[cfe] Remove language version from test data

Change-Id: I2288a4fd1fa93044436f161f07b9b3fb7ea441f9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/250847
Reviewed-by: Jens Johansen <jensj@google.com>
Commit-Queue: Johnni Winther <johnniwinther@google.com>
diff --git a/pkg/front_end/test/analyser_ignored/load_dill_twice_lib_1.dart b/pkg/front_end/test/analyser_ignored/load_dill_twice_lib_1.dart
index 443c3b5..ca76918 100644
--- a/pkg/front_end/test/analyser_ignored/load_dill_twice_lib_1.dart
+++ b/pkg/front_end/test/analyser_ignored/load_dill_twice_lib_1.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 = 2.9
-
 export 'load_dill_twice_lib_2.dart';
 
 // Use annotation to force proper printing.
diff --git a/pkg/front_end/test/analyser_ignored/load_dill_twice_lib_2.dart b/pkg/front_end/test/analyser_ignored/load_dill_twice_lib_2.dart
index 0ba97dd..5e9d38a 100644
--- a/pkg/front_end/test/analyser_ignored/load_dill_twice_lib_2.dart
+++ b/pkg/front_end/test/analyser_ignored/load_dill_twice_lib_2.dart
@@ -2,6 +2,4 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// @dart = 2.9
-
 int foo() => 42;
diff --git a/pkg/front_end/test/covariance_check/data/field.dart b/pkg/front_end/test/covariance_check/data/field.dart
index 743548d..f44a638 100644
--- a/pkg/front_end/test/covariance_check/data/field.dart
+++ b/pkg/front_end/test/covariance_check/data/field.dart
@@ -2,14 +2,16 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// @dart = 2.9
-
 class Class<T> {
+  T get value => throw '';
   T direct;
   void Function(T) functionArgument;
   T Function() functionReturn;
   T Function(T) functionArgumentReturn;
 
+  Class(this.direct, this.functionArgument, this.functionReturn,
+      this.functionArgumentReturn);
+
   void method(Class<T> other) {
     direct;
     this.direct;
@@ -17,11 +19,11 @@
 
     functionArgument;
     this.functionArgument;
-    other. /*as: void Function(T)*/ functionArgument;
+    other. /*as: void Function(T%)!*/ functionArgument;
 
-    functionArgument(null);
-    this.functionArgument(null);
-    other. /*as: void Function(T)*/ functionArgument(null);
+    functionArgument(value);
+    this.functionArgument(value);
+    other. /*as: void Function(T%)!*/ functionArgument(value);
 
     functionReturn;
     this.functionReturn;
@@ -33,10 +35,10 @@
 
     functionArgumentReturn;
     this.functionArgumentReturn;
-    other. /*as: T Function(T)*/ functionArgumentReturn;
+    other. /*as: T% Function(T%)!*/ functionArgumentReturn;
 
-    functionArgumentReturn(null);
-    this.functionArgumentReturn(null);
-    other. /*as: T Function(T)*/ functionArgumentReturn(null);
+    functionArgumentReturn(value);
+    this.functionArgumentReturn(value);
+    other. /*as: T% Function(T%)!*/ functionArgumentReturn(value);
   }
 }
diff --git a/pkg/front_end/test/covariance_check/data/getter.dart b/pkg/front_end/test/covariance_check/data/getter.dart
index 95d8e1a..6d64717 100644
--- a/pkg/front_end/test/covariance_check/data/getter.dart
+++ b/pkg/front_end/test/covariance_check/data/getter.dart
@@ -2,13 +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 = 2.9
-
 class Class<T> {
-  T get direct => null;
-  void Function(T) get functionArgument => null;
-  T Function() get functionReturn => null;
-  T Function(T) get functionArgumentReturn => null;
+  T get value => throw '';
+  T get direct => value;
+  void Function(T) get functionArgument => throw '';
+  T Function() get functionReturn => throw '';
+  T Function(T) get functionArgumentReturn => throw '';
 
   void method(Class<T> other) {
     direct;
@@ -17,11 +16,11 @@
 
     functionArgument;
     this.functionArgument;
-    other. /*as: void Function(T)*/ functionArgument;
+    other. /*as: void Function(T%)!*/ functionArgument;
 
-    functionArgument(null);
-    this.functionArgument(null);
-    other. /*as: void Function(T)*/ functionArgument(null);
+    functionArgument(value);
+    this.functionArgument(value);
+    other. /*as: void Function(T%)!*/ functionArgument(value);
 
     functionReturn;
     this.functionReturn;
@@ -33,10 +32,10 @@
 
     functionArgumentReturn;
     this.functionArgumentReturn;
-    other. /*as: T Function(T)*/ functionArgumentReturn;
+    other. /*as: T% Function(T%)!*/ functionArgumentReturn;
 
-    functionArgumentReturn(null);
-    this.functionArgumentReturn(null);
-    other. /*as: T Function(T)*/ functionArgumentReturn(null);
+    functionArgumentReturn(value);
+    this.functionArgumentReturn(value);
+    other. /*as: T% Function(T%)!*/ functionArgumentReturn(value);
   }
 }
diff --git a/pkg/front_end/test/covariance_check/data/method.dart b/pkg/front_end/test/covariance_check/data/method.dart
index 91bb44f..7f27f0f 100644
--- a/pkg/front_end/test/covariance_check/data/method.dart
+++ b/pkg/front_end/test/covariance_check/data/method.dart
@@ -2,13 +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 = 2.9
-
 class Class<T> {
-  T direct() => null;
-  void Function(T) functionArgument() => null;
-  T Function() functionReturn() => null;
-  T Function(T) functionArgumentReturn() => null;
+  T get value => throw '';
+  T direct() => value;
+  void Function(T) functionArgument() => throw '';
+  T Function() functionReturn() => throw '';
+  T Function(T) functionArgumentReturn() => throw '';
 
   void method(Class<T> other) {
     direct;
@@ -21,15 +20,15 @@
 
     functionArgument;
     this.functionArgument;
-    other. /*as: void Function(T) Function()*/ functionArgument;
+    other. /*as: void Function(T%)! Function()!*/ functionArgument;
 
     functionArgument();
     this.functionArgument();
-    other. /*as: void Function(T)*/ functionArgument();
+    other. /*as: void Function(T%)!*/ functionArgument();
 
