[cfe] Add symbolic language versions for testing

Change-Id: I0f8bb91d30fac442d781710b24908cd933d86388 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/365142 Reviewed-by: Jens Johansen <jensj@google.com> Commit-Queue: Johnni Winther <johnniwinther@google.com>
2024-09-16 00:09:49 +00:00 · 2024-05-01 13:11:10 +00:00 · 2024-05-01 13:11:10 +00:00 · 3c9d05f255
parent 36fb02deca
commit 3c9d05f255
96 changed files with 273 additions and 168 deletions
--- a/pkg/_fe_analyzer_shared/lib/src/testing/id_generation.dart
+++ b/pkg/_fe_analyzer_shared/lib/src/testing/id_generation.dart
@ -6,6 +6,8 @@ import 'package:_fe_analyzer_shared/src/testing/annotated_code_helper.dart';
 import 'package:_fe_analyzer_shared/src/testing/id.dart';
 import 'package:_fe_analyzer_shared/src/testing/id_testing.dart';

+String _noProcessing(String text) => text;
+
 Map<Uri, List<Annotation>> computeAnnotationsPerUri<T>(
    Map<Uri, AnnotatedCode> annotatedCode,
    Map<String, MemberAnnotations<IdValue>> expectedMaps,
@ -13,7 +15,8 @@ Map<Uri, List<Annotation>> computeAnnotationsPerUri<T>(
    Map<String, Map<Uri, Map<Id, ActualData<T>>>> actualData,
    DataInterpreter<T> dataInterpreter,
    {Annotation? Function(Annotation? expected, Annotation? actual)? createDiff,
-    bool forceUpdate = false}) {
+    bool forceUpdate = false,
+    String Function(String) postProcessData = _noProcessing}) {
  Set<Uri> uriSet = {};
  Set<String> actualMarkers = actualData.keys.toSet();
  Map<Uri, Map<Id, Map<String, IdValue>>> idValuePerUri = {};
@ -64,7 +67,10 @@ Map<Uri, List<Annotation>> computeAnnotationsPerUri<T>(
      // Annotations are not computed from synthesized code.
      result[uri] = _computeAnnotations(code, expectedMaps.keys, actualMarkers,
          idValuePerId, actualDataPerId, dataInterpreter,
-          sortMarkers: false, createDiff: createDiff, forceUpdate: forceUpdate);
+          sortMarkers: false,
+          createDiff: createDiff,
+          forceUpdate: forceUpdate,
+          postProcessData: postProcessData);
    }
  }
  return result;
@ -81,7 +87,8 @@ List<Annotation> _computeAnnotations<T>(
    String defaultSuffix = '*/',
    bool sortMarkers = true,
    Annotation? Function(Annotation? expected, Annotation? actual)? createDiff,
-    bool forceUpdate = false}) {
+    bool forceUpdate = false,
+    required String Function(String) postProcessData}) {
  Annotation createAnnotationFromData(
      ActualData<T> actualData, Annotation? annotation) {
    String getIndentationFromOffset(int offset) {
@ -142,8 +149,10 @@ List<Annotation> _computeAnnotations<T>(
        annotation?.columnNo ?? -1,
        offset,
        prefix,
-        IdValue.idToString(actualData.id,
-            dataInterpreter.getText(actualData.value, indentation)),
+        IdValue.idToString(
+            actualData.id,
+            postProcessData(
+                dataInterpreter.getText(actualData.value, indentation))),
        suffix);
  }

--- a/pkg/_fe_analyzer_shared/lib/src/testing/id_testing.dart
+++ b/pkg/_fe_analyzer_shared/lib/src/testing/id_testing.dart
@ -263,6 +263,7 @@ TestData computeTestData(FileSystemEntity testFile,
    {required Iterable<String> supportedMarkers,
    required Uri createTestUri(Uri uri, String fileName),
    required void onFailure(String message),
+    String Function(String) preprocessFile = _noProcessing,
    bool preserveWhitespaceInAnnotations = false,
    bool preserveInfixWhitespaceInAnnotations = false}) {
  Uri? entryPoint;
@ -296,7 +297,8 @@ TestData computeTestData(FileSystemEntity testFile,
    throw new UnimplementedError();
  }

-  String annotatedCode = new File.fromUri(mainTestFile!.uri).readAsStringSync();
+  String annotatedCode =
+      preprocessFile(new File.fromUri(mainTestFile!.uri).readAsStringSync());
  Map<Uri, AnnotatedCode> code = {
    entryPoint!:
        new AnnotatedCode.fromText(annotatedCode, commentStart, commentEnd)
@ -320,7 +322,7 @@ TestData computeTestData(FileSystemEntity testFile,
      String libFileName = additionalFileData.key;
      File libEntity = additionalFileData.value;
      Uri libFileUri = createTestUri(libEntity.uri, libFileName);
-      String libCode = libEntity.readAsStringSync();
+      String libCode = preprocessFile(libEntity.readAsStringSync());
      AnnotatedCode annotatedLibCode =
          new AnnotatedCode.fromText(libCode, commentStart, commentEnd);
      memorySourceFiles[libFileUri.path] = annotatedLibCode.sourceCode;
@ -820,6 +822,8 @@ const List<Option> idTestOptions = [
  Options.forceUpdate,
 ];

+String _noProcessing(String s) => s;
+
 /// Check code for all tests in [dataDir] using [runTest].
 Future<void> runTests<T>(Directory dataDir,
    {List<String> args = const <String>[],
@ -832,7 +836,9 @@ Future<void> runTests<T>(Directory dataDir,
    List<String>? skipList,
    Map<String, List<String>>? skipMap,
    bool preserveWhitespaceInAnnotations = false,
-    bool preserveInfixWhitespaceInAnnotations = false}) async {
+    bool preserveInfixWhitespaceInAnnotations = false,
+    String Function(String) preprocessFile = _noProcessing,
+    String Function(String) postProcessData = _noProcessing}) async {
  ParsedOptions parsedOptions = ParsedOptions.parse(args, idTestOptions);
  MarkerOptions markerOptions =
      new MarkerOptions.fromDataDir(dataDir, shouldFindScript: shards == 1);
@ -903,7 +909,8 @@ Future<void> runTests<T>(Directory dataDir,
        onFailure: onFailure,
        preserveWhitespaceInAnnotations: preserveWhitespaceInAnnotations,
        preserveInfixWhitespaceInAnnotations:
-            preserveInfixWhitespaceInAnnotations);
+            preserveInfixWhitespaceInAnnotations,
+        preprocessFile: preprocessFile);
    print('Test: ${testData.testFileUri}');

