label (for ex. if the label includes things like (…)). If
   // either are missing then label will be used by the client.
@@ -269,6 +268,8 @@
               lsp.CompletionItemTag.Deprecated
           ]
         : null,
+    commitCharacters:
+        includeCommitCharacters ? lsp.dartCompletionCommitCharacters : null,
     detail: getDeclarationCompletionDetail(declaration, completionKind,
         supportsDeprecatedFlag || supportsDeprecatedTag),
     deprecated:
@@ -764,8 +765,9 @@
   server.LineInfo lineInfo,
   server.CompletionSuggestion suggestion,
   int replacementOffset,
-  int replacementLength,
-) {
+  int replacementLength, {
+  @required bool includeCommitCharacters,
+}) {
   // Build display labels and text to insert. insertText and filterText may
   // differ from label (for ex. if the label includes things like (…)). If
   // either are missing then label will be used by the client.
@@ -826,6 +828,8 @@
               lsp.CompletionItemTag.Deprecated
           ]
         : null,
+    commitCharacters:
+        includeCommitCharacters ? dartCompletionCommitCharacters : null,
     detail: getCompletionDetail(suggestion, completionKind,
         supportsDeprecatedFlag || supportsDeprecatedTag),
     documentation:
diff --git a/pkg/analysis_server/lib/src/plugin/request_converter.dart b/pkg/analysis_server/lib/src/plugin/request_converter.dart
index a08bc7b..82b2bf4 100644
--- a/pkg/analysis_server/lib/src/plugin/request_converter.dart
+++ b/pkg/analysis_server/lib/src/plugin/request_converter.dart
@@ -3,7 +3,6 @@
 // BSD-style license that can be found in the LICENSE file.
 
 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_generated.dart' as plugin;
 
 /// An object used to convert between similar objects defined by both the plugin
diff --git a/pkg/analysis_server/lib/src/protocol_server.dart b/pkg/analysis_server/lib/src/protocol_server.dart
index 1e68c39..ba01e37 100644
--- a/pkg/analysis_server/lib/src/protocol_server.dart
+++ b/pkg/analysis_server/lib/src/protocol_server.dart
@@ -9,19 +9,13 @@
     as engine;
 import 'package:analyzer/dart/analysis/results.dart' as engine;
 import 'package:analyzer/dart/ast/ast.dart' as engine;
-import 'package:analyzer/dart/ast/visitor.dart' as engine;
 import 'package:analyzer/dart/element/element.dart' as engine;
-import 'package:analyzer/dart/element/type.dart' as engine;
 import 'package:analyzer/diagnostic/diagnostic.dart' as engine;
 import 'package:analyzer/error/error.dart' as engine;
 import 'package:analyzer/exception/exception.dart';
 import 'package:analyzer/source/error_processor.dart';
 import 'package:analyzer/source/line_info.dart';
-import 'package:analyzer/src/dart/ast/utilities.dart' as engine;
-import 'package:analyzer/src/error/codes.dart' as engine;
-import 'package:analyzer/src/generated/engine.dart' as engine;
 import 'package:analyzer/src/generated/source.dart' as engine;
-import 'package:analyzer/src/generated/utilities_dart.dart' as engine;
 import 'package:analyzer_plugin/protocol/protocol_common.dart';
 
 export 'package:analysis_server/plugin/protocol/protocol_dart.dart';
diff --git a/pkg/analysis_server/test/lsp/completion_test.dart b/pkg/analysis_server/test/lsp/completion_test.dart
index 07446e9..92789b23 100644
--- a/pkg/analysis_server/test/lsp/completion_test.dart
+++ b/pkg/analysis_server/test/lsp/completion_test.dart
@@ -30,6 +30,30 @@
     );
   }
 
+  Future<void> test_commitCharacter_completionItem() async {
+    await provideConfig(
+      () => initialize(
+        textDocumentCapabilities: withAllSupportedDynamicRegistrations(
+            emptyTextDocumentClientCapabilities),
+        workspaceCapabilities:
+            withConfigurationSupport(emptyWorkspaceClientCapabilities),
+      ),
+      {'previewCommitCharacters': true},
+    );
+
+    final content = '''
+main() {
+  pri^
+}
+    ''';
+
+    await openFile(mainFileUri, withoutMarkers(content));
+    final res = await getCompletion(mainFileUri, positionFromMarker(content));
+
+    final print = res.singleWhere((c) => c.label == 'print(…)');
+    expect(print.commitCharacters, equals(dartCompletionCommitCharacters));
+  }
+
   Future<void> test_commitCharacter_config() async {
     final registrations = <Registration>[];
     // Provide empty config and collect dynamic registrations during
diff --git a/pkg/analyzer/lib/src/dart/analysis/context_locator.dart b/pkg/analyzer/lib/src/dart/analysis/context_locator.dart
index db71f9e..b4571c0 100644
--- a/pkg/analyzer/lib/src/dart/analysis/context_locator.dart
+++ b/pkg/analyzer/lib/src/dart/analysis/context_locator.dart
@@ -101,9 +101,10 @@
       root.packagesFile = defaultPackagesFile ?? _findPackagesFile(folder);
       root.optionsFile = defaultOptionsFile ?? _findOptionsFile(folder);
       root.included.add(folder);
+      root.excludedGlobs = _getExcludedGlobs(root);
       roots.add(root);
       _createContextRootsIn(roots, folder, excludedFolders, root,
-          _getExcludedFiles(root), defaultOptionsFile, defaultPackagesFile);
+          root.excludedGlobs, defaultOptionsFile, defaultPackagesFile);
     }
     Map<Folder, ContextRoot> rootMap = <Folder, ContextRoot>{};
     for (File file in includedFiles) {
@@ -135,14 +136,14 @@
   /// file will be used even if there is a local version of the file.
   ///
   /// For each directory within the given [folder] that is neither in the list
-  /// of [excludedFolders] nor excluded by the [excludedFilePatterns],
-  /// recursively search for nested context roots.
+  /// of [excludedFolders] nor excluded by the [excludedGlobs], recursively
+  /// search for nested context roots.
   void _createContextRoots(
       List<ContextRoot> roots,
       Folder folder,
       List<Folder> excludedFolders,
       ContextRoot containingRoot,
-      List<Glob> excludedFilePatterns,
+      List<Glob> excludedGlobs,
       File optionsFile,
       File packagesFile) {
     //
@@ -175,16 +176,16 @@
       containingRoot.excluded.add(folder);
       roots.add(root);
       containingRoot = root;
-      excludedFilePatterns = _getExcludedFiles(root);
+      excludedGlobs = _getExcludedGlobs(root);
+      root.excludedGlobs = excludedGlobs;
     }
     _createContextRootsIn(roots, folder, excludedFolders, containingRoot,
-        excludedFilePatterns, optionsFile, packagesFile);
+        excludedGlobs, optionsFile, packagesFile);
   }
 
   /// For each directory within the given [folder] that is neither in the list
-  /// of [excludedFolders] nor excluded by the [excludedFilePatterns],
-  /// recursively search for nested context roots and add them to the list of
-  /// [roots].
+  /// of [excludedFolders] nor excluded by the [excludedGlobs], recursively
+  /// search for nested context roots and add them to the list of [roots].
   ///
   /// If either the [optionsFile] or [packagesFile] is non-`null` then the given
   /// file will be used even if there is a local version of the file.
@@ -193,7 +194,7 @@
       Folder folder,
       List<Folder> excludedFolders,
       ContextRoot containingRoot,
-      List<Glob> excludedFilePatterns,
+      List<Glob> excludedGlobs,
       File optionsFile,
       File packagesFile) {
     bool isExcluded(Folder folder) {
@@ -201,7 +202,7 @@
           folder.shortName.startsWith('.')) {
         return true;
       }
-      for (Glob pattern in excludedFilePatterns) {
+      for (Glob pattern in excludedGlobs) {
         if (pattern.matches(folder.path)) {
           return true;
         }
@@ -220,7 +221,7 @@
             containingRoot.excluded.add(child);
           } else {
             _createContextRoots(roots, child, excludedFolders, containingRoot,
-                excludedFilePatterns, optionsFile, packagesFile);
+                excludedGlobs, optionsFile, packagesFile);
           }
         }
       }
@@ -235,9 +236,9 @@
   /// folder or any parent folder.
   File _findOptionsFile(Folder folder) {
     while (folder != null) {
-      File packagesFile = _getOptionsFile(folder);
-      if (packagesFile != null) {
-        return packagesFile;
+      File optionsFile = _getOptionsFile(folder);
+      if (optionsFile != null) {
+        return optionsFile;
       }
       folder = folder.parent;
     }
@@ -263,7 +264,7 @@
   /// file associated with the context root. The list will be empty if there are
   /// no exclusion patterns in the options file, or if there is no options file
   /// associated with the context root.
-  List<Glob> _getExcludedFiles(ContextRootImpl root) {
+  List<Glob> _getExcludedGlobs(ContextRootImpl root) {
     List<Glob> patterns = [];
     File optionsFile = root.optionsFile;
     if (optionsFile != null) {
diff --git a/pkg/analyzer/lib/src/dart/analysis/context_root.dart b/pkg/analyzer/lib/src/dart/analysis/context_root.dart
index e652710..5888139 100644
--- a/pkg/analyzer/lib/src/dart/analysis/context_root.dart
+++ b/pkg/analyzer/lib/src/dart/analysis/context_root.dart
@@ -4,6 +4,7 @@
 
 import 'package:analyzer/dart/analysis/context_root.dart';
 import 'package:analyzer/file_system/file_system.dart';
+import 'package:glob/glob.dart';
 import 'package:path/path.dart';
 
 /// An implementation of a context root.
@@ -15,10 +16,14 @@
   final Folder root;
 
   @override
-  final List<Resource> included = <Resource>[];
+  final List<Resource> included = [];
 
   @override
-  final List<Resource> excluded = <Resource>[];
+  final List<Resource> excluded = [];
+
+  /// A list of the globs for excluded files that were read from the analysis
+  /// options file.
+  List<Glob> excludedGlobs = [];
 
   @override
   File optionsFile;
@@ -109,6 +114,11 @@
         }
       }
     }
+    for (Glob pattern in excludedGlobs) {
+      if (pattern.matches(path)) {
+        return true;
+      }
+    }
     return false;
   }
 
diff --git a/pkg/analyzer/test/src/dart/analysis/context_locator_test.dart b/pkg/analyzer/test/src/dart/analysis/context_locator_test.dart
index bed8770..df58649 100644
--- a/pkg/analyzer/test/src/dart/analysis/context_locator_test.dart
+++ b/pkg/analyzer/test/src/dart/analysis/context_locator_test.dart
@@ -476,9 +476,7 @@
     expect(outerRoot.packagesFile, outerPackagesFile);
   }
 
-  @failingTest
   void test_locateRoots_options_withExclude() {
-    // https://github.com/dart-lang/sdk/issues/35519
     Folder rootFolder = newFolder('/test/outer');
     newFolder('/test/outer/test/data');
     File dataFile = newFile('/test/outer/test/data/test.dart');
diff --git a/pkg/analyzer_plugin/test/utilities/analyzer_converter_test.dart b/pkg/analyzer_plugin/test/utilities/analyzer_converter_test.dart
index b22629a..681f5a4 100644
--- a/pkg/analyzer_plugin/test/utilities/analyzer_converter_test.dart
+++ b/pkg/analyzer_plugin/test/utilities/analyzer_converter_test.dart
@@ -2,21 +2,15 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import 'package:analyzer/dart/ast/ast.dart' as analyzer;
 import 'package:analyzer/dart/element/element.dart' as analyzer;
-import 'package:analyzer/dart/element/type.dart' as analyzer;
 import 'package:analyzer/error/error.dart' as analyzer;
-import 'package:analyzer/exception/exception.dart' as analyzer;
 import 'package:analyzer/source/error_processor.dart' as analyzer;
 import 'package:analyzer/src/dart/element/element.dart' as analyzer;
 import 'package:analyzer/src/diagnostic/diagnostic.dart' as analyzer;
 import 'package:analyzer/src/error/codes.dart' as analyzer;
 import 'package:analyzer/src/generated/engine.dart' as analyzer;
 import 'package:analyzer/src/generated/source.dart' as analyzer;
-import 'package:analyzer/src/generated/utilities_dart.dart' as analyzer;
 import 'package:analyzer_plugin/protocol/protocol_common.dart' as plugin;
-import 'package:analyzer_plugin/protocol/protocol_constants.dart' as plugin;
-import 'package:analyzer_plugin/protocol/protocol_generated.dart' as plugin;
 import 'package:analyzer_plugin/utilities/analyzer_converter.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
diff --git a/pkg/compiler/lib/src/js_model/element_map_impl.dart b/pkg/compiler/lib/src/js_model/element_map_impl.dart
index 4c5e0a1..a7ad980 100644
--- a/pkg/compiler/lib/src/js_model/element_map_impl.dart
+++ b/pkg/compiler/lib/src/js_model/element_map_impl.dart
@@ -1182,8 +1182,7 @@
       reportLocatedMessage(reporter, message, context);
     },
         environment: _environment.toMap(),
-        enableTripleShift:
-            options.languageExperiments[ir.ExperimentalFlag.tripleShift],
+        enableTripleShift: options.enableTripleShift,
         evaluationMode: options.useLegacySubtyping
             ? ir.EvaluationMode.weak
             : ir.EvaluationMode.strong);
diff --git a/pkg/compiler/lib/src/kernel/element_map_impl.dart b/pkg/compiler/lib/src/kernel/element_map_impl.dart
index d4fba7c..b176c21 100644
--- a/pkg/compiler/lib/src/kernel/element_map_impl.dart
+++ b/pkg/compiler/lib/src/kernel/element_map_impl.dart
@@ -816,8 +816,7 @@
       reportLocatedMessage(reporter, message, context);
     },
         environment: _environment.toMap(),
-        enableTripleShift:
-            options.languageExperiments[ir.ExperimentalFlag.tripleShift],
+        enableTripleShift: options.enableTripleShift,
         evaluationMode: options.useLegacySubtyping
             ? ir.EvaluationMode.weak
             : ir.EvaluationMode.strong);
diff --git a/pkg/compiler/lib/src/kernel/loader.dart b/pkg/compiler/lib/src/kernel/loader.dart
index 496d69b..d40a061 100644
--- a/pkg/compiler/lib/src/kernel/loader.dart
+++ b/pkg/compiler/lib/src/kernel/loader.dart
@@ -144,7 +144,7 @@
           ..target = target
           ..librariesSpecificationUri = _options.librariesSpecificationUri
           ..packagesFileUri = _options.packageConfig
-          ..experimentalFlags = _options.languageExperiments
+          ..explicitExperimentalFlags = _options.explicitExperimentalFlags
           ..verbose = verbose
           ..fileSystem = fileSystem
           ..onDiagnostic = onDiagnostic;
@@ -167,7 +167,7 @@
             _options.librariesSpecificationUri,
             dependencies,
             _options.packageConfig,
-            experimentalFlags: _options.languageExperiments,
+            explicitExperimentalFlags: _options.explicitExperimentalFlags,
             nnbdMode: _options.useLegacySubtyping
                 ? fe.NnbdMode.Weak
                 : fe.NnbdMode.Strong);
diff --git a/pkg/compiler/lib/src/options.dart b/pkg/compiler/lib/src/options.dart
index 6d336a5..c0638c2 100644
--- a/pkg/compiler/lib/src/options.dart
+++ b/pkg/compiler/lib/src/options.dart
@@ -105,14 +105,22 @@
   Map<String, String> environment = const <String, String>{};
 
   /// Flags enabling language experiments.
-  Map<fe.ExperimentalFlag, bool> languageExperiments = {};
+  Map<fe.ExperimentalFlag, bool> explicitExperimentalFlags = {};
 
   /// `true` if variance is enabled.
-  bool get enableVariance => languageExperiments[fe.ExperimentalFlag.variance];
+  bool get enableVariance =>
+      fe.isExperimentEnabled(fe.ExperimentalFlag.variance,
+          explicitExperimentalFlags: explicitExperimentalFlags);
 
   /// Whether `--enable-experiment=non-nullable` is provided.
   bool get enableNonNullable =>
-      languageExperiments[fe.ExperimentalFlag.nonNullable];
+      fe.isExperimentEnabled(fe.ExperimentalFlag.nonNullable,
+          explicitExperimentalFlags: explicitExperimentalFlags);
+
+  /// Whether `--enable-experiment=triple-shift` is provided.
+  bool get enableTripleShift =>
+      fe.isExperimentEnabled(fe.ExperimentalFlag.tripleShift,
+          explicitExperimentalFlags: explicitExperimentalFlags);
 
   /// A possibly null state object for kernel compilation.
   fe.InitializedCompilerState kernelInitializedCompilerState;
@@ -399,7 +407,7 @@
       Uri platformBinaries,
       void Function(String) onError,
       void Function(String) onWarning}) {
-    Map<fe.ExperimentalFlag, bool> languageExperiments =
+    Map<fe.ExperimentalFlag, bool> explicitExperimentalFlags =
         _extractExperiments(options, onError: onError, onWarning: onWarning);
 
     // The null safety experiment can result in requiring different experiments
@@ -423,7 +431,7 @@
       ..suppressHints = _hasOption(options, Flags.suppressHints)
       ..shownPackageWarnings =
           _extractOptionalCsvOption(options, Flags.showPackageWarnings)
-      ..languageExperiments = languageExperiments
+      ..explicitExperimentalFlags = explicitExperimentalFlags
       ..disableInlining = _hasOption(options, Flags.disableInlining)
       ..disableProgramSplit = _hasOption(options, Flags.disableProgramSplit)
       ..disableTypeInference = _hasOption(options, Flags.disableTypeInference)
@@ -507,8 +515,11 @@
       throw new ArgumentError(
           "[librariesSpecificationUri] should be a file: $librariesSpecificationUri");
     }
+    Map<fe.ExperimentalFlag, bool> experimentalFlags =
+        new Map.from(fe.defaultExperimentalFlags);
+    experimentalFlags.addAll(explicitExperimentalFlags);
     if (platformBinaries == null &&
-        equalMaps(languageExperiments, fe.defaultExperimentalFlags)) {
+        equalMaps(experimentalFlags, fe.defaultExperimentalFlags)) {
       throw new ArgumentError("Missing required ${Flags.platformBinaries}");
     }
     if (_legacyJavaScript && _noLegacyJavaScript) {
@@ -534,6 +545,7 @@
     if (benchmarkingExperiment) {
       // Set flags implied by '--benchmarking-x'.
       // TODO(sra): Use this for some NNBD variant.
+      useContentSecurityPolicy = true;
     }
 
     if (_noLegacyJavaScript) legacyJavaScript = false;
diff --git a/pkg/compiler/test/end_to_end/modular_loader_test.dart b/pkg/compiler/test/end_to_end/modular_loader_test.dart
index 76afdb2..3dccb70 100644
--- a/pkg/compiler/test/end_to_end/modular_loader_test.dart
+++ b/pkg/compiler/test/end_to_end/modular_loader_test.dart
@@ -83,7 +83,7 @@
     ..fileSystem = new TestFileSystem(fs)
     ..additionalDills = additionalDills
     ..packagesFileUri = toTestUri('.packages')
-    ..experimentalFlags = {ExperimentalFlag.nonNullable: true};
+    ..explicitExperimentalFlags = {ExperimentalFlag.nonNullable: true};
   var inputUris = inputs.map(toTestUri).toList();
   var inputUriSet = inputUris.toSet();
   var component = (await kernelForModule(inputUris, options)).component;
diff --git a/pkg/compiler/test/end_to_end/no_platform_test.dart b/pkg/compiler/test/end_to_end/no_platform_test.dart
index 8c23651..00578fc 100644
--- a/pkg/compiler/test/end_to_end/no_platform_test.dart
+++ b/pkg/compiler/test/end_to_end/no_platform_test.dart
@@ -23,7 +23,7 @@
             sdkLibrariesSpecificationUri,
             [], // additionalDills
             Uri.base.resolve('.packages'), // packagesFileUri
-            experimentalFlags: experimentalFlags,
+            explicitExperimentalFlags: experimentalFlags,
             verify: true);
     ir.Component component = await fe.compile(
         initializedCompilerState, false, fe.StandardFileSystem.instance,
diff --git a/pkg/dartdev/lib/src/commands/fix.dart b/pkg/dartdev/lib/src/commands/fix.dart
index 8a360e7..7fd3750 100644
--- a/pkg/dartdev/lib/src/commands/fix.dart
+++ b/pkg/dartdev/lib/src/commands/fix.dart
@@ -13,6 +13,7 @@
 import '../core.dart';
 import '../events.dart';
 import '../sdk.dart';
+import '../utils.dart';
 
 class FixCommand extends DartdevCommand<int> {
   static const String cmdName = 'fix';
@@ -76,7 +77,7 @@
       var fileCount = await _applyFixes(edits);
       progress.finish(showTiming: true);
       if (fileCount > 0) {
-        log.stdout('Fixed $fileCount files.');
+        log.stdout('Fixed $fileCount ${pluralize("file", fileCount)}.');
       }
     }
 
diff --git a/pkg/dartdev/test/commands/analyze_test.dart b/pkg/dartdev/test/commands/analyze_test.dart
index f7791c2..2d88b65 100644
--- a/pkg/dartdev/test/commands/analyze_test.dart
+++ b/pkg/dartdev/test/commands/analyze_test.dart
@@ -164,7 +164,7 @@
   });
 
   test('info implicit no --fatal-infos', () {
-    p = project(mainSrc: 'String foo() {}');
+    p = project(mainSrc: dartVersionFilePrefix2_9 + 'String foo() {}');
     var result = p.runSync('analyze', [p.dirPath]);
 
     expect(result.exitCode, 0);
@@ -173,7 +173,7 @@
   });
 
   test('info --fatal-infos', () {
-    p = project(mainSrc: 'String foo() {}');
+    p = project(mainSrc: dartVersionFilePrefix2_9 + 'String foo() {}');
     var result = p.runSync('analyze', ['--fatal-infos', p.dirPath]);
 
     expect(result.exitCode, 1);
diff --git a/pkg/dartdev/test/commands/fix_test.dart b/pkg/dartdev/test/commands/fix_test.dart
index 7778a0e..8881e4d 100644
--- a/pkg/dartdev/test/commands/fix_test.dart
+++ b/pkg/dartdev/test/commands/fix_test.dart
@@ -39,7 +39,7 @@
     var result = p.runSync('fix', [], workingDir: p.dirPath);
     expect(result.exitCode, 0);
     expect(result.stderr, isEmpty);
-    expect(result.stdout, contains('Fixed 1 files.'));
+    expect(result.stdout, contains('Fixed 1 file.'));
   });
 
   test('.', () {
@@ -56,7 +56,7 @@
     var result = p.runSync('fix', ['.'], workingDir: p.dirPath);
     expect(result.exitCode, 0);
     expect(result.stderr, isEmpty);
-    expect(result.stdout, contains('Fixed 1 files.'));
+    expect(result.stdout, contains('Fixed 1 file.'));
   });
 
   // todo (pq): add tests for analyzer excludes, ignores, etc.
diff --git a/pkg/dartdev/test/commands/migrate_test.dart b/pkg/dartdev/test/commands/migrate_test.dart
index a0df79e..307c85a 100644
--- a/pkg/dartdev/test/commands/migrate_test.dart
+++ b/pkg/dartdev/test/commands/migrate_test.dart
@@ -31,7 +31,7 @@
   });
 
   test('directory implicit', () {
-    p = project(mainSrc: 'int get foo => 1;\n');
+    p = project(mainSrc: dartVersionFilePrefix2_9 + 'int get foo => 1;\n');
     var result =
         p.runSync('migrate', ['--no-web-preview'], workingDir: p.dirPath);
     expect(result.exitCode, 0);
@@ -40,7 +40,7 @@
   });
 
   test('directory explicit', () {
-    p = project(mainSrc: 'int get foo => 1;\n');
+    p = project(mainSrc: dartVersionFilePrefix2_9 + 'int get foo => 1;\n');
     var result = p.runSync('migrate', ['--no-web-preview', p.dirPath]);
     expect(result.exitCode, 0);
     expect(result.stderr, isEmpty);
diff --git a/pkg/dartdev/test/commands/pub_test.dart b/pkg/dartdev/test/commands/pub_test.dart
index 7f2ca78..76c1ab3 100644
--- a/pkg/dartdev/test/commands/pub_test.dart
+++ b/pkg/dartdev/test/commands/pub_test.dart
@@ -66,25 +66,6 @@
     expect(result.stderr, result2.stderr);
   });
 
-  test('--enable-experiment pub run', () {
-    p = project();
-    p.file('bin/main.dart',
-        "void main() { int a; a = null; print('a is \$a.'); }");
-
-    // run 'pub get'
-    p.runSync('pub', ['get']);
-
-    var result = p.runSync(
-        '--enable-experiment=non-nullable', ['pub', 'run', 'main.dart']);
-
-    expect(result.exitCode, 254);
-    expect(result.stdout, isEmpty);
-    expect(
-        result.stderr,
-        contains("A value of type 'Null' can't be assigned to a variable of "
-            "type 'int'"));
-  });
-
   test('pub run --enable-experiment', () {
     p = project();
     p.file('bin/main.dart',
diff --git a/pkg/dartdev/test/commands/run_test.dart b/pkg/dartdev/test/commands/run_test.dart
index 5738c65..c380bcd 100644
--- a/pkg/dartdev/test/commands/run_test.dart
+++ b/pkg/dartdev/test/commands/run_test.dart
@@ -37,20 +37,6 @@
     expect(result.exitCode, 0);
   });
 
-  test('--enable-experiment', () {
-    p = project();
-    p.file('main.dart', "void main() { int a; a = null; print('a is \$a.'); }");
-    var result =
-        p.runSync('--enable-experiment=non-nullable', ['run', 'main.dart']);
-
-    expect(result.exitCode, 254);
-    expect(result.stdout, isEmpty);
-    expect(
-        result.stderr,
-        contains("A value of type 'Null' can't be assigned to a variable of "
-            "type 'int'"));
-  });
-
   test('no such file', () {
     p = project(mainSrc: "void main() { print('Hello World'); }");
     ProcessResult result =
@@ -88,7 +74,7 @@
     p = project();
     p.file('main.dart', 'void main(args) { print(args); }');
     ProcessResult result = p.runSync('run', [
-      '--enable-experiment=non-nullable',
+      '--enable-experiment=triple-shift',
       'main.dart',
       'argument1',
       'argument2',
@@ -106,7 +92,7 @@
     // Test with absolute path
     final name = path.join(p.dirPath, 'main.dart');
     final result = p.runSync('run', [
-      '--enable-experiment=non-nullable',
+      '--enable-experiment=triple-shift',
       name,
       '--argument1',
       'argument2',
@@ -124,7 +110,6 @@
     // Test with File uri
     final name = path.join(p.dirPath, 'main.dart');
     final result = p.runSync('run', [
-      '--enable-experiment=non-nullable',
       Uri.file(name).toString(),
       '--argument1',
       'argument2',
@@ -160,7 +145,7 @@
     expect(
       result.stdout,
       matches(
-          r'Observatory listening on http://127.0.0.1:8181/[a-zA-Z0-9]+=/\n.*'),
+          r'Observatory listening on http:\/\/127.0.0.1:8181\/[a-zA-Z0-9]+=\/\n.*'),
     );
     expect(result.stderr, isEmpty);
     expect(result.exitCode, 0);
diff --git a/pkg/dartdev/test/smoke/implicit_smoke_test.dart b/pkg/dartdev/test/smoke/implicit_smoke_test.dart
index 95053da..0f58378 100644
--- a/pkg/dartdev/test/smoke/implicit_smoke_test.dart
+++ b/pkg/dartdev/test/smoke/implicit_smoke_test.dart
@@ -24,9 +24,9 @@
               script,
             ],
           );
-          expect(result.exitCode, 0);
-          expect(result.stdout, contains('Smoke test!'));
           expect(result.stderr, isEmpty);
+          expect(result.stdout, contains('Smoke test!'));
+          expect(result.exitCode, 0);
         }
       });
 
@@ -44,9 +44,9 @@
               script,
             ],
           );
-          expect(result.exitCode, 0);
-          expect(result.stdout, contains('Smoke test!'));
           expect(result.stderr, isEmpty);
+          expect(result.stdout, contains('Smoke test!'));
+          expect(result.exitCode, 0);
         }
       });
     },
diff --git a/pkg/dartdev/test/smoke/smoke_test.dart b/pkg/dartdev/test/smoke/smoke_test.dart
index cb07f32..17abdc3 100644
--- a/pkg/dartdev/test/smoke/smoke_test.dart
+++ b/pkg/dartdev/test/smoke/smoke_test.dart
@@ -25,9 +25,9 @@
               script,
             ],
           );
-          expect(result.exitCode, 0);
-          expect(result.stdout, contains('Smoke test!'));
           expect(result.stderr, isEmpty);
+          expect(result.stdout, contains('Smoke test!'));
+          expect(result.exitCode, 0);
         }
       });
 
@@ -45,27 +45,48 @@
               script,
             ],
           );
-          expect(result.exitCode, 0);
-          expect(result.stdout, contains('Smoke test!'));
           expect(result.stderr, isEmpty);
+          expect(result.stdout, contains('Smoke test!'));
+          expect(result.exitCode, 0);
         }
       });
 
+      // This test verifies that an error isn't thrown when a valid experiment
+      // is passed.
+      // Experiments are lists here:
+      // https://github.com/dart-lang/sdk/blob/master/tools/experimental_features.yaml
       test(
-          'dart --sound-null-safety --enable-experiment=non-nullable '
+          'dart --enable-experiment=variance '
           'run smoke.dart', () async {
         final result = await Process.run(
           Platform.executable,
           [
-            '--sound-null-safety',
-            '--enable-experiment=non-nullable',
+            '--enable-experiment=variance',
             'run',
             script,
           ],
         );
-        expect(result.exitCode, 0);
-        expect(result.stdout, contains('Smoke test!'));
         expect(result.stderr, isEmpty);
+        expect(result.stdout, contains('Smoke test!'));
+        expect(result.exitCode, 0);
+      });
+
+      // This test verifies that an error is thrown when an invalid experiment
+      // is passed.
+      test(
+          'dart --enable-experiment=invalid-experiment-name '
+          'run smoke.dart', () async {
+        final result = await Process.run(
+          Platform.executable,
+          [
+            '--enable-experiment=invalid-experiment-name',
+            'run',
+            script,
+          ],
+        );
+        expect(result.stderr, isNotEmpty);
+        expect(result.stdout, isEmpty);
+        expect(result.exitCode, 254);
       });
     },
     timeout: Timeout.none,
diff --git a/pkg/dartdev/test/test_all.dart b/pkg/dartdev/test/test_all.dart
index ca092a4..797a9b3 100644
--- a/pkg/dartdev/test/test_all.dart
+++ b/pkg/dartdev/test/test_all.dart
@@ -20,6 +20,9 @@
 import 'events_test.dart' as events;
 import 'experiments_test.dart' as experiments;
 import 'sdk_test.dart' as sdk;
+import 'smoke/implicit_smoke_test.dart' as implicit_smoke;
+import 'smoke/invalid_smoke_test.dart' as invalid_smoke;
+import 'smoke/smoke_test.dart' as smoke;
 import 'utils_test.dart' as utils;
 
 void main() {
@@ -33,6 +36,8 @@
     flag.main();
     format.main();
     help.main();
+    implicit_smoke.main();
+    invalid_smoke.main();
     migrate.main();
     pub.main();
     run.main();
@@ -40,6 +45,7 @@
     test.main();
     core.main();
     sdk.main();
+    smoke.main();
     utils.main();
   });
 }
diff --git a/pkg/dartdev/test/utils.dart b/pkg/dartdev/test/utils.dart
index 513f2dc..62364e0 100644
--- a/pkg/dartdev/test/utils.dart
+++ b/pkg/dartdev/test/utils.dart
@@ -12,6 +12,10 @@
 /// invocation requires the VM to compile the entire dependency graph.
 const Timeout longTimeout = Timeout(Duration(minutes: 5));
 
+/// This version of dart is the last guaranteed pre-null safety language
+/// version:
+const String dartVersionFilePrefix2_9 = '// @dart = 2.9\n';
+
 TestProject project({String mainSrc, String analysisOptions}) =>
     TestProject(mainSrc: mainSrc, analysisOptions: analysisOptions);
 
diff --git a/pkg/dev_compiler/lib/src/kernel/command.dart b/pkg/dev_compiler/lib/src/kernel/command.dart
index 6540497..fb3f3c8 100644
--- a/pkg/dev_compiler/lib/src/kernel/command.dart
+++ b/pkg/dev_compiler/lib/src/kernel/command.dart
@@ -248,7 +248,7 @@
     fe.printDiagnosticMessage(message, print);
   }
 
-  var experiments = fe.parseExperimentalFlags(options.experiments,
+  var explicitExperimentalFlags = fe.parseExperimentalFlags(options.experiments,
       onError: stderr.writeln, onWarning: print);
 
   var trackWidgetCreation =
@@ -275,7 +275,7 @@
             trackWidgetCreation: trackWidgetCreation,
             enableNullSafety: options.enableNullSafety)),
         fileSystem: fileSystem,
-        experiments: experiments,
+        explicitExperimentalFlags: explicitExperimentalFlags,
         environmentDefines: declaredVariables,
         nnbdMode:
             options.soundNullSafety ? fe.NnbdMode.Strong : fe.NnbdMode.Weak);
@@ -314,7 +314,7 @@
             trackWidgetCreation: trackWidgetCreation,
             enableNullSafety: options.enableNullSafety)),
         fileSystem: fileSystem,
-        experiments: experiments,
+        explicitExperimentalFlags: explicitExperimentalFlags,
         environmentDefines: declaredVariables,
         trackNeededDillLibraries: recordUsedInputs,
         nnbdMode:
@@ -349,7 +349,8 @@
   var component = result.component;
   var librariesFromDill = result.computeLibrariesFromDill();
   var compiledLibraries =
-      Component(nameRoot: component.root, uriToSource: component.uriToSource);
+      Component(nameRoot: component.root, uriToSource: component.uriToSource)
+        ..setMainMethodAndMode(null, false, component.mode);
   for (var lib in component.libraries) {
     if (!librariesFromDill.contains(lib)) compiledLibraries.libraries.add(lib);
   }
diff --git a/pkg/dev_compiler/lib/src/kernel/expression_compiler_worker.dart b/pkg/dev_compiler/lib/src/kernel/expression_compiler_worker.dart
index ec08c67..9e77102 100644
--- a/pkg/dev_compiler/lib/src/kernel/expression_compiler_worker.dart
+++ b/pkg/dev_compiler/lib/src/kernel/expression_compiler_worker.dart
@@ -135,7 +135,7 @@
       fileSystem = AssetFileSystem(
           fileSystem, assetServerAddress, assetServerPort ?? '8080');
     }
-    var experimentalFlags = parseExperimentalFlags(
+    var explicitExperimentalFlags = parseExperimentalFlags(
         parseExperimentalArguments(
             parsedArgs['enable-experiment'] as List<String>),
         onError: (e) => throw e);
@@ -146,7 +146,7 @@
       sdkSummary: _argToUri(parsedArgs['dart-sdk-summary'] as String),
       fileSystem: fileSystem,
       environmentDefines: environmentDefines,
-      experimentalFlags: experimentalFlags,
+      explicitExperimentalFlags: explicitExperimentalFlags,
       sdkRoot: _argToUri(parsedArgs['sdk-root'] as String),
       trackWidgetCreation: parsedArgs['track-widget-creation'] as bool,
       soundNullSafety: parsedArgs['sound-null-safety'] as bool,
@@ -166,7 +166,7 @@
     @required FileSystem fileSystem,
     Uri packagesFile,
     Map<String, String> environmentDefines = const {},
-    Map<ExperimentalFlag, bool> experimentalFlags = const {},
+    Map<ExperimentalFlag, bool> explicitExperimentalFlags = const {},
     Uri sdkRoot,
     bool trackWidgetCreation = false,
     bool soundNullSafety = false,
@@ -186,7 +186,7 @@
       ..fileSystem = fileSystem
       ..omitPlatform = true
       ..environmentDefines = environmentDefines
-      ..experimentalFlags = experimentalFlags
+      ..explicitExperimentalFlags = explicitExperimentalFlags
       ..onDiagnostic = _onDiagnosticHandler(errors, warnings)
       ..nnbdMode = soundNullSafety ? NnbdMode.Strong : NnbdMode.Weak
       ..verbose = verbose;
diff --git a/pkg/dev_compiler/test/nullable_inference_test.dart b/pkg/dev_compiler/test/nullable_inference_test.dart
index 315dca1..9326ea29 100644
--- a/pkg/dev_compiler/test/nullable_inference_test.dart
+++ b/pkg/dev_compiler/test/nullable_inference_test.dart
@@ -676,7 +676,7 @@
   _compilerState = await fe.initializeCompiler(oldCompilerState, false, null,
       sdkUri, packagesUri, null, [], DevCompilerTarget(TargetFlags()),
       fileSystem: _fileSystem,
-      experiments: const {},
+      explicitExperimentalFlags: const {},
       environmentDefines: const {},
       nnbdMode: fe.NnbdMode.Weak);
   if (!identical(oldCompilerState, _compilerState)) inference = null;
diff --git a/pkg/front_end/lib/src/api_prototype/compiler_options.dart b/pkg/front_end/lib/src/api_prototype/compiler_options.dart
index 564b09e..28f961e 100644
--- a/pkg/front_end/lib/src/api_prototype/compiler_options.dart
+++ b/pkg/front_end/lib/src/api_prototype/compiler_options.dart
@@ -25,7 +25,10 @@
         parseExperimentalFlag;
 
 import 'experimental_flags.dart' as flags
-    show getExperimentEnabledVersionInLibrary, isExperimentEnabledInLibrary;
+    show
+        getExperimentEnabledVersionInLibrary,
+        isExperimentEnabled,
+        isExperimentEnabledInLibrary;
 
 import 'file_system.dart' show FileSystem;
 
@@ -133,7 +136,8 @@
   /// Enable or disable experimental features. Features mapping to `true` are
   /// explicitly enabled. Features mapping to `false` are explicitly disabled.
   /// Features not mentioned in the map will have their default value.
-  Map<ExperimentalFlag, bool> experimentalFlags = <ExperimentalFlag, bool>{};
+  Map<ExperimentalFlag, bool> explicitExperimentalFlags =
+      <ExperimentalFlag, bool>{};
 
   Map<ExperimentalFlag, bool> defaultExperimentFlagsForTesting;
   AllowedExperimentalFlags allowedExperimentalFlagsForTesting;
@@ -255,16 +259,29 @@
   /// compiling the platform dill.
   bool emitDeps = true;
 
+  bool isExperimentEnabledByDefault(ExperimentalFlag flag) {
+    return flags.isExperimentEnabled(flag,
+        defaultExperimentFlagsForTesting: defaultExperimentFlagsForTesting);
+  }
+
+  /// Returns
+  bool isExperimentEnabled(ExperimentalFlag flag) {
+    return flags.isExperimentEnabled(flag,
+        explicitExperimentalFlags: explicitExperimentalFlags,
+        defaultExperimentFlagsForTesting: defaultExperimentFlagsForTesting);
+  }
+
   bool isExperimentEnabledInLibrary(ExperimentalFlag flag, Uri importUri) {
     return flags.isExperimentEnabledInLibrary(flag, importUri,
         defaultExperimentFlagsForTesting: defaultExperimentFlagsForTesting,
-        experimentalFlags: experimentalFlags,
+        explicitExperimentalFlags: explicitExperimentalFlags,
         allowedExperimentalFlags: allowedExperimentalFlagsForTesting);
   }
 
   Version getExperimentEnabledVersionInLibrary(
       ExperimentalFlag flag, Uri importUri) {
-    return flags.getExperimentEnabledVersionInLibrary(flag, importUri,
+    return flags.getExperimentEnabledVersionInLibrary(
+        flag, importUri, explicitExperimentalFlags,
         defaultExperimentFlagsForTesting: defaultExperimentFlagsForTesting,
         allowedExperimentalFlags: allowedExperimentalFlagsForTesting,
         experimentEnabledVersionForTesting: experimentEnabledVersionForTesting,
@@ -292,7 +309,10 @@
     if (compileSdk != compileSdk) return false;
     // chaseDependencies aren't used anywhere, so ignored here.
     // targetPatches aren't used anywhere, so ignored here.
-    if (!equalMaps(experimentalFlags, other.experimentalFlags)) return false;
+    if (!equalMaps(
+        explicitExperimentalFlags, other.explicitExperimentalFlags)) {
+      return false;
+    }
     if (!equalMaps(environmentDefines, other.environmentDefines)) return false;
     if (errorOnUnevaluatedConstant != other.errorOnUnevaluatedConstant) {
       return false;
@@ -352,9 +372,7 @@
 }
 
 /// Parse a map of experimental flags to values that can be passed to
-/// [CompilerOptions.experimentalFlags].
-/// The returned map is normalized to contain default values for unmentioned
-/// flags.
+/// [CompilerOptions.explicitExperimentalFlags].
 ///
 /// If an unknown flag is mentioned, or a flag is mentioned more than once,
 /// the supplied error handler is called with an error message.
diff --git a/pkg/front_end/lib/src/api_prototype/experimental_flags.dart b/pkg/front_end/lib/src/api_prototype/experimental_flags.dart
index 9e21c12..d0057f7 100644
--- a/pkg/front_end/lib/src/api_prototype/experimental_flags.dart
+++ b/pkg/front_end/lib/src/api_prototype/experimental_flags.dart
@@ -42,15 +42,17 @@
   }
 }
 
-/// Returns `true` if [flag] is enabled using global [experimentalFlags].
+/// Returns `true` if [flag] is enabled either by default or through
+/// [explicitExperimentalFlags].
 ///
-/// If [experimentalFlags] is `null` or doesn't contain [flag], the default
-/// value from [defaultExperimentalFlags] is returned.
+/// If [explicitExperimentalFlags] is `null` or doesn't contain [flag], the
+/// default value from [defaultExperimentalFlags] is returned.
 ///
 /// If [flag] is marked as expired in [expiredExperimentalFlags], the value from
 /// [defaultExperimentalFlags] is always returned.
 bool isExperimentEnabled(ExperimentalFlag flag,
-    {Map<ExperimentalFlag, bool> experimentalFlags}) {
+    {Map<ExperimentalFlag, bool> explicitExperimentalFlags,
+    Map<ExperimentalFlag, bool> defaultExperimentFlagsForTesting}) {
   assert(defaultExperimentalFlags.containsKey(flag),
       "No default value for $flag.");
   assert(expiredExperimentalFlags.containsKey(flag),
@@ -59,19 +61,22 @@
     return defaultExperimentalFlags[flag];
   }
   bool enabled;
-  if (experimentalFlags != null) {
-    enabled = experimentalFlags[flag];
+  if (explicitExperimentalFlags != null) {
+    enabled = explicitExperimentalFlags[flag];
+  }
+  if (defaultExperimentFlagsForTesting != null) {
+    enabled ??= defaultExperimentFlagsForTesting[flag];
   }
   enabled ??= defaultExperimentalFlags[flag];
   return enabled;
 }
 
 /// Returns `true` if [flag] is enabled in the library with the [canonicalUri]
-/// either globally using [experimentalFlags] or per library using
+/// either globally using [explicitExperimentalFlags] or per library using
 /// [allowedExperimentalFlags].
 ///
-/// If [experimentalFlags] is `null` or doesn't contain [flag], the default
-/// value from [defaultExperimentalFlags] used as the global flag state.
+/// If [explicitExperimentalFlags] is `null` or doesn't contain [flag], the
+/// default value from [defaultExperimentalFlags] used as the global flag state.
 ///
 /// If [allowedExperimentalFlags] is `null` [defaultAllowedExperimentalFlags] is
 /// used for the per library flag state.
@@ -84,7 +89,7 @@
 /// or `file:///path/dir/file.dart`.
 bool isExperimentEnabledInLibrary(ExperimentalFlag flag, Uri canonicalUri,
     {Map<ExperimentalFlag, bool> defaultExperimentFlagsForTesting,
-    Map<ExperimentalFlag, bool> experimentalFlags,
+    Map<ExperimentalFlag, bool> explicitExperimentalFlags,
     AllowedExperimentalFlags allowedExperimentalFlags}) {
   assert(defaultExperimentalFlags.containsKey(flag),
       "No default value for $flag.");
@@ -94,8 +99,8 @@
     return defaultExperimentalFlags[flag];
   }
   bool enabled;
-  if (experimentalFlags != null) {
-    enabled = experimentalFlags[flag];
+  if (explicitExperimentalFlags != null) {
+    enabled = explicitExperimentalFlags[flag];
   }
   if (defaultExperimentFlagsForTesting != null) {
     enabled ??= defaultExperimentFlagsForTesting[flag];
@@ -125,8 +130,8 @@
 
 /// Returns the version in which [flag] is enabled for the library with the
 /// [canonicalUri].
-Version getExperimentEnabledVersionInLibrary(
-    ExperimentalFlag flag, Uri canonicalUri,
+Version getExperimentEnabledVersionInLibrary(ExperimentalFlag flag,
+    Uri canonicalUri, Map<ExperimentalFlag, bool> explicitExperimentalFlags,
     {AllowedExperimentalFlags allowedExperimentalFlags,
     Map<ExperimentalFlag, bool> defaultExperimentFlagsForTesting,
     Map<ExperimentalFlag, Version> experimentEnabledVersionForTesting,
@@ -152,8 +157,12 @@
     enabledByDefault = defaultExperimentFlagsForTesting[flag];
   }
   enabledByDefault ??= defaultExperimentalFlags[flag];
+
+  bool enabledExplicitly = explicitExperimentalFlags[flag] ?? false;
+
   if (!enabledByDefault ||
-      allowedFlags != null && allowedFlags.contains(flag)) {
+      enabledExplicitly ||
+      (allowedFlags != null && allowedFlags.contains(flag))) {
     // If the feature is not enabled by default or is enabled by the allowed
     // list use the experiment release version.
     if (experimentReleasedVersionForTesting != null) {
diff --git a/pkg/front_end/lib/src/api_unstable/bazel_worker.dart b/pkg/front_end/lib/src/api_unstable/bazel_worker.dart
index 66f4a23..24c779d 100644
--- a/pkg/front_end/lib/src/api_unstable/bazel_worker.dart
+++ b/pkg/front_end/lib/src/api_unstable/bazel_worker.dart
@@ -94,7 +94,7 @@
       workerInputDigests,
       target,
       fileSystem: fileSystem,
-      experimentalFlags: experimentalFlags,
+      explicitExperimentalFlags: experimentalFlags,
       outlineOnly: outlineOnly,
       omitPlatform: true,
       trackNeededDillLibraries: trackNeededDillLibraries,
@@ -129,7 +129,7 @@
     ..target = target
     ..fileSystem = fileSystem
     ..environmentDefines = environmentDefines
-    ..experimentalFlags = parseExperimentalFlags(
+    ..explicitExperimentalFlags = parseExperimentalFlags(
         parseExperimentalArguments(experiments),
         onError: (e) => throw e)
     ..verbose = verbose
diff --git a/pkg/front_end/lib/src/api_unstable/dart2js.dart b/pkg/front_end/lib/src/api_unstable/dart2js.dart
index 35d49c2..85cb35a 100644
--- a/pkg/front_end/lib/src/api_unstable/dart2js.dart
+++ b/pkg/front_end/lib/src/api_unstable/dart2js.dart
@@ -102,7 +102,7 @@
     show CompilerOptions, parseExperimentalFlags, parseExperimentalArguments;
 
 export '../api_prototype/experimental_flags.dart'
-    show defaultExperimentalFlags, ExperimentalFlag;
+    show defaultExperimentalFlags, ExperimentalFlag, isExperimentEnabled;
 
 export '../api_prototype/file_system.dart'
     show FileSystem, FileSystemEntity, FileSystemException;
@@ -138,7 +138,7 @@
     Uri librariesSpecificationUri,
     List<Uri> additionalDills,
     Uri packagesFileUri,
-    {Map<ExperimentalFlag, bool> experimentalFlags,
+    {Map<ExperimentalFlag, bool> explicitExperimentalFlags,
     bool verify: false,
     NnbdMode nnbdMode}) {
   additionalDills.sort((a, b) => a.toString().compareTo(b.toString()));
@@ -150,7 +150,8 @@
       oldState.options.packagesFileUri == packagesFileUri &&
       oldState.options.librariesSpecificationUri == librariesSpecificationUri &&
       equalLists(oldState.options.additionalDills, additionalDills) &&
-      equalMaps(oldState.options.experimentalFlags, experimentalFlags) &&
+      equalMaps(oldState.options.explicitExperimentalFlags,
+          explicitExperimentalFlags) &&
       oldState.options.verify == verify &&
       oldState.options.nnbdMode == nnbdMode) {
     return oldState;
@@ -161,7 +162,7 @@
     ..additionalDills = additionalDills
     ..librariesSpecificationUri = librariesSpecificationUri
     ..packagesFileUri = packagesFileUri
-    ..experimentalFlags = experimentalFlags
+    ..explicitExperimentalFlags = explicitExperimentalFlags
     ..verify = verify;
   if (nnbdMode != null) options.nnbdMode = nnbdMode;
 
diff --git a/pkg/front_end/lib/src/api_unstable/ddc.dart b/pkg/front_end/lib/src/api_unstable/ddc.dart
index 18a00ef..d9506f7 100644
--- a/pkg/front_end/lib/src/api_unstable/ddc.dart
+++ b/pkg/front_end/lib/src/api_unstable/ddc.dart
@@ -113,7 +113,7 @@
     List<Uri> additionalDills,
     Target target,
     {FileSystem fileSystem,
-    Map<ExperimentalFlag, bool> experiments,
+    Map<ExperimentalFlag, bool> explicitExperimentalFlags,
     Map<String, String> environmentDefines,
     NnbdMode nnbdMode}) async {
   assert(nnbdMode != null, "No NnbdMode provided.");
@@ -126,7 +126,8 @@
       oldState.options.librariesSpecificationUri == librariesSpecificationUri &&
       oldState.options.nnbdMode == nnbdMode &&
       equalLists(oldState.options.additionalDills, additionalDills) &&
-      equalMaps(oldState.options.experimentalFlags, experiments) &&
+      equalMaps(oldState.options.explicitExperimentalFlags,
+          explicitExperimentalFlags) &&
       equalMaps(oldState.options.environmentDefines, environmentDefines)) {
     // Reuse old state.
     return oldState;
@@ -143,7 +144,9 @@
     ..fileSystem = fileSystem ?? StandardFileSystem.instance
     ..environmentDefines = environmentDefines
     ..nnbdMode = nnbdMode;
-  if (experiments != null) options.experimentalFlags = experiments;
+  if (explicitExperimentalFlags != null) {
+    options.explicitExperimentalFlags = explicitExperimentalFlags;
+  }
 
   ProcessedOptions processedOpts = new ProcessedOptions(options: options);
 
@@ -167,7 +170,7 @@
     Map<Uri, List<int>> workerInputDigests,
     Target target,
     {FileSystem fileSystem,
-    Map<ExperimentalFlag, bool> experiments,
+    Map<ExperimentalFlag, bool> explicitExperimentalFlags,
     Map<String, String> environmentDefines,
     bool trackNeededDillLibraries: false,
     NnbdMode nnbdMode}) async {
@@ -184,7 +187,7 @@
       compileSdk: compileSdk,
       sdkRoot: sdkRoot,
       fileSystem: fileSystem ?? StandardFileSystem.instance,
-      experimentalFlags: experiments,
+      explicitExperimentalFlags: explicitExperimentalFlags,
       environmentDefines:
           environmentDefines ?? const <ExperimentalFlag, bool>{},
       outlineOnly: false,
diff --git a/pkg/front_end/lib/src/api_unstable/modular_incremental_compilation.dart b/pkg/front_end/lib/src/api_unstable/modular_incremental_compilation.dart
index 291a914..0044b4c 100644
--- a/pkg/front_end/lib/src/api_unstable/modular_incremental_compilation.dart
+++ b/pkg/front_end/lib/src/api_unstable/modular_incremental_compilation.dart
@@ -51,7 +51,7 @@
     {bool compileSdk: false,
     Uri sdkRoot: null,
     FileSystem fileSystem,
-    Map<ExperimentalFlag, bool> experimentalFlags,
+    Map<ExperimentalFlag, bool> explicitExperimentalFlags,
     Map<String, String> environmentDefines: const {},
     bool outlineOnly,
     bool omitPlatform: false,
@@ -82,7 +82,8 @@
           oldState.options.compileSdk != compileSdk ||
           oldState.incrementalCompiler.outlineOnly != outlineOnly ||
           oldState.options.nnbdMode != nnbdMode ||
-          !equalMaps(oldState.options.experimentalFlags, experimentalFlags) ||
+          !equalMaps(oldState.options.explicitExperimentalFlags,
+              explicitExperimentalFlags) ||
           !equalMaps(oldState.options.environmentDefines, environmentDefines) ||
           !equalSets(oldState.tags, tags) ||
           cachedSdkInput == null ||
@@ -103,7 +104,7 @@
           ..fileSystem = fileSystem
           ..omitPlatform = omitPlatform
           ..environmentDefines = environmentDefines
-          ..experimentalFlags = experimentalFlags
+          ..explicitExperimentalFlags = explicitExperimentalFlags
           ..verbose = verbose
           ..nnbdMode = nnbdMode;
 
diff --git a/pkg/front_end/lib/src/base/processed_options.dart b/pkg/front_end/lib/src/base/processed_options.dart
index 2e20ff0..78bf4f4 100644
--- a/pkg/front_end/lib/src/base/processed_options.dart
+++ b/pkg/front_end/lib/src/base/processed_options.dart
@@ -342,9 +342,22 @@
   /// This is `true` either if the [flag] is passed through an explicit
   /// `--enable-experiment` option or if the [flag] is expired and on by
   /// default.
+  bool isExperimentEnabledByDefault(flags.ExperimentalFlag flag) {
+    return flags.isExperimentEnabled(flag,
+        defaultExperimentFlagsForTesting:
+            _raw.defaultExperimentFlagsForTesting);
+  }
+
+  /// Returns `true` if the [flag] is enabled globally.
+  ///
+  /// This is `true` either if the [flag] is passed through an explicit
+  /// `--enable-experiment` option or if the [flag] is expired and on by
+  /// default.
   bool isExperimentEnabledGlobally(flags.ExperimentalFlag flag) {
     return flags.isExperimentEnabled(flag,
-        experimentalFlags: _raw.experimentalFlags);
+        explicitExperimentalFlags: _raw.explicitExperimentalFlags,
+        defaultExperimentFlagsForTesting:
+            _raw.defaultExperimentFlagsForTesting);
   }
 