-    functionArgument()(null);
-    this.functionArgument()(null);
-    other. /*as: void Function(T)*/ functionArgument()(null);
+    functionArgument()(value);
+    this.functionArgument()(value);
+    other. /*as: void Function(T%)!*/ functionArgument()(value);
 
     functionReturn;
     this.functionReturn;
@@ -45,14 +44,14 @@
 
     functionArgumentReturn;
     this.functionArgumentReturn;
-    other. /*as: T Function(T) Function()*/ functionArgumentReturn;
+    other. /*as: T% Function(T%)! Function()!*/ functionArgumentReturn;
 
     functionArgumentReturn();
     this.functionArgumentReturn();
-    other. /*as: T Function(T)*/ functionArgumentReturn();
+    other. /*as: T% Function(T%)!*/ functionArgumentReturn();
 
-    functionArgumentReturn()(null);
-    this.functionArgumentReturn()(null);
-    other. /*as: T Function(T)*/ functionArgumentReturn()(null);
+    functionArgumentReturn()(value);
+    this.functionArgumentReturn()(value);
+    other. /*as: T% Function(T%)!*/ functionArgumentReturn()(value);
   }
 }
diff --git a/pkg/front_end/test/extensions/data/ambiguous/lib1.dart b/pkg/front_end/test/extensions/data/ambiguous/lib1.dart
index d2ec93e..0ee1710 100644
--- a/pkg/front_end/test/extensions/data/ambiguous/lib1.dart
+++ b/pkg/front_end/test/extensions/data/ambiguous/lib1.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 = 2.9
-
 /*library: scope=[
   AmbiguousExtension1,
   AmbiguousExtension2,
@@ -18,7 +16,7 @@
  extension-members=[
   static ambiguousStaticMethod1=AmbiguousExtension1|ambiguousStaticMethod1],
  extension-name=AmbiguousExtension1,
- extension-onType=String
+ extension-onType=String!
 */
 extension AmbiguousExtension1 on String {
   /*member: AmbiguousExtension1|ambiguousStaticMethod1:
@@ -34,7 +32,7 @@
  extension-members=[
   static unambiguousStaticMethod1=AmbiguousExtension2|unambiguousStaticMethod1],
  extension-name=AmbiguousExtension2,
- extension-onType=String
+ extension-onType=String!
 */
 extension AmbiguousExtension2 on String {
   /*member: AmbiguousExtension2|unambiguousStaticMethod1:
@@ -50,7 +48,7 @@
  extension-members=[
   static ambiguousStaticMethod2=UnambiguousExtension1|ambiguousStaticMethod2],
  extension-name=UnambiguousExtension1,
- extension-onType=String
+ extension-onType=String!
 */
 extension UnambiguousExtension1 on String {
   /*member: UnambiguousExtension1|ambiguousStaticMethod2:
diff --git a/pkg/front_end/test/extensions/data/ambiguous/lib2.dart b/pkg/front_end/test/extensions/data/ambiguous/lib2.dart
index 5554fab..882d2fc 100644
--- a/pkg/front_end/test/extensions/data/ambiguous/lib2.dart
+++ b/pkg/front_end/test/extensions/data/ambiguous/lib2.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 = 2.9
-
 /*library: scope=[
   AmbiguousExtension1,
   AmbiguousExtension2,
@@ -18,7 +16,7 @@
  extension-members=[
   static ambiguousStaticMethod1=AmbiguousExtension1|ambiguousStaticMethod1],
  extension-name=AmbiguousExtension1,
- extension-onType=String
+ extension-onType=String!
 */
 extension AmbiguousExtension1 on String {
   /*member: AmbiguousExtension1|ambiguousStaticMethod1:
@@ -34,7 +32,7 @@
  extension-members=[
   static unambiguousStaticMethod2=AmbiguousExtension2|unambiguousStaticMethod2],
  extension-name=AmbiguousExtension2,
- extension-onType=String
+ extension-onType=String!
 */
 extension AmbiguousExtension2 on String {
   /*member: AmbiguousExtension2|unambiguousStaticMethod2:
@@ -50,7 +48,7 @@
  extension-members=[
   static ambiguousStaticMethod2=UnambiguousExtension2|ambiguousStaticMethod2],
  extension-name=UnambiguousExtension2,
- extension-onType=String
+ extension-onType=String!
 */
 extension UnambiguousExtension2 on String {
   /*member: UnambiguousExtension2|ambiguousStaticMethod2:
diff --git a/pkg/front_end/test/extensions/data/ambiguous/main.dart b/pkg/front_end/test/extensions/data/ambiguous/main.dart
index b3032bc..adf03ea 100644
--- a/pkg/front_end/test/extensions/data/ambiguous/main.dart
+++ b/pkg/front_end/test/extensions/data/ambiguous/main.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 = 2.9
-
 /*library: scope=[
   async.dart.FutureExtensions,
   core.dart.EnumByName,
diff --git a/pkg/front_end/test/extensions/data/as_show/lib.dart b/pkg/front_end/test/extensions/data/as_show/lib.dart
index 0f83439..56d26bd 100644
--- a/pkg/front_end/test/extensions/data/as_show/lib.dart
+++ b/pkg/front_end/test/extensions/data/as_show/lib.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 = 2.9
-
 /*library: scope=[
   Extension1,
   async.dart.FutureExtensions,
@@ -17,7 +15,7 @@
   method1=Extension1|method1,
   tearoff method1=Extension1|get#method1],
  extension-name=Extension1,
- extension-onType=int
+ extension-onType=int!
 */
 extension Extension1 on int {
   /*member: Extension1|method1:
diff --git a/pkg/front_end/test/extensions/data/as_show/main.dart b/pkg/front_end/test/extensions/data/as_show/main.dart
index 6d3e459..47a09d2 100644
--- a/pkg/front_end/test/extensions/data/as_show/main.dart
+++ b/pkg/front_end/test/extensions/data/as_show/main.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 = 2.9
-
 /*library: scope=[
   async.dart.FutureExtensions,
   core.dart.EnumByName,
diff --git a/pkg/front_end/test/extensions/data/as_show/origin.dart b/pkg/front_end/test/extensions/data/as_show/origin.dart
index 3ba1c97..b067a10 100644
--- a/pkg/front_end/test/extensions/data/as_show/origin.dart
+++ b/pkg/front_end/test/extensions/data/as_show/origin.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 = 2.9
-
 /*library: scope=[
   Extension2,
   async.dart.FutureExtensions,
@@ -17,7 +15,7 @@
   method2=Extension2|method2,
   tearoff method2=Extension2|get#method2],
  extension-name=Extension2,
- extension-onType=String
+ extension-onType=String!
 */
 extension Extension2 on String {
 /*member: Extension2|method2:
diff --git a/pkg/front_end/test/extensions/data/explicit_this.dart b/pkg/front_end/test/extensions/data/explicit_this.dart
index 3fa67bc..8f47acc 100644
--- a/pkg/front_end/test/extensions/data/explicit_this.dart
+++ b/pkg/front_end/test/extensions/data/explicit_this.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 = 2.9
-
 /*library: scope=[
   A2,
   async.dart.FutureExtensions,
@@ -11,7 +9,7 @@
   core.dart.EnumName]*/
 
 class A1 {
-  Object field;
+  Object? field;
   void method1() {}
 }
 
@@ -26,7 +24,7 @@
   tearoff method3=A2|get#method3,
   tearoff method4=A2|get#method4],
  extension-name=A2,
- extension-onType=A1
+ extension-onType=A1!
 */
 extension A2 on A1 {
   /*member: A2|method2:
@@ -50,7 +48,7 @@
    member-name=A2|method3,
    member-params=[#this]
   */
-  Object method3() => this.field;
+  Object? method3() => this.field;
 
   /*member: A2|get#method3:
    builder-name=method3,
@@ -65,7 +63,7 @@
    member-name=A2|method4,
    member-params=[#this,o]
   */
-  void method4(Object o) {
+  void method4(Object? o) {
     this.field = o;
   }
 
diff --git a/pkg/front_end/test/extensions/data/export_twice/lib1.dart b/pkg/front_end/test/extensions/data/export_twice/lib1.dart
index 98bceb7..c4d9386 100644
--- a/pkg/front_end/test/extensions/data/export_twice/lib1.dart
+++ b/pkg/front_end/test/extensions/data/export_twice/lib1.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 = 2.9
-
 /*library: scope=[
   E,
   async.dart.FutureExtensions,
@@ -18,7 +16,8 @@
  extension-members=[
   foo=E|foo,
   tearoff foo=E|get#foo],
- extension-name=E,extension-onType=A
+ extension-name=E,
+ extension-onType=A!
 */
 extension E on A {
   /*member: E|foo:
diff --git a/pkg/front_end/test/extensions/data/export_twice/lib2.dart b/pkg/front_end/test/extensions/data/export_twice/lib2.dart
index 2ec4f6e..c6b5edb 100644
--- a/pkg/front_end/test/extensions/data/export_twice/lib2.dart
+++ b/pkg/front_end/test/extensions/data/export_twice/lib2.dart
@@ -7,6 +7,4 @@
   core.dart.EnumByName,
   core.dart.EnumName]*/
 