    Map<String, TestResult<T>> results = await runTest(markerOptions, testData,
@ -966,7 +973,8 @@ Future<void> runTests<T>(Directory dataDir,
            testData.entryPoint,
            actualData,
            dataInterpreter!,
-            forceUpdate: forceUpdate);
+            forceUpdate: forceUpdate,
+            postProcessData: postProcessData);
        annotations.forEach((Uri uri, List<Annotation> annotations) {
          AnnotatedCode? code = testData.code[uri];
          assert(code != null,
--- a/pkg/front_end/test/incremental_suite.dart
+++ b/pkg/front_end/test/incremental_suite.dart
@ -74,6 +74,7 @@ import "incremental_utils.dart" as util;
 import 'test_utils.dart';
 import 'testing_utils.dart' show checkEnvironment;
 import 'utils/io_utils.dart' show computeRepoDir;
+import 'utils/symbolic_language_versions.dart';
 import 'utils/values.dart';

 void main([List<String> arguments = const []]) => internalMain(createContext,
@ -772,14 +773,6 @@ Future<Map<String, List<int>>> createModules(
  return moduleResult;
 }

-String doStringReplacements(String input) {
-  Version enableNonNullableVersion =
-      ExperimentalFlag.nonNullable.experimentEnabledVersion;
-  String output = input.replaceAll("%NNBD_VERSION_MARKER%",
-      "${enableNonNullableVersion.major}.${enableNonNullableVersion.minor}");
-  return output;
-}
-
 class ExpressionCompilation {
  final bool errors;
  final bool warnings;
@ -1250,7 +1243,7 @@ class NewWorldTest {
          packagesUri = uri;
        }
        if (world.enableStringReplacement) {
-          data = doStringReplacements(data);
+          data = replaceMarkersWithVersions(data);
        }
        fs.entityForUri(uri).writeAsStringSync(data);
      }
--- a/pkg/front_end/test/language_versioning/data/allowed_experiments_with_json/foo/bin/bin_file.dart
+++ b/pkg/front_end/test/language_versioning/data/allowed_experiments_with_json/foo/bin/bin_file.dart
@ -3,7 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.

 /*library: 
- languageVersion=2.8,
+ languageVersion=%CURRENT_VERSION_MARKER%,
 packageUri=package:collection
 */

--- a/pkg/front_end/test/language_versioning/data/allowed_experiments_with_json/foo/lib/foo.dart
+++ b/pkg/front_end/test/language_versioning/data/allowed_experiments_with_json/foo/lib/foo.dart
@ -2,6 +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.

-/*library: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 method2() {}
--- a/pkg/front_end/test/language_versioning/data/allowed_experiments_with_json/foo/test/test_file.dart
+++ b/pkg/front_end/test/language_versioning/data/allowed_experiments_with_json/foo/test/test_file.dart
@ -3,7 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.

 /*library: 
- languageVersion=2.8,
+ languageVersion=%CURRENT_VERSION_MARKER%,
 packageUri=package:collection
 */

--- a/pkg/front_end/test/language_versioning/data/allowed_experiments_with_json/main.dart
+++ b/pkg/front_end/test/language_versioning/data/allowed_experiments_with_json/main.dart
@ -2,7 +2,7 @@
 // for 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: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 import 'foo/bin/bin_file.dart';
 import 'foo/test/test_file.dart';
--- a/pkg/front_end/test/language_versioning/data/both_packages_and_json/foo2/foo.dart
+++ b/pkg/front_end/test/language_versioning/data/both_packages_and_json/foo2/foo.dart
@ -1,4 +1,4 @@
-/*library: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 String foo() {
  return "42";
--- a/pkg/front_end/test/language_versioning/data/both_packages_and_json/main.dart
+++ b/pkg/front_end/test/language_versioning/data/both_packages_and_json/main.dart
@ -5,11 +5,11 @@
 // Set version of this file (not technically in package) explicitly to test as
 // much as possibly separately.

-// @dart = 2.4
+// @dart = %VERSION_MARKER0%

 import 'package:foo/foo.dart';

-/*library: languageVersion=2.4*/
+/*library: languageVersion=%VERSION_MARKER0%*/

 main() {
  var result = foo();
--- a/pkg/front_end/test/language_versioning/data/issue42661a/.dart_tool/package_config.json
+++ b/pkg/front_end/test/language_versioning/data/issue42661a/.dart_tool/package_config.json
@ -4,7 +4,7 @@
    {
      "name": "pack",
      "rootUri": "../pack/lib/",
-      "languageVersion": "2.7"
+      "languageVersion": "%VERSION_MARKER2%"
    }
  ]
 }
--- a/pkg/front_end/test/language_versioning/data/issue42661a/main.dart
+++ b/pkg/front_end/test/language_versioning/data/issue42661a/main.dart
@ -1,3 +1,3 @@
-/*library: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 import 'pack/web/pack.dart';
--- a/pkg/front_end/test/language_versioning/data/issue42661a/pack/web/pack.dart
+++ b/pkg/front_end/test/language_versioning/data/issue42661a/pack/web/pack.dart
@ -1,4 +1,4 @@
-/*library: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/
 library pack;

 part /*error: errors=LanguageVersionMismatchInPart*/ 'package:pack/src/part.dart';
--- a/pkg/front_end/test/language_versioning/data/issue42661b/.dart_tool/package_config.json
+++ b/pkg/front_end/test/language_versioning/data/issue42661b/.dart_tool/package_config.json
@ -5,7 +5,7 @@
      "name": "pack",
      "rootUri": "../",
      "packageUri": "lib/",
-      "languageVersion": "2.7"
+      "languageVersion": "%VERSION_MARKER2%"
    }
  ]
 }
--- a/pkg/front_end/test/language_versioning/data/issue42661b/main.dart
+++ b/pkg/front_end/test/language_versioning/data/issue42661b/main.dart
@ -1,5 +1,5 @@
 /*library: 
- languageVersion=2.7,
+ languageVersion=%VERSION_MARKER2%,
 packageUri=package:pack
 */

--- a/pkg/front_end/test/language_versioning/data/issue42661b/web/pack.dart
+++ b/pkg/front_end/test/language_versioning/data/issue42661b/web/pack.dart
@ -1,5 +1,5 @@
 /*library: 
- languageVersion=2.7,
+ languageVersion=%VERSION_MARKER2%,
 packageUri=package:pack
 */
 library pack;
--- a/pkg/front_end/test/language_versioning/data/library_with_bad_version.dart
+++ b/pkg/front_end/test/language_versioning/data/library_with_bad_version.dart
@ -3,11 +3,10 @@
 // BSD-style license that can be found in the LICENSE file.

