Version 2.18.0-5.0.dev

Merge commit '30413a1c5fb4ea399abda158123342002faa89d6' into 'dev'
diff --git a/.dart_tool/package_config.json b/.dart_tool/package_config.json
index 66edc3a..c37cde6 100644
--- a/.dart_tool/package_config.json
+++ b/.dart_tool/package_config.json
@@ -183,7 +183,7 @@
       "name": "compiler",
       "rootUri": "../pkg/compiler",
       "packageUri": "lib/",
-      "languageVersion": "2.6"
+      "languageVersion": "2.16"
     },
     {
       "name": "convert",
diff --git a/pkg/compiler/lib/src/commandline_options.dart b/pkg/compiler/lib/src/commandline_options.dart
index 6a7da07..6f7a96a 100644
--- a/pkg/compiler/lib/src/commandline_options.dart
+++ b/pkg/compiler/lib/src/commandline_options.dart
@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// @dart=2.12
-
 library dart2js.cmdline.options;
 
 /// Commandline flags used in `dart2js.dart` and/or `apiimpl.dart`.
diff --git a/pkg/compiler/lib/src/options.dart b/pkg/compiler/lib/src/options.dart
index 23f019d..70860ff 100644
--- a/pkg/compiler/lib/src/options.dart
+++ b/pkg/compiler/lib/src/options.dart
@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// @dart=2.12
-
 library dart2js.src.options;
 
 import 'package:front_end/src/api_unstable/dart2js.dart' as fe;
diff --git a/pkg/compiler/lib/src/util/command_line.dart b/pkg/compiler/lib/src/util/command_line.dart
index e1da5b8..8bd13a1 100644
--- a/pkg/compiler/lib/src/util/command_line.dart
+++ b/pkg/compiler/lib/src/util/command_line.dart
@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// @dart=2.12
-
 library dart2js.util.command_line;
 
 /// The accepted escapes in the input of the --batch processor.
diff --git a/pkg/compiler/lib/src/util/enumset.dart b/pkg/compiler/lib/src/util/enumset.dart
index e301cf4..520fb98 100644
--- a/pkg/compiler/lib/src/util/enumset.dart
+++ b/pkg/compiler/lib/src/util/enumset.dart
@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// @dart=2.12
-
 library dart2js.util.enumset;
 
 import 'dart:collection';
diff --git a/pkg/compiler/lib/src/util/maplet.dart b/pkg/compiler/lib/src/util/maplet.dart
index 1afe289..4aca54b 100644
--- a/pkg/compiler/lib/src/util/maplet.dart
+++ b/pkg/compiler/lib/src/util/maplet.dart
@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// @dart=2.12
-
 library dart2js.util.maplet;
 
 import 'dart:collection' show MapBase, IterableBase;
diff --git a/pkg/compiler/lib/src/util/setlet.dart b/pkg/compiler/lib/src/util/setlet.dart
index f44b330..4b21f35 100644
--- a/pkg/compiler/lib/src/util/setlet.dart
+++ b/pkg/compiler/lib/src/util/setlet.dart
@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// @dart=2.12
-
 library dart2js.util.setlet;
 
 import 'dart:collection' show SetBase;
diff --git a/pkg/compiler/lib/src/util/testing.dart b/pkg/compiler/lib/src/util/testing.dart
index 405d495..bc19e92 100644
--- a/pkg/compiler/lib/src/util/testing.dart
+++ b/pkg/compiler/lib/src/util/testing.dart
@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// @dart = 2.15
-
 /// Marks its argument as live and prevents tree-shaking.
 ///
 /// This is more hermetic than using `package:expect` or `print`. This function
diff --git a/pkg/compiler/lib/src/util/util.dart b/pkg/compiler/lib/src/util/util.dart
index c9fa382..8943c58 100644
--- a/pkg/compiler/lib/src/util/util.dart
+++ b/pkg/compiler/lib/src/util/util.dart
@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// @dart=2.12
-
 library dart2js.util;
 
 import 'package:front_end/src/api_unstable/dart2js.dart'
diff --git a/pkg/compiler/pubspec.yaml b/pkg/compiler/pubspec.yaml
index e9e7fd7..6a45f08 100644
--- a/pkg/compiler/pubspec.yaml
+++ b/pkg/compiler/pubspec.yaml
@@ -4,7 +4,7 @@
 # This package is not intended for consumption on pub.dev. DO NOT publish.
 publish_to: none
 environment:
-  sdk: '>=2.6.0 <3.0.0'
+  sdk: '>=2.16.0 <3.0.0'
 
 # NOTE: `pub get / pub upgrade` are generally not needed when working on this
 # package. The `.packages` file in the repository root will be used by default.
diff --git a/tools/VERSION b/tools/VERSION
index 9df6a11..a959df0 100644
--- a/tools/VERSION
+++ b/tools/VERSION
@@ -27,5 +27,5 @@
 MAJOR 2
 MINOR 18
 PATCH 0
-PRERELEASE 4
+PRERELEASE 5
 PRERELEASE_PATCH 0
\ No newline at end of file