   /// Returns `true` if the [flag] is enabled in the library with the given
diff --git a/pkg/front_end/lib/src/fasta/builder/class_builder.dart b/pkg/front_end/lib/src/fasta/builder/class_builder.dart
index cea8ff8..6f675d8 100644
--- a/pkg/front_end/lib/src/fasta/builder/class_builder.dart
+++ b/pkg/front_end/lib/src/fasta/builder/class_builder.dart
@@ -6,28 +6,19 @@
 
 import 'package:kernel/ast.dart'
     show
-        Arguments,
-        AsExpression,
-        AsyncMarker,
         Class,
         Constructor,
         DartType,
         DynamicType,
-        Expression,
         FunctionNode,
         FunctionType,
         FutureOrType,
         InterfaceType,
         Member,
-        MethodInvocation,
         Name,
         Nullability,
-        Procedure,
-        ReturnStatement,
         Supertype,
-        ThisExpression,
         TypeParameter,
-        VoidType,
         getAsTypeArguments;
 
 import 'package:kernel/class_hierarchy.dart' show ClassHierarchy;
@@ -49,8 +40,6 @@
 
 import '../kernel/redirecting_factory_body.dart' show getRedirectingFactoryBody;
 
-import '../kernel/kernel_target.dart' show KernelTarget;
-
 import '../loader.dart';
 
 import '../modifier.dart';
@@ -773,48 +762,6 @@
     return noSuchMethod != null && noSuchMethod.enclosingClass != objectClass;
   }
 
-  void transformProcedureToNoSuchMethodForwarder(
-      Member noSuchMethodInterface, KernelTarget target, Procedure procedure) {
-    String prefix = procedure.isGetter
-        ? 'get:'
-        : procedure.isSetter
-            ? 'set:'
-            : '';
-    String invocationName = prefix + procedure.name.text;
-    if (procedure.isSetter) invocationName += '=';
-    Expression invocation = target.backendTarget.instantiateInvocation(
-        target.loader.coreTypes,
-        new ThisExpression(),
-        invocationName,
-        new Arguments.forwarded(procedure.function, library.library),
-        procedure.fileOffset,
-        /*isSuper=*/ false);
-    Expression result = new MethodInvocation(new ThisExpression(),
-        noSuchMethodName, new Arguments([invocation]), noSuchMethodInterface)
-      ..fileOffset = procedure.fileOffset;
-    if (procedure.function.returnType is! VoidType) {
-      result = new AsExpression(result, procedure.function.returnType)
-        ..isTypeError = true
-        ..isForDynamic = true
-        ..isForNonNullableByDefault = library.isNonNullableByDefault
-        ..fileOffset = procedure.fileOffset;
-    }
-    procedure.function.body = new ReturnStatement(result)
-      ..fileOffset = procedure.fileOffset;
-    procedure.function.body.parent = procedure.function;
-    procedure.function.asyncMarker = AsyncMarker.Sync;
-    procedure.function.dartAsyncMarker = AsyncMarker.Sync;
-
-    procedure.isAbstract = false;
-    procedure.isNoSuchMethodForwarder = true;
-    procedure.isMemberSignature = false;
-    procedure.isForwardingStub = false;
-    procedure.isForwardingSemiStub = false;
-    procedure.memberSignatureOrigin = null;
-    procedure.forwardingStubInterfaceTarget = null;
-    procedure.forwardingStubSuperTarget = null;
-  }
-
   @override
   String get fullNameForErrors {
     return isMixinApplication && !isNamedMixinApplication
@@ -1216,17 +1163,3 @@
 
   ConstructorRedirection(this.target) : cycleReported = false;
 }
-
-/// Returns `true` if override problems should be overlooked.
-///
-/// This is needed for the current encoding of some JavaScript implementation
-/// classes that are not valid Dart. For instance `JSInt` in
-/// 'dart:_interceptors' that implements both `int` and `double`, and `JsArray`
-/// in `dart:js` that implement both `ListMixin` and `JsObject`.
-bool shouldOverrideProblemBeOverlooked(ClassBuilder classBuilder) {
-  String uri = '${classBuilder.library.importUri}';
-  return uri == 'dart:js' &&
-          classBuilder.fileUri.pathSegments.last == 'js.dart' ||
-      uri == 'dart:_interceptors' &&
-          classBuilder.fileUri.pathSegments.last == 'js_number.dart';
-}
diff --git a/pkg/front_end/lib/src/fasta/incremental_serializer.dart b/pkg/front_end/lib/src/fasta/incremental_serializer.dart
index 59d8488..e22b912 100644
--- a/pkg/front_end/lib/src/fasta/incremental_serializer.dart
+++ b/pkg/front_end/lib/src/fasta/incremental_serializer.dart
@@ -302,6 +302,7 @@
         libraries: libraries,
         uriToSource: component.uriToSource,
         nameRoot: component.root);
+    singlePackageLibraries.setMainMethodAndMode(null, false, component.mode);
 
     ByteSink byteSink = new ByteSink();
     final BinaryPrinter printer = new BinaryPrinter(byteSink);
diff --git a/pkg/front_end/lib/src/fasta/kernel/class_hierarchy_builder.dart b/pkg/front_end/lib/src/fasta/kernel/class_hierarchy_builder.dart
index 9868a51..c08ebe5 100644
--- a/pkg/front_end/lib/src/fasta/kernel/class_hierarchy_builder.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/class_hierarchy_builder.dart
@@ -61,8 +61,6 @@
 
 import '../names.dart' show noSuchMethodName;
 
-import '../problems.dart' show unhandled;
-
 import '../scope.dart' show Scope;
 
 import '../source/source_class_builder.dart';
@@ -81,6 +79,8 @@
 
 import '../type_inference/type_schema_environment.dart' show TypeConstraint;
 
+import 'combined_member_signature.dart';
+
 import 'forwarding_node.dart' show ForwardingNode;
 
 import 'kernel_builder.dart' show ImplicitFieldType;
@@ -684,8 +684,8 @@
       Set<ClassMember> overriddenMemberSet =
           toSet(declaredMember.classBuilder, overriddenMembers);
       if (classBuilder.library.isNonNullableByDefault) {
-        CombinedMemberSignature combinedMemberSignature =
-            new CombinedMemberSignature(
+        CombinedClassMemberSignature combinedMemberSignature =
+            new CombinedClassMemberSignature(
                 hierarchy, classBuilder, overriddenMemberSet.toList(),
                 forSetter: false);
         FunctionType combinedMemberSignatureType = combinedMemberSignature
@@ -1101,8 +1101,8 @@
 
         void inferFrom(List<ClassMember> members, {bool forSetter}) {
           assert(forSetter != null);
-          CombinedMemberSignature combinedMemberSignature =
-              new CombinedMemberSignature(hierarchy, classBuilder, members,
+          CombinedClassMemberSignature combinedMemberSignature =
+              new CombinedClassMemberSignature(hierarchy, classBuilder, members,
                   forSetter: forSetter);
           DartType combinedMemberSignatureType =
               combinedMemberSignature.combinedMemberSignatureType;
@@ -1228,8 +1228,8 @@
 
         void inferFrom(List<ClassMember> members, {bool forSetter}) {
           assert(forSetter != null);
-          CombinedMemberSignature combinedMemberSignature =
-              new CombinedMemberSignature(hierarchy, classBuilder, members,
+          CombinedClassMemberSignature combinedMemberSignature =
+              new CombinedClassMemberSignature(hierarchy, classBuilder, members,
                   forSetter: forSetter);
           DartType combinedMemberSignatureType =
               combinedMemberSignature.combinedMemberSignatureType;
@@ -1392,8 +1392,8 @@
 
         DartType inferFrom(List<ClassMember> members, {bool forSetter}) {
           assert(forSetter != null);
-          CombinedMemberSignature combinedMemberSignature =
-              new CombinedMemberSignature(hierarchy, classBuilder, members,
+          CombinedClassMemberSignature combinedMemberSignature =
+              new CombinedClassMemberSignature(hierarchy, classBuilder, members,
                   forSetter: forSetter);
           return combinedMemberSignature.combinedMemberSignatureType;
         }
@@ -3181,11 +3181,11 @@
           declarations.first.getMember(hierarchy);
     }
 
-    CombinedMemberSignature combinedMemberSignature =
-        new CombinedMemberSignature(hierarchy, classBuilder, declarations,
+    CombinedClassMemberSignature combinedMemberSignature =
+        new CombinedClassMemberSignature(hierarchy, classBuilder, declarations,
             forSetter: isSetter);
 
-    if (combinedMemberSignature.canonicalClassMember == null) {
+    if (combinedMemberSignature.canonicalMember == null) {
       String name = classBuilder.fullNameForErrors;
       int length = classBuilder.isAnonymousMixinApplication ? 1 : name.length;
       List<LocatedMessage> context = declarations.map((ClassMember d) {
@@ -3206,13 +3206,13 @@
           declarations.first.getMember(hierarchy);
     }
     debug?.log("Combined Member Signature of ${fullNameForErrors}: "
-        "${combinedMemberSignature.canonicalClassMember.fullName}");
+        "${combinedMemberSignature.canonicalMember.fullName}");
 
     if (modifyKernel) {
       ProcedureKind kind = ProcedureKind.Method;
       Member bestMemberSoFar =
-          combinedMemberSignature.canonicalClassMember.getMember(hierarchy);
-      if (combinedMemberSignature.canonicalClassMember.isProperty) {
+          combinedMemberSignature.canonicalMember.getMember(hierarchy);
+      if (combinedMemberSignature.canonicalMember.isProperty) {
         kind = isSetter ? ProcedureKind.Setter : ProcedureKind.Getter;
       } else if (bestMemberSoFar is Procedure &&
           bestMemberSoFar.kind == ProcedureKind.Operator) {
@@ -3221,7 +3221,7 @@
 
       debug?.log("Combined Member Signature of ${fullNameForErrors}: new "
           "ForwardingNode($classBuilder, "
-          "${combinedMemberSignature.canonicalClassMember}, "
+          "${combinedMemberSignature.canonicalMember}, "
           "$declarations, $kind)");
       Member stub =
           new ForwardingNode(combinedMemberSignature, kind).finalize();
@@ -3229,7 +3229,7 @@
         classBuilder.cls.addMember(stub);
         SourceLibraryBuilder library = classBuilder.library;
         Member bestMemberSoFar =
-            combinedMemberSignature.canonicalClassMember.getMember(hierarchy);
+            combinedMemberSignature.canonicalMember.getMember(hierarchy);
         if (bestMemberSoFar is Procedure) {
           library.forwardersOrigins..add(stub)..add(bestMemberSoFar);
         }
@@ -3242,7 +3242,7 @@
     debug?.log(
         "Combined Member Signature of ${fullNameForErrors}: picked bestSoFar");
     return combinedMemberSignatureResult =
-        combinedMemberSignature.canonicalClassMember.getMember(hierarchy);
+        combinedMemberSignature.canonicalMember.getMember(hierarchy);
   }
 