 /*error: errors=LanguageVersionTooHigh*/
-// @dart = 3.5
+// @dart = %TOO_HIGH_VERSION_MARKER%

-// If no valid language version is specified, we default to the most reason one.
-// In the tests this is hard-coded to 2.8.
+// If no valid language version is specified, we default to the most recent one.

-/*library: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 main() {}
--- a/pkg/front_end/test/language_versioning/data/library_with_bad_version_before_good_version.dart
+++ b/pkg/front_end/test/language_versioning/data/library_with_bad_version_before_good_version.dart
@ -3,13 +3,13 @@
 // BSD-style license that can be found in the LICENSE file.

 /*error: errors=LanguageVersionTooHigh*/
-// @dart = 3.5
+// @dart = %TOO_HIGH_VERSION_MARKER%

-// @dart = 2.5
+// @dart = %VERSION_MARKER1%

 // If the first language version specified is not a valid language version,
-// we default to the most reason one.  In the tests this is hard-coded to 2.8.
+// we default to the most recent one.

-/*library: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 main() {}
--- a/pkg/front_end/test/language_versioning/data/library_with_no_version.dart
+++ b/pkg/front_end/test/language_versioning/data/library_with_no_version.dart
@ -3,9 +3,8 @@
 // BSD-style license that can be found in the LICENSE file.

 // If no language version is specified, and none if given in a
-// .dart_tool/package_config.json file,
-// we default to the most reason one. In the tests this is hard-coded to 2.8.
+// .dart_tool/package_config.json file, we default to the most recent one.

-/*library: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 main() {}
--- a/pkg/front_end/test/language_versioning/data/library_with_two_versions.dart
+++ b/pkg/front_end/test/language_versioning/data/library_with_two_versions.dart
@ -4,9 +4,9 @@

 // With several valid versions the first one wins.

-// @dart = 2.5
-// @dart = 2.4
+// @dart = %VERSION_MARKER1%
+// @dart = %VERSION_MARKER0%

-/*library: languageVersion=2.5*/
+/*library: languageVersion=%VERSION_MARKER1%*/

 main() {}
--- a/pkg/front_end/test/language_versioning/data/library_with_two_versions_2.dart
+++ b/pkg/front_end/test/language_versioning/data/library_with_two_versions_2.dart
@ -4,9 +4,9 @@

 // With several versions where the first one is valid, the first one wins.

-// @dart = 2.5
-// @dart = 42.5
+// @dart = %VERSION_MARKER1%
+// @dart = %TOO_HIGH_VERSION_MARKER%

-/*library: languageVersion=2.5*/
+/*library: languageVersion=%VERSION_MARKER1%*/

 main() {}
--- a/pkg/front_end/test/language_versioning/data/library_with_version.dart
+++ b/pkg/front_end/test/language_versioning/data/library_with_version.dart
@ -2,8 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

-// @dart = 2.4
+// @dart = %VERSION_MARKER0%

-/*library: languageVersion=2.4*/
+/*library: languageVersion=%VERSION_MARKER0%*/

 main() {}
--- a/pkg/front_end/test/language_versioning/data/package_default_version/.dart_tool/package_config.json
+++ b/pkg/front_end/test/language_versioning/data/package_default_version/.dart_tool/package_config.json
@ -4,7 +4,7 @@
        {
            "name": "foo",
            "rootUri": "../lib/",
-            "languageVersion": "2.5"
+            "languageVersion": "%VERSION_MARKER1%"
        }
    ]
 }
--- a/pkg/front_end/test/language_versioning/data/package_default_version/lib/foo.dart
+++ b/pkg/front_end/test/language_versioning/data/package_default_version/lib/foo.dart
@ -2,7 +2,7 @@
 // for 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: languageVersion=2.5*/
+/*library: languageVersion=%VERSION_MARKER1%*/

 import 'foo2.dart';
 import 'foo3.dart';
--- a/pkg/front_end/test/language_versioning/data/package_default_version/lib/foo2.dart
+++ b/pkg/front_end/test/language_versioning/data/package_default_version/lib/foo2.dart
@ -2,9 +2,9 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

-// @dart = 2.4
+// @dart = %VERSION_MARKER0%

-/*library: languageVersion=2.4*/
+/*library: languageVersion=%VERSION_MARKER0%*/

 foo2() {
  print("Hello from foo2!");
--- a/pkg/front_end/test/language_versioning/data/package_default_version/lib/foo3.dart
+++ b/pkg/front_end/test/language_versioning/data/package_default_version/lib/foo3.dart
@ -2,12 +2,12 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

-// .dart_tool/package_config.json specifies 2.5, this library tries to go above
-// that, which is fine.
+// .dart_tool/package_config.json specifies %VERSION_MARKER1%, this library
+// tries to go above that, which is fine.

-// @dart = 2.6
+// @dart = %VERSION_MARKER2%

-/*library: languageVersion=2.6*/
+/*library: languageVersion=%VERSION_MARKER2%*/

 foo3() {
  print("Hello from foo3!");
--- a/pkg/front_end/test/language_versioning/data/package_default_version/lib/foo4.dart
+++ b/pkg/front_end/test/language_versioning/data/package_default_version/lib/foo4.dart
@ -2,15 +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.

-// .dart_tool/package_config.json specifies 2.5, this library tries to go above
-// that, which is fine, except it still has to be within the range of the sdk.
-// The library stays on the .dart_tool/package_config.json specified one (2.5)
-// and an error is issued.
+// .dart_tool/package_config.json specifies %VERSION_MARKER1%, this library
+// tries to go above that, which is fine, except it still has to be within the
+// range of the sdk. The library stays on the .dart_tool/package_config.json
+// specified one (%VERSION_MARKER1%) and an error is issued.

 /*error: errors=LanguageVersionTooHigh*/
-// @dart = 2.9
+// @dart = %TOO_HIGH_VERSION_MARKER%

-/*library: languageVersion=2.5*/
+/*library: languageVersion=%VERSION_MARKER1%*/

 foo4() {
  print("Hello from foo4!");
--- a/pkg/front_end/test/language_versioning/data/package_default_version/lib/foo_with_part.dart
+++ b/pkg/front_end/test/language_versioning/data/package_default_version/lib/foo_with_part.dart
@ -2,7 +2,7 @@
 // for 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: languageVersion=2.5*/
+/*library: languageVersion=%VERSION_MARKER1%*/

 part 'foos_part.dart';

--- a/pkg/front_end/test/language_versioning/data/package_default_version/main.dart
+++ b/pkg/front_end/test/language_versioning/data/package_default_version/main.dart
@ -5,12 +5,12 @@
 // Set version of this file (not technically in package) explicitly to test as
 // much as possibly separately.

