[DAS] Fixes create method for enums and extension types

Fixes: https://github.com/dart-lang/sdk/issues/60562
Change-Id: I8bbc92205f5900c025e9dc31110f3e1cb2343643
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/423240
Reviewed-by: Samuel Rawlins <srawlins@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Auto-Submit: Felipe Morschel <git@fmorschel.dev>
Commit-Queue: Samuel Rawlins <srawlins@google.com>

pkg/analysis_server/lib/src/services/correction/dart/create_method.dart

@@ -150,6 +150,9 @@ class CreateMethod extends ResolvedCorrectionProducer {
       } else if (targetClassElement is ExtensionTypeElement2) {
         var fragment = targetClassElement.firstFragment;
         targetNode = await getExtensionTypeDeclaration(fragment);
+      } else if (targetClassElement is EnumElement2) {
+        var fragment = targetClassElement.firstFragment;
+        targetNode = await getEnumDeclaration(fragment);
       }
       if (targetNode == null) {
         return;
@@ -158,6 +161,7 @@ class CreateMethod extends ResolvedCorrectionProducer {
       if (target is Identifier) {
         staticModifier =
             target.element?.kind == ElementKind.CLASS ||
+            target.element?.kind == ElementKind.ENUM ||
             target.element?.kind == ElementKind.EXTENSION_TYPE ||
             target.element?.kind == ElementKