annotation validation for extension types

validation/tests for application of

* `@mustCallSuper`
* `@nonVirtual`
* `@reopen`
* `@sealed`

to extension types

See: #53434

Change-Id: I005523507044e7d5879a5589c132384e7bb8be56
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/324768
Reviewed-by: Brian Wilkerson <[email protected]>
Commit-Queue: Phil Quitslund <[email protected]>

Author: pq

pkg/analyzer/lib/src/error/annotation_verifier.dart

@@ -227,6 +227,7 @@ class AnnotationVerifier {
     if ((parent is MethodDeclaration && parent.isStatic) ||
         (parent is FieldDeclaration && parent.isStatic) ||
         parent.parent is ExtensionDeclaration ||
+        parent.parent is ExtensionTypeDeclaration ||
         parent.parent is EnumDeclaration) {
       _errorReporter.reportErrorForNode(
         WarningCode.INVALID_ANNOTATION_TARGET,
@@ -247,6 +248,7 @@ class AnnotationVerifier {
       }
     } else if (parent is MethodDeclaration) {
       if (parent.parent is ExtensionDeclaration ||
+          parent.parent is ExtensionTypeDeclaration ||
           parent.isStatic ||
           parent.isAbstract) {
         _errorReporter.reportErrorForNode(

pkg/analyzer/test/src/diagnostics/invalid_annotation_target_test.dart

@@ -334,6 +334,19 @@ extension E on String {
     ]);
   }
 
+  test_extensionType_instance_method() async {
+    await assertErrorsInCode(r'''
+import 'package:meta/meta.dart';
+
+extension type E(int i) {
+  @mustCallSuper
+  void m() { }
+}
+''', [
+      error(WarningCode.INVALID_ANNOTATION_TARGET, 62, 14),
+    ]);
+  }
+
   test_mixin_instance_method() async {
     await assertNoErrorsInCode(r'''
 import 'package:meta/meta.dart';

pkg/analyzer/test/src/diagnostics/invalid_non_virtual_annotation_test.dart

@@ -167,6 +167,19 @@ extension E on Object {
     ]);
   }
 
+  test_extensionType_instance_method() async {
+    await assertErrorsInCode(r'''
+import 'package:meta/meta.dart';
+
+extension type E(int i) {
+  @nonVirtual
+  void m() { }
+}
+''', [
+      error(WarningCode.INVALID_NON_VIRTUAL_ANNOTATION, 62, 11),
+    ]);
+  }
+
   test_import() async {
     await assertErrorsInCode(r'''
 @nonVirtual

pkg/analyzer/test/src/diagnostics/invalid_reopen_annotation_test.dart

@@ -108,6 +108,19 @@ base mixin class B implements A {}
     ]);
   }
 
+  test_extensionType() async {
+    await assertErrorsInCode(r'''
+import 'package:meta/meta.dart';
+
+@reopen
+extension type E(int i) {
+  void m() { }
+}
+''', [
+      error(WarningCode.INVALID_ANNOTATION_TARGET, 35, 6),
+    ]);
+  }
+
   test_finalClass_supertypeIsFinal() async {
     await assertErrorsInCode(r'''
 import 'package:meta/meta.dart';

pkg/analyzer/test/src/diagnostics/invalid_sealed_annotation_test.dart

@@ -29,6 +29,19 @@ import 'package:meta/meta.dart';
 ''');
   }
 
+  test_extensionType() async {
+    await assertErrorsInCode(r'''
+import 'package:meta/meta.dart';
+
+@sealed
+extension type E(int i) {
+  void m() { }
+}
+''', [
+      error(WarningCode.INVALID_SEALED_ANNOTATION, 34, 7),
+    ]);
+  }
+
   test_mixin() async {
     await assertErrorsInCode(r'''
 import 'package:meta/meta.dart';