-// @dart = 2.4
+// @dart = %VERSION_MARKER0%

 import 'package:foo/foo.dart';
 import 'package:foo/foo_with_part.dart';

-/*library: languageVersion=2.4*/
+/*library: languageVersion=%VERSION_MARKER0%*/

 main() {
  foo();
--- a/pkg/front_end/test/language_versioning/data/package_default_version_is_empty/lib/foo.dart
+++ b/pkg/front_end/test/language_versioning/data/package_default_version_is_empty/lib/foo.dart
@ -3,7 +3,7 @@
 // for 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: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 import 'foo2.dart';

--- a/pkg/front_end/test/language_versioning/data/package_default_version_is_empty/lib/foo2.dart
+++ b/pkg/front_end/test/language_versioning/data/package_default_version_is_empty/lib/foo2.dart
@ -3,9 +3,9 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

-// @dart = 2.4
+// @dart = %VERSION_MARKER0%

-/*library: languageVersion=2.4*/
+/*library: languageVersion=%VERSION_MARKER0%*/

 foo2() {
  print("Hello from foo2!");
--- a/pkg/front_end/test/language_versioning/data/package_default_version_is_empty/main.dart
+++ b/pkg/front_end/test/language_versioning/data/package_default_version_is_empty/main.dart
@ -5,11 +5,11 @@
 // Set version of this file (not technically in package) explicitly to test as
 // much as possibly separately.

-// @dart = 2.4
+// @dart = %VERSION_MARKER0%

 import 'package:foo/foo.dart';

-/*library: languageVersion=2.4*/
+/*library: languageVersion=%VERSION_MARKER0%*/

 main() {
  foo();
--- a/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong/lib/foo.dart
+++ b/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong/lib/foo.dart
@ -3,7 +3,7 @@
 // for 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: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 import 'foo2.dart';

--- a/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong/lib/foo2.dart
+++ b/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong/lib/foo2.dart
@ -3,9 +3,9 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

-// @dart = 2.4
+// @dart = %VERSION_MARKER0%

-/*library: languageVersion=2.4*/
+/*library: languageVersion=%VERSION_MARKER0%*/

 foo2() {
  print("Hello from foo2!");
--- a/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong/main.dart
+++ b/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong/main.dart
@ -5,11 +5,11 @@
 // Set version of this file (not technically in package) explicitly to test as
 // much as possibly separately.

-// @dart = 2.4
+// @dart = %VERSION_MARKER0%

 import 'package:foo/foo.dart';

-/*library: languageVersion=2.4*/
+/*library: languageVersion=%VERSION_MARKER0%*/

 main() {
  foo();
--- a/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong_2/.dart_tool/package_config.json
+++ b/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong_2/.dart_tool/package_config.json
@ -5,7 +5,7 @@
            "name": "foo",
            "rootUri": "../lib/",
            "languageVersion": "arglebargle",
-            "languageVersion": "2.5"
+            "languageVersion": "%VERSION_MARKER1%"
        }
    ]
 }
--- a/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong_2/lib/foo.dart
+++ b/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong_2/lib/foo.dart
@ -3,7 +3,7 @@
 // for 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: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 import 'foo2.dart';

--- a/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong_2/lib/foo2.dart
+++ b/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong_2/lib/foo2.dart
@ -3,9 +3,9 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

-// @dart = 2.4
+// @dart = %VERSION_MARKER0%

-/*library: languageVersion=2.4*/
+/*library: languageVersion=%VERSION_MARKER0%*/

 foo2() {
  print("Hello from foo2!");
--- a/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong_2/main.dart
+++ b/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong_2/main.dart
@ -5,11 +5,11 @@
 // Set version of this file (not technically in package) explicitly to test as
 // much as possibly separately.

-// @dart = 2.4
+// @dart = %VERSION_MARKER0%

 import 'package:foo/foo.dart';

-/*library: languageVersion=2.4*/
+/*library: languageVersion=%VERSION_MARKER0%*/

 main() {
  foo();
--- a/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong_3/.dart_tool/package_config.json
+++ b/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong_3/.dart_tool/package_config.json
@ -5,7 +5,7 @@
        {
            "name": "foo",
            "rootUri": "../lib/",
-            "languageVersion": "2.5",
+            "languageVersion": "%VERSION_MARKER1%",
            "languageVersion": "arglebargle"
        }
    ]
--- a/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong_3/lib/foo.dart
+++ b/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong_3/lib/foo.dart
@ -3,7 +3,7 @@
 // for 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: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 import 'foo2.dart';

--- a/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong_3/lib/foo2.dart
+++ b/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong_3/lib/foo2.dart
@ -3,9 +3,9 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

-// @dart = 2.4
+// @dart = %VERSION_MARKER0%

-/*library: languageVersion=2.4*/
+/*library: languageVersion=%VERSION_MARKER0%*/

 foo2() {
  print("Hello from foo2!");
--- a/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong_3/main.dart
+++ b/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong_3/main.dart
@ -5,11 +5,11 @@
 // Set version of this file (not technically in package) explicitly to test as
 // much as possibly separately.

-// @dart = 2.4
+// @dart = %VERSION_MARKER0%

 import 'package:foo/foo.dart';

-/*library: languageVersion=2.4*/
+/*library: languageVersion=%VERSION_MARKER0%*/

 main() {
  foo();
--- a/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong_4/lib/foo.dart
+++ b/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong_4/lib/foo.dart
@ -3,7 +3,7 @@
 // for 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: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 import 'foo2.dart';

--- a/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong_4/lib/foo2.dart
+++ b/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong_4/lib/foo2.dart
@ -3,9 +3,9 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

-// @dart = 2.4
+// @dart = %VERSION_MARKER0%

-/*library: languageVersion=2.4*/
+/*library: languageVersion=%VERSION_MARKER0%*/

 foo2() {
  print("Hello from foo2!");
--- a/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong_4/main.dart
+++ b/pkg/front_end/test/language_versioning/data/package_default_version_is_wrong_4/main.dart
@ -5,11 +5,11 @@
 // Set version of this file (not technically in package) explicitly to test as
 // much as possibly separately.

-// @dart = 2.4
+// @dart = %VERSION_MARKER0%

 import 'package:foo/foo.dart';

-/*library: languageVersion=2.4*/
+/*library: languageVersion=%VERSION_MARKER0%*/

 main() {
  foo();
--- a/pkg/front_end/test/language_versioning/data/package_no_default_version/lib/foo.dart
+++ b/pkg/front_end/test/language_versioning/data/package_no_default_version/lib/foo.dart
@ -3,10 +3,9 @@
 // BSD-style license that can be found in the LICENSE file.