   @override
@@ -3342,8 +3342,9 @@
         // This call will add a body to the abstract method if needed for
         // isGenericCovariantImpl checks.
         new ForwardingNode(
-                new CombinedMemberSignature.internal(
-                    hierarchy, classBuilder, 1, declarations),
+                new CombinedClassMemberSignature.internal(
+                    hierarchy, classBuilder, 1, declarations,
+                    forSetter: isSetter),
                 kind)
             .finalize();
       }
@@ -3574,300 +3575,3 @@
     }
   }
 }
-
-/// Class used for computing and inspecting the combined member signature for
-/// a set of overridden/inherited members.
-class CombinedMemberSignature {
-  /// The class hierarchy builder used for building this class.
-  final ClassHierarchyBuilder hierarchy;
-
-  /// The target class for the combined member signature.
-  ///
-  /// The [_memberTypes] are computed in terms of each member is inherited into
-  /// [classBuilder].
-  ///
-  /// [classBuilder] is also used for determining whether the combined member
-  /// signature should be computed using nnbd or legacy semantics.
-  final SourceClassBuilder classBuilder;
-
-  /// The list of the members inherited into or overridden in [classBuilder].
-  final List<ClassMember> members;
-
-  /// The index within [members] for the member whose type is the most specific
-  /// among [members]. If `null`, the combined member signature is not defined
-  /// for [members] in [classBuilder].
-  ///
-  /// For the legacy computation, the type of this member defines the combined
-  /// member signature.
-  ///
-  /// For the nnbd computation, this is one of the members whose type define
-  /// the combined member signature, and the indices of the remaining members
-  /// are stored in [_mutualSubtypes].
-  int _canonicalMemberIndex;
-
-  /// For the nnbd computation, this maps each distinct but most specific member
-  /// type to the index of one of the [members] with that type.
-  ///
-  /// If there is only one most specific member type, this is `null`.
-  Map<DartType, int> _mutualSubtypes;
-
-  /// Cache for the types of [members] as inherited into [classBuilder].
-  List<DartType> _memberTypes;
-
-  /// Cache for the this type of [classBuilder].
-  DartType _thisType;
-
-  /// If `true` the combined member signature type has been computed.
-  ///
-  /// Note that the combined member signature type might be undefined in which
-  /// case [_combinedMemberSignatureType] is `null`.
-  bool _isCombinedMemberSignatureTypeComputed = false;
-
-  /// Cache the computed combined member signature type.
-  ///
-  /// If the combined member signature type is undefined this is set to `null`.
-  DartType _combinedMemberSignatureType;
-
-  /// Creates a [CombinedMemberSignature] whose canonical member is already
-  /// defined.
-  CombinedMemberSignature.internal(this.hierarchy, this.classBuilder,
-      this._canonicalMemberIndex, this.members);
-
-  /// Creates a [CombinedMemberSignature] for [members] inherited into
-  /// [classBuilder].
-  ///
-  /// If [forSetter] is `true`, contravariance of the setter types is used to
-  /// compute the most specific member type. Otherwise covariance of the getter
-  /// types or function types is used.
-  CombinedMemberSignature(this.hierarchy, this.classBuilder, this.members,
-      {bool forSetter}) {
-    assert(forSetter != null);
-    ClassMember bestSoFar;
-    int bestSoFarIndex;
-    if (members.length == 1) {
-      bestSoFar = members.first;
-      bestSoFarIndex = 0;
-    } else {
-      bool isNonNullableByDefault = classBuilder.library.isNonNullableByDefault;
-
-      DartType bestTypeSoFar;
-      for (int candidateIndex = members.length - 1;
-          candidateIndex >= 0;
-          candidateIndex--) {
-        ClassMember candidate = members[candidateIndex];
-        DartType candidateType = getMemberType(candidateIndex);
-        if (bestSoFar == null) {
-          bestSoFar = candidate;
-          bestTypeSoFar = candidateType;
-          bestSoFarIndex = candidateIndex;
-        } else {
-          if (_isMoreSpecific(candidateType, bestTypeSoFar, forSetter)) {
-            if (isNonNullableByDefault &&
-                _isMoreSpecific(bestTypeSoFar, candidateType, forSetter)) {
-              if (_mutualSubtypes == null) {
-                _mutualSubtypes = {
-                  bestTypeSoFar: bestSoFarIndex,
-                  candidateType: candidateIndex
-                };
-              } else {
-                _mutualSubtypes[candidateType] = candidateIndex;
-              }
-            } else {
-              _mutualSubtypes = null;
-            }
-            bestSoFarIndex = candidateIndex;
-            bestSoFar = candidate;
-            bestTypeSoFar = candidateType;
-          }
-        }
-      }
-      if (bestSoFar != null) {
-        for (int candidateIndex = 0;
-            candidateIndex < members.length;
-            candidateIndex++) {
-          DartType candidateType = getMemberType(candidateIndex);
-          if (!_isMoreSpecific(bestTypeSoFar, candidateType, forSetter)) {
-            if (!shouldOverrideProblemBeOverlooked(classBuilder)) {
-              bestSoFar = null;
-              bestSoFarIndex = null;
-              bestTypeSoFar = null;
-              _mutualSubtypes = null;
-            }
-            break;
-          }
-        }
-      }
-    }
-
-    _canonicalMemberIndex = bestSoFarIndex;
-  }
-
-  /// The member within [members] type is the most specific among [members].
-  /// If `null`, the combined member signature is not defined for [members] in
-  /// [classBuilder].
-  ///
-  /// For the legacy computation, the type of this member defines the combined
-  /// member signature.
-  ///
-  /// For the nnbd computation, this is one of the members whose type define
-  /// the combined member signature, and the indices of the all members whose
-  /// type define the combined member signature are in [mutualSubtypeIndices].
-  ClassMember get canonicalClassMember =>
-      _canonicalMemberIndex != null ? members[_canonicalMemberIndex] : null;
-
-  /// The index within [members] for the member whose type is the most specific
-  /// among [members]. If `null`, the combined member signature is not defined
-  /// for [members] in [classBuilder].
-  ///
-  /// For the legacy computation, the type of this member defines the combined
-  /// member signature.
-  ///
-  /// For the nnbd computation, this is one of the members whose type define
-  /// the combined member signature, and the indices of the all members whose
-  /// type define the combined member signature are in [mutualSubtypeIndices].
-  int get classMemberIndex => _canonicalMemberIndex;
-
-  /// For the nnbd computation, the indices of the [members] with most specific
-  /// member type.
-  ///
-  /// If there is only one most specific member type, this is `null`.
-  Set<int> get mutualSubtypeIndices => _mutualSubtypes?.values?.toSet();
-
-  /// The this type of [classBuilder].
-  DartType get thisType {
-    return _thisType ??= hierarchy.coreTypes
-        .thisInterfaceType(classBuilder.cls, classBuilder.library.nonNullable);
-  }
-
-  /// Returns type of the [index]th member in [members] as inherited in
-  /// [classBuilder].
-  DartType getMemberType(int index) {
-    _memberTypes ??= new List<DartType>(members.length);
-    DartType candidateType = _memberTypes[index];
-    if (candidateType == null) {
-      ClassMember candidate = members[index];
-      Member target = candidate.getMember(hierarchy);
-      assert(target != null,
-          "No member computed for ${candidate} (${candidate.runtimeType})");
-      candidateType = _computeMemberType(thisType, target);
-      if (!classBuilder.library.isNonNullableByDefault) {
-        candidateType = legacyErasure(hierarchy.coreTypes, candidateType);
-      }
-      _memberTypes[index] = candidateType;
-    }
-    return candidateType;
-  }
-
-  /// Returns the type of the combined member signature, if defined.
-  DartType get combinedMemberSignatureType {
-    if (!_isCombinedMemberSignatureTypeComputed) {
-      _isCombinedMemberSignatureTypeComputed = true;
-      if (_canonicalMemberIndex == null) {
-        return null;
-      }
-      if (classBuilder.library.isNonNullableByDefault) {
-        _combinedMemberSignatureType = getMemberType(_canonicalMemberIndex);
-        if (_mutualSubtypes != null) {
-          _combinedMemberSignatureType =
-              norm(hierarchy.coreTypes, _combinedMemberSignatureType);
-          for (int index in _mutualSubtypes.values) {
-            if (_canonicalMemberIndex != index) {
-              _combinedMemberSignatureType = nnbdTopMerge(
-                  hierarchy.coreTypes,
-                  _combinedMemberSignatureType,
-                  norm(hierarchy.coreTypes, getMemberType(index)));
-            }
-          }
-        }
-      } else {
-        _combinedMemberSignatureType = legacyErasure(
-            hierarchy.coreTypes, getMemberType(_canonicalMemberIndex));
-      }
-    }
-    return _combinedMemberSignatureType;
-  }
-
-  /// Returns the type of the combined member signature, if defined, with
-  /// all method type parameters substituted with [typeParameters].
-  ///
-  /// This is used for inferring types on a declared member from the type of the
-  /// combined member signature.
-  DartType getCombinedSignatureTypeInContext(
-      List<TypeParameter> typeParameters) {
-    DartType type = combinedMemberSignatureType;
-    if (type == null) {
-      return null;
-    }
-    int typeParameterCount = typeParameters.length;
-    if (type is FunctionType) {
-      List<TypeParameter> signatureTypeParameters = type.typeParameters;
-      if (typeParameterCount != signatureTypeParameters.length) {
-        return null;
-      }
-      if (typeParameterCount == 0) {
-        return type;
-      }
-      List<DartType> types = new List<DartType>(typeParameterCount);
-      for (int i = 0; i < typeParameterCount; i++) {
-        types[i] = new TypeParameterType.forAlphaRenaming(
-            signatureTypeParameters[i], typeParameters[i]);
-      }
-      Substitution substitution =
-          Substitution.fromPairs(signatureTypeParameters, types);
-      for (int i = 0; i < typeParameterCount; i++) {
-        DartType typeParameterBound = typeParameters[i].bound;
-        DartType signatureTypeParameterBound =
-            substitution.substituteType(signatureTypeParameters[i].bound);
-        if (!hierarchy.types
-            .performNullabilityAwareMutualSubtypesCheck(
-                typeParameterBound, signatureTypeParameterBound)
-            .isSubtypeWhenUsingNullabilities()) {
-          return null;
-        }
-      }
-      return substitution.substituteType(type.withoutTypeParameters);
-    } else if (typeParameterCount != 0) {
-      return null;
-    }
-    return type;
-  }
-
-  DartType _computeMemberType(DartType thisType, Member member) {
-    DartType type;
-    if (member is Procedure) {
-      if (member.isGetter) {
-        type = member.getterType;
-      } else if (member.isSetter) {
-        type = member.setterType;
-      } else {
-        type = member.function
-            .computeFunctionType(member.enclosingLibrary.nonNullable);
-      }
-    } else if (member is Field) {
-      type = member.type;
-    } else {
-      unhandled("${member.runtimeType}", "$member", classBuilder.charOffset,
-          classBuilder.fileUri);
-    }
-    InterfaceType instance = hierarchy.getTypeAsInstanceOf(
-        thisType,
-        member.enclosingClass,
-        classBuilder.library.library,
-        hierarchy.coreTypes);
-    assert(
-        instance != null,
-        "No instance of $thisType as ${member.enclosingClass} found for "
-        "$member.");
-    return Substitution.fromInterfaceType(instance).substituteType(type);
-  }
-
-  bool _isMoreSpecific(DartType a, DartType b, bool forSetter) {
-    if (forSetter) {
-      return hierarchy.types
-          .isSubtypeOf(b, a, SubtypeCheckMode.withNullabilities);
-    } else {
-      return hierarchy.types
-          .isSubtypeOf(a, b, SubtypeCheckMode.withNullabilities);
-    }
-  }
-}
diff --git a/pkg/front_end/lib/src/fasta/kernel/combined_member_signature.dart b/pkg/front_end/lib/src/fasta/kernel/combined_member_signature.dart
new file mode 100644
index 0000000..dff2894
--- /dev/null
+++ b/pkg/front_end/lib/src/fasta/kernel/combined_member_signature.dart
@@ -0,0 +1,583 @@
+// Copyright (c) 2018, 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.
+
+library fasta.class_hierarchy_builder;
+
+import 'package:kernel/ast.dart' hide MapEntry;
+
+import 'package:kernel/class_hierarchy.dart' show ClassHierarchyBase;
+
+import 'package:kernel/core_types.dart' show CoreTypes;
+
+import 'package:kernel/type_algebra.dart' show Substitution;
+import 'package:kernel/type_environment.dart';
+
+import 'package:kernel/src/legacy_erasure.dart';
+import 'package:kernel/src/nnbd_top_merge.dart';
+import 'package:kernel/src/norm.dart';
+import 'package:kernel/src/types.dart' show Types;
+
+import '../problems.dart' show unhandled;
+
+import '../source/source_class_builder.dart';
+
+import 'class_hierarchy_builder.dart';
+
+/// Class used for computing and inspecting the combined member signature for
+/// a set of overridden/inherited members.
+abstract class CombinedMemberSignatureBase<T> {
+  ClassHierarchyBase get hierarchy;
+
+  /// The target class for the combined member signature.
+  ///
+  /// The [_memberTypes] are computed in terms of each member is inherited into
+  /// [classBuilder].
+  ///
+  /// [classBuilder] is also used for determining whether the combined member
+  /// signature should be computed using nnbd or legacy semantics.
+  final SourceClassBuilder classBuilder;
+
+  /// The list of members from which the combined member signature is computed.
+  List<T> get members;
+
+  /// If `true` the combined member signature is for the setter aspect of the
+  /// members. Otherwise it is for the getter/method aspect of the members.
+  final bool forSetter;
+
+  /// The index within [members] for the member whose type is the most specific
+  /// among [members]. If `null`, the combined member signature is not defined
+  /// for [members] in [classBuilder].
+  ///
+  /// For the legacy computation, the type of this member defines the combined
+  /// member signature.
+  ///
+  /// For the nnbd computation, this is one of the members whose type define
+  /// the combined member signature, and the indices of the remaining members
+  /// are stored in [_mutualSubtypes].
+  int _canonicalMemberIndex;
+
+  /// For the nnbd computation, this maps each distinct but most specific member
+  /// type to the index of one of the [members] with that type.
+  ///
+  /// If there is only one most specific member type, this is `null`.
+  Map<DartType, int> _mutualSubtypes;
+
+  /// Cache for the types of [members] as inherited into [classBuilder].
+  List<DartType> _memberTypes;
+
+  /// Cache for the this type of [classBuilder].
+  DartType _thisType;
+
+  /// If `true` the combined member signature type has been computed.
+  ///
+  /// Note that the combined member signature type might be undefined in which
+  /// case [_combinedMemberSignatureType] is `null`.
+  bool _isCombinedMemberSignatureTypeComputed = false;
+
+  /// Cache the computed combined member signature type.
+  ///
+  /// If the combined member signature type is undefined this is set to `null`.
+  DartType _combinedMemberSignatureType;
+
+  /// Accumulated result for [neededLegacyErasure]. This is fully computed when
+  /// [combinedMemberSignatureType] has been computed.
+  bool _neededLegacyErasure = false;
+
+  /// Creates a [CombinedClassMemberSignature] whose canonical member is already
+  /// defined.
+  CombinedMemberSignatureBase.internal(
+      this.classBuilder, this._canonicalMemberIndex, this.forSetter)
+      : assert(forSetter != null);
+
+  /// Creates a [CombinedClassMemberSignature] for [members] inherited into
+  /// [classBuilder].
+  ///
+  /// If [forSetter] is `true`, contravariance of the setter types is used to
+  /// compute the most specific member type. Otherwise covariance of the getter
+  /// types or function types is used.
+  CombinedMemberSignatureBase(this.classBuilder, {this.forSetter}) {
+    assert(forSetter != null);
+    int bestSoFarIndex;
+    if (members.length == 1) {
+      bestSoFarIndex = 0;
+    } else {
+      bool isNonNullableByDefault = classBuilder.library.isNonNullableByDefault;
+
+      DartType bestTypeSoFar;
+      for (int candidateIndex = members.length - 1;
+          candidateIndex >= 0;
+          candidateIndex--) {
+        DartType candidateType = getMemberType(candidateIndex);
+        if (bestSoFarIndex == null) {
+          bestTypeSoFar = candidateType;
+          bestSoFarIndex = candidateIndex;
+        } else {
+          if (_isMoreSpecific(candidateType, bestTypeSoFar, forSetter)) {
+            if (isNonNullableByDefault &&
+                _isMoreSpecific(bestTypeSoFar, candidateType, forSetter)) {
+              if (_mutualSubtypes == null) {
+                _mutualSubtypes = {
+                  bestTypeSoFar: bestSoFarIndex,
+                  candidateType: candidateIndex
+                };
+              } else {
+                _mutualSubtypes[candidateType] = candidateIndex;
+              }
+            } else {
+              _mutualSubtypes = null;
+            }
+            bestSoFarIndex = candidateIndex;
+            bestTypeSoFar = candidateType;
+          }
+        }
+      }
+      if (_mutualSubtypes?.length == 1) {
+        /// If all mutual subtypes have the same type, the type should not
+        /// be normalized.
+        _mutualSubtypes = null;
+      }
+      if (bestSoFarIndex != null) {
+        for (int candidateIndex = 0;
+            candidateIndex < members.length;
+            candidateIndex++) {
+          DartType candidateType = getMemberType(candidateIndex);
+          if (!_isMoreSpecific(bestTypeSoFar, candidateType, forSetter)) {
+            if (!shouldOverrideProblemBeOverlooked(classBuilder)) {
+              bestSoFarIndex = null;
+              bestTypeSoFar = null;
+              _mutualSubtypes = null;
+            }
+            break;
+          }
+        }
+      }
+    }
+
+    _canonicalMemberIndex = bestSoFarIndex;
+  }
+
+  /// The member within [members] type is the most specific among [members].
+  /// If `null`, the combined member signature is not defined for [members] in
+  /// [classBuilder].
+  ///
+  /// For the legacy computation, the type of this member defines the combined
+  /// member signature.
+  ///
+  /// For the nnbd computation, this is one of the members whose type define
+  /// the combined member signature, and the indices of the all members whose
+  /// type define the combined member signature are in [mutualSubtypeIndices].
+  T get canonicalMember =>
+      _canonicalMemberIndex != null ? members[_canonicalMemberIndex] : null;
+
+  /// The index within [members] for the member whose type is the most specific
+  /// among [members]. If `null`, the combined member signature is not defined
+  /// for [members] in [classBuilder].
+  ///
+  /// For the legacy computation, the type of this member defines the combined
+  /// member signature.
+  ///
+  /// For the nnbd computation, this is one of the members whose type define
+  /// the combined member signature, and the indices of the all members whose
+  /// type define the combined member signature are in [mutualSubtypeIndices].
+  int get canonicalMemberIndex => _canonicalMemberIndex;
+
+  /// For the nnbd computation, the indices of the [members] with most specific
+  /// member type.
+  ///
+  /// If there is only one most specific member type, this is `null`.
+  Set<int> get mutualSubtypeIndices => _mutualSubtypes?.values?.toSet();
+
+  Member _getMember(int index);
+
+  CoreTypes get _coreTypes => hierarchy.coreTypes;
+
+  Types get _types;
+
+  /// Returns `true` if legacy erasure was needed to compute the combined
+  /// member signature type.
+  ///
+  /// Legacy erasure is considered need of if the used of it resulted in a
+  /// different type.
+  bool get neededLegacyErasure {
+    _ensureCombinedMemberSignatureType();
+    return _neededLegacyErasure;
+  }
+
+  /// The this type of [classBuilder].
+  DartType get thisType {
+    return _thisType ??= _coreTypes.thisInterfaceType(
+        classBuilder.cls, classBuilder.library.nonNullable);
+  }
+
+  /// Returns type of the [index]th member in [members] as inherited in
+  /// [classBuilder].
+  DartType getMemberType(int index) {
+    _memberTypes ??= new List<DartType>(members.length);
+    DartType candidateType = _memberTypes[index];
+    if (candidateType == null) {
+      Member target = _getMember(index);
+      assert(target != null,
+          "No member computed for index ${index} in ${members}");
+      candidateType = _computeMemberType(thisType, target);
+      if (!classBuilder.library.isNonNullableByDefault) {
+        DartType legacyErasure = rawLegacyErasure(_coreTypes, candidateType);
+        if (legacyErasure != null) {
+          _neededLegacyErasure = true;
+          candidateType = legacyErasure;
+        }
+      }
+      _memberTypes[index] = candidateType;
+    }
+    return candidateType;
+  }
+
+  void _ensureCombinedMemberSignatureType() {
+    if (!_isCombinedMemberSignatureTypeComputed) {
+      _isCombinedMemberSignatureTypeComputed = true;
+      if (_canonicalMemberIndex == null) {
+        return null;
+      }
+      if (classBuilder.library.isNonNullableByDefault) {
+        _combinedMemberSignatureType = getMemberType(_canonicalMemberIndex);
+        if (_mutualSubtypes != null) {
+          _combinedMemberSignatureType =
+              norm(_coreTypes, _combinedMemberSignatureType);
+          for (int index in _mutualSubtypes.values) {
+            if (_canonicalMemberIndex != index) {
+              _combinedMemberSignatureType = nnbdTopMerge(
+                  _coreTypes,
+                  _combinedMemberSignatureType,
+                  norm(_coreTypes, getMemberType(index)));
+            }
+          }
+        }
+      } else {
+        _combinedMemberSignatureType = getMemberType(_canonicalMemberIndex);
+      }
+    }
+  }
+
+  /// Returns the type of the combined member signature, if defined.
+  DartType get combinedMemberSignatureType {
+    _ensureCombinedMemberSignatureType();
+    return _combinedMemberSignatureType;
+  }
+
+  /// Returns the type of the combined member signature, if defined, with
+  /// all method type parameters substituted with [typeParameters].
+  ///
+  /// This is used for inferring types on a declared member from the type of the
+  /// combined member signature.
+  DartType getCombinedSignatureTypeInContext(
+      List<TypeParameter> typeParameters) {
+    DartType type = combinedMemberSignatureType;
+    if (type == null) {
+      return null;
+    }
+    int typeParameterCount = typeParameters.length;
+    if (type is FunctionType) {
+      List<TypeParameter> signatureTypeParameters = type.typeParameters;
+      if (typeParameterCount != signatureTypeParameters.length) {
+        return null;
+      }
+      if (typeParameterCount == 0) {
+        return type;
+      }
+      List<DartType> types = new List<DartType>(typeParameterCount);
+      for (int i = 0; i < typeParameterCount; i++) {
+        types[i] = new TypeParameterType.forAlphaRenaming(
+            signatureTypeParameters[i], typeParameters[i]);
+      }
+      Substitution substitution =
+          Substitution.fromPairs(signatureTypeParameters, types);
+      for (int i = 0; i < typeParameterCount; i++) {
+        DartType typeParameterBound = typeParameters[i].bound;
+        DartType signatureTypeParameterBound =
+            substitution.substituteType(signatureTypeParameters[i].bound);
+        if (!_types
+            .performNullabilityAwareMutualSubtypesCheck(
+                typeParameterBound, signatureTypeParameterBound)
+            .isSubtypeWhenUsingNullabilities()) {
+          return null;
+        }
+      }
+      return substitution.substituteType(type.withoutTypeParameters);
+    } else if (typeParameterCount != 0) {
+      return null;
+    }
+    return type;
+  }
+
+  /// Create a member signature with the [combinedMemberSignatureType] using the
+  /// [canonicalMember] as member signature origin.
+  Procedure createMemberFromSignature() {
+    if (canonicalMemberIndex == null) {
+      return null;
+    }
+    Member member = _getMember(canonicalMemberIndex);
+    if (member is Procedure) {
+      switch (member.kind) {
+        case ProcedureKind.Getter:
+          return _createGetterMemberSignature(
+              member, combinedMemberSignatureType);
+        case ProcedureKind.Setter:
+          VariableDeclaration parameter =
+              member.function.positionalParameters.first;
+          return _createSetterMemberSignature(
+              member, combinedMemberSignatureType,
+              isGenericCovariantImpl: parameter.isGenericCovariantImpl,
+              isCovariant: parameter.isCovariant,
+              parameterName: parameter.name);
+        case ProcedureKind.Method:
+        case ProcedureKind.Operator:
+          return _createMethodSignature(member, combinedMemberSignatureType);
+        case ProcedureKind.Factory:
+        default:
+          throw new UnsupportedError(
+              'Unexpected canonical member kind ${member.kind} for $member');
+      }
+    } else if (member is Field) {
+      if (forSetter) {
+        return _createSetterMemberSignature(member, combinedMemberSignatureType,
+            isGenericCovariantImpl: member.isGenericCovariantImpl,
+            isCovariant: member.isCovariant);
+      } else {
+        return _createGetterMemberSignature(
+            member, combinedMemberSignatureType);
+      }
+    } else {
+      throw new UnsupportedError(
+          'Unexpected canonical member $member (${member.runtimeType})');
+    }
+  }
+
+  /// Creates a getter member signature for [member] with the given
+  /// [type].
+  Member _createGetterMemberSignature(Member member, DartType type) {
+    Class enclosingClass = classBuilder.cls;
+    Procedure referenceFrom;
+    if (classBuilder.referencesFromIndexed != null) {
+      referenceFrom = classBuilder.referencesFromIndexed
+          .lookupProcedureNotSetter(member.name.text);
+    }
+    Uri fileUri = member.fileUri;
+    int startFileOffset =
+        member is Procedure ? member.startFileOffset : member.fileOffset;
+    int fileOffset = member.fileOffset;
+    return new Procedure(member.name, ProcedureKind.Getter,
+        new FunctionNode(null, returnType: type),
+        isAbstract: true,
+        isMemberSignature: true,
+        fileUri: fileUri,
+        memberSignatureOrigin: member.memberSignatureOrigin ?? member,
+        reference: referenceFrom?.reference)
+      ..startFileOffset = startFileOffset
+      ..fileOffset = fileOffset
+      ..parent = enclosingClass;
+  }
+
+  /// Creates a setter member signature for [member] with the given
+  /// [type]. The flags of parameter is set according to [isCovariant] and
+  /// [isGenericCovariantImpl] and the [parameterName] is used, if provided.
+  Member _createSetterMemberSignature(Member member, DartType type,
+      {bool isCovariant, bool isGenericCovariantImpl, String parameterName}) {
+    assert(isCovariant != null);
+    assert(isGenericCovariantImpl != null);
+    Class enclosingClass = classBuilder.cls;
+    Procedure referenceFrom;
+    if (classBuilder.referencesFromIndexed != null) {
+      referenceFrom = classBuilder.referencesFromIndexed
+          .lookupProcedureSetter(member.name.text);
+    }
+    Uri fileUri = member.fileUri;
+    int startFileOffset =
+        member is Procedure ? member.startFileOffset : member.fileOffset;
+    int fileOffset = member.fileOffset;
+    return new Procedure(
+        member.name,
+        ProcedureKind.Setter,
+        new FunctionNode(null,
+            returnType: const VoidType(),
+            positionalParameters: [
+              new VariableDeclaration(parameterName ?? 'value',
+                  type: type, isCovariant: isCovariant)
+                ..isGenericCovariantImpl = isGenericCovariantImpl
+            ]),
+        isAbstract: true,
+        isMemberSignature: true,
+        fileUri: fileUri,
+        memberSignatureOrigin: member.memberSignatureOrigin ?? member,
+        reference: referenceFrom?.reference)
+      ..startFileOffset = startFileOffset
+      ..fileOffset = fileOffset
+      ..parent = enclosingClass;
+  }
+
+  Member _createMethodSignature(
+      Procedure procedure, FunctionType functionType) {
+    Class enclosingClass = classBuilder.cls;
+    Procedure referenceFrom;
+    if (classBuilder.referencesFromIndexed != null) {
+      referenceFrom = classBuilder.referencesFromIndexed
+          .lookupProcedureNotSetter(procedure.name.text);
+    }
+    Uri fileUri = procedure.fileUri;
+    int startFileOffset = procedure.startFileOffset;
+    int fileOffset = procedure.fileOffset;
+    FunctionNode function = procedure.function;
+    List<VariableDeclaration> positionalParameters = [];
+    for (int i = 0; i < function.positionalParameters.length; i++) {
+      VariableDeclaration parameter = function.positionalParameters[i];
+      DartType parameterType = functionType.positionalParameters[i];
+      if (i == 0 && procedure == hierarchy.coreTypes.objectEquals) {
+        // In legacy code we special case `Object.==` to infer `dynamic`
+        // instead `Object!`.
+        parameterType = const DynamicType();
+      }
+      positionalParameters.add(new VariableDeclaration(parameter.name,
+          type: parameterType, isCovariant: parameter.isCovariant)
+        ..isGenericCovariantImpl = parameter.isGenericCovariantImpl);
+    }
+    List<VariableDeclaration> namedParameters = [];
+    int namedParameterCount = function.namedParameters.length;
+    if (namedParameterCount == 1) {
+      NamedType namedType = functionType.namedParameters.first;
+      VariableDeclaration parameter = function.namedParameters.first;
+      namedParameters.add(new VariableDeclaration(parameter.name,
+          type: namedType.type, isCovariant: parameter.isCovariant)
+        ..isGenericCovariantImpl = parameter.isGenericCovariantImpl);
+    } else if (namedParameterCount > 1) {
+      Map<String, DartType> namedTypes = {};
+      for (NamedType namedType in functionType.namedParameters) {
+        namedTypes[namedType.name] = namedType.type;
+      }
+      for (int i = 0; i < namedParameterCount; i++) {
+        VariableDeclaration parameter = function.namedParameters[i];
+        DartType parameterType = namedTypes[parameter.name];
+        namedParameters.add(new VariableDeclaration(parameter.name,
+            type: parameterType, isCovariant: parameter.isCovariant)
+          ..isGenericCovariantImpl = parameter.isGenericCovariantImpl);
+      }
+    }
+    return new Procedure(
+        procedure.name,
+        procedure.kind,
+        new FunctionNode(null,
+            typeParameters: functionType.typeParameters,
+            returnType: functionType.returnType,
+            positionalParameters: positionalParameters,
+            namedParameters: namedParameters,
+            requiredParameterCount: function.requiredParameterCount),
+        isAbstract: true,
+        isMemberSignature: true,
+        fileUri: fileUri,
+        memberSignatureOrigin: procedure.memberSignatureOrigin ?? procedure,
+        reference: referenceFrom?.reference)
+      ..startFileOffset = startFileOffset
+      ..fileOffset = fileOffset
+      ..parent = enclosingClass;
+  }
+
+  DartType _computeMemberType(DartType thisType, Member member) {
+    DartType type;
+    if (member is Procedure) {
+      if (member.isGetter) {
+        type = member.getterType;
+      } else if (member.isSetter) {
+        type = member.setterType;
+      } else {
+        type = member.function
+            .computeFunctionType(classBuilder.cls.enclosingLibrary.nonNullable);
+      }
+    } else if (member is Field) {
+      type = member.type;
+    } else {
+      unhandled("${member.runtimeType}", "$member", classBuilder.charOffset,
+          classBuilder.fileUri);
+    }
+    if (member.enclosingClass.typeParameters.isEmpty) {
+      return type;
+    }
+    InterfaceType instance = hierarchy.getTypeAsInstanceOf(
+        thisType,
+        member.enclosingClass,
+        classBuilder.library.library,
+        hierarchy.coreTypes);
+    assert(
+        instance != null,
+        "No instance of $thisType as ${member.enclosingClass} found for "
+        "$member.");
+    return Substitution.fromInterfaceType(instance).substituteType(type);
+  }
+
+  bool _isMoreSpecific(DartType a, DartType b, bool forSetter) {
+    if (forSetter) {
+      return _types.isSubtypeOf(b, a, SubtypeCheckMode.withNullabilities);
+    } else {
+      return _types.isSubtypeOf(a, b, SubtypeCheckMode.withNullabilities);
+    }
+  }
+}
+
+/// Class used for computing and inspecting the combined member signature for
+/// a set of overridden/inherited [ClassMember]s.
+class CombinedClassMemberSignature
+    extends CombinedMemberSignatureBase<ClassMember> {
+  /// The class hierarchy builder used for building this class.
+  final ClassHierarchyBuilder hierarchy;
+
+  /// The list of the members inherited into or overridden in [classBuilder].
+  final List<ClassMember> members;
+
+  /// Creates a [CombinedClassMemberSignature] whose canonical member is already
+  /// defined.
+  CombinedClassMemberSignature.internal(this.hierarchy,
+      SourceClassBuilder classBuilder, int canonicalMemberIndex, this.members,
+      {bool forSetter})
+      : super.internal(classBuilder, canonicalMemberIndex, forSetter);
+
+  /// Creates a [CombinedClassMemberSignature] for [members] inherited into
+  /// [classBuilder].
+  ///
+  /// If [forSetter] is `true`, contravariance of the setter types is used to
+  /// compute the most specific member type. Otherwise covariance of the getter
+  /// types or function types is used.
+  CombinedClassMemberSignature(
+      this.hierarchy, SourceClassBuilder classBuilder, this.members,
+      {bool forSetter})
+      : super(classBuilder, forSetter: forSetter);
+
+  Types get _types => hierarchy.types;
+
+  Member _getMember(int index) {
+    ClassMember candidate = members[index];
+    Member target = candidate.getMember(hierarchy);
+    assert(target != null,
+        "No member computed for ${candidate} (${candidate.runtimeType})");
+    return target;
+  }
+}
+
+/// Class used for computing and inspecting the combined member signature for
+/// a set of overridden/inherited [Member]s.
+class CombinedMemberSignatureBuilder
+    extends CombinedMemberSignatureBase<Member> {
+  @override
+  final ClassHierarchyBase hierarchy;
+
+  @override
+  final Types _types;
+
+  @override
+  final List<Member> members;
+
+  CombinedMemberSignatureBuilder(
+      this.hierarchy, SourceClassBuilder classBuilder, this.members,
+      {bool forSetter})
+      : _types = new Types(hierarchy),
+        super(classBuilder, forSetter: forSetter);
+
+  @override
+  Member _getMember(int index) => members[index];
+}
diff --git a/pkg/front_end/lib/src/fasta/kernel/forwarding_node.dart b/pkg/front_end/lib/src/fasta/kernel/forwarding_node.dart
index 08a6f34..21dd2f3 100644
--- a/pkg/front_end/lib/src/fasta/kernel/forwarding_node.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/forwarding_node.dart
@@ -11,12 +11,9 @@
         Expression,
         Field,
         FunctionNode,
-        FunctionType,
         Member,
         Name,
         NamedExpression,
-        NamedType,
-        Nullability,
         Procedure,
         ProcedureKind,
         ReturnStatement,
@@ -48,6 +45,7 @@
 import "../type_inference/type_inferrer.dart" show getNamedFormal;
 
 import 'class_hierarchy_builder.dart';
+import 'combined_member_signature.dart';
 
 class ForwardingNode {
   ClassHierarchyBuilder get hierarchy => _combinedMemberSignature.hierarchy;
@@ -56,13 +54,13 @@
 
   // TODO(johnniwinther): Use [_combinedMemberSignature] more directly in
   // the forwarding node computation.
-  final CombinedMemberSignature _combinedMemberSignature;
+  final CombinedClassMemberSignature _combinedMemberSignature;
 
   ClassMember get combinedMemberSignatureResult =>
-      _combinedMemberSignature.canonicalClassMember;
+      _combinedMemberSignature.canonicalMember;
 
   /// The index of [combinedMemberSignatureResult] in [_candidates].
-  int get _combinedMemberIndex => _combinedMemberSignature.classMemberIndex;
+  int get _combinedMemberIndex => _combinedMemberSignature.canonicalMemberIndex;
 
   final ProcedureKind kind;
 
@@ -84,203 +82,6 @@
   /// forwarding stubs if necessary.
   Member finalize() => _computeCovarianceFixes();
 