-// @dart = 2.9
-
 export 'lib1.dart' show E;
diff --git a/pkg/front_end/test/extensions/data/export_twice/main.dart b/pkg/front_end/test/extensions/data/export_twice/main.dart
index 50f805b..65aa4a0 100644
--- a/pkg/front_end/test/extensions/data/export_twice/main.dart
+++ b/pkg/front_end/test/extensions/data/export_twice/main.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 = 2.9
-
 /*library: scope=[
   async.dart.FutureExtensions,
   core.dart.EnumByName,
diff --git a/pkg/front_end/test/extensions/data/export_unnamed/lib.dart b/pkg/front_end/test/extensions/data/export_unnamed/lib.dart
index dcba01e..d8f08bf 100644
--- a/pkg/front_end/test/extensions/data/export_unnamed/lib.dart
+++ b/pkg/front_end/test/extensions/data/export_unnamed/lib.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 = 2.9
-
 /*library: scope=[
   NamedExtension,
   _extension#0,
@@ -16,7 +14,7 @@
  builder-onType=String,
  extension-members=[static staticMethod=_extension#0|staticMethod],
  extension-name=_extension#0,
- extension-onType=String
+ extension-onType=String!
 */
 extension on String {
   /*member: _extension#0|staticMethod:
@@ -31,7 +29,7 @@
  builder-onType=String,
  extension-members=[static staticMethod=NamedExtension|staticMethod],
  extension-name=NamedExtension,
- extension-onType=String
+ extension-onType=String!
 */
 extension NamedExtension on String {
   /*member: NamedExtension|staticMethod:
diff --git a/pkg/front_end/test/extensions/data/export_unnamed/main.dart b/pkg/front_end/test/extensions/data/export_unnamed/main.dart
index 3eabaef..eafdc7d 100644
--- a/pkg/front_end/test/extensions/data/export_unnamed/main.dart
+++ b/pkg/front_end/test/extensions/data/export_unnamed/main.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 = 2.9
-
 /*library: scope=[
   async.dart.FutureExtensions,
   core.dart.EnumByName,
diff --git a/pkg/front_end/test/extensions/data/extension_on_type_variable.dart b/pkg/front_end/test/extensions/data/extension_on_type_variable.dart
index e40cd1c..baf80b2 100644
--- a/pkg/front_end/test/extensions/data/extension_on_type_variable.dart
+++ b/pkg/front_end/test/extensions/data/extension_on_type_variable.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 = 2.9
-
 /*library: scope=[
   GeneralGeneric,
   async.dart.FutureExtensions,
@@ -18,7 +16,7 @@
   method=GeneralGeneric|method,
   tearoff method=GeneralGeneric|get#method],
  extension-name=GeneralGeneric,
- extension-onType=T,
+ extension-onType=T%,
  extension-type-params=[T]
 */
 extension GeneralGeneric<T> on T {
diff --git a/pkg/front_end/test/extensions/data/implicit_this.dart b/pkg/front_end/test/extensions/data/implicit_this.dart
index 2dd48a4..a186361 100644
--- a/pkg/front_end/test/extensions/data/implicit_this.dart
+++ b/pkg/front_end/test/extensions/data/implicit_this.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 = 2.9
-
 /*library: scope=[
   A2,
   async.dart.FutureExtensions,
@@ -11,7 +9,7 @@
   core.dart.EnumName]*/
 
 class A1 {
-  Object field;
+  Object? field;
   void method1() {}
 }
 
@@ -26,7 +24,7 @@
   tearoff method3=A2|get#method3,
   tearoff method4=A2|get#method4],
  extension-name=A2,
- extension-onType=A1
+ extension-onType=A1!
 */
 extension A2 on A1 {
   /*member: A2|method2:
@@ -49,7 +47,7 @@
    member-name=A2|method3,
    member-params=[#this]
   */
-  Object method3() => field;
+  Object? method3() => field;
 
   /*member: A2|get#method3:
    builder-name=method3,
@@ -64,7 +62,7 @@
    member-name=A2|method4,
    member-params=[#this,o]
   */
-  void method4(Object o) {
+  void method4(Object? o) {
     field = o;
   }
 
diff --git a/pkg/front_end/test/extensions/data/instance_members.dart b/pkg/front_end/test/extensions/data/instance_members.dart
index e7ee05b..10c036b 100644
--- a/pkg/front_end/test/extensions/data/instance_members.dart
+++ b/pkg/front_end/test/extensions/data/instance_members.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 = 2.9
-
 /*library: scope=[
   A2,
   B2,
@@ -26,7 +24,7 @@
   tearoff method3=A2|get#method3,
   tearoff method4=A2|get#method4],
  extension-name=A2,
- extension-onType=A1
+ extension-onType=A1!
 */
 extension A2 on A1 {
   /*member: A2|method1:
@@ -77,7 +75,7 @@
      member-pos-params=[o],
      member-type-params=[T]
   */
-  A1 method3<T>([T o]) {
+  A1 method3<T>([T? o]) {
     print(o);
     return this;
   }
@@ -101,7 +99,7 @@
      member-named-params=[o],
      member-type-params=[T]
   */
-  A1 method4<T>({T o}) {
+  A1 method4<T>({T? o}) {
     print(o);
     return this;
   }
@@ -128,7 +126,7 @@
   tearoff method1=B2|get#method1,
   tearoff method2=B2|get#method2],
  extension-name=B2,
- extension-onType=B1<T>,
+ extension-onType=B1<T%>!,
  extension-type-params=[T]
 */
 extension B2<T> on B1<T> {
diff --git a/pkg/front_end/test/extensions/data/named_declarations.dart b/pkg/front_end/test/extensions/data/named_declarations.dart
index c108a11..5c08328 100644
--- a/pkg/front_end/test/extensions/data/named_declarations.dart
+++ b/pkg/front_end/test/extensions/data/named_declarations.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 = 2.9
-
 /*library: scope=[
   A2,
   B2,
@@ -19,7 +17,7 @@
  builder-name=A2,
  builder-onType=A1,
  extension-name=A2,
- extension-onType=A1
+ extension-onType=A1!
 */
 extension A2 on A1 {}
 
@@ -30,7 +28,7 @@
  builder-onType=B1<T>,
  builder-type-params=[T],
  extension-name=B2,
- extension-onType=B1<T>,
+ extension-onType=B1<T%>!,
  extension-type-params=[T]
 */
 extension B2<T> on B1<T> {}
@@ -39,7 +37,7 @@
  builder-name=B3,
  builder-onType=B1<A1>,
  extension-name=B3,
- extension-onType=B1<A1>
+ extension-onType=B1<A1!>!
 */
 extension B3 on B1<A1> {}
 