 // If no language version is specified, and none if given in a
-// .dart_tool/package_config.json file,
-// we default to the most reason one. In the tests this is hard-coded to 2.8.
+// .dart_tool/package_config.json file, we default to the most recent one.

-/*library: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 foo() {
  print("Hello from foo!");
--- a/pkg/front_end/test/language_versioning/data/package_no_default_version/main.dart
+++ b/pkg/front_end/test/language_versioning/data/package_no_default_version/main.dart
@ -2,11 +2,11 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

-// @dart = 2.5
+// @dart = %VERSION_MARKER1%

 import 'package:foo/foo.dart';

-/*library: languageVersion=2.5*/
+/*library: languageVersion=%VERSION_MARKER1%*/

 main() {
  foo();
--- a/pkg/front_end/test/language_versioning/data/package_non_package_default_version/.dart_tool/package_config.json
+++ b/pkg/front_end/test/language_versioning/data/package_non_package_default_version/.dart_tool/package_config.json
@ -5,7 +5,7 @@
            "name": "foo",
            "rootUri": "../",
            "packageUri": "lib/",
-            "languageVersion": "2.5"
+            "languageVersion": "%VERSION_MARKER1%"
        }
    ]
 }
--- a/pkg/front_end/test/language_versioning/data/package_non_package_default_version/lib/foo.dart
+++ b/pkg/front_end/test/language_versioning/data/package_non_package_default_version/lib/foo.dart
@ -2,7 +2,7 @@
 // for 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: languageVersion=2.5*/
+/*library: languageVersion=%VERSION_MARKER1%*/

 foo() {
  print("Hello from foo!");
--- a/pkg/front_end/test/language_versioning/data/package_non_package_default_version/main.dart
+++ b/pkg/front_end/test/language_versioning/data/package_non_package_default_version/main.dart
@ -7,7 +7,7 @@ import 'package:foo/foo.dart';
 // Version comes from the package foo having this file in it's root uri.

 /*library: 
- languageVersion=2.5,
+ languageVersion=%VERSION_MARKER1%,
 packageUri=package:foo
 */

--- a/pkg/front_end/test/language_versioning/data/package_non_package_no_default_version/.dart_tool/package_config.json
+++ b/pkg/front_end/test/language_versioning/data/package_non_package_no_default_version/.dart_tool/package_config.json
@ -4,7 +4,7 @@
        {
            "name": "foo",
            "rootUri": "../lib/",
-            "languageVersion": "2.5"
+            "languageVersion": "%VERSION_MARKER1%"
        }
    ]
 }
--- a/pkg/front_end/test/language_versioning/data/package_non_package_no_default_version/lib/foo.dart
+++ b/pkg/front_end/test/language_versioning/data/package_non_package_no_default_version/lib/foo.dart
@ -2,7 +2,7 @@
 // for 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: languageVersion=2.5*/
+/*library: languageVersion=%VERSION_MARKER1%*/

 foo() {
  print("Hello from foo!");
--- a/pkg/front_end/test/language_versioning/data/package_non_package_no_default_version/main.dart
+++ b/pkg/front_end/test/language_versioning/data/package_non_package_no_default_version/main.dart
@ -4,7 +4,7 @@

 import 'package:foo/foo.dart';

-/*library: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 main() {
  foo();
--- a/pkg/front_end/test/language_versioning/data/package_to_high_default_version/.dart_tool/package_config.json
+++ b/pkg/front_end/test/language_versioning/data/package_to_high_default_version/.dart_tool/package_config.json
@ -4,7 +4,7 @@
        {
            "name": "foo",
            "rootUri": "../lib/",
-            "languageVersion": "2.9"
+            "languageVersion": "%TOO_HIGH_VERSION_MARKER%"
        }
    ]
 }
--- a/pkg/front_end/test/language_versioning/data/package_to_high_default_version/lib/foo.dart
+++ b/pkg/front_end/test/language_versioning/data/package_to_high_default_version/lib/foo.dart
@ -3,7 +3,7 @@
 // for 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: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 import 'foo2.dart';
 import 'foo3.dart';
--- a/pkg/front_end/test/language_versioning/data/package_to_high_default_version/lib/foo2.dart
+++ b/pkg/front_end/test/language_versioning/data/package_to_high_default_version/lib/foo2.dart
@ -4,9 +4,9 @@
 // BSD-style license that can be found in the LICENSE file.

 /*error: errors=LanguageVersionTooHigh*/
-// @dart = 2.9
+// @dart = %TOO_HIGH_VERSION_MARKER%

-/*library: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 foo2() {
  print("Hello from foo2!");
--- a/pkg/front_end/test/language_versioning/data/package_to_high_default_version/lib/foo3.dart
+++ b/pkg/front_end/test/language_versioning/data/package_to_high_default_version/lib/foo3.dart
@ -3,9 +3,9 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

-// @dart = 2.7
+// @dart = %VERSION_MARKER2%

-/*library: languageVersion=2.7*/
+/*library: languageVersion=%VERSION_MARKER2%*/

 foo3() {
  print("Hello from foo3!");
--- a/pkg/front_end/test/language_versioning/data/package_to_high_default_version/main.dart
+++ b/pkg/front_end/test/language_versioning/data/package_to_high_default_version/main.dart
@ -5,11 +5,11 @@
 // Set version of this file (not technically in package) explicitly to test as
 // much as possibly separately.

-// @dart = 2.4
+// @dart = %VERSION_MARKER0%

 import 'package:foo/foo.dart';

-/*library: languageVersion=2.4*/
+/*library: languageVersion=%VERSION_MARKER0%*/

 main() {
  foo();
--- a/pkg/front_end/test/language_versioning/data/package_with_test_json/foo/bin/bin_file.dart
+++ b/pkg/front_end/test/language_versioning/data/package_with_test_json/foo/bin/bin_file.dart
@ -3,7 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.

 /*library: 
- languageVersion=2.8,
+ languageVersion=%CURRENT_VERSION_MARKER%,
 packageUri=package:foo
 */

--- a/pkg/front_end/test/language_versioning/data/package_with_test_json/foo/lib/foo.dart
+++ b/pkg/front_end/test/language_versioning/data/package_with_test_json/foo/lib/foo.dart
@ -2,6 +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.

-/*library: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 method2() {}
--- a/pkg/front_end/test/language_versioning/data/package_with_test_json/foo/test/test_file.dart
+++ b/pkg/front_end/test/language_versioning/data/package_with_test_json/foo/test/test_file.dart
@ -3,7 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.