-  /// Creates a getter member signature for [interfaceMember] with the given
-  /// [type].
-  Member _createGetterMemberSignature(Member interfaceMember, DartType type) {
-    Procedure referenceFrom;
-    if (classBuilder.referencesFromIndexed != null) {
-      referenceFrom = classBuilder.referencesFromIndexed
-          .lookupProcedureNotSetter(name.text);
-    }
-    return new Procedure(name, kind, new FunctionNode(null, returnType: type),
-        isAbstract: true,
-        isMemberSignature: true,
-        fileUri: enclosingClass.fileUri,
-        memberSignatureOrigin: interfaceMember,
-        reference: referenceFrom?.reference)
-      ..startFileOffset = enclosingClass.fileOffset
-      ..fileOffset = enclosingClass.fileOffset
-      ..parent = enclosingClass;
-  }
-
-  /// Creates a setter member signature for [interfaceMember] with the given
-  /// [type]. The flags of parameter is set according to [isCovariant] and
-  /// [isGenericCovariantImpl] and the [parameterName] is used, if provided.
-  Member _createSetterMemberSignature(Member interfaceMember, DartType type,
-      {bool isCovariant, bool isGenericCovariantImpl, String parameterName}) {
-    assert(isCovariant != null);
-    assert(isGenericCovariantImpl != null);
-    Procedure referenceFrom;
-    if (classBuilder.referencesFromIndexed != null) {
-      referenceFrom =
-          classBuilder.referencesFromIndexed.lookupProcedureSetter(name.text);
-    }
-    return new Procedure(
-        name,
-        kind,
-        new FunctionNode(null,
-            returnType: const VoidType(),
-            positionalParameters: [
-              new VariableDeclaration(parameterName ?? '_',
-                  type: type, isCovariant: isCovariant)
-                ..isGenericCovariantImpl = isGenericCovariantImpl
-            ]),
-        isAbstract: true,
-        isMemberSignature: true,
-        fileUri: enclosingClass.fileUri,
-        memberSignatureOrigin: interfaceMember,
-        reference: referenceFrom?.reference)
-      ..startFileOffset = enclosingClass.fileOffset
-      ..fileOffset = enclosingClass.fileOffset
-      ..parent = enclosingClass;
-  }
-
-  /// Creates a legacy member signature for the field [interfaceMember] if the
-  /// type of [interfaceMember] contains non-legacy nullabilities.
-  Member _createLegacyMemberSignatureForField(Field interfaceMember) {
-    DartType type = interfaceMember.type;
-    if (interfaceMember.enclosingClass.typeParameters.isNotEmpty) {
-      Substitution substitution =
-          _substitutionFor(null, interfaceMember, enclosingClass);
-      type = substitution.substituteType(type);
-    }
-    DartType legacyType = rawLegacyErasure(hierarchy.coreTypes, type);
-    if (legacyType == null) {
-      return interfaceMember;
-    } else {
-      // We base the decision to add a member signature on whether the legacy
-      // erasure of the declared type is different from the declared type, i.e.
-      // whether the declared type contained non-legacy nullabilities.
-      //
-      // This is slightly different from checking whether the legacy erasure of
-      // the inherited type is different from the
-      if (kind == ProcedureKind.Getter) {
-        return _createGetterMemberSignature(interfaceMember, legacyType);
-      } else {
-        assert(kind == ProcedureKind.Setter);
-        return _createSetterMemberSignature(interfaceMember, legacyType,
-            isCovariant: interfaceMember.isCovariant,
-            isGenericCovariantImpl: interfaceMember.isGenericCovariantImpl);
-      }
-    }
-  }
-
-  /// Creates a legacy member signature for procedure [interfaceMember] if the
-  /// type of [interfaceMember] contains non-legacy nullabilities.
-  Member _createLegacyMemberSignatureForProcedure(Procedure interfaceMember) {
-    if (interfaceMember.kind == ProcedureKind.Getter) {
-      DartType type = interfaceMember.getterType;
-      if (interfaceMember.enclosingClass.typeParameters.isNotEmpty) {
-        Substitution substitution =
-            _substitutionFor(null, interfaceMember, enclosingClass);
-        type = substitution.substituteType(type);
-      }
-      DartType legacyType = rawLegacyErasure(hierarchy.coreTypes, type);
-      if (legacyType == null) {
-        return interfaceMember;
-      } else {
-        return _createGetterMemberSignature(interfaceMember, legacyType);
-      }
-    } else if (interfaceMember.kind == ProcedureKind.Setter) {
-      DartType type = interfaceMember.setterType;
-      if (interfaceMember.enclosingClass.typeParameters.isNotEmpty) {
-        Substitution substitution =
-            _substitutionFor(null, interfaceMember, enclosingClass);
-        type = substitution.substituteType(type);
-      }
-      DartType legacyType = rawLegacyErasure(hierarchy.coreTypes, type);
-      if (legacyType == null) {
-        return interfaceMember;
-      } else {
-        VariableDeclaration parameter =
-            interfaceMember.function.positionalParameters.first;
-        return _createSetterMemberSignature(interfaceMember, legacyType,
-            isCovariant: parameter.isCovariant,
-            isGenericCovariantImpl: parameter.isGenericCovariantImpl,
-            parameterName: parameter.name);
-      }
-    } else {
-      FunctionNode function = interfaceMember.function;
-      FunctionType type = function.computeFunctionType(Nullability.legacy);
-      if (interfaceMember.enclosingClass.typeParameters.isNotEmpty) {
-        Substitution substitution =
-            _substitutionFor(null, interfaceMember, enclosingClass);
-        type = substitution.substituteType(type);
-      }
-      FunctionType legacyType = rawLegacyErasure(hierarchy.coreTypes, type);
-      if (legacyType == null) {
-        return interfaceMember;
-      }
-      Procedure referenceFrom;
-      if (classBuilder.referencesFromIndexed != null) {
-        referenceFrom = classBuilder.referencesFromIndexed
-            .lookupProcedureNotSetter(name.text);
-      }
-      List<VariableDeclaration> positionalParameters = [];
-      for (int i = 0; i < function.positionalParameters.length; i++) {
-        VariableDeclaration parameter = function.positionalParameters[i];
-        DartType parameterType = legacyType.positionalParameters[i];
-        if (i == 0 && interfaceMember == hierarchy.coreTypes.objectEquals) {
-          // In legacy code we special case `Object.==` to infer `dynamic`
-          // instead `Object!`.
-          parameterType = const DynamicType();
-        }
-        positionalParameters.add(new VariableDeclaration(parameter.name,
-            type: parameterType, isCovariant: parameter.isCovariant)
-          ..isGenericCovariantImpl = parameter.isGenericCovariantImpl);
-      }
-      List<VariableDeclaration> namedParameters = [];
-      int namedParameterCount = function.namedParameters.length;
-      if (namedParameterCount == 1) {
-        NamedType namedType = legacyType.namedParameters.first;
-        VariableDeclaration parameter = function.namedParameters.first;
-        namedParameters.add(new VariableDeclaration(parameter.name,
-            type: namedType.type, isCovariant: parameter.isCovariant)
-          ..isGenericCovariantImpl = parameter.isGenericCovariantImpl);
-      } else if (namedParameterCount > 1) {
-        Map<String, DartType> namedTypes = {};
-        for (NamedType namedType in legacyType.namedParameters) {
-          namedTypes[namedType.name] = namedType.type;
-        }
-        for (int i = 0; i < namedParameterCount; i++) {
-          VariableDeclaration parameter = function.namedParameters[i];
-          DartType parameterType = namedTypes[parameter.name];
-          namedParameters.add(new VariableDeclaration(parameter.name,
-              type: parameterType, isCovariant: parameter.isCovariant)
-            ..isGenericCovariantImpl = parameter.isGenericCovariantImpl);
-        }
-      }
-      return new Procedure(
-          name,
-          kind,
-          new FunctionNode(null,
-              typeParameters: legacyType.typeParameters,
-              returnType: legacyType.returnType,
-              positionalParameters: positionalParameters,
-              namedParameters: namedParameters,
-              requiredParameterCount: function.requiredParameterCount),
-          isAbstract: true,
-          isMemberSignature: true,
-          fileUri: enclosingClass.fileUri,
-          memberSignatureOrigin: interfaceMember,
-          reference: referenceFrom?.reference)
-        ..startFileOffset = enclosingClass.fileOffset
-        ..fileOffset = enclosingClass.fileOffset
-        ..parent = enclosingClass;
-    }
-  }
-
-  /// Creates a legacy member signature for [interfaceMember] if the type of
-  /// [interfaceMember] contains non-legacy nullabilities.
-  Member _createLegacyMemberSignature(Member interfaceMember) {
-    if (interfaceMember is Field) {
-      return _createLegacyMemberSignatureForField(interfaceMember);
-    } else {
-      assert(interfaceMember is Procedure);
-      return _createLegacyMemberSignatureForProcedure(interfaceMember);
-    }
-  }
-
   /// Tag the parameters of [interfaceMember] that need type checks
   ///
   /// Parameters can need type checks for calls coming from statically typed
@@ -296,10 +97,8 @@
     if (_candidates.length == 1) {
       // Covariance can only come from [interfaceMember] so we never need a
       // forwarding stub.
-      if (interfaceMember.isNonNullableByDefault &&
-          !classBuilder.library.isNonNullableByDefault) {
-        // Create a member signature with the legacy erasure type.
-        return _createLegacyMemberSignature(interfaceMember);
+      if (_combinedMemberSignature.neededLegacyErasure) {
+        return _combinedMemberSignature.createMemberFromSignature();
       } else {
         // Nothing to do.
         return interfaceMember;
diff --git a/pkg/front_end/lib/src/fasta/kernel/utils.dart b/pkg/front_end/lib/src/fasta/kernel/utils.dart
index ee062fb..aae5538 100644
--- a/pkg/front_end/lib/src/fasta/kernel/utils.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/utils.dart
@@ -120,7 +120,10 @@
   }
 
   // TODO(vegorov) find a way to preserve metadata.
-  return new Component(libraries: [fakeLibrary]);
+  Component component = new Component(libraries: [fakeLibrary]);
+  component.setMainMethodAndMode(
+      null, false, fakeLibrary.nonNullableByDefaultCompiledMode);
+  return component;
 }
 
 List<int> serializeProcedure(Procedure procedure) {
diff --git a/pkg/front_end/lib/src/fasta/source/source_class_builder.dart b/pkg/front_end/lib/src/fasta/source/source_class_builder.dart
index 80f035d..badb39d 100644
--- a/pkg/front_end/lib/src/fasta/source/source_class_builder.dart
+++ b/pkg/front_end/lib/src/fasta/source/source_class_builder.dart
@@ -4,16 +4,14 @@
 
 library fasta.source_class_builder;
 
+import 'package:front_end/src/fasta/kernel/combined_member_signature.dart';
 import 'package:kernel/ast.dart' hide MapEntry;
 import 'package:kernel/class_hierarchy.dart' show ClassHierarchy;
-import 'package:kernel/clone.dart' show CloneProcedureWithoutBody;
 import 'package:kernel/reference_from_index.dart' show IndexedClass;
 import 'package:kernel/src/bounds_checks.dart';
 import 'package:kernel/src/legacy_erasure.dart';
 import 'package:kernel/src/types.dart' show Types;
 import 'package:kernel/type_algebra.dart' show Substitution;
-import 'package:kernel/type_algebra.dart' as type_algebra
-    show getSubstitutionMap;
 import 'package:kernel/type_environment.dart';
 
 import '../builder/builder.dart';
@@ -634,103 +632,12 @@
     return charOffset.compareTo(other.charOffset);
   }
 
-  void addNoSuchMethodForwarderForProcedure(Member noSuchMethod,
-      KernelTarget target, Procedure procedure, ClassHierarchy hierarchy) {
-    Procedure referenceFrom;
-    if (referencesFromIndexed != null) {
-      if (procedure.isSetter) {
-        referenceFrom =
-            referencesFromIndexed.lookupProcedureSetter(procedure.name.text);
-      } else {
-        referenceFrom =
-            referencesFromIndexed.lookupProcedureNotSetter(procedure.name.text);
-      }
-    }
-
-    CloneProcedureWithoutBody cloner = new CloneProcedureWithoutBody(
-        typeSubstitution: type_algebra.getSubstitutionMap(
-            hierarchy.getClassAsInstanceOf(cls, procedure.enclosingClass)),
-        cloneAnnotations: false);
-    Procedure cloned = cloner.cloneProcedure(procedure, referenceFrom)
-      ..isExternal = false;
-    transformProcedureToNoSuchMethodForwarder(noSuchMethod, target, cloned);
-    cls.procedures.add(cloned);
-    cloned.parent = cls;
-
-    library.forwardersOrigins.add(cloned);
-    library.forwardersOrigins.add(procedure);
-  }
-
-  void addNoSuchMethodForwarderGetterForField(
-      Field field, Member noSuchMethod, KernelTarget target) {
-    ClassHierarchy hierarchy = target.loader.hierarchy;
-    Substitution substitution = Substitution.fromSupertype(
-        hierarchy.getClassAsInstanceOf(cls, field.enclosingClass));
-
-    Procedure referenceFrom;
-    if (referencesFromIndexed != null) {
-      referenceFrom =
-          referencesFromIndexed.lookupProcedureNotSetter(field.name.text);
-    }
-    Procedure getter = new Procedure(
-        field.name,
-        ProcedureKind.Getter,
-        new FunctionNode(null,
-            typeParameters: <TypeParameter>[],
-            positionalParameters: <VariableDeclaration>[],
-            namedParameters: <VariableDeclaration>[],
-            requiredParameterCount: 0,
-            returnType: substitution.substituteType(field.type)),
-        fileUri: field.fileUri,
-        reference: referenceFrom?.reference)
-      ..fileOffset = field.fileOffset
-      ..isNonNullableByDefault = cls.enclosingLibrary.isNonNullableByDefault;
-    transformProcedureToNoSuchMethodForwarder(noSuchMethod, target, getter);
-    cls.procedures.add(getter);
-    getter.parent = cls;
-  }
-
-  void addNoSuchMethodForwarderSetterForField(
-      Field field, Member noSuchMethod, KernelTarget target) {
-    ClassHierarchy hierarchy = target.loader.hierarchy;
-    Substitution substitution = Substitution.fromSupertype(
-        hierarchy.getClassAsInstanceOf(cls, field.enclosingClass));
-
-    Procedure referenceFrom;
-    if (referencesFromIndexed != null) {
-      referenceFrom =
-          referencesFromIndexed.lookupProcedureSetter(field.name.text);
-    }
-
-    Procedure setter = new Procedure(
-        field.name,
-        ProcedureKind.Setter,
-        new FunctionNode(null,
-            typeParameters: <TypeParameter>[],
-            positionalParameters: <VariableDeclaration>[
-              new VariableDeclaration("value",
-                  type: substitution.substituteType(field.type))
-            ],
-            namedParameters: <VariableDeclaration>[],
-            requiredParameterCount: 1,
-            returnType: const VoidType()),
-        fileUri: field.fileUri,
-        reference: referenceFrom?.reference)
-      ..fileOffset = field.fileOffset
-      ..isNonNullableByDefault = cls.enclosingLibrary.isNonNullableByDefault;
-    transformProcedureToNoSuchMethodForwarder(noSuchMethod, target, setter);
-    cls.procedures.add(setter);
-    setter.parent = cls;
-  }
-
   bool _addMissingNoSuchMethodForwarders(
       KernelTarget target, Set<Member> existingForwarders,
       {bool forSetters}) {
     assert(forSetters != null);
 
     ClassHierarchy hierarchy = target.loader.hierarchy;
-    TypeEnvironment typeEnvironment =
-        target.loader.typeInferenceEngine.typeSchemaEnvironment;
 
     List<Member> allMembers =
         hierarchy.getInterfaceMembers(cls, setters: forSetters);
@@ -758,97 +665,33 @@
     for (Name name in sameNameMembers.keys) {
       List<Member> members = sameNameMembers[name];
       assert(members.isNotEmpty);
-      List<DartType> memberTypes = [];
-
-      // The most specific member has the type that is subtype of the types of
-      // all other members.
-      Member bestSoFar = members.first;
-      DartType bestSoFarType =
-          forSetters ? bestSoFar.setterType : bestSoFar.getterType;
-      Supertype supertype =
-          hierarchy.getClassAsInstanceOf(cls, bestSoFar.enclosingClass);
-      assert(
-          supertype != null,
-          "No supertype of enclosing class ${bestSoFar.enclosingClass} for "
-          "$bestSoFar found for $cls.");
-      bestSoFarType =
-          Substitution.fromSupertype(supertype).substituteType(bestSoFarType);
-      for (int i = 1; i < members.length; ++i) {
-        Member candidate = members[i];
-        DartType candidateType =
-            forSetters ? candidate.setterType : candidate.getterType;
-        Supertype supertype =
-            hierarchy.getClassAsInstanceOf(cls, candidate.enclosingClass);
-        assert(
-            supertype != null,
-            "No supertype of enclosing class ${candidate.enclosingClass} for "
-            "$candidate found for $cls.");
-        Substitution substitution = Substitution.fromSupertype(supertype);
-        candidateType = substitution.substituteType(candidateType);
-        memberTypes.add(candidateType);
-        bool isMoreSpecific = forSetters
-            ? typeEnvironment.isSubtypeOf(bestSoFarType, candidateType,
-                SubtypeCheckMode.withNullabilities)
-            : typeEnvironment.isSubtypeOf(candidateType, bestSoFarType,
-                SubtypeCheckMode.withNullabilities);
-        if (isMoreSpecific) {
-          bestSoFar = candidate;
-          bestSoFarType = candidateType;
-        }
-      }
-      // Since isSubtypeOf isn't a linear order on types, we need to check once
-      // again that the found member is indeed the most specific one.
-      bool isActuallyBestSoFar = true;
-      for (DartType memberType in memberTypes) {
-        bool isMoreSpecific = forSetters
-            ? typeEnvironment.isSubtypeOf(
-                memberType, bestSoFarType, SubtypeCheckMode.withNullabilities)
-            : typeEnvironment.isSubtypeOf(
-                bestSoFarType, memberType, SubtypeCheckMode.withNullabilities);
-        if (!isMoreSpecific) {
-          isActuallyBestSoFar = false;
-          break;
-        }
-      }
-      if (!isActuallyBestSoFar) {
-        // It's a member conflict that is reported elsewhere.
-      } else {
-        Member member = bestSoFar;
-
+      CombinedMemberSignatureBuilder combinedMemberSignature =
+          new CombinedMemberSignatureBuilder(hierarchy, this, members,
+              forSetter: forSetters);
+      Member member = combinedMemberSignature.canonicalMember;
+      if (member != null) {
         if (_isForwarderRequired(
                 clsHasUserDefinedNoSuchMethod, member, cls, concreteMembers,
                 isPatch: member.fileUri != member.enclosingClass.fileUri) &&
             !existingForwarders.contains(member)) {
-          if (member is Procedure) {
-            // If there's a declared member with such name, then it's abstract
-            // -- transform it into a noSuchMethod forwarder.
-            if (ClassHierarchy.findMemberByName(declaredMembers, member.name) !=
-                null) {
-              transformProcedureToNoSuchMethodForwarder(
-                  noSuchMethod, target, member);
-            } else {
-              addNoSuchMethodForwarderForProcedure(
-                  noSuchMethod, target, member, hierarchy);
-            }
-            changed = true;
-          } else if (member is Field) {
-            // Current class isn't abstract, so it can't have an abstract field
-            // with the same name -- just insert the forwarder.
-            if (forSetters) {
-              addNoSuchMethodForwarderSetterForField(
-                  member, noSuchMethod, target);
-            } else {
-              addNoSuchMethodForwarderGetterForField(
-                  member, noSuchMethod, target);
-            }
-            changed = true;
+          if (ClassHierarchy.findMemberByName(declaredMembers, member.name) !=
+              null) {
+            _transformProcedureToNoSuchMethodForwarder(
+                noSuchMethod, target, member);
           } else {
-            return unhandled(
-                "${member.runtimeType}",
-                "addNoSuchMethodForwarders",
-                cls.fileOffset,
-                cls.enclosingLibrary.fileUri);
+            Procedure memberSignature =
+                combinedMemberSignature.createMemberFromSignature();
+            _transformProcedureToNoSuchMethodForwarder(
+                noSuchMethod, target, memberSignature);
+            cls.procedures.add(memberSignature);
+            memberSignature.parent = cls;
+
+            if (member is Procedure) {
+              library.forwardersOrigins.add(memberSignature);
+              library.forwardersOrigins.add(member);
+            }
           }
+          changed = true;
         }
       }
     }
@@ -939,7 +782,49 @@
     return isForwarderRequired;
   }
 
-  void addRedirectingConstructor(ProcedureBuilder constructorBuilder,
+  void _transformProcedureToNoSuchMethodForwarder(
+      Member noSuchMethodInterface, KernelTarget target, Procedure procedure) {
+    String prefix = procedure.isGetter
+        ? 'get:'
+        : procedure.isSetter
+            ? 'set:'
+            : '';
+    String invocationName = prefix + procedure.name.text;
+    if (procedure.isSetter) invocationName += '=';
+    Expression invocation = target.backendTarget.instantiateInvocation(
+        target.loader.coreTypes,
+        new ThisExpression(),
+        invocationName,
+        new Arguments.forwarded(procedure.function, library.library),
+        procedure.fileOffset,
+        /*isSuper=*/ false);
+    Expression result = new MethodInvocation(new ThisExpression(),
+        noSuchMethodName, new Arguments([invocation]), noSuchMethodInterface)
+      ..fileOffset = procedure.fileOffset;
+    if (procedure.function.returnType is! VoidType) {
+      result = new AsExpression(result, procedure.function.returnType)
+        ..isTypeError = true
+        ..isForDynamic = true
+        ..isForNonNullableByDefault = library.isNonNullableByDefault
+        ..fileOffset = procedure.fileOffset;
+    }
+    procedure.function.body = new ReturnStatement(result)
+      ..fileOffset = procedure.fileOffset;
+    procedure.function.body.parent = procedure.function;
+    procedure.function.asyncMarker = AsyncMarker.Sync;
+    procedure.function.dartAsyncMarker = AsyncMarker.Sync;
+
+    procedure.isAbstract = false;
+    procedure.isNoSuchMethodForwarder = true;
+    procedure.isMemberSignature = false;
+    procedure.isForwardingStub = false;
+    procedure.isForwardingSemiStub = false;
+    procedure.memberSignatureOrigin = null;
+    procedure.forwardingStubInterfaceTarget = null;
+    procedure.forwardingStubSuperTarget = null;
+  }
+
+  void _addRedirectingConstructor(ProcedureBuilder constructorBuilder,
       SourceLibraryBuilder library, Field referenceFrom) {
     // Add a new synthetic field to this class for representing factory
     // constructors. This is used to support resolving such constructors in
@@ -1006,7 +891,7 @@
                 // only legal to do to things in the kernel tree.
                 Field referenceFrom =
                     referencesFromIndexed?.lookupField("_redirecting#");
-                addRedirectingConstructor(declaration, library, referenceFrom);
+                _addRedirectingConstructor(declaration, library, referenceFrom);
               }
               if (targetBuilder is FunctionBuilder) {
                 List<DartType> typeArguments = declaration.typeArguments ??
@@ -1845,3 +1730,17 @@
     }
   }
 }
+
+/// Returns `true` if override problems should be overlooked.
+///
+/// This is needed for the current encoding of some JavaScript implementation
+/// classes that are not valid Dart. For instance `JSInt` in
+/// 'dart:_interceptors' that implements both `int` and `double`, and `JsArray`
+/// in `dart:js` that implement both `ListMixin` and `JsObject`.
+bool shouldOverrideProblemBeOverlooked(ClassBuilder classBuilder) {
+  String uri = '${classBuilder.library.importUri}';
+  return uri == 'dart:js' &&
+          classBuilder.fileUri.pathSegments.last == 'js.dart' ||
+      uri == 'dart:_interceptors' &&
+          classBuilder.fileUri.pathSegments.last == 'js_number.dart';
+}
diff --git a/pkg/front_end/lib/src/fasta/source/source_loader.dart b/pkg/front_end/lib/src/fasta/source/source_loader.dart
index 50dcccf..7dfb32e 100644
--- a/pkg/front_end/lib/src/fasta/source/source_loader.dart
+++ b/pkg/front_end/lib/src/fasta/source/source_loader.dart
@@ -1511,8 +1511,6 @@
 const String defaultDartAsyncSource = """
 _asyncErrorWrapperHelper(continuation) {}
 
-void _asyncStarListenHelper(var object, var awaiter) {}
-
 void _asyncStarMoveNextHelper(var stream) {}
 
 _asyncStackTraceHelper(async_op) {}
diff --git a/pkg/front_end/lib/src/fasta/source/stack_listener_impl.dart b/pkg/front_end/lib/src/fasta/source/stack_listener_impl.dart
index 0e6a737..f3af4a5 100644
--- a/pkg/front_end/lib/src/fasta/source/stack_listener_impl.dart
+++ b/pkg/front_end/lib/src/fasta/source/stack_listener_impl.dart
@@ -110,6 +110,19 @@
             token.charOffset,
             token.charCount);
       }
+    } else if (libraryBuilder.loader.target
+        .isExperimentEnabledByDefault(ExperimentalFlag.nonNullable)) {
+      if (libraryBuilder.languageVersion.version <
+          libraryBuilder.enableNonNullableVersionInLibrary) {
+        addProblem(
+            templateExperimentDisabledInvalidLanguageVersion.withArguments(
+                libraryBuilder.enableNonNullableVersionInLibrary.toText()),
+            token.offset,
+            noLength);
+      } else {
+        addProblem(templateExperimentDisabled.withArguments('non-nullable'),
+            token.offset, noLength);
+      }
     } else if (!libraryBuilder.loader.target
         .isExperimentEnabledGlobally(ExperimentalFlag.nonNullable)) {
       if (libraryBuilder.languageVersion.version <
diff --git a/pkg/front_end/lib/src/fasta/target_implementation.dart b/pkg/front_end/lib/src/fasta/target_implementation.dart
index 57a4369..60b0625 100644
--- a/pkg/front_end/lib/src/fasta/target_implementation.dart
+++ b/pkg/front_end/lib/src/fasta/target_implementation.dart
@@ -66,6 +66,16 @@
     return _options.getExperimentEnabledVersionInLibrary(flag, importUri);
   }
 
+  /// Returns `true` if the [flag] is enabled by default.
+  bool isExperimentEnabledByDefault(ExperimentalFlag flag) {
+    return _options.isExperimentEnabledByDefault(flag);
+  }
+
+  /// Returns `true` if the [flag] is enabled globally.
+  ///
+  /// This is `true` either if the [flag] is passed through an explicit
+  /// `--enable-experiment` option or if the [flag] is expired and on by
+  /// default.
   bool isExperimentEnabledGlobally(ExperimentalFlag flag) {
     return _options.isExperimentEnabledGlobally(flag);
   }
diff --git a/pkg/front_end/lib/src/fasta/type_inference/closure_context.dart b/pkg/front_end/lib/src/fasta/type_inference/closure_context.dart
index 2aad555..c641616 100644
--- a/pkg/front_end/lib/src/fasta/type_inference/closure_context.dart
+++ b/pkg/front_end/lib/src/fasta/type_inference/closure_context.dart
@@ -294,15 +294,16 @@
       {bool hasImplicitReturn}) {
     assert(_needToInferReturnType);
     assert(hasImplicitReturn != null);
-    DartType inferredType;
+    DartType actualReturnedType;
+    DartType inferredReturnType;
     if (inferrer.isNonNullableByDefault) {
       if (hasImplicitReturn) {
         // No explicit returns we have an implicit `return null`.
-        inferredType = inferrer.typeSchemaEnvironment.nullType;
+        actualReturnedType = inferrer.typeSchemaEnvironment.nullType;
       } else {
         // No explicit return and the function doesn't complete normally; that
         // is, it throws.
-        inferredType = new NeverType(inferrer.library.nonNullable);
+        actualReturnedType = new NeverType(inferrer.library.nonNullable);
       }
       // Use the types seen from the explicit return statements.
       for (int i = 0; i < _returnStatements.length; i++) {
@@ -315,13 +316,32 @@
             type = inferrer.computeGreatestClosure(_returnContext);
           }
         }
-        if (inferredType == null) {
-          inferredType = type;
+        if (actualReturnedType == null) {
+          actualReturnedType = type;
         } else {
-          inferredType = inferrer.typeSchemaEnvironment.getStandardUpperBound(
-              inferredType, type, inferrer.library.library);
+          actualReturnedType = inferrer.typeSchemaEnvironment
+              .getStandardUpperBound(
+                  actualReturnedType, type, inferrer.library.library);
         }
       }
+
+      // Let T be the actual returned type of a function literal as computed
+      // above. Let R be the greatest closure of the typing context K as
+      // computed above.
+      DartType returnContext =
+          inferrer.computeGreatestClosure2(_declaredReturnType);
+      if (returnContext is VoidType) {
+        // With null safety: if R is void, or the function literal is marked
+        // async and R is FutureOr<void>, let S be void.
+        inferredReturnType = const VoidType();
+      } else if (inferrer.typeSchemaEnvironment.isSubtypeOf(actualReturnedType,
+          returnContext, SubtypeCheckMode.withNullabilities)) {
+        // Otherwise, if T <: R then let S be T.
+        inferredReturnType = actualReturnedType;
+      } else {
+        // Otherwise, let S be R.
+        inferredReturnType = returnContext;
+      }
     } else {
       if (_returnStatements.isNotEmpty) {
         // Use the types seen from the explicit return statements.
@@ -335,37 +355,41 @@
               type = inferrer.computeGreatestClosure(_returnContext);
             }
           }
-          if (inferredType == null) {
-            inferredType = type;
+          if (actualReturnedType == null) {
+            actualReturnedType = type;
           } else {
-            inferredType = inferrer.typeSchemaEnvironment.getStandardUpperBound(
-                inferredType, type, inferrer.library.library);
+            actualReturnedType = inferrer.typeSchemaEnvironment
+                .getStandardUpperBound(
+                    actualReturnedType, type, inferrer.library.library);
           }
         }
       } else if (hasImplicitReturn) {
         // No explicit returns we have an implicit `return null`.
-        inferredType = inferrer.typeSchemaEnvironment.nullType;
+        actualReturnedType = inferrer.typeSchemaEnvironment.nullType;
       } else {
         // No explicit return and the function doesn't complete normally; that
         // is, it throws.
-        inferredType = inferrer.typeSchemaEnvironment.nullType;
+        actualReturnedType = inferrer.typeSchemaEnvironment.nullType;
+      }
+
+      if (!inferrer.typeSchemaEnvironment.isSubtypeOf(actualReturnedType,
+          _returnContext, SubtypeCheckMode.withNullabilities)) {
+        // If the inferred return type isn't a subtype of the context, we use
+        // the context.
+        inferredReturnType =
+            inferrer.computeGreatestClosure2(_declaredReturnType);
+      } else {
+        inferredReturnType = actualReturnedType;
       }
     }
 
-    if (!inferrer.typeSchemaEnvironment.isSubtypeOf(
-        inferredType, _returnContext, SubtypeCheckMode.withNullabilities)) {
-      // If the inferred return type isn't a subtype of the context, we use the
-      // context.
-      inferredType = inferrer.computeGreatestClosure2(_declaredReturnType);
-    }
-
     for (int i = 0; i < _returnStatements.length; ++i) {
-      _checkValidReturn(inferrer, inferredType, _returnStatements[i],
+      _checkValidReturn(inferrer, inferredReturnType, _returnStatements[i],
           _returnExpressionTypes[i]);
     }
 
     return _inferredReturnType =
-        demoteTypeInLibrary(inferredType, inferrer.library.library);
+        demoteTypeInLibrary(inferredReturnType, inferrer.library.library);
   }
 
   @override
diff --git a/pkg/front_end/lib/src/testing/id_testing_helper.dart b/pkg/front_end/lib/src/testing/id_testing_helper.dart
index 9051ce0..52c8586 100644
--- a/pkg/front_end/lib/src/testing/id_testing_helper.dart
+++ b/pkg/front_end/lib/src/testing/id_testing_helper.dart
@@ -33,23 +33,23 @@
 /// default state.
 const TestConfig cfeNoNonNullableConfig = const TestConfig(
     cfeMarker, 'cfe without nnbd',
-    experimentalFlags: const {ExperimentalFlag.nonNullable: false});
+    explicitExperimentalFlags: const {ExperimentalFlag.nonNullable: false});
 
 /// Test configuration used for testing CFE with nnbd in addition to the
 /// default state.
 const TestConfig cfeNonNullableConfig = const TestConfig(
     cfeWithNnbdMarker, 'cfe with nnbd',
-    experimentalFlags: const {ExperimentalFlag.nonNullable: true});
+    explicitExperimentalFlags: const {ExperimentalFlag.nonNullable: true});
 
 /// Test configuration used for testing CFE with nnbd as the default state.
 const TestConfig cfeNonNullableOnlyConfig = const TestConfig(
     cfeMarker, 'cfe with nnbd',
-    experimentalFlags: const {ExperimentalFlag.nonNullable: true});
+    explicitExperimentalFlags: const {ExperimentalFlag.nonNullable: true});
 
 class TestConfig {
   final String marker;
   final String name;
-  final Map<ExperimentalFlag, bool> experimentalFlags;
+  final Map<ExperimentalFlag, bool> explicitExperimentalFlags;
   final AllowedExperimentalFlags allowedExperimentalFlags;
   final Uri librariesSpecificationUri;
   // TODO(johnniwinther): Tailor support to redefine selected platform
@@ -59,7 +59,7 @@
   final NnbdMode nnbdMode;
 
   const TestConfig(this.marker, this.name,
-      {this.experimentalFlags = const {},
+      {this.explicitExperimentalFlags = const {},
       this.allowedExperimentalFlags,
       this.librariesSpecificationUri,
       this.compileSdk: false,
@@ -306,7 +306,7 @@
   };
   options.debugDump = printCode;
   options.target = new NoneTarget(config.targetFlags);
-  options.experimentalFlags.addAll(config.experimentalFlags);
+  options.explicitExperimentalFlags.addAll(config.explicitExperimentalFlags);
   options.allowedExperimentalFlagsForTesting = config.allowedExperimentalFlags;
   options.nnbdMode = config.nnbdMode;
   if (config.librariesSpecificationUri != null) {
diff --git a/pkg/front_end/messages.status b/pkg/front_end/messages.status
index 969f40c..30cf0bb 100644
--- a/pkg/front_end/messages.status
+++ b/pkg/front_end/messages.status
@@ -222,6 +222,8 @@
 ExpectedType/example: Fail
 ExpectedUri/analyzerCode: Fail
 ExpectedUri/example: Fail
+ExperimentDisabled/example: Fail
+ExperimentDisabledInvalidLanguageVersion/example: Fail
 ExperimentNotEnabled/example: Fail
 ExperimentNotEnabledNoFlag/example: Fail
 ExperimentNotEnabledNoFlagInvalidLanguageVersion/example: Fail
diff --git a/pkg/front_end/messages.yaml b/pkg/front_end/messages.yaml
index 14e312f..9428be9 100644
--- a/pkg/front_end/messages.yaml
+++ b/pkg/front_end/messages.yaml
@@ -265,6 +265,15 @@
   tip: "You can enable the experiment using the '--enable-experiment=non-nullable' command line option."
   analyzerCode: ParserErrorCode.EXPERIMENT_NOT_ENABLED
 
+ExperimentDisabled:
+  template: "This requires the '#string' language feature to be enabled."
+  tip: "The feature is on by default but is currently disabled, maybe because the '--enable-experiment=no-#string' command line option is passed."
+  analyzerCode: ParserErrorCode.EXPERIMENT_NOT_ENABLED
+
+ExperimentDisabledInvalidLanguageVersion:
+  template: "This requires the null safety language feature, which requires language version of #string2 or higher."
+  analyzerCode: ParserErrorCode.EXPERIMENT_NOT_ENABLED
+
 EmptyNamedParameterList:
   template: "Named parameter lists cannot be empty."
   tip: "Try adding a named parameter to the list."
diff --git a/pkg/front_end/test/crashing_test_case_minimizer.dart b/pkg/front_end/test/crashing_test_case_minimizer.dart
index c6aca7f..4f043ed 100644
--- a/pkg/front_end/test/crashing_test_case_minimizer.dart
+++ b/pkg/front_end/test/crashing_test_case_minimizer.dart
@@ -550,7 +550,7 @@
   CompilerOptions options = getOptions();
 
   if (nnbd) {
-    options.experimentalFlags = {ExperimentalFlag.nonNullable: true};
+    options.explicitExperimentalFlags = {ExperimentalFlag.nonNullable: true};
   }
 
   TargetFlags targetFlags = new TargetFlags(
diff --git a/pkg/front_end/test/enable_non_nullable/enable_non_nullable_test.dart b/pkg/front_end/test/enable_non_nullable/enable_non_nullable_test.dart
index 96722a8..8887306 100644
--- a/pkg/front_end/test/enable_non_nullable/enable_non_nullable_test.dart
+++ b/pkg/front_end/test/enable_non_nullable/enable_non_nullable_test.dart
@@ -25,6 +25,7 @@
   print('--------------------------------------------------------------------');
   await test(
       enableNonNullableByDefault: false,
+      enableNonNullableExplicitly: true,
       // When the flag is off by default, the experiment release version should
       // be used as the opt-in criterion for all libraries.
       versionImpliesOptIn: experimentReleaseVersion,
@@ -35,16 +36,30 @@
   print('--------------------------------------------------------------------');
   await test(
       enableNonNullableByDefault: true,
+      enableNonNullableExplicitly: false,
       // When the flag is on by default, the experiment release version should
       // be used as the opt-in criterion only for libraries in allowed packages
       // and the experiment enabled version should be used as the opt-in
       // criterion for all other libraries.
       versionImpliesOptIn: experimentEnabledVersion,
       versionOptsInAllowed: experimentReleaseVersion);
+
+  print('--------------------------------------------------------------------');
+  print('Test on-by-default and explicitly with command-line flag');
+  print('--------------------------------------------------------------------');
+  await test(
+      enableNonNullableByDefault: true,
+      enableNonNullableExplicitly: true,
+      // When the flag is on by default but the experiment is enabled explicitly
+      // the experiment release version should be used as the opt-in criterion
+      // for all libraries.
+      versionImpliesOptIn: experimentReleaseVersion,
+      versionOptsInAllowed: experimentReleaseVersion);
 }
 
 test(
     {bool enableNonNullableByDefault,
+    bool enableNonNullableExplicitly,
     Version versionImpliesOptIn,
     Version versionOptsInAllowed}) async {
   CompilerOptions options = new CompilerOptions();
@@ -54,10 +69,14 @@
       ExperimentalFlag.nonNullable: true
     };
   } else {
-    // Pretend non-nullable is off by default but enabled on command-line.
-    options
-      ..defaultExperimentFlagsForTesting = {ExperimentalFlag.nonNullable: false}
-      ..experimentalFlags = {ExperimentalFlag.nonNullable: true};
+    // Pretend non-nullable is off by default.
+    options.defaultExperimentFlagsForTesting = {
+      ExperimentalFlag.nonNullable: false
+    };
+  }
+  if (enableNonNullableExplicitly) {
+    // Enable non-nullable explicitly on the command-line.
+    options..explicitExperimentalFlags = {ExperimentalFlag.nonNullable: true};
   }
 
   Uri sdkSummary = computePlatformBinariesLocation(forceBuildDir: true)
diff --git a/pkg/front_end/test/fasta/expression_suite.dart b/pkg/front_end/test/fasta/expression_suite.dart
index 85d3302..46811fb 100644
--- a/pkg/front_end/test/fasta/expression_suite.dart
+++ b/pkg/front_end/test/fasta/expression_suite.dart
@@ -413,7 +413,7 @@
       errors.add(message);
     }
     ..environmentDefines = const {}
-    ..experimentalFlags = {ExperimentalFlag.nonNullable: false}
+    ..explicitExperimentalFlags = {ExperimentalFlag.nonNullable: false}
     ..allowedExperimentalFlagsForTesting = const AllowedExperimentalFlags();
 
   final ProcessedOptions options =
diff --git a/pkg/front_end/test/fasta/incremental_suite.dart b/pkg/front_end/test/fasta/incremental_suite.dart
index 34889b7..656da97 100644
--- a/pkg/front_end/test/fasta/incremental_suite.dart
+++ b/pkg/front_end/test/fasta/incremental_suite.dart
@@ -224,7 +224,7 @@
     ..verbose = true
     ..fileSystem = fs
     ..sdkSummary = sdkSummary
-    ..experimentalFlags = {ExperimentalFlag.nonNullable: false}
+    ..explicitExperimentalFlags = {ExperimentalFlag.nonNullable: false}
     ..onDiagnostic = (DiagnosticMessage message) {
       printDiagnosticMessage(message, print);
       if (message.severity == Severity.error) {
diff --git a/pkg/front_end/test/fasta/messages_suite.dart b/pkg/front_end/test/fasta/messages_suite.dart
index d657ebf..2992f1e 100644
--- a/pkg/front_end/test/fasta/messages_suite.dart
+++ b/pkg/front_end/test/fasta/messages_suite.dart
@@ -77,10 +77,10 @@
 
   CompilerOptions apply(CompilerOptions options) {
     if (nnbdMode != null) {
-      options.experimentalFlags[ExperimentalFlag.nonNullable] = true;
+      options.explicitExperimentalFlags[ExperimentalFlag.nonNullable] = true;
       options.nnbdMode = nnbdMode;
     } else {
-      options.experimentalFlags[ExperimentalFlag.nonNullable] = false;
+      options.explicitExperimentalFlags[ExperimentalFlag.nonNullable] = false;
     }
     return options;
   }
diff --git a/pkg/front_end/test/fasta/testing/suite.dart b/pkg/front_end/test/fasta/testing/suite.dart
index 9e69886..8c4d01e 100644
--- a/pkg/front_end/test/fasta/testing/suite.dart
+++ b/pkg/front_end/test/fasta/testing/suite.dart
@@ -30,7 +30,6 @@
         AllowedExperimentalFlags,
         ExperimentalFlag,
         defaultAllowedExperimentalFlags,
-        defaultExperimentalFlags,
         isExperimentEnabled;
 
 import 'package:front_end/src/api_prototype/standard_file_system.dart'
@@ -206,7 +205,7 @@
 /// This is used for instance for defining target, mode, and experiment specific
 /// test folders.
 class FolderOptions {
-  final Map<ExperimentalFlag, bool> _experimentalFlags;
+  final Map<ExperimentalFlag, bool> _explicitExperimentalFlags;
   final bool forceLateLowering;
   final bool forceLateLoweringSentinel;
   final bool forceStaticFieldLowering;
@@ -217,7 +216,7 @@
   final String target;
   final String overwriteCurrentSdkVersion;
 
-  FolderOptions(this._experimentalFlags,
+  FolderOptions(this._explicitExperimentalFlags,
       {this.forceLateLowering: false,
       this.forceLateLoweringSentinel: false,
       this.forceStaticFieldLowering: false,
@@ -240,10 +239,10 @@
         assert(noVerify != null),
         assert(target != null);
 
-  Map<ExperimentalFlag, bool> computeExperimentalFlags(
+  Map<ExperimentalFlag, bool> computeExplicitExperimentalFlags(
       Map<ExperimentalFlag, bool> forcedExperimentalFlags) {
-    Map<ExperimentalFlag, bool> flags = new Map.from(defaultExperimentalFlags);
-    flags.addAll(_experimentalFlags);
+    Map<ExperimentalFlag, bool> flags = {};
+    flags.addAll(_explicitExperimentalFlags);
     flags.addAll(forcedExperimentalFlags);
     return flags;
   }
@@ -275,7 +274,7 @@
   final List<Step> steps;
   final Uri vm;
   final bool onlyCrashes;
-  final Map<ExperimentalFlag, bool> experimentalFlags;
+  final Map<ExperimentalFlag, bool> explicitExperimentalFlags;
   final bool skipVm;
   final bool verify;
   final bool weak;
@@ -308,7 +307,7 @@
       this.vm,
       this.platformBinaries,
       this.onlyCrashes,
-      this.experimentalFlags,
+      this.explicitExperimentalFlags,
       bool ignoreExpectations,
       this.updateExpectations,
       bool updateComments,
@@ -510,8 +509,8 @@
         ..sdkRoot = sdk
         ..packagesFileUri = uriConfiguration.packageConfigUri ?? packages
         ..environmentDefines = folderOptions.defines
-        ..experimentalFlags =
-            folderOptions.computeExperimentalFlags(experimentalFlags)
+        ..explicitExperimentalFlags = folderOptions
+            .computeExplicitExperimentalFlags(explicitExperimentalFlags)
         ..nnbdMode = weak
             ? NnbdMode.Weak
             : (folderOptions.nnbdAgnosticMode
@@ -734,8 +733,8 @@
   Future<Result<int>> run(ComponentResult result, FastaContext context) async {
     FolderOptions folderOptions =
         context.computeFolderOptions(result.description);
-    Map<ExperimentalFlag, bool> experimentalFlags =
-        folderOptions.computeExperimentalFlags(context.experimentalFlags);
+    Map<ExperimentalFlag, bool> experimentalFlags = folderOptions
+        .computeExplicitExperimentalFlags(context.explicitExperimentalFlags);
     switch (folderOptions.target) {
       case "vm":
         if (context.platformUri == null) {
@@ -965,11 +964,11 @@
         context.computeLibrariesSpecificationUri(description);
     TestOptions testOptions = context.computeTestOptions(description);
     FolderOptions folderOptions = context.computeFolderOptions(description);
-    Map<ExperimentalFlag, bool> experimentalFlags =
-        folderOptions.computeExperimentalFlags(context.experimentalFlags);
+    Map<ExperimentalFlag, bool> experimentalFlags = folderOptions
+        .computeExplicitExperimentalFlags(context.explicitExperimentalFlags);
     NnbdMode nnbdMode = context.weak ||
             !isExperimentEnabled(ExperimentalFlag.nonNullable,
-                experimentalFlags: experimentalFlags)
+                explicitExperimentalFlags: experimentalFlags)
         ? NnbdMode.Weak
         : (folderOptions.nnbdAgnosticMode
             ? NnbdMode.Agnostic
@@ -986,7 +985,7 @@
           errors.add(message.plainTextFormatted);
         }
         ..environmentDefines = folderOptions.defines
-        ..experimentalFlags = experimentalFlags
+        ..explicitExperimentalFlags = experimentalFlags
         ..nnbdMode = nnbdMode
         ..librariesSpecificationUri = librariesSpecificationUri
         ..allowedExperimentalFlagsForTesting = allowedExperimentalFlags
diff --git a/pkg/front_end/test/fasta/type_inference/factor_type_test.dart b/pkg/front_end/test/fasta/type_inference/factor_type_test.dart
index c8ed120..4310dac 100644
--- a/pkg/front_end/test/fasta/type_inference/factor_type_test.dart
+++ b/pkg/front_end/test/fasta/type_inference/factor_type_test.dart
@@ -102,7 +102,7 @@
 
 main() async {
   CompilerOptions options = new CompilerOptions()
-    ..experimentalFlags[ExperimentalFlag.nonNullable] = true;
+    ..explicitExperimentalFlags[ExperimentalFlag.nonNullable] = true;
   InternalCompilerResult result = await compileScript('',
       options: options, requireMain: false, retainDataForTesting: true);
   new FactorTypeTest(
diff --git a/pkg/front_end/test/id_tests/inheritance_test.dart b/pkg/front_end/test/id_tests/inheritance_test.dart
index 39f382a..2089d9a 100644
--- a/pkg/front_end/test/id_tests/inheritance_test.dart
+++ b/pkg/front_end/test/id_tests/inheritance_test.dart
@@ -25,11 +25,15 @@
       onFailure: onFailure,
       runTest: runTestFor(const InheritanceDataComputer(), [
         new TestConfig(cfeMarker, 'cfe with nnbd',
-            experimentalFlags: const {ExperimentalFlag.nonNullable: true},
+            explicitExperimentalFlags: const {
+              ExperimentalFlag.nonNullable: true
+            },
             librariesSpecificationUri: createUriForFileName('libraries.json'),
             compileSdk: true),
         new TestConfig(cfeFromBuilderMarker, 'cfe from builder',
-            experimentalFlags: const {ExperimentalFlag.nonNullable: true},
+            explicitExperimentalFlags: const {
+              ExperimentalFlag.nonNullable: true
+            },
             librariesSpecificationUri: createUriForFileName('libraries.json'),
             compileSdk: true)
       ]));
diff --git a/pkg/front_end/test/incremental_dart2js_tester.dart b/pkg/front_end/test/incremental_dart2js_tester.dart
index 28ee1d6..59c95ee 100644
--- a/pkg/front_end/test/incremental_dart2js_tester.dart
+++ b/pkg/front_end/test/incremental_dart2js_tester.dart
@@ -176,7 +176,7 @@
     stopwatch.start();
     Uri input = Platform.script.resolve("../../compiler/bin/dart2js.dart");
     CompilerOptions options = helper.getOptions();
-    options.experimentalFlags[ExperimentalFlag
+    options.explicitExperimentalFlags[ExperimentalFlag
         .alternativeInvalidationStrategy] = useExperimentalInvalidation;
     helper.TestIncrementalCompiler compiler =
         new helper.TestIncrementalCompiler(options, input);
diff --git a/pkg/front_end/test/incremental_flutter_tester.dart b/pkg/front_end/test/incremental_flutter_tester.dart
index 7b292c4..ac3be91 100644
--- a/pkg/front_end/test/incremental_flutter_tester.dart
+++ b/pkg/front_end/test/incremental_flutter_tester.dart
@@ -78,8 +78,8 @@
 
   Stopwatch stopwatch = new Stopwatch()..start();
   CompilerOptions options = getOptions(flutterPatchedSdk.uri);
-  options.experimentalFlags[ExperimentalFlag.alternativeInvalidationStrategy] =
-      useExperimentalInvalidation;
+  options.explicitExperimentalFlags[ExperimentalFlag
+      .alternativeInvalidationStrategy] = useExperimentalInvalidation;
   helper.TestIncrementalCompiler compiler =
       new helper.TestIncrementalCompiler(options, inputFile.uri);
   Component c = await compiler.computeDelta();
diff --git a/pkg/front_end/test/incremental_load_from_dill_suite.dart b/pkg/front_end/test/incremental_load_from_dill_suite.dart
index 2dfa384..2d9449c 100644
--- a/pkg/front_end/test/incremental_load_from_dill_suite.dart
+++ b/pkg/front_end/test/incremental_load_from_dill_suite.dart
@@ -353,7 +353,8 @@
     if (wantedLibs.length != moduleSources.length) {
       throw "Module probably not setup right.";
     }
-    Component result = new Component(libraries: wantedLibs);
+    Component result = new Component(libraries: wantedLibs)
+      ..setMainMethodAndMode(null, false, c.mode);
     List<int> resultBytes = util.postProcess(result);
     moduleResult[moduleName] = resultBytes;
   }
@@ -533,13 +534,15 @@
           // flag is on by default.
           // TODO(johnniwinther,jensj): Update tests to explicitly opt out.
           flagsFromOptions['non-nullable'] ??= false;
-          Map<ExperimentalFlag, bool> experimentalFlags =
+          Map<ExperimentalFlag, bool> explicitExperimentalFlags =
               parseExperimentalFlags(flagsFromOptions,
                   onError: (e) =>
                       throw "Error on parsing experiments flags: $e");
-          options.experimentalFlags = experimentalFlags;
+          options.explicitExperimentalFlags = explicitExperimentalFlags;
         } else {
-          options.experimentalFlags = {ExperimentalFlag.nonNullable: false};
+          options.explicitExperimentalFlags = {
+            ExperimentalFlag.nonNullable: false
+          };
         }
         if (world["nnbdMode"] != null) {
           String nnbdMode = world["nnbdMode"];
@@ -839,7 +842,8 @@
             data,
             InitializedFromDillMismatch,
             "Expected that initializedFromDill would be "
-            "$expectInitializeFromDill but was ${compiler.initializedFromDill}");
+            "$expectInitializeFromDill but was "
+            "${compiler.initializedFromDill}");
       }
 
       if (incrementalSerialization == true && compiler.initializedFromDill) {
@@ -1305,7 +1309,8 @@
     IncrementalSerializer incrementalSerializer,
     YamlMap world) {
   if (incrementalSerialization == true) {
-    Component c = new Component(nameRoot: component.root);
+    Component c = new Component(nameRoot: component.root)
+      ..setMainMethodAndMode(null, false, component.mode);
     c.libraries.addAll(component.libraries);
     c.uriToSource.addAll(component.uriToSource);
     Map<String, Set<String>> originalContent = buildMapOfContent(c);
diff --git a/pkg/front_end/test/patching/patching_test.dart b/pkg/front_end/test/patching/patching_test.dart
index 586412d..9e5e116 100644
--- a/pkg/front_end/test/patching/patching_test.dart
+++ b/pkg/front_end/test/patching/patching_test.dart
@@ -54,7 +54,7 @@
       AllowedExperimentalFlags allowedExperimentalFlags})
       : super(marker, name,
             librariesSpecificationUri: librariesSpecificationUri,
-            experimentalFlags: experimentalFlags,
+            explicitExperimentalFlags: experimentalFlags,
             allowedExperimentalFlags: allowedExperimentalFlags);
 
   @override
diff --git a/pkg/front_end/test/predicates/predicate_test.dart b/pkg/front_end/test/predicates/predicate_test.dart
index 8320f85..89ddb9f 100644
--- a/pkg/front_end/test/predicates/predicate_test.dart
+++ b/pkg/front_end/test/predicates/predicate_test.dart
@@ -22,7 +22,9 @@
       onFailure: onFailure,
       runTest: runTestFor(const PredicateDataComputer(), [
         const TestConfig(cfeMarker, 'cfe',
-            experimentalFlags: const {ExperimentalFlag.nonNullable: true},
+            explicitExperimentalFlags: const {
+              ExperimentalFlag.nonNullable: true
+            },
             targetFlags: const TargetFlags(forceLateLoweringForTesting: true))
       ]));
 }
diff --git a/pkg/front_end/test/spell_checking_list_code.txt b/pkg/front_end/test/spell_checking_list_code.txt
index 77adce1..a0d5c8c 100644
--- a/pkg/front_end/test/spell_checking_list_code.txt
+++ b/pkg/front_end/test/spell_checking_list_code.txt
@@ -54,6 +54,7 @@
 artificial
 asgerf
 askesc
+aspect
 aspx
 assigning
 assigns
diff --git a/pkg/front_end/test/spell_checking_list_tests.txt b/pkg/front_end/test/spell_checking_list_tests.txt
index 164bb07..8022b92 100644
--- a/pkg/front_end/test/spell_checking_list_tests.txt
+++ b/pkg/front_end/test/spell_checking_list_tests.txt
@@ -45,6 +45,7 @@
 backed
 background
 bail
+bailing
 bailout
 bash
 bat
@@ -545,6 +546,7 @@
 reducer
 referring
 reflectee
+refusing
 regenerate
 regressions
 reify
diff --git a/pkg/front_end/test/src/base/processed_options_test.dart b/pkg/front_end/test/src/base/processed_options_test.dart
index 5c8d0bf..50a7939 100644
--- a/pkg/front_end/test/src/base/processed_options_test.dart
+++ b/pkg/front_end/test/src/base/processed_options_test.dart
@@ -12,7 +12,12 @@
 import 'package:front_end/src/fasta/fasta_codes.dart';
 import 'package:kernel/binary/ast_to_binary.dart' show BinaryPrinter;
 import 'package:kernel/kernel.dart'
-    show CanonicalName, Library, Component, loadComponentFromBytes;
+    show
+        CanonicalName,
+        Library,
+        Component,
+        loadComponentFromBytes,
+        NonNullableByDefaultCompiledMode;
 import 'package:package_config/package_config.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
@@ -34,7 +39,8 @@
   Component _mockOutline;
 
   Component get mockSummary => _mockOutline ??= new Component(
-      libraries: [new Library(Uri.parse('org-dartlang-test:///a/b.dart'))]);
+      libraries: [new Library(Uri.parse('org-dartlang-test:///a/b.dart'))])
+    ..setMainMethodAndMode(null, false, NonNullableByDefaultCompiledMode.Weak);
 
   test_compileSdk_false() {
     for (var value in [false, true]) {
diff --git a/pkg/front_end/test/text_representation/text_representation_test.dart b/pkg/front_end/test/text_representation/text_representation_test.dart
index daff068..8d57260 100644
--- a/pkg/front_end/test/text_representation/text_representation_test.dart
+++ b/pkg/front_end/test/text_representation/text_representation_test.dart
@@ -81,7 +81,9 @@
 class TextRepresentationConfig extends TestConfig {
   const TextRepresentationConfig(String marker, String name)
       : super(marker, name,
-            experimentalFlags: const {ExperimentalFlag.nonNullable: true},
+            explicitExperimentalFlags: const {
+              ExperimentalFlag.nonNullable: true
+            },
             nnbdMode: NnbdMode.Strong);
 
   void customizeCompilerOptions(CompilerOptions options, TestData testData) {
diff --git a/pkg/front_end/test/utils/kernel_chain.dart b/pkg/front_end/test/utils/kernel_chain.dart
index 4b0f44e..abdc1d4 100644
--- a/pkg/front_end/test/utils/kernel_chain.dart
+++ b/pkg/front_end/test/utils/kernel_chain.dart
@@ -211,7 +211,8 @@
 
       ByteSink sink = new ByteSink();
       Component writeMe = new Component(
-          libraries: component.libraries.where(result.isUserLibrary).toList());
+          libraries: component.libraries.where(result.isUserLibrary).toList())
+        ..setMainMethodAndMode(null, false, component.mode);
       writeMe.uriToSource.addAll(component.uriToSource);
       if (component.problemsAsJson != null) {
         writeMe.problemsAsJson =
diff --git a/pkg/front_end/testcases/extensions/ambiguous.dart.outline.expect b/pkg/front_end/testcases/extensions/ambiguous.dart.outline.expect
index 5ee4ba9..16c230a 100644
--- a/pkg/front_end/testcases/extensions/ambiguous.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/ambiguous.dart.outline.expect
@@ -5,16 +5,16 @@
 class C extends core::Object {
   synthetic constructor •() → self::C*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A on self::C* {
   method method = self::A|method;
diff --git a/pkg/front_end/testcases/extensions/ambiguous.dart.strong.expect b/pkg/front_end/testcases/extensions/ambiguous.dart.strong.expect
index a54a55b..399704a 100644
--- a/pkg/front_end/testcases/extensions/ambiguous.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/ambiguous.dart.strong.expect
@@ -153,16 +153,16 @@
   synthetic constructor •() → self::C*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A on self::C* {
   method method = self::A|method;
diff --git a/pkg/front_end/testcases/extensions/ambiguous.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/ambiguous.dart.strong.transformed.expect
index a54a55b..399704a 100644
--- a/pkg/front_end/testcases/extensions/ambiguous.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/ambiguous.dart.strong.transformed.expect
@@ -153,16 +153,16 @@
   synthetic constructor •() → self::C*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A on self::C* {
   method method = self::A|method;
diff --git a/pkg/front_end/testcases/extensions/annotations.dart.outline.expect b/pkg/front_end/testcases/extensions/annotations.dart.outline.expect
index ff75d1b..2fe5083 100644
--- a/pkg/front_end/testcases/extensions/annotations.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/annotations.dart.outline.expect
@@ -11,16 +11,16 @@
   @core::pragma::_("dart2js:noInline")
   static method staticMethod() → dynamic
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method extensionInstanceMethod = self::Extension|extensionInstanceMethod;
diff --git a/pkg/front_end/testcases/extensions/annotations.dart.strong.expect b/pkg/front_end/testcases/extensions/annotations.dart.strong.expect
index 44c7c8a..8eb9132 100644
--- a/pkg/front_end/testcases/extensions/annotations.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/annotations.dart.strong.expect
@@ -10,16 +10,16 @@
   method instanceMethod() → dynamic {}
   @#C3
   static method staticMethod() → dynamic {}
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method extensionInstanceMethod = self::Extension|extensionInstanceMethod;
diff --git a/pkg/front_end/testcases/extensions/annotations.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/annotations.dart.strong.transformed.expect
index 44c7c8a..8eb9132 100644
--- a/pkg/front_end/testcases/extensions/annotations.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/annotations.dart.strong.transformed.expect
@@ -10,16 +10,16 @@
   method instanceMethod() → dynamic {}
   @#C3
   static method staticMethod() → dynamic {}
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method extensionInstanceMethod = self::Extension|extensionInstanceMethod;
diff --git a/pkg/front_end/testcases/extensions/call_methods.dart.outline.expect b/pkg/front_end/testcases/extensions/call_methods.dart.outline.expect
index f5610f5..c4b3280 100644
--- a/pkg/front_end/testcases/extensions/call_methods.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/call_methods.dart.outline.expect
@@ -7,32 +7,32 @@
     ;
   get call() → core::String*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B extends core::Object {
   synthetic constructor •() → self::B*
     ;
   get call() → () →* core::String*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension _extension#0 on core::int* {
   get call = self::_extension#0|get#call;
diff --git a/pkg/front_end/testcases/extensions/call_methods.dart.strong.expect b/pkg/front_end/testcases/extensions/call_methods.dart.strong.expect
index 6ad9135..387c002 100644
--- a/pkg/front_end/testcases/extensions/call_methods.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/call_methods.dart.strong.expect
@@ -101,16 +101,16 @@
     ;
   get call() → core::String*
     return "My name is A";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B extends core::Object {
   synthetic constructor •() → self::B*
@@ -118,16 +118,16 @@
     ;
   get call() → () →* core::String*
     return () → core::String* => "My name is B";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension _extension#0 on core::int* {
   get call = self::_extension#0|get#call;
diff --git a/pkg/front_end/testcases/extensions/check_bounds.dart.outline.expect b/pkg/front_end/testcases/extensions/check_bounds.dart.outline.expect
index 1a72e8b..abf68cd 100644
--- a/pkg/front_end/testcases/extensions/check_bounds.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/check_bounds.dart.outline.expect
@@ -6,16 +6,16 @@
 class A extends core::Object {
   synthetic constructor •() → self::A*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B extends self::A {
   synthetic constructor •() → self::B*
@@ -24,16 +24,16 @@
 class Class<T extends self::A* = self::A*> extends core::Object {
   synthetic constructor •() → self::Class<self::Class::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends self::B* = self::B*> on self::Class<T*>* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/check_bounds.dart.strong.expect b/pkg/front_end/testcases/extensions/check_bounds.dart.strong.expect
index 1d88a8a..f8cf127 100644
--- a/pkg/front_end/testcases/extensions/check_bounds.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/check_bounds.dart.strong.expect
@@ -811,16 +811,16 @@
   synthetic constructor •() → self::A*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B extends self::A {
   synthetic constructor •() → self::B*
@@ -831,16 +831,16 @@
   synthetic constructor •() → self::Class<self::Class::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends self::B* = self::B*> on self::Class<T*>* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/check_bounds.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/check_bounds.dart.strong.transformed.expect
index 1d88a8a..f8cf127 100644
--- a/pkg/front_end/testcases/extensions/check_bounds.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/check_bounds.dart.strong.transformed.expect
@@ -811,16 +811,16 @@
   synthetic constructor •() → self::A*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B extends self::A {
   synthetic constructor •() → self::B*
@@ -831,16 +831,16 @@
   synthetic constructor •() → self::Class<self::Class::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends self::B* = self::B*> on self::Class<T*>* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/compounds.dart.outline.expect b/pkg/front_end/testcases/extensions/compounds.dart.outline.expect
index a4408ae..4a17e87 100644
--- a/pkg/front_end/testcases/extensions/compounds.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/compounds.dart.outline.expect
@@ -12,43 +12,43 @@
     ;
   method toString() → core::String*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class extends core::Object {
   field self::Number* field;
   constructor •(self::Number* field) → self::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class IntClass extends core::Object {
   field core::int* field;
   constructor •(core::int* field) → self::IntClass*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension NumberExtension on self::Number* {
   operator + = self::NumberExtension|+;
diff --git a/pkg/front_end/testcases/extensions/compounds.dart.strong.expect b/pkg/front_end/testcases/extensions/compounds.dart.strong.expect
index b69e531..b8c8a05 100644
--- a/pkg/front_end/testcases/extensions/compounds.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/compounds.dart.strong.expect
@@ -13,45 +13,45 @@
     return other is self::Number* && this.{self::Number::value}.{core::num::==}(other{self::Number*}.{self::Number::value});
   method toString() → core::String*
     return "Number(${this.{self::Number::value}})";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class extends core::Object {
   field self::Number* field;
   constructor •(self::Number* field) → self::Class*
     : self::Class::field = field, super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class IntClass extends core::Object {
   field core::int* field;
   constructor •(core::int* field) → self::IntClass*
     : self::IntClass::field = field, super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension NumberExtension on self::Number* {
   operator + = self::NumberExtension|+;
diff --git a/pkg/front_end/testcases/extensions/compounds.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/compounds.dart.strong.transformed.expect
index b69e531..b8c8a05 100644
--- a/pkg/front_end/testcases/extensions/compounds.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/compounds.dart.strong.transformed.expect
@@ -13,45 +13,45 @@
     return other is self::Number* && this.{self::Number::value}.{core::num::==}(other{self::Number*}.{self::Number::value});
   method toString() → core::String*
     return "Number(${this.{self::Number::value}})";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class extends core::Object {
   field self::Number* field;
   constructor •(self::Number* field) → self::Class*
     : self::Class::field = field, super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class IntClass extends core::Object {
   field core::int* field;
   constructor •(core::int* field) → self::IntClass*
     : self::IntClass::field = field, super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension NumberExtension on self::Number* {
   operator + = self::NumberExtension|+;
diff --git a/pkg/front_end/testcases/extensions/conflicts.dart.outline.expect b/pkg/front_end/testcases/extensions/conflicts.dart.outline.expect
index 6fb3b5f..b200d91 100644
--- a/pkg/front_end/testcases/extensions/conflicts.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/conflicts.dart.outline.expect
@@ -22,30 +22,30 @@
 class Class1 extends core::Object {
   synthetic constructor •() → self::Class1*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class2 extends core::Object {
   synthetic constructor •() → self::Class2*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension DuplicateExtensionName on self::Class1* {
   method uniqueMethod1 = self::DuplicateExtensionName|uniqueMethod1;
diff --git a/pkg/front_end/testcases/extensions/conflicts.dart.strong.expect b/pkg/front_end/testcases/extensions/conflicts.dart.strong.expect
index 9764dae..e7354bb 100644
--- a/pkg/front_end/testcases/extensions/conflicts.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/conflicts.dart.strong.expect
@@ -29,31 +29,31 @@
   synthetic constructor •() → self::Class1*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class2 extends core::Object {
   synthetic constructor •() → self::Class2*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension DuplicateExtensionName on self::Class1* {
   method uniqueMethod1 = self::DuplicateExtensionName|uniqueMethod1;
diff --git a/pkg/front_end/testcases/extensions/conflicts.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/conflicts.dart.strong.transformed.expect
index 9764dae..e7354bb 100644
--- a/pkg/front_end/testcases/extensions/conflicts.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/conflicts.dart.strong.transformed.expect
@@ -29,31 +29,31 @@
   synthetic constructor •() → self::Class1*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class2 extends core::Object {
   synthetic constructor •() → self::Class2*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension DuplicateExtensionName on self::Class1* {
   method uniqueMethod1 = self::DuplicateExtensionName|uniqueMethod1;
diff --git a/pkg/front_end/testcases/extensions/default_values.dart.outline.expect b/pkg/front_end/testcases/extensions/default_values.dart.outline.expect
index 04ed817..ee79db6 100644
--- a/pkg/front_end/testcases/extensions/default_values.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/default_values.dart.outline.expect
@@ -5,16 +5,16 @@
 class Class extends core::Object {
   synthetic constructor •() → self::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method method0 = self::Extension|method0;
diff --git a/pkg/front_end/testcases/extensions/default_values.dart.strong.expect b/pkg/front_end/testcases/extensions/default_values.dart.strong.expect
index c31a720..77d66dc 100644
--- a/pkg/front_end/testcases/extensions/default_values.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/default_values.dart.strong.expect
@@ -6,16 +6,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method method0 = self::Extension|method0;
diff --git a/pkg/front_end/testcases/extensions/default_values.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/default_values.dart.strong.transformed.expect
index c31a720..77d66dc 100644
--- a/pkg/front_end/testcases/extensions/default_values.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/default_values.dart.strong.transformed.expect
@@ -6,16 +6,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method method0 = self::Extension|method0;
diff --git a/pkg/front_end/testcases/extensions/direct_instance_access.dart.outline.expect b/pkg/front_end/testcases/extensions/direct_instance_access.dart.outline.expect
index 2d17121..92cc66a 100644
--- a/pkg/front_end/testcases/extensions/direct_instance_access.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/direct_instance_access.dart.outline.expect
@@ -6,31 +6,31 @@
   field dynamic field;
   synthetic constructor •() → self::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   generic-covariant-impl field self::GenericClass::T* field;
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method readGetter = self::Extension|readGetter;
diff --git a/pkg/front_end/testcases/extensions/direct_instance_access.dart.strong.expect b/pkg/front_end/testcases/extensions/direct_instance_access.dart.strong.expect
index 17dadac..e2d649a 100644
--- a/pkg/front_end/testcases/extensions/direct_instance_access.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/direct_instance_access.dart.strong.expect
@@ -7,32 +7,32 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   generic-covariant-impl field self::GenericClass::T* field = null;
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method readGetter = self::Extension|readGetter;
diff --git a/pkg/front_end/testcases/extensions/direct_instance_access.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/direct_instance_access.dart.strong.transformed.expect
index 17dadac..e2d649a 100644
--- a/pkg/front_end/testcases/extensions/direct_instance_access.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/direct_instance_access.dart.strong.transformed.expect
@@ -7,32 +7,32 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   generic-covariant-impl field self::GenericClass::T* field = null;
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method readGetter = self::Extension|readGetter;
diff --git a/pkg/front_end/testcases/extensions/direct_static_access.dart.outline.expect b/pkg/front_end/testcases/extensions/direct_static_access.dart.outline.expect
index 7dd4ee1..bf7e89f 100644
--- a/pkg/front_end/testcases/extensions/direct_static_access.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/direct_static_access.dart.outline.expect
@@ -6,16 +6,16 @@
   static field dynamic field;
   synthetic constructor •() → self::Class<self::Class::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends core::Object* = dynamic> on self::Class<T*>* {
   static get property = get self::Extension|property;
diff --git a/pkg/front_end/testcases/extensions/direct_static_access.dart.strong.expect b/pkg/front_end/testcases/extensions/direct_static_access.dart.strong.expect
index 1a55006..c08eaf19 100644
--- a/pkg/front_end/testcases/extensions/direct_static_access.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/direct_static_access.dart.strong.expect
@@ -7,16 +7,16 @@
   synthetic constructor •() → self::Class<self::Class::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends core::Object* = dynamic> on self::Class<T*>* {
   static get property = get self::Extension|property;
diff --git a/pkg/front_end/testcases/extensions/direct_static_access.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/direct_static_access.dart.strong.transformed.expect
index 1a55006..c08eaf19 100644
--- a/pkg/front_end/testcases/extensions/direct_static_access.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/direct_static_access.dart.strong.transformed.expect
@@ -7,16 +7,16 @@
   synthetic constructor •() → self::Class<self::Class::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends core::Object* = dynamic> on self::Class<T*>* {
   static get property = get self::Extension|property;
diff --git a/pkg/front_end/testcases/extensions/dynamic_invoke.dart.outline.expect b/pkg/front_end/testcases/extensions/dynamic_invoke.dart.outline.expect
index a2ea0ee..166c1f6 100644
--- a/pkg/front_end/testcases/extensions/dynamic_invoke.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/dynamic_invoke.dart.outline.expect
@@ -7,15 +7,15 @@
     ;
   method noSuchMethod(core::Invocation* i) → dynamic
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension ClassExtension on self::Class* {
   method method = self::ClassExtension|method;
diff --git a/pkg/front_end/testcases/extensions/dynamic_invoke.dart.strong.expect b/pkg/front_end/testcases/extensions/dynamic_invoke.dart.strong.expect
index 627b139..964fb26 100644
--- a/pkg/front_end/testcases/extensions/dynamic_invoke.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/dynamic_invoke.dart.strong.expect
@@ -8,15 +8,15 @@
     ;
   method noSuchMethod(core::Invocation* i) → dynamic
     return 123;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension ClassExtension on self::Class* {
   method method = self::ClassExtension|method;
diff --git a/pkg/front_end/testcases/extensions/dynamic_invoke.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/dynamic_invoke.dart.strong.transformed.expect
index 627b139..964fb26 100644
--- a/pkg/front_end/testcases/extensions/dynamic_invoke.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/dynamic_invoke.dart.strong.transformed.expect
@@ -8,15 +8,15 @@
     ;
   method noSuchMethod(core::Invocation* i) → dynamic
     return 123;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension ClassExtension on self::Class* {
   method method = self::ClassExtension|method;
diff --git a/pkg/front_end/testcases/extensions/explicit_extension_access.dart.outline.expect b/pkg/front_end/testcases/extensions/explicit_extension_access.dart.outline.expect
index 293f3df..60d7163 100644
--- a/pkg/front_end/testcases/extensions/explicit_extension_access.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/explicit_extension_access.dart.outline.expect
@@ -7,16 +7,16 @@
   field core::int* field2;
   synthetic constructor •() → self::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class* {
   get field = self::Extension1|get#field;
diff --git a/pkg/front_end/testcases/extensions/explicit_extension_access.dart.strong.expect b/pkg/front_end/testcases/extensions/explicit_extension_access.dart.strong.expect
index 1de117d..b18b268 100644
--- a/pkg/front_end/testcases/extensions/explicit_extension_access.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/explicit_extension_access.dart.strong.expect
@@ -8,16 +8,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class* {
   get field = self::Extension1|get#field;
diff --git a/pkg/front_end/testcases/extensions/explicit_extension_access.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/explicit_extension_access.dart.strong.transformed.expect
index 47097a2..465effe 100644
--- a/pkg/front_end/testcases/extensions/explicit_extension_access.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/explicit_extension_access.dart.strong.transformed.expect
@@ -8,16 +8,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class* {
   get field = self::Extension1|get#field;
diff --git a/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.outline.expect b/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.outline.expect
index 21fc22e..5b69371 100644
--- a/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.outline.expect
@@ -5,16 +5,16 @@
 class A extends core::Object {
   synthetic constructor •() → self::A*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B extends self::A {
   synthetic constructor •() → self::B*
@@ -27,16 +27,16 @@
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension GenericExtension<T extends core::Object* = dynamic> on self::GenericClass<T*>* {
   get property = self::GenericExtension|get#property;
diff --git a/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.strong.expect b/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.strong.expect
index 3d6532f..d15b0fc 100644
--- a/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.strong.expect
@@ -6,16 +6,16 @@
   synthetic constructor •() → self::A*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B extends self::A {
   synthetic constructor •() → self::B*
@@ -31,16 +31,16 @@
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension GenericExtension<T extends core::Object* = dynamic> on self::GenericClass<T*>* {
   get property = self::GenericExtension|get#property;
diff --git a/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.strong.transformed.expect
index 3d6532f..d15b0fc 100644
--- a/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/explicit_extension_inference.dart.strong.transformed.expect
@@ -6,16 +6,16 @@
   synthetic constructor •() → self::A*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B extends self::A {
   synthetic constructor •() → self::B*
@@ -31,16 +31,16 @@
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension GenericExtension<T extends core::Object* = dynamic> on self::GenericClass<T*>* {
   get property = self::GenericExtension|get#property;
diff --git a/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.outline.expect b/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.outline.expect
index c63ea7d..fd4705e 100644
--- a/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.outline.expect
@@ -7,16 +7,16 @@
   generic-covariant-impl field self::Class::T* field2;
   constructor •(self::Class::T* field1, self::Class::T* field2) → self::Class<self::Class::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1<T extends core::num* = core::num*> on self::Class<T*>* {
   static field latestType = self::Extension1|latestType;
diff --git a/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.strong.expect b/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.strong.expect
index adc49e4..e7c4a0c 100644
--- a/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.strong.expect
@@ -8,16 +8,16 @@
   constructor •(self::Class::T* field1, self::Class::T* field2) → self::Class<self::Class::T*>*
     : self::Class::field1 = field1, self::Class::field2 = field2, super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1<T extends core::num* = core::num*> on self::Class<T*>* {
   static field latestType = self::Extension1|latestType;
diff --git a/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.strong.transformed.expect
index 7239cba..2782699 100644
--- a/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/explicit_generic_extension_access.dart.strong.transformed.expect
@@ -8,16 +8,16 @@
   constructor •(self::Class::T* field1, self::Class::T* field2) → self::Class<self::Class::T*>*
     : self::Class::field1 = field1, self::Class::field2 = field2, super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1<T extends core::num* = core::num*> on self::Class<T*>* {
   static field latestType = self::Extension1|latestType;
diff --git a/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.outline.expect b/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.outline.expect
index f5961c4..3d7ea6e 100644
--- a/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.outline.expect
@@ -5,16 +5,16 @@
 class Class extends core::Object {
   synthetic constructor •() → self::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
 }
diff --git a/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.strong.expect b/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.strong.expect
index f0bae7e..5c22ecf 100644
--- a/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.strong.expect
@@ -29,16 +29,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
 }
diff --git a/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.strong.transformed.expect
index f0bae7e..5c22ecf 100644
--- a/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/explicit_invalid_access.dart.strong.transformed.expect
@@ -29,16 +29,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
 }
diff --git a/pkg/front_end/testcases/extensions/explicit_this.dart.outline.expect b/pkg/front_end/testcases/extensions/explicit_this.dart.outline.expect
index fee8d56..42f3e5d 100644
--- a/pkg/front_end/testcases/extensions/explicit_this.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/explicit_this.dart.outline.expect
@@ -8,16 +8,16 @@
     ;
   method method1() → void
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A2 on self::A1* {
   method method2 = self::A2|method2;
diff --git a/pkg/front_end/testcases/extensions/explicit_this.dart.strong.expect b/pkg/front_end/testcases/extensions/explicit_this.dart.strong.expect
index ef5a89a..08b2bca 100644
--- a/pkg/front_end/testcases/extensions/explicit_this.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/explicit_this.dart.strong.expect
@@ -8,16 +8,16 @@
     : super core::Object::•()
     ;
   method method1() → void {}
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A2 on self::A1* {
   method method2 = self::A2|method2;
diff --git a/pkg/front_end/testcases/extensions/explicit_this.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/explicit_this.dart.strong.transformed.expect
index ef5a89a..08b2bca 100644
--- a/pkg/front_end/testcases/extensions/explicit_this.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/explicit_this.dart.strong.transformed.expect
@@ -8,16 +8,16 @@
     : super core::Object::•()
     ;
   method method1() → void {}
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A2 on self::A1* {
   method method2 = self::A2|method2;
diff --git a/pkg/front_end/testcases/extensions/export_twice.dart.outline.expect b/pkg/front_end/testcases/extensions/export_twice.dart.outline.expect
index 1ee21db..ef8bae9 100644
--- a/pkg/front_end/testcases/extensions/export_twice.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/export_twice.dart.outline.expect
@@ -14,16 +14,16 @@
 class Class extends core::Object {
   synthetic constructor •() → self2::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self2::Class* {
   method method = self2::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/export_twice.dart.strong.expect b/pkg/front_end/testcases/extensions/export_twice.dart.strong.expect
index bc0e513..cbd92ef 100644
--- a/pkg/front_end/testcases/extensions/export_twice.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/export_twice.dart.strong.expect
@@ -17,16 +17,16 @@
   synthetic constructor •() → exp::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on exp::Class* {
   method method = exp::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/export_twice.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/export_twice.dart.strong.transformed.expect
index bc0e513..cbd92ef 100644
--- a/pkg/front_end/testcases/extensions/export_twice.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/export_twice.dart.strong.transformed.expect
@@ -17,16 +17,16 @@
   synthetic constructor •() → exp::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on exp::Class* {
   method method = exp::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/extension_call.dart.outline.expect b/pkg/front_end/testcases/extensions/extension_call.dart.outline.expect
index b95b9c6..aebf9c6 100644
--- a/pkg/front_end/testcases/extensions/extension_call.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/extension_call.dart.outline.expect
@@ -7,16 +7,16 @@
     ;
   method method(generic-covariant-impl self::Class::T* a) → self::Class::T*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends core::Object* = dynamic> on self::Class<T*>* {
   method call = self::Extension|call;
diff --git a/pkg/front_end/testcases/extensions/extension_call.dart.strong.expect b/pkg/front_end/testcases/extensions/extension_call.dart.strong.expect
index 946cf57..46c2f58 100644
--- a/pkg/front_end/testcases/extensions/extension_call.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/extension_call.dart.strong.expect
@@ -8,16 +8,16 @@
     ;
   method method(generic-covariant-impl self::Class::T* a) → self::Class::T*
     return a;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends core::Object* = dynamic> on self::Class<T*>* {
   method call = self::Extension|call;
diff --git a/pkg/front_end/testcases/extensions/extension_call.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/extension_call.dart.strong.transformed.expect
index 946cf57..46c2f58 100644
--- a/pkg/front_end/testcases/extensions/extension_call.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/extension_call.dart.strong.transformed.expect
@@ -8,16 +8,16 @@
     ;
   method method(generic-covariant-impl self::Class::T* a) → self::Class::T*
     return a;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends core::Object* = dynamic> on self::Class<T*>* {
   method call = self::Extension|call;
diff --git a/pkg/front_end/testcases/extensions/extension_constructor.dart.outline.expect b/pkg/front_end/testcases/extensions/extension_constructor.dart.outline.expect
index 85085ee..dbb4f7d 100644
--- a/pkg/front_end/testcases/extensions/extension_constructor.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/extension_constructor.dart.outline.expect
@@ -42,16 +42,16 @@
 class Class extends core::Object {
   synthetic constructor •() → self::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/extension_constructor.dart.strong.expect b/pkg/front_end/testcases/extensions/extension_constructor.dart.strong.expect
index d5d8cb2..c1a2daf 100644
--- a/pkg/front_end/testcases/extensions/extension_constructor.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/extension_constructor.dart.strong.expect
@@ -43,16 +43,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/extension_constructor.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/extension_constructor.dart.strong.transformed.expect
index d5d8cb2..c1a2daf 100644
--- a/pkg/front_end/testcases/extensions/extension_constructor.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/extension_constructor.dart.strong.transformed.expect
@@ -43,16 +43,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/extension_methods.dart.outline.expect b/pkg/front_end/testcases/extensions/extension_methods.dart.outline.expect
index f327887..fe9807d 100644
--- a/pkg/front_end/testcases/extensions/extension_methods.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/extension_methods.dart.outline.expect
@@ -9,16 +9,16 @@
     ;
   get one() → core::int*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension E on self::C* {
   get two = self::E|get#two;
diff --git a/pkg/front_end/testcases/extensions/extension_methods.dart.strong.expect b/pkg/front_end/testcases/extensions/extension_methods.dart.strong.expect
index b6a1193..17c4511 100644
--- a/pkg/front_end/testcases/extensions/extension_methods.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/extension_methods.dart.strong.expect
@@ -11,16 +11,16 @@
     ;
   get one() → core::int*
     return 1;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension E on self::C* {
   get two = self::E|get#two;
diff --git a/pkg/front_end/testcases/extensions/extension_methods.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/extension_methods.dart.strong.transformed.expect
index b6a1193..17c4511 100644
--- a/pkg/front_end/testcases/extensions/extension_methods.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/extension_methods.dart.strong.transformed.expect
@@ -11,16 +11,16 @@
     ;
   get one() → core::int*
     return 1;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension E on self::C* {
   get two = self::E|get#two;
diff --git a/pkg/front_end/testcases/extensions/extension_setter.dart.outline.expect b/pkg/front_end/testcases/extensions/extension_setter.dart.outline.expect
index a46d986..aae8168 100644
--- a/pkg/front_end/testcases/extensions/extension_setter.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/extension_setter.dart.outline.expect
@@ -6,30 +6,30 @@
   field core::int* field;
   synthetic constructor •() → self::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   get simpleSetter = self::Extension|get#simpleSetter;
diff --git a/pkg/front_end/testcases/extensions/extension_setter.dart.strong.expect b/pkg/front_end/testcases/extensions/extension_setter.dart.strong.expect
index 98f08d2..a4bb6ed 100644
--- a/pkg/front_end/testcases/extensions/extension_setter.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/extension_setter.dart.strong.expect
@@ -7,31 +7,31 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   get simpleSetter = self::Extension|get#simpleSetter;
diff --git a/pkg/front_end/testcases/extensions/extension_setter.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/extension_setter.dart.strong.transformed.expect
index 245ead1..b951605 100644
--- a/pkg/front_end/testcases/extensions/extension_setter.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/extension_setter.dart.strong.transformed.expect
@@ -7,31 +7,31 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   get simpleSetter = self::Extension|get#simpleSetter;
diff --git a/pkg/front_end/testcases/extensions/extension_setter_error.dart.outline.expect b/pkg/front_end/testcases/extensions/extension_setter_error.dart.outline.expect
index 4044e84..1423f19 100644
--- a/pkg/front_end/testcases/extensions/extension_setter_error.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/extension_setter_error.dart.outline.expect
@@ -5,16 +5,16 @@
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension GenericExtension<T extends core::Object* = dynamic> on self::GenericClass<T*>* {
   set setter = self::GenericExtension|set#setter;
diff --git a/pkg/front_end/testcases/extensions/extension_setter_error.dart.strong.expect b/pkg/front_end/testcases/extensions/extension_setter_error.dart.strong.expect
index 917ce53..9e347d5 100644
--- a/pkg/front_end/testcases/extensions/extension_setter_error.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/extension_setter_error.dart.strong.expect
@@ -14,16 +14,16 @@
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension GenericExtension<T extends core::Object* = dynamic> on self::GenericClass<T*>* {
   set setter = self::GenericExtension|set#setter;
diff --git a/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.outline.expect b/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.outline.expect
index 6155609..54fb6a7d 100644
--- a/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.outline.expect
@@ -5,16 +5,16 @@
 class Class<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::Class<self::Class::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends core::Object* = dynamic> on self::Class<T*>* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.strong.expect b/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.strong.expect
index f7c38aa..2f09d15 100644
--- a/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.strong.expect
@@ -6,16 +6,16 @@
   synthetic constructor •() → self::Class<self::Class::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends core::Object* = dynamic> on self::Class<T*>* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.strong.transformed.expect
index f7c38aa..2f09d15 100644
--- a/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/generic_function_in_generic_extension.dart.strong.transformed.expect
@@ -6,16 +6,16 @@
   synthetic constructor •() → self::Class<self::Class::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<T extends core::Object* = dynamic> on self::Class<T*>* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.outline.expect b/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.outline.expect
index 9d49790..3b49162 100644
--- a/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.outline.expect
@@ -9,16 +9,16 @@
     ;
   set m2(core::int* x) → void
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension0 on self::Class* {
   get m2 = self::Extension0|get#m2;
diff --git a/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.strong.expect b/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.strong.expect
index 966e6eb..01b0f59 100644
--- a/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.strong.expect
@@ -72,16 +72,16 @@
   get m1() → core::int*
     return 0;
   set m2(core::int* x) → void {}
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension0 on self::Class* {
   get m2 = self::Extension0|get#m2;
diff --git a/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.strong.transformed.expect
index 966e6eb..01b0f59 100644
--- a/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/getter_setter_conflict.dart.strong.transformed.expect
@@ -72,16 +72,16 @@
   get m1() → core::int*
     return 0;
   set m2(core::int* x) → void {}
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension0 on self::Class* {
   get m2 = self::Extension0|get#m2;
diff --git a/pkg/front_end/testcases/extensions/if_null.dart.outline.expect b/pkg/front_end/testcases/extensions/if_null.dart.outline.expect
index 3d3aea8..793e929 100644
--- a/pkg/front_end/testcases/extensions/if_null.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/if_null.dart.outline.expect
@@ -6,16 +6,16 @@
   field core::int* field;
   synthetic constructor •() → self::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   get property = self::Extension|get#property;
diff --git a/pkg/front_end/testcases/extensions/if_null.dart.strong.expect b/pkg/front_end/testcases/extensions/if_null.dart.strong.expect
index 4a04ad0..3b988f9 100644
--- a/pkg/front_end/testcases/extensions/if_null.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/if_null.dart.strong.expect
@@ -7,16 +7,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   get property = self::Extension|get#property;
diff --git a/pkg/front_end/testcases/extensions/if_null.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/if_null.dart.strong.transformed.expect
index cd0b1b3..611d1c8 100644
--- a/pkg/front_end/testcases/extensions/if_null.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/if_null.dart.strong.transformed.expect
@@ -7,16 +7,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   get property = self::Extension|get#property;
diff --git a/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.outline.expect b/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.outline.expect
index 21fc22e..5b69371 100644
--- a/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.outline.expect
@@ -5,16 +5,16 @@
 class A extends core::Object {
   synthetic constructor •() → self::A*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B extends self::A {
   synthetic constructor •() → self::B*
@@ -27,16 +27,16 @@
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension GenericExtension<T extends core::Object* = dynamic> on self::GenericClass<T*>* {
   get property = self::GenericExtension|get#property;
diff --git a/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.strong.expect b/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.strong.expect
index e9f7f82..6d27bcd 100644
--- a/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.strong.expect
@@ -6,16 +6,16 @@
   synthetic constructor •() → self::A*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B extends self::A {
   synthetic constructor •() → self::B*
@@ -31,16 +31,16 @@
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension GenericExtension<T extends core::Object* = dynamic> on self::GenericClass<T*>* {
   get property = self::GenericExtension|get#property;
diff --git a/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.strong.transformed.expect
index e9f7f82..6d27bcd 100644
--- a/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/implicit_extension_inference.dart.strong.transformed.expect
@@ -6,16 +6,16 @@
   synthetic constructor •() → self::A*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B extends self::A {
   synthetic constructor •() → self::B*
@@ -31,16 +31,16 @@
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension GenericExtension<T extends core::Object* = dynamic> on self::GenericClass<T*>* {
   get property = self::GenericExtension|get#property;
diff --git a/pkg/front_end/testcases/extensions/implicit_this.dart.outline.expect b/pkg/front_end/testcases/extensions/implicit_this.dart.outline.expect
index fee8d56..42f3e5d 100644
--- a/pkg/front_end/testcases/extensions/implicit_this.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/implicit_this.dart.outline.expect
@@ -8,16 +8,16 @@
     ;
   method method1() → void
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A2 on self::A1* {
   method method2 = self::A2|method2;
diff --git a/pkg/front_end/testcases/extensions/implicit_this.dart.strong.expect b/pkg/front_end/testcases/extensions/implicit_this.dart.strong.expect
index ef5a89a..08b2bca 100644
--- a/pkg/front_end/testcases/extensions/implicit_this.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/implicit_this.dart.strong.expect
@@ -8,16 +8,16 @@
     : super core::Object::•()
     ;
   method method1() → void {}
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A2 on self::A1* {
   method method2 = self::A2|method2;
diff --git a/pkg/front_end/testcases/extensions/implicit_this.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/implicit_this.dart.strong.transformed.expect
index ef5a89a..08b2bca 100644
--- a/pkg/front_end/testcases/extensions/implicit_this.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/implicit_this.dart.strong.transformed.expect
@@ -8,16 +8,16 @@
     : super core::Object::•()
     ;
   method method1() → void {}
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A2 on self::A1* {
   method method2 = self::A2|method2;
diff --git a/pkg/front_end/testcases/extensions/index.dart.outline.expect b/pkg/front_end/testcases/extensions/index.dart.outline.expect
index da0ddd9..6e37096 100644
--- a/pkg/front_end/testcases/extensions/index.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/index.dart.outline.expect
@@ -10,16 +10,16 @@
     ;
   method put(generic-covariant-impl self::MapLike::K* key, generic-covariant-impl self::MapLike::V* value) → self::MapLike::V*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<K extends core::Object* = dynamic, V extends core::Object* = dynamic> on self::MapLike<K*, V*>* {
   operator [] = self::Extension|[];
diff --git a/pkg/front_end/testcases/extensions/index.dart.strong.expect b/pkg/front_end/testcases/extensions/index.dart.strong.expect
index 67d8909..27bbfae 100644
--- a/pkg/front_end/testcases/extensions/index.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/index.dart.strong.expect
@@ -11,16 +11,16 @@
     return this.{self::MapLike::_map}.{core::Map::[]}(key);
   method put(generic-covariant-impl self::MapLike::K* key, generic-covariant-impl self::MapLike::V* value) → self::MapLike::V*
     return let final core::Map<self::MapLike::K*, self::MapLike::V*>* #t1 = this.{self::MapLike::_map} in let final self::MapLike::K* #t2 = key in let final self::MapLike::V* #t3 = value in let final void #t4 = #t1.{core::Map::[]=}(#t2, #t3) in #t3;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<K extends core::Object* = dynamic, V extends core::Object* = dynamic> on self::MapLike<K*, V*>* {
   operator [] = self::Extension|[];
diff --git a/pkg/front_end/testcases/extensions/index.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/index.dart.strong.transformed.expect
index f406204..dadf664 100644
--- a/pkg/front_end/testcases/extensions/index.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/index.dart.strong.transformed.expect
@@ -11,16 +11,16 @@
     return this.{self::MapLike::_map}.{core::Map::[]}(key);
   method put(generic-covariant-impl self::MapLike::K* key, generic-covariant-impl self::MapLike::V* value) → self::MapLike::V*
     return let final core::Map<self::MapLike::K*, self::MapLike::V*>* #t1 = this.{self::MapLike::_map} in let final self::MapLike::K* #t2 = key in let final self::MapLike::V* #t3 = value in let final void #t4 = #t1.{core::Map::[]=}(#t2, #t3) in #t3;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension<K extends core::Object* = dynamic, V extends core::Object* = dynamic> on self::MapLike<K*, V*>* {
   operator [] = self::Extension|[];
diff --git a/pkg/front_end/testcases/extensions/instance_access.dart.outline.expect b/pkg/front_end/testcases/extensions/instance_access.dart.outline.expect
index 7bdfef2..4c95115 100644
--- a/pkg/front_end/testcases/extensions/instance_access.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/instance_access.dart.outline.expect
@@ -8,15 +8,15 @@
     ;
   method toString() → core::String*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class2 extends core::Object {
   field core::int* field;
@@ -24,15 +24,15 @@
     ;
   method toString() → core::String*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class1* {
   method method = self::Extension1|method;
diff --git a/pkg/front_end/testcases/extensions/instance_access.dart.strong.expect b/pkg/front_end/testcases/extensions/instance_access.dart.strong.expect
index ca462d0..d04e6106 100644
--- a/pkg/front_end/testcases/extensions/instance_access.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/instance_access.dart.strong.expect
@@ -9,15 +9,15 @@
     ;
   method toString() → core::String*
     return "Class1(${this.{self::Class1::field}})";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class2 extends core::Object {
   field core::int* field;
@@ -26,15 +26,15 @@
     ;
   method toString() → core::String*
     return "Class2(${this.{self::Class2::field}})";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class1* {
   method method = self::Extension1|method;
diff --git a/pkg/front_end/testcases/extensions/instance_access.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/instance_access.dart.strong.transformed.expect
index b117363..0a149ba 100644
--- a/pkg/front_end/testcases/extensions/instance_access.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/instance_access.dart.strong.transformed.expect
@@ -9,15 +9,15 @@
     ;
   method toString() → core::String*
     return "Class1(${this.{self::Class1::field}})";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class2 extends core::Object {
   field core::int* field;
@@ -26,15 +26,15 @@
     ;
   method toString() → core::String*
     return "Class2(${this.{self::Class2::field}})";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class1* {
   method method = self::Extension1|method;
diff --git a/pkg/front_end/testcases/extensions/instance_access_of_static.dart.outline.expect b/pkg/front_end/testcases/extensions/instance_access_of_static.dart.outline.expect
index e33cdbd..010dee1 100644
--- a/pkg/front_end/testcases/extensions/instance_access_of_static.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/instance_access_of_static.dart.outline.expect
@@ -5,16 +5,16 @@
 class Class1 extends core::Object {
   synthetic constructor •() → self::Class1*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class1* {
   static method staticMethod = self::Extension1|staticMethod;
diff --git a/pkg/front_end/testcases/extensions/instance_access_of_static.dart.strong.expect b/pkg/front_end/testcases/extensions/instance_access_of_static.dart.strong.expect
index 948d21b..edeff7b 100644
--- a/pkg/front_end/testcases/extensions/instance_access_of_static.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/instance_access_of_static.dart.strong.expect
@@ -45,16 +45,16 @@
   synthetic constructor •() → self::Class1*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class1* {
   static method staticMethod = self::Extension1|staticMethod;
diff --git a/pkg/front_end/testcases/extensions/instance_access_of_static.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/instance_access_of_static.dart.strong.transformed.expect
index 948d21b..edeff7b 100644
--- a/pkg/front_end/testcases/extensions/instance_access_of_static.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/instance_access_of_static.dart.strong.transformed.expect
@@ -45,16 +45,16 @@
   synthetic constructor •() → self::Class1*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class1* {
   static method staticMethod = self::Extension1|staticMethod;
diff --git a/pkg/front_end/testcases/extensions/instance_members.dart.outline.expect b/pkg/front_end/testcases/extensions/instance_members.dart.outline.expect
index 04be94e..78fd7df 100644
--- a/pkg/front_end/testcases/extensions/instance_members.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/instance_members.dart.outline.expect
@@ -5,30 +5,30 @@
 class A1 extends core::Object {
   synthetic constructor •() → self::A1*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B1<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::B1<self::B1::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A2 on self::A1* {
   method method1 = self::A2|method1;
diff --git a/pkg/front_end/testcases/extensions/instance_members.dart.strong.expect b/pkg/front_end/testcases/extensions/instance_members.dart.strong.expect
index 72cb315d..df3a40c 100644
--- a/pkg/front_end/testcases/extensions/instance_members.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/instance_members.dart.strong.expect
@@ -6,31 +6,31 @@
   synthetic constructor •() → self::A1*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B1<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::B1<self::B1::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A2 on self::A1* {
   method method1 = self::A2|method1;
diff --git a/pkg/front_end/testcases/extensions/instance_members.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/instance_members.dart.strong.transformed.expect
index 72cb315d..df3a40c 100644
--- a/pkg/front_end/testcases/extensions/instance_members.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/instance_members.dart.strong.transformed.expect
@@ -6,31 +6,31 @@
   synthetic constructor •() → self::A1*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class B1<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::B1<self::B1::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension A2 on self::A1* {
   method method1 = self::A2|method1;
diff --git a/pkg/front_end/testcases/extensions/instance_tearoff.dart.outline.expect b/pkg/front_end/testcases/extensions/instance_tearoff.dart.outline.expect
index 08380b2..4486c85 100644
--- a/pkg/front_end/testcases/extensions/instance_tearoff.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/instance_tearoff.dart.outline.expect
@@ -8,15 +8,15 @@
     ;
   method toString() → core::String*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class2 extends core::Object {
   field core::int* field;
@@ -24,15 +24,15 @@
     ;
   method toString() → core::String*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class1* {
   method method = self::Extension1|method;
diff --git a/pkg/front_end/testcases/extensions/instance_tearoff.dart.strong.expect b/pkg/front_end/testcases/extensions/instance_tearoff.dart.strong.expect
index 9508bad..8bc8b21 100644
--- a/pkg/front_end/testcases/extensions/instance_tearoff.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/instance_tearoff.dart.strong.expect
@@ -9,15 +9,15 @@
     ;
   method toString() → core::String*
     return "Class1(${this.{self::Class1::field}})";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class2 extends core::Object {
   field core::int* field;
@@ -26,15 +26,15 @@
     ;
   method toString() → core::String*
     return "Class2(${this.{self::Class2::field}})";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class1* {
   method method = self::Extension1|method;
diff --git a/pkg/front_end/testcases/extensions/instance_tearoff.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/instance_tearoff.dart.strong.transformed.expect
index aabacb2..1083c18 100644
--- a/pkg/front_end/testcases/extensions/instance_tearoff.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/instance_tearoff.dart.strong.transformed.expect
@@ -9,15 +9,15 @@
     ;
   method toString() → core::String*
     return "Class1(${this.{self::Class1::field}})";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class Class2 extends core::Object {
   field core::int* field;
@@ -26,15 +26,15 @@
     ;
   method toString() → core::String*
     return "Class2(${this.{self::Class2::field}})";
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::Class1* {
   method method = self::Extension1|method;
diff --git a/pkg/front_end/testcases/extensions/internal_resolution.dart.outline.expect b/pkg/front_end/testcases/extensions/internal_resolution.dart.outline.expect
index 1c64152..4ea05c6 100644
--- a/pkg/front_end/testcases/extensions/internal_resolution.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/internal_resolution.dart.outline.expect
@@ -6,16 +6,16 @@
   field core::int* field;
   synthetic constructor •() → self::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension _extension#0 on self::Class* {
   get property1 = self::_extension#0|get#property1;
diff --git a/pkg/front_end/testcases/extensions/internal_resolution.dart.strong.expect b/pkg/front_end/testcases/extensions/internal_resolution.dart.strong.expect
index dadb2db..36d8d33 100644
--- a/pkg/front_end/testcases/extensions/internal_resolution.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/internal_resolution.dart.strong.expect
@@ -7,16 +7,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension _extension#0 on self::Class* {
   get property1 = self::_extension#0|get#property1;
diff --git a/pkg/front_end/testcases/extensions/internal_resolution.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/internal_resolution.dart.strong.transformed.expect
index d9024f1..311c941 100644
--- a/pkg/front_end/testcases/extensions/internal_resolution.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/internal_resolution.dart.strong.transformed.expect
@@ -7,16 +7,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension _extension#0 on self::Class* {
   get property1 = self::_extension#0|get#property1;
diff --git a/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.outline.expect b/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.outline.expect
index 0b7201a..bbcd313 100644
--- a/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.outline.expect
@@ -5,30 +5,30 @@
 class Class extends core::Object {
   synthetic constructor •() → self::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.strong.expect b/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.strong.expect
index 431609f..4aa3725 100644
--- a/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.strong.expect
@@ -128,31 +128,31 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.strong.transformed.expect
index 431609f..4aa3725 100644
--- a/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/invalid_explicit_access.dart.strong.transformed.expect
@@ -128,31 +128,31 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 class GenericClass<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::GenericClass<self::GenericClass::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method method = self::Extension|method;
diff --git a/pkg/front_end/testcases/extensions/issue38600.dart.outline.expect b/pkg/front_end/testcases/extensions/issue38600.dart.outline.expect
index ed495ec..fbece28 100644
--- a/pkg/front_end/testcases/extensions/issue38600.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/issue38600.dart.outline.expect
@@ -51,16 +51,16 @@
 class Class<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::Class<self::Class::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension _extension#0 on invalid-type {
 }
diff --git a/pkg/front_end/testcases/extensions/issue38600.dart.strong.expect b/pkg/front_end/testcases/extensions/issue38600.dart.strong.expect
index 373bda2..af7f9d0 100644
--- a/pkg/front_end/testcases/extensions/issue38600.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/issue38600.dart.strong.expect
@@ -52,16 +52,16 @@
   synthetic constructor •() → self::Class<self::Class::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension _extension#0 on invalid-type {
 }
diff --git a/pkg/front_end/testcases/extensions/issue38600.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/issue38600.dart.strong.transformed.expect
index 373bda2..af7f9d0 100644
--- a/pkg/front_end/testcases/extensions/issue38600.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/issue38600.dart.strong.transformed.expect
@@ -52,16 +52,16 @@
   synthetic constructor •() → self::Class<self::Class::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension _extension#0 on invalid-type {
 }
diff --git a/pkg/front_end/testcases/extensions/issue38745.dart.outline.expect b/pkg/front_end/testcases/extensions/issue38745.dart.outline.expect
index 166ad22..83e0f7d 100644
--- a/pkg/front_end/testcases/extensions/issue38745.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/issue38745.dart.outline.expect
@@ -31,16 +31,16 @@
 class C<T extends core::Object* = dynamic> extends core::Object {
   synthetic constructor •() → self::C<self::C::T*>*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension ext<T extends core::Object* = dynamic> on self::C<T*>* {
   field field = self::ext|field;
diff --git a/pkg/front_end/testcases/extensions/issue38745.dart.strong.expect b/pkg/front_end/testcases/extensions/issue38745.dart.strong.expect
index 40c2392..ffc0450 100644
--- a/pkg/front_end/testcases/extensions/issue38745.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/issue38745.dart.strong.expect
@@ -102,16 +102,16 @@
   synthetic constructor •() → self::C<self::C::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension ext<T extends core::Object* = dynamic> on self::C<T*>* {
   field field = self::ext|field;
diff --git a/pkg/front_end/testcases/extensions/issue38745.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/issue38745.dart.strong.transformed.expect
index 40c2392..ffc0450 100644
--- a/pkg/front_end/testcases/extensions/issue38745.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/issue38745.dart.strong.transformed.expect
@@ -102,16 +102,16 @@
   synthetic constructor •() → self::C<self::C::T*>*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension ext<T extends core::Object* = dynamic> on self::C<T*>* {
   field field = self::ext|field;
diff --git a/pkg/front_end/testcases/extensions/issue38750.dart.outline.expect b/pkg/front_end/testcases/extensions/issue38750.dart.outline.expect
index 30d8538..849d249 100644
--- a/pkg/front_end/testcases/extensions/issue38750.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/issue38750.dart.outline.expect
@@ -24,16 +24,16 @@
     ;
   static method staticFoo() → dynamic
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension ext on self2::C* {
   method _bar = self2::ext|_bar;
diff --git a/pkg/front_end/testcases/extensions/issue38750.dart.strong.expect b/pkg/front_end/testcases/extensions/issue38750.dart.strong.expect
index ed20ca4..d6f688c 100644
--- a/pkg/front_end/testcases/extensions/issue38750.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/issue38750.dart.strong.expect
@@ -67,16 +67,16 @@
   }
   static method staticFoo() → dynamic
     return iss::C::_staticFoo();
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension ext on iss::C* {
   method _bar = iss::ext|_bar;
diff --git a/pkg/front_end/testcases/extensions/issue38750.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/issue38750.dart.strong.transformed.expect
index ed20ca4..d6f688c 100644
--- a/pkg/front_end/testcases/extensions/issue38750.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/issue38750.dart.strong.transformed.expect
@@ -67,16 +67,16 @@
   }
   static method staticFoo() → dynamic
     return iss::C::_staticFoo();
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension ext on iss::C* {
   method _bar = iss::ext|_bar;
diff --git a/pkg/front_end/testcases/extensions/issue38915.dart.outline.expect b/pkg/front_end/testcases/extensions/issue38915.dart.outline.expect
index 6231a80..623d69d 100644
--- a/pkg/front_end/testcases/extensions/issue38915.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/issue38915.dart.outline.expect
@@ -5,16 +5,16 @@
 class Class extends core::Object {
   synthetic constructor •() → self::Class*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method method1 = self::Extension|method1;
diff --git a/pkg/front_end/testcases/extensions/issue38915.dart.strong.expect b/pkg/front_end/testcases/extensions/issue38915.dart.strong.expect
index 59a9add..1326d70 100644
--- a/pkg/front_end/testcases/extensions/issue38915.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/issue38915.dart.strong.expect
@@ -6,16 +6,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method method1 = self::Extension|method1;
diff --git a/pkg/front_end/testcases/extensions/issue38915.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/issue38915.dart.strong.transformed.expect
index 59a9add..1326d70 100644
--- a/pkg/front_end/testcases/extensions/issue38915.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/issue38915.dart.strong.transformed.expect
@@ -6,16 +6,16 @@
   synthetic constructor •() → self::Class*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension on self::Class* {
   method method1 = self::Extension|method1;
diff --git a/pkg/front_end/testcases/extensions/issue39527.dart.outline.expect b/pkg/front_end/testcases/extensions/issue39527.dart.outline.expect
index 1055553..9ffdbaa 100644
--- a/pkg/front_end/testcases/extensions/issue39527.dart.outline.expect
+++ b/pkg/front_end/testcases/extensions/issue39527.dart.outline.expect
@@ -6,16 +6,16 @@
   field core::int* value;
   synthetic constructor •() → self::C*
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::C* {
   operator [] = self::Extension1|[];
diff --git a/pkg/front_end/testcases/extensions/issue39527.dart.strong.expect b/pkg/front_end/testcases/extensions/issue39527.dart.strong.expect
index 32a70a4..36552a6 100644
--- a/pkg/front_end/testcases/extensions/issue39527.dart.strong.expect
+++ b/pkg/front_end/testcases/extensions/issue39527.dart.strong.expect
@@ -7,16 +7,16 @@
   synthetic constructor •() → self::C*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ runtimeType() → core::Type*; -> core::Object::runtimeType
 }
 extension Extension1 on self::C* {
   operator [] = self::Extension1|[];
diff --git a/pkg/front_end/testcases/extensions/issue39527.dart.strong.transformed.expect b/pkg/front_end/testcases/extensions/issue39527.dart.strong.transformed.expect
index a4adb78..9a913e5 100644
--- a/pkg/front_end/testcases/extensions/issue39527.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/extensions/issue39527.dart.strong.transformed.expect
@@ -7,16 +7,16 @@
   synthetic constructor •() → self::C*
     : super core::Object::•()
     ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _identityHashCode() → core::int*; -> core::Object::_identityHashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
+  abstract member-signature operator /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ ==(dynamic other) → core::bool*; -> core::Object::==
+  abstract member-signature get /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ hashCode() → core::int*; -> core::Object::hashCode
+  abstract member-signature method /* from org-dartlang-sdk:///sdk/lib/_internal/vm/lib/object_patch.dart */ toString() → core::String*; -> core::Object::toString
+  abstract member-signature method /* from org-dartlang-sdk:///s