@@ -47,8 +45,9 @@
  builder-name=B4,
  builder-onType=B1<T>,
  builder-type-params=[T extends A1],
- extension-name=B4,extension-onType=B1<T>,
- extension-type-params=[T extends A1]
+ extension-name=B4,
+ extension-onType=B1<T!>!,
+ extension-type-params=[T extends A1!]
 */
 extension B4<T extends A1> on B1<T> {}
 
diff --git a/pkg/front_end/test/extensions/data/other_kinds.dart b/pkg/front_end/test/extensions/data/other_kinds.dart
index 38003af..1e1e0a9 100644
--- a/pkg/front_end/test/extensions/data/other_kinds.dart
+++ b/pkg/front_end/test/extensions/data/other_kinds.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 = 2.9
-
 /*library: scope=[
   A2,
   async.dart.FutureExtensions,
@@ -11,7 +9,7 @@
   core.dart.EnumName]*/
 
 class A1 {
-  int _instanceField;
+  int _instanceField = 0;
   int getInstanceField() => _instanceField;
   void setInstanceField(int value) {
     _instanceField = value;
@@ -27,14 +25,14 @@
  builder-name=A2,
  builder-onType=A1,
  extension-members=[
-  operator +=A2|+,
   getter instanceProperty=A2|get#instanceProperty,
+  operator +=A2|+,
   setter instanceProperty=A2|set#instanceProperty,
   static field staticField=A2|staticField,
   static getter staticProperty=A2|staticProperty,
   static setter staticProperty=A2|staticProperty=],
  extension-name=A2,
- extension-onType=A1
+ extension-onType=A1!
 */
 extension A2 on A1 {
   /*member: A2|get#instanceProperty:
diff --git a/pkg/front_end/test/extensions/data/patching/main.dart b/pkg/front_end/test/extensions/data/patching/main.dart
index c73c1b6..f53b2a1 100644
--- a/pkg/front_end/test/extensions/data/patching/main.dart
+++ b/pkg/front_end/test/extensions/data/patching/main.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 = 2.9
-
 /*library: scope=[
   async.dart.FutureExtensions,
   core.dart.EnumByName,
diff --git a/pkg/front_end/test/extensions/data/patching/origin.dart b/pkg/front_end/test/extensions/data/patching/origin.dart
index ee167d4..34b5cfc 100644
--- a/pkg/front_end/test/extensions/data/patching/origin.dart
+++ b/pkg/front_end/test/extensions/data/patching/origin.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 = 2.9
-
 /*library: scope=[
   Extension,
   GenericExtension,
@@ -24,10 +22,9 @@
   static setter staticProperty=Extension|staticProperty=,
   static staticMethod=Extension|staticMethod,
   tearoff genericInstanceMethod=Extension|get#genericInstanceMethod,
-  tearoff instanceMethod=Extension|get#instanceMethod,
- ],
+  tearoff instanceMethod=Extension|get#instanceMethod],
  extension-name=Extension,
- extension-onType=String
+ extension-onType=String!
 */
 extension Extension on String {
   /*member: Extension|get#instanceMethod:
@@ -74,10 +71,9 @@
   static setter staticProperty=GenericExtension|staticProperty=,
   static staticMethod=GenericExtension|staticMethod,
   tearoff genericInstanceMethod=GenericExtension|get#genericInstanceMethod,
-  tearoff instanceMethod=GenericExtension|get#instanceMethod
-  ],
+  tearoff instanceMethod=GenericExtension|get#instanceMethod],
  extension-name=GenericExtension,
- extension-onType=T,
+ extension-onType=T%,
  extension-type-params=[T]
 */
 extension GenericExtension<T> on T {
diff --git a/pkg/front_end/test/extensions/data/patching/patch.dart b/pkg/front_end/test/extensions/data/patching/patch.dart
index 2f929c7..638ee90a 100644
--- a/pkg/front_end/test/extensions/data/patching/patch.dart
+++ b/pkg/front_end/test/extensions/data/patching/patch.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 = 2.9
-
 // ignore: import_internal_library
 import 'dart:_internal';
 
diff --git a/pkg/front_end/test/extensions/data/prefix/lib1.dart b/pkg/front_end/test/extensions/data/prefix/lib1.dart
index 66eef24..19d099a 100644
--- a/pkg/front_end/test/extensions/data/prefix/lib1.dart
+++ b/pkg/front_end/test/extensions/data/prefix/lib1.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 = 2.9
-
 /*library: scope=[
   HiddenExtension1,
   ShownExtension1,
@@ -16,7 +14,7 @@
  builder-onType=String,
  extension-members=[static staticMethod=ShownExtension1|staticMethod],
  extension-name=ShownExtension1,
- extension-onType=String
+ extension-onType=String!
 */
 extension ShownExtension1 on String {
   /*member: ShownExtension1|staticMethod:
@@ -31,7 +29,7 @@
  builder-onType=String,
  extension-members=[static staticMethod=HiddenExtension1|staticMethod],
  extension-name=HiddenExtension1,
- extension-onType=String
+ extension-onType=String!
 */
 extension HiddenExtension1 on String {
   /*member: HiddenExtension1|staticMethod:
diff --git a/pkg/front_end/test/extensions/data/prefix/lib2.dart b/pkg/front_end/test/extensions/data/prefix/lib2.dart
index 6bc2749..dae3ef6 100644
--- a/pkg/front_end/test/extensions/data/prefix/lib2.dart
+++ b/pkg/front_end/test/extensions/data/prefix/lib2.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 = 2.9
-
 /*library: scope=[
   HiddenExtension2,
   ShownExtension2,
@@ -16,7 +14,7 @@
  builder-onType=String,
  extension-members=[static staticMethod=HiddenExtension2|staticMethod],
  extension-name=HiddenExtension2,
- extension-onType=String
+ extension-onType=String!
 */
 extension HiddenExtension2 on String {
   /*member: HiddenExtension2|staticMethod:
@@ -31,7 +29,7 @@
  builder-onType=String,
  extension-members=[static staticMethod=ShownExtension2|staticMethod],
  extension-name=ShownExtension2,
- extension-onType=String
+ extension-onType=String!
 */
 extension ShownExtension2 on String {
   /*member: ShownExtension2|staticMethod:
diff --git a/pkg/front_end/test/extensions/data/prefix/lib3.dart b/pkg/front_end/test/extensions/data/prefix/lib3.dart
index f56416d..f166d1f 100644
--- a/pkg/front_end/test/extensions/data/prefix/lib3.dart
+++ b/pkg/front_end/test/extensions/data/prefix/lib3.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 = 2.9
-
 /*library: scope=[
   ShownExtension3,
   async.dart.FutureExtensions,
@@ -15,7 +13,7 @@
  builder-onType=String,
  extension-members=[static staticMethod=ShownExtension3|staticMethod],
  extension-name=ShownExtension3,
- extension-onType=String
+ extension-onType=String!
 */
 extension ShownExtension3 on String {
   /*member: ShownExtension3|staticMethod:
diff --git a/pkg/front_end/test/extensions/data/prefix/main.dart b/pkg/front_end/test/extensions/data/prefix/main.dart
index 05a1e8c..a9f5a9d 100644
--- a/pkg/front_end/test/extensions/data/prefix/main.dart
+++ b/pkg/front_end/test/extensions/data/prefix/main.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 = 2.9
-
 /*library: scope=[
   async.dart.FutureExtensions,
   core.dart.EnumByName,
diff --git a/pkg/front_end/test/extensions/data/reexport/lib.dart b/pkg/front_end/test/extensions/data/reexport/lib.dart
index f9286f6..2b06562 100644
--- a/pkg/front_end/test/extensions/data/reexport/lib.dart
+++ b/pkg/front_end/test/extensions/data/reexport/lib.dart
@@ -7,8 +7,6 @@
   core.dart.EnumByName,
   core.dart.EnumName]*/
 
-// @dart = 2.9
-
 export 'lib1.dart';
 /*error: errors=['ClashingExtension' is exported from both 'org-dartlang-test:///a/b/c/lib1.dart' and 'org-dartlang-test:///a/b/c/lib2.dart'.]*/
 export 'lib2.dart';
diff --git a/pkg/front_end/test/extensions/data/reexport/lib1.dart b/pkg/front_end/test/extensions/data/reexport/lib1.dart
index 0e1aef3..cf3ae62 100644
--- a/pkg/front_end/test/extensions/data/reexport/lib1.dart
+++ b/pkg/front_end/test/extensions/data/reexport/lib1.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 = 2.9
-
 /*library: scope=[
   ClashingExtension,
   UniqueExtension1,
@@ -16,7 +14,7 @@
  builder-onType=String,
  extension-members=[static staticMethod=ClashingExtension|staticMethod],
  extension-name=ClashingExtension,
- extension-onType=String
+ extension-onType=String!
 */
 extension ClashingExtension on String {
   /*member: ClashingExtension|staticMethod:
@@ -32,7 +30,7 @@
  builder-onType=String,
  extension-members=[static staticMethod=UniqueExtension1|staticMethod],
  extension-name=UniqueExtension1,
- extension-onType=String
+ extension-onType=String!
 */
 extension UniqueExtension1 on String {
   /*member: UniqueExtension1|staticMethod:
diff --git a/pkg/front_end/test/extensions/data/reexport/lib2.dart b/pkg/front_end/test/extensions/data/reexport/lib2.dart
index a6a9289..3059376 100644
--- a/pkg/front_end/test/extensions/data/reexport/lib2.dart
+++ b/pkg/front_end/test/extensions/data/reexport/lib2.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 = 2.9
-
 /*library: scope=[
   ClashingExtension,
   UniqueExtension2,
@@ -16,7 +14,7 @@
  builder-onType=String,
  extension-members=[static staticMethod=ClashingExtension|staticMethod],
  extension-name=ClashingExtension,
- extension-onType=String
+ extension-onType=String!
 */
 extension ClashingExtension on String {
   /*member: ClashingExtension|staticMethod:
@@ -31,7 +29,7 @@
  builder-onType=String,
  extension-members=[static staticMethod=UniqueExtension2|staticMethod],
  extension-name=UniqueExtension2,
- extension-onType=String
+ extension-onType=String!
 */
 extension UniqueExtension2 on String {
   /*member: UniqueExtension2|staticMethod:
diff --git a/pkg/front_end/test/extensions/data/reexport/main.dart b/pkg/front_end/test/extensions/data/reexport/main.dart
index cec1552..1dfe0ae 100644
--- a/pkg/front_end/test/extensions/data/reexport/main.dart
+++ b/pkg/front_end/test/extensions/data/reexport/main.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 = 2.9
-
 /*library: scope=[
   async.dart.FutureExtensions,
   core.dart.EnumByName,
diff --git a/pkg/front_end/test/extensions/data/show_hide/lib1.dart b/pkg/front_end/test/extensions/data/show_hide/lib1.dart
index 66eef24..19d099a 100644
--- a/pkg/front_end/test/extensions/data/show_hide/lib1.dart
+++ b/pkg/front_end/test/extensions/data/show_hide/lib1.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 = 2.9
-
 /*library: scope=[
   HiddenExtension1,
   ShownExtension1,
@@ -16,7 +14,7 @@
  builder-onType=String,
  extension-members=[static staticMethod=ShownExtension1|staticMethod],
  extension-name=ShownExtension1,
- extension-onType=String
+ extension-onType=String!
 */
 extension ShownExtension1 on String {
   /*member: ShownExtension1|staticMethod:
@@ -31,7 +29,7 @@
  builder-onType=String,
  extension-members=[static staticMethod=HiddenExtension1|staticMethod],
  extension-name=HiddenExtension1,
- extension-onType=String
+ extension-onType=String!
 */
 extension HiddenExtension1 on String {
   /*member: HiddenExtension1|staticMethod:
diff --git a/pkg/front_end/test/extensions/data/show_hide/lib2.dart b/pkg/front_end/test/extensions/data/show_hide/lib2.dart
index 6bc2749..dae3ef6 100644
--- a/pkg/front_end/test/extensions/data/show_hide/lib2.dart
+++ b/pkg/front_end/test/extensions/data/show_hide/lib2.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 = 2.9
-
 /*library: scope=[
   HiddenExtension2,
   ShownExtension2,
@@ -16,7 +14,7 @@
  builder-onType=String,
  extension-members=[static staticMethod=HiddenExtension2|staticMethod],
  extension-name=HiddenExtension2,
- extension-onType=String
+ extension-onType=String!
 */
 extension HiddenExtension2 on String {
   /*member: HiddenExtension2|staticMethod:
@@ -31,7 +29,7 @@
  builder-onType=String,
  extension-members=[static staticMethod=ShownExtension2|staticMethod],
  extension-name=ShownExtension2,
- extension-onType=String
+ extension-onType=String!
 */
 extension ShownExtension2 on String {
   /*member: ShownExtension2|staticMethod:
diff --git a/pkg/front_end/test/extensions/data/show_hide/main.dart b/pkg/front_end/test/extensions/data/show_hide/main.dart
index 470c0ca..c137caa 100644
--- a/pkg/front_end/test/extensions/data/show_hide/main.dart
+++ b/pkg/front_end/test/extensions/data/show_hide/main.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 = 2.9
-
 /*library: scope=[
   async.dart.FutureExtensions,
   core.dart.EnumByName,
diff --git a/pkg/front_end/test/extensions/data/static_members.dart b/pkg/front_end/test/extensions/data/static_members.dart
index 0796bc8..4f0a7b1 100644
--- a/pkg/front_end/test/extensions/data/static_members.dart
+++ b/pkg/front_end/test/extensions/data/static_members.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 = 2.9
-
 /*library: scope=[
   A2,
   B2,
@@ -19,7 +17,8 @@
  extension-members=[
   static method1=A2|method1,
   static method2=A2|method2],
- extension-name=A2,extension-onType=A1
+ extension-name=A2,
+ extension-onType=A1!
 */
 extension A2 on A1 {
   /*member: A2|method1:
@@ -51,7 +50,7 @@
   static method1=B2|method1,
   static method2=B2|method2],
  extension-name=B2,
- extension-onType=B1<T>,
+ extension-onType=B1<T%>!,
  extension-type-params=[T]
 */
 extension B2<T> on B1<T> {
diff --git a/pkg/front_end/test/extensions/data/super.dart b/pkg/front_end/test/extensions/data/super.dart
index e01d659..3e96943 100644
--- a/pkg/front_end/test/extensions/data/super.dart
+++ b/pkg/front_end/test/extensions/data/super.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 = 2.9
-
 /*library: scope=[
   A2,
   async.dart.FutureExtensions,
@@ -21,7 +19,7 @@
   method2=A2|method2,
   tearoff method2=A2|get#method2],
  extension-name=A2,
- extension-onType=A1
+ extension-onType=A1!
 */
 extension A2 on A1 {
   /*member: A2|method2:
diff --git a/pkg/front_end/test/extensions/data/type_variables.dart b/pkg/front_end/test/extensions/data/type_variables.dart
index 26c0198..296775d 100644
--- a/pkg/front_end/test/extensions/data/type_variables.dart
+++ b/pkg/front_end/test/extensions/data/type_variables.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 = 2.9
-
 /*library: scope=[
   A2,
   A3,
@@ -24,17 +22,21 @@
   tearoff method1=A2|get#method1,
   tearoff method2=A2|get#method2],
  extension-name=A2,
- extension-onType=A1<T>,
+ extension-onType=A1<T%>!,
  extension-type-params=[T]
 */
 extension A2<T> on A1<T> {
   /*member: A2|method1:
-     builder-name=method1,
-     builder-params=[#this],
-     builder-type-params=[T,S extends T],
-     member-name=A2|method1,
-     member-params=[#this],
-     member-type-params=[T,S extends T]
+   builder-name=method1,
+   builder-params=[#this],
+   builder-type-params=[
+    T,
+    S extends T],
+   member-name=A2|method1,
+   member-params=[#this],
+   member-type-params=[
+    T,
+    S extends T%]
   */
   A1<T> method1<S extends T>() {
     return this;
@@ -50,12 +52,20 @@
   */
 
   /*member: A2|method2:
-     builder-name=method2,
-     builder-params=[#this,o],
-     builder-type-params=[T,S extends A1<T>],
-     member-name=A2|method2,
-     member-params=[#this,o],
-     member-type-params=[T,S extends A1<T>]
+   builder-name=method2,
+   builder-params=[
+    #this,
+    o],
+   builder-type-params=[
+    T,
+    S extends A1<T>],
+   member-name=A2|method2,
+   member-params=[
+    #this,
+    o],
+   member-type-params=[
+    T,
+    S extends A1<T%>!]
   */
   A1<T> method2<S extends A1<T>>(S o) {
     print(o);
@@ -77,8 +87,8 @@
  builder-onType=A1<T>,
  builder-type-params=[T extends A1<T>],
  extension-name=A3,
- extension-onType=A1<T>,
- extension-type-params=[T extends A1<T>]
+ extension-onType=A1<T!>!,
+ extension-type-params=[T extends A1<T!>!]
 */
 extension A3<T extends A1<T>> on A1<T> {
 }
@@ -91,7 +101,7 @@
   method=A4|method,
   tearoff method=A4|get#method],
  extension-name=A4,
- extension-onType=A1<T>,
+ extension-onType=A1<T%>!,
  extension-type-params=[T]
 */
 extension A4<T> on A1<T> {
diff --git a/pkg/front_end/test/extensions/data/unnamed_declarations.dart b/pkg/front_end/test/extensions/data/unnamed_declarations.dart
index df8a014..8c5d73f 100644
--- a/pkg/front_end/test/extensions/data/unnamed_declarations.dart
+++ b/pkg/front_end/test/extensions/data/unnamed_declarations.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 = 2.9
-
 /*library: scope=[
   _extension#0,
   _extension#1,
@@ -23,7 +21,7 @@
   method=_extension#0|method,
   tearoff method=_extension#0|get#method],
  extension-name=_extension#0,
- extension-onType=A1
+ extension-onType=A1!
 */
 extension on A1 {
   /*member: _extension#0|method:
@@ -49,7 +47,7 @@
   method=_extension#1|method,
   tearoff method=_extension#1|get#method],
  extension-name=_extension#1,
- extension-onType=A1
+ extension-onType=A1!
 */
 extension on A1 {
   /*member: _extension#1|method:
@@ -78,7 +76,7 @@
   method=_extension#2|method,
   tearoff method=_extension#2|get#method],
  extension-name=_extension#2,
- extension-onType=B1<T>,
+ extension-onType=B1<T%>!,
  extension-type-params=[T]
 */
 extension <T> on B1<T> {
@@ -109,7 +107,7 @@
   method=_extension#3|method,
   tearoff method=_extension#3|get#method],
  extension-name=_extension#3,
- extension-onType=B1<A1>
+ extension-onType=B1<A1!>!
 */
 extension on B1<A1> {
   /*member: _extension#3|method:
@@ -136,17 +134,17 @@
   method=_extension#4|method,
   tearoff method=_extension#4|get#method],
  extension-name=_extension#4,
- extension-onType=B1<T>,
- extension-type-params=[T extends A1]
+ extension-onType=B1<T!>!,
+ extension-type-params=[T extends A1!]
 */
 extension <T extends A1> on B1<T> {
   /*member: _extension#4|method:
-     builder-name=method,
-     builder-params=[#this],
-     builder-type-params=[T extends A1],
-     member-name=_extension#4|method,
-     member-params=[#this],
-     member-type-params=[T extends A1]
+   builder-name=method,
+   builder-params=[#this],
+   builder-type-params=[T extends A1],
+   member-name=_extension#4|method,
+   member-params=[#this],
+   member-type-params=[T extends A1!]
   */
   method() {}
 
@@ -156,7 +154,7 @@
    builder-type-params=[T extends A1],
    member-name=_extension#4|get#method,
    member-params=[#this],
-   member-type-params=[T extends A1]
+   member-type-params=[T extends A1!]
   */
 }
 
diff --git a/pkg/front_end/test/extensions/data/use_as_type.dart b/pkg/front_end/test/extensions/data/use_as_type.dart
index 824d8f1..297f763 100644
--- a/pkg/front_end/test/extensions/data/use_as_type.dart
+++ b/pkg/front_end/test/extensions/data/use_as_type.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 = 2.9
-
 /*library: scope=[
   A2,
   B2,
@@ -17,7 +15,7 @@
  builder-name=A2,
  builder-onType=A1,
  extension-name=A2,
- extension-onType=A1
+ extension-onType=A1!
 */
 extension A2 on A1 {}
 
@@ -28,7 +26,7 @@
  builder-onType=B1<T>,
  builder-type-params=[T],
  extension-name=B2,
- extension-onType=B1<T>,
+ extension-onType=B1<T%>!,
  extension-type-params=[T]
 */
 extension B2<T> on B1<T> {}
@@ -47,6 +45,6 @@
 // TODO(johnniwinther): We should report an error on the number of type
 // arguments here.
 /*error: errors=[This requires the experimental 'extension-types' language feature to be enabled.]*/
-B2<A1> method2() => null;
+B2<A1> method2() => throw '';
 
-B1</*error: errors=[This requires the experimental 'extension-types' language feature to be enabled.]*/A2> method3() => null;
+B1</*error: errors=[This requires the experimental 'extension-types' language feature to be enabled.]*/A2> method3() => throw '';
diff --git a/pkg/front_end/test/id_testing/data/declarations.dart b/pkg/front_end/test/id_testing/data/declarations.dart
index dfe8054..8f00ad4 100644
--- a/pkg/front_end/test/id_testing/data/declarations.dart
+++ b/pkg/front_end/test/id_testing/data/declarations.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 = 2.7
-
 /*library: file=main.dart*/
 
 /*member: main:main*/
diff --git a/pkg/front_end/test/id_testing/data/errors.dart b/pkg/front_end/test/id_testing/data/errors.dart
index c2693b3..e58d6c4 100644
--- a/pkg/front_end/test/id_testing/data/errors.dart
+++ b/pkg/front_end/test/id_testing/data/errors.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 = 2.7
-
 /*cfe.library: file=main.dart*/
 
 /*cfe.member: main:main*/
diff --git a/pkg/front_end/test/id_testing/data/library_with_name.dart b/pkg/front_end/test/id_testing/data/library_with_name.dart
index fabca66..cd9b07e 100644
--- a/pkg/front_end/test/id_testing/data/library_with_name.dart
+++ b/pkg/front_end/test/id_testing/data/library_with_name.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 = 2.9
-
 /*library: file=main.dart,name=lib*/
 library lib;