 /*library: 
- languageVersion=2.8,
+ languageVersion=%CURRENT_VERSION_MARKER%,
 packageUri=package:foo
 */

--- a/pkg/front_end/test/language_versioning/data/package_with_test_json/main.dart
+++ b/pkg/front_end/test/language_versioning/data/package_with_test_json/main.dart
@ -2,7 +2,7 @@
 // for 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: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 // Test that bin and test files within the root folder of a package are
 // associated with the package.
--- a/pkg/front_end/test/language_versioning/data/package_without_test_json/foo/bin/bin_file.dart
+++ b/pkg/front_end/test/language_versioning/data/package_without_test_json/foo/bin/bin_file.dart
@ -2,6 +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.

-/*library: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 method1() {}
--- a/pkg/front_end/test/language_versioning/data/package_without_test_json/foo/lib/foo.dart
+++ b/pkg/front_end/test/language_versioning/data/package_without_test_json/foo/lib/foo.dart
@ -2,6 +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.

-/*library: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 method2() {}
--- a/pkg/front_end/test/language_versioning/data/package_without_test_json/foo/test/test_file.dart
+++ b/pkg/front_end/test/language_versioning/data/package_without_test_json/foo/test/test_file.dart
@ -2,6 +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.

-/*library: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 method3() {}
--- a/pkg/front_end/test/language_versioning/data/package_without_test_json/main.dart
+++ b/pkg/front_end/test/language_versioning/data/package_without_test_json/main.dart
@ -2,7 +2,7 @@
 // for 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: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 // Test that bin and test files within the root folder of a package are
 // associated with the package.
--- a/pkg/front_end/test/language_versioning/data/parts_agreeing/main.dart
+++ b/pkg/front_end/test/language_versioning/data/parts_agreeing/main.dart
@ -2,11 +2,11 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

-// @dart = 2.5
+// @dart = %VERSION_MARKER1%

 part 'part.dart';

-/*library: languageVersion=2.5*/
+/*library: languageVersion=%VERSION_MARKER1%*/

 main() {
  // foo();
--- a/pkg/front_end/test/language_versioning/data/parts_agreeing/part.dart
+++ b/pkg/front_end/test/language_versioning/data/parts_agreeing/part.dart
@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

-// @dart = 2.5
+// @dart = %VERSION_MARKER1%

 part of 'main.dart';

--- a/pkg/front_end/test/language_versioning/data/parts_agreeing_two_versions/main.dart
+++ b/pkg/front_end/test/language_versioning/data/parts_agreeing_two_versions/main.dart
@ -2,12 +2,12 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

-// @dart = 2.5
-// @dart = 2.4
+// @dart = %VERSION_MARKER1%
+// @dart = %VERSION_MARKER0%

 part 'part.dart';

-/*library: languageVersion=2.5*/
+/*library: languageVersion=%VERSION_MARKER1%*/

 main() {
  // foo();
--- a/pkg/front_end/test/language_versioning/data/parts_agreeing_two_versions/part.dart
+++ b/pkg/front_end/test/language_versioning/data/parts_agreeing_two_versions/part.dart
@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

-// @dart = 2.5
+// @dart = %VERSION_MARKER1%

 part of 'main.dart';

--- a/pkg/front_end/test/language_versioning/data/parts_disagreeing/main.dart
+++ b/pkg/front_end/test/language_versioning/data/parts_disagreeing/main.dart
@ -2,11 +2,11 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

-// @dart = 2.5
+// @dart = %VERSION_MARKER1%

 part /*error: errors=LanguageVersionMismatchInPart*/ 'part.dart';

-/*library: languageVersion=2.5*/
+/*library: languageVersion=%VERSION_MARKER1%*/

 main() {
  foo();
--- a/pkg/front_end/test/language_versioning/data/parts_disagreeing/part.dart
+++ b/pkg/front_end/test/language_versioning/data/parts_disagreeing/part.dart
@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

-// @dart = 2.4
+// @dart = %VERSION_MARKER0%

 part of 'main.dart';

--- a/pkg/front_end/test/language_versioning/data/parts_disagreeing_has_package/.dart_tool/package_config.json
+++ b/pkg/front_end/test/language_versioning/data/parts_disagreeing_has_package/.dart_tool/package_config.json
@ -4,7 +4,7 @@
        {
            "name": "foo",
            "rootUri": "../lib/",
-            "languageVersion": "2.5"
+            "languageVersion": "%VERSION_MARKER1%"
        }
    ]
 }
--- a/pkg/front_end/test/language_versioning/data/parts_disagreeing_has_package/lib/foo.dart
+++ b/pkg/front_end/test/language_versioning/data/parts_disagreeing_has_package/lib/foo.dart
@ -2,14 +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.

-// The library and its part is both technically at language version 2.5,
-// but one is explicitly set, the other is not. That's an error.
+// The library and its part is both technically at language version
+// %VERSION_MARKER1%, but one is explicitly set, the other is not. That's an
+// error.

-// @dart = 2.5
+// @dart = %VERSION_MARKER1%

 part /*error: errors=LanguageVersionMismatchInPart*/ 'part.dart';

-/*library: languageVersion=2.5*/
+/*library: languageVersion=%VERSION_MARKER1%*/

 foo() {
  bar();
--- a/pkg/front_end/test/language_versioning/data/parts_disagreeing_has_package/main.dart
+++ b/pkg/front_end/test/language_versioning/data/parts_disagreeing_has_package/main.dart
@ -5,11 +5,11 @@
 // Set version of this file (not technically in package) explicitly to test as
 // much as possibly separately.

-// @dart = 2.4
+// @dart = %VERSION_MARKER0%

 import 'package:foo/foo.dart';

-/*library: languageVersion=2.4*/
+/*library: languageVersion=%VERSION_MARKER0%*/

 main() {
  main();
--- a/pkg/front_end/test/language_versioning/data/parts_disagreeing_has_package_2/.dart_tool/package_config.json
+++ b/pkg/front_end/test/language_versioning/data/parts_disagreeing_has_package_2/.dart_tool/package_config.json
@ -4,7 +4,7 @@
        {
            "name": "foo",
            "rootUri": "../lib/",
-            "languageVersion": "2.5"
+            "languageVersion": "%VERSION_MARKER1%"
        }
    ]
 }
--- a/pkg/front_end/test/language_versioning/data/parts_disagreeing_has_package_2/lib/foo.dart
+++ b/pkg/front_end/test/language_versioning/data/parts_disagreeing_has_package_2/lib/foo.dart
@ -2,12 +2,13 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

-// The library and its part is both technically at language version 2.5,
-// but one is explicitly set, the other is not. That's an error.
+// The library and its part is both technically at language version
+// %VERSION_MARKER1%, but one is explicitly set, the other is not. That's an
+// error.

 part /*error: errors=LanguageVersionMismatchInPart*/ 'part.dart';

-/*library: languageVersion=2.5*/
+/*library: languageVersion=%VERSION_MARKER1%*/

 foo() {
  bar();
--- a/pkg/front_end/test/language_versioning/data/parts_disagreeing_has_package_2/lib/part.dart
+++ b/pkg/front_end/test/language_versioning/data/parts_disagreeing_has_package_2/lib/part.dart
@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

-// @dart = 2.5
+// @dart = %VERSION_MARKER1%

 part of 'foo.dart';

--- a/pkg/front_end/test/language_versioning/data/parts_disagreeing_has_package_2/main.dart
+++ b/pkg/front_end/test/language_versioning/data/parts_disagreeing_has_package_2/main.dart
@ -5,11 +5,11 @@
 // Set version of this file (not technically in package) explicitly to test as
 // much as possibly separately.

-// @dart = 2.4
+// @dart = %VERSION_MARKER0%

 import 'package:foo/foo.dart';

-/*library: languageVersion=2.4*/
+/*library: languageVersion=%VERSION_MARKER0%*/

 main() {
  main();
--- a/pkg/front_end/test/language_versioning/data/specified_packages_01/foo2/foo.dart
+++ b/pkg/front_end/test/language_versioning/data/specified_packages_01/foo2/foo.dart
@ -1,4 +1,4 @@
-/*library: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 String foo() {
  return "42";
--- a/pkg/front_end/test/language_versioning/data/specified_packages_01/main.dart
+++ b/pkg/front_end/test/language_versioning/data/specified_packages_01/main.dart
@ -5,11 +5,11 @@
 // Set version of this file (not technically in package) explicitly to test as
 // much as possibly separately.

-// @dart = 2.4
+// @dart = %VERSION_MARKER0%

 import 'package:foo/foo.dart';

-/*library: languageVersion=2.4*/
+/*library: languageVersion=%VERSION_MARKER0%*/

 main() {
  var result = foo();
--- a/pkg/front_end/test/language_versioning/data/specified_packages_02/main.dart
+++ b/pkg/front_end/test/language_versioning/data/specified_packages_02/main.dart
@ -5,11 +5,11 @@
 // Set version of this file (not technically in package) explicitly to test as
 // much as possibly separately.

-// @dart = 2.4
+// @dart = %VERSION_MARKER0%

 import /*error: errors=UntranslatableUri*/ 'package:foo/foo.dart';

-/*library: languageVersion=2.4*/
+/*library: languageVersion=%VERSION_MARKER0%*/

 main() {
  var result = /*error: errors=MethodNotFound*/ notNamedFoo();
--- a/pkg/front_end/test/language_versioning/data/specified_packages_03/foo2/foo.dart
+++ b/pkg/front_end/test/language_versioning/data/specified_packages_03/foo2/foo.dart
@ -1,4 +1,4 @@
-/*library: languageVersion=2.8*/
+/*library: languageVersion=%CURRENT_VERSION_MARKER%*/

 String foo() {
  return "42";
--- a/pkg/front_end/test/language_versioning/data/specified_packages_03/main.dart
+++ b/pkg/front_end/test/language_versioning/data/specified_packages_03/main.dart
@ -5,11 +5,11 @@
 // Set version of this file (not technically in package) explicitly to test as
 // much as possibly separately.

-// @dart = 2.4
+// @dart = %VERSION_MARKER0%

 import 'package:foo/foo.dart';

-/*library: languageVersion=2.4*/
+/*library: languageVersion=%VERSION_MARKER0%*/

 main() {
  var result = foo();
--- a/pkg/front_end/test/language_versioning/data/specified_packages_04/main.dart
+++ b/pkg/front_end/test/language_versioning/data/specified_packages_04/main.dart
@ -5,11 +5,11 @@
 // Set version of this file (not technically in package) explicitly to test as
 // much as possibly separately.

-// @dart = 2.4
+// @dart = %VERSION_MARKER0%

 import /*error: errors=UntranslatableUri*/ 'package:foo/foo.dart';

-/*library: languageVersion=2.4*/
+/*library: languageVersion=%VERSION_MARKER0%*/

 main() {
  var result = /*error: errors=MethodNotFound*/ notNamedFoo();
--- a/pkg/front_end/test/language_versioning/language_versioning_test.dart
+++ b/pkg/front_end/test/language_versioning/language_versioning_test.dart
@ -25,6 +25,8 @@ import 'package:front_end/src/testing/id_testing_helper.dart'
 import 'package:front_end/src/testing/id_testing_utils.dart';
 import 'package:kernel/ast.dart' show Component, Library, Version;

+import '../utils/symbolic_language_versions.dart';
+
 Future<void> main(List<String> args) async {
  // Fix default/max major and minor version so we can test it.
  // This config sets it to 2.8.
@ -40,7 +42,9 @@ Future<void> main(List<String> args) async {
      skipList: [
        // Two language versions specified, the last one is ok and is used here.
        "package_default_version_is_wrong_2",
-      ]);
+      ],
+      preprocessFile: replaceMarkersWithVersions,
+      postProcessData: replaceVersionsWithMarkers);
 }

 class TestConfigWithLanguageVersion extends CfeTestConfig {
@ -50,7 +54,8 @@ class TestConfigWithLanguageVersion extends CfeTestConfig {
  @override
  CompilerOptions customizeCompilerOptions(
      CompilerOptions options, TestData testData) {
-    options.currentSdkVersion = "2.8";
+    options.currentSdkVersion =
+        SymbolicLanguageVersion.currentVersion.version.toText();

    File f = new File.fromUri(testData.testFileUri.resolve("test.options"));
    if (f.existsSync()) {
--- a/pkg/front_end/test/patching/data/opt_in/origin.dart
+++ b/pkg/front_end/test/patching/data/opt_in/origin.dart
@ -4,6 +4,6 @@

 /*cfe:nnbd.library: nnbd=true*/

-// @dart=2.9999
+// @dart=%NNBD_VERSION_MARKER%

 external int method(int? i);
--- a/pkg/front_end/test/patching/data/opt_in/patch.dart
+++ b/pkg/front_end/test/patching/data/opt_in/patch.dart
@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

-// @dart=2.9999
+// @dart=%NNBD_VERSION_MARKER%

 // ignore: import_internal_library
 import 'dart:_internal';
--- a/pkg/front_end/test/patching/data/opt_in_patch/origin.dart
+++ b/pkg/front_end/test/patching/data/opt_in_patch/origin.dart
@ -4,6 +4,6 @@

 /*cfe:nnbd.library: nnbd=false*/

-// @dart=2.6
+// @dart=%LEGACY_VERSION_MARKER%

 external int method(int i);
--- a/pkg/front_end/test/patching/data/opt_in_patch/patch.dart
+++ b/pkg/front_end/test/patching/data/opt_in_patch/patch.dart
@ -3,7 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.

 /*cfe:nnbd.error: message=The language version override has to be the same in the library and its patch(es).*/
-// @dart=2.9999
+// @dart=%NNBD_VERSION_MARKER%

 // ignore: import_internal_library
 import 'dart:_internal';
--- a/pkg/front_end/test/patching/data/opt_out/origin.dart
+++ b/pkg/front_end/test/patching/data/opt_out/origin.dart
@ -4,6 +4,6 @@

 /*cfe:nnbd.library: nnbd=false*/

-// @dart=2.6
+// @dart=%LEGACY_VERSION_MARKER%

 external int method();
--- a/pkg/front_end/test/patching/data/opt_out/patch.dart
+++ b/pkg/front_end/test/patching/data/opt_out/patch.dart
@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

-// @dart=2.6
+// @dart=%LEGACY_VERSION_MARKER%

 // ignore: import_internal_library
 import 'dart:_internal';
--- a/pkg/front_end/test/patching/data/opt_out_patch/origin.dart
+++ b/pkg/front_end/test/patching/data/opt_out_patch/origin.dart
@ -4,6 +4,6 @@

 /*cfe:nnbd.library: nnbd=true*/

-// @dart=2.9999
+// @dart=%NNBD_VERSION_MARKER%

 external int method();
--- a/pkg/front_end/test/patching/data/opt_out_patch/patch.dart
+++ b/pkg/front_end/test/patching/data/opt_out_patch/patch.dart
@ -3,7 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.

 /*cfe:nnbd.error: message=The language version override has to be the same in the library and its patch(es).*/
-// @dart=2.6
+// @dart=%LEGACY_VERSION_MARKER%

 // ignore: import_internal_library
 import 'dart:_internal';
--- a/pkg/front_end/test/patching/patching_test.dart
+++ b/pkg/front_end/test/patching/patching_test.dart
@ -20,6 +20,7 @@ import 'package:front_end/src/fasta/scope.dart';
 import 'package:front_end/src/testing/id_testing_helper.dart';
 import 'package:front_end/src/testing/id_testing_utils.dart';
 import 'package:kernel/ast.dart';
+import '../utils/symbolic_language_versions.dart';

 Future<void> main(List<String> args) async {
  Directory dataDir = new Directory.fromUri(Platform.script.resolve('data'));
@ -46,7 +47,9 @@ Future<void> main(List<String> args) async {
          'opt_out',
          'opt_out_patch',
        ]
-      });
+      },
+      preprocessFile: replaceMarkersWithVersions,
+      postProcessData: replaceVersionsWithMarkers);
 }

 class TestConfigWithLanguageVersion extends CfeTestConfig {
@ -61,7 +64,8 @@ class TestConfigWithLanguageVersion extends CfeTestConfig {

  @override
  void customizeCompilerOptions(CompilerOptions options, TestData testData) {
-    options.currentSdkVersion = "2.9999";
+    options.currentSdkVersion =
+        SymbolicLanguageVersion.nnbdVersion.version.toText();
  }
 }

--- a/pkg/front_end/test/utils/symbolic_language_versions.dart
+++ b/pkg/front_end/test/utils/symbolic_language_versions.dart
@ -0,0 +1,87 @@
+// Copyright (c) 2024, 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.
+
+import 'package:kernel/ast.dart';
+
+/// Symbolic language versions for use in testing.
+enum SymbolicLanguageVersion {
+  /// A valid language version the opts out of null safety.
+  legacyVersion("%LEGACY_VERSION_MARKER%", const Version(2, 6)),
+
+  /// A valid language version the opts in to null safety.
+  nnbdVersion("%NNBD_VERSION_MARKER%", const Version(2, 12)),
+
+  /// An invalid language version that is lower than [lowestVersion].
+  // TODO(johnniwinther): Report error on this.
+  tooLowVersion("%TOO_LOW_VERSION_MARKER%", const Version(1, 0)),
+
+  /// The lowest supported language version.
+  lowestVersion("%LOWEST_VERSION_MARKER%", const Version(2, 0)),
+
+  /// A valid language version larger than [lowestVersion] and lower than
+  /// [version1].
+  version0("%VERSION_MARKER0%", const Version(2, 4)),
+
+  /// A valid language version larger than [version0] and lower than
+  /// [version2].
+  version1("%VERSION_MARKER1%", const Version(2, 5)),
+
+  /// A valid language version larger than [version1] and lower than
+  /// [currentVersion].
+  version2("%VERSION_MARKER2%", const Version(2, 6)),
+
+  /// The current language version. This is also the highest supported version.
+  currentVersion("%CURRENT_VERSION_MARKER%", const Version(2, 8)),
+
+  /// An invalid language version that is higher than [currentVersion].
+  tooHighVersion("%TOO_HIGH_VERSION_MARKER%", const Version(2, 9999));
+
+  final String marker;
+  final Version version;
+
+  const SymbolicLanguageVersion(this.marker, this.version);
+}
+
+late final bool _validMarkers = _checkMarkers();
+
+bool _checkMarkers() {
+  return SymbolicLanguageVersion.tooLowVersion.version <
+          SymbolicLanguageVersion.lowestVersion.version &&
+      SymbolicLanguageVersion.lowestVersion.version <
+          SymbolicLanguageVersion.version0.version &&
+      SymbolicLanguageVersion.version0.version <
+          SymbolicLanguageVersion.version1.version &&
+      SymbolicLanguageVersion.version1.version <
+          SymbolicLanguageVersion.version2.version &&
+      SymbolicLanguageVersion.version2.version <
+          SymbolicLanguageVersion.currentVersion.version &&
+      SymbolicLanguageVersion.currentVersion.version <
+          SymbolicLanguageVersion.tooHighVersion.version;
+}
+
+/// Replaces all occurrences of symbolic language markers in [text] with their
+/// corresponding version as text.
+String replaceMarkersWithVersions(String text) {
+  assert(_validMarkers);
+  for (SymbolicLanguageVersion symbolicVersion
+      in SymbolicLanguageVersion.values) {
+    String marker = symbolicVersion.marker;
+    Version version = symbolicVersion.version;
+    text = text.replaceAll(marker, version.toText());
+  }
+  return text;
+}
+
+/// Replaces all occurrences language versions as text in [text] with the
+/// corresponding symbolic language markers.
+String replaceVersionsWithMarkers(String text) {
+  assert(_validMarkers);
+  for (SymbolicLanguageVersion symbolicVersion
+      in SymbolicLanguageVersion.values) {
+    String marker = symbolicVersion.marker;
+    Version version = symbolicVersion.version;
+    text = text.replaceAll(version.toText(), marker);
+  }
+  return text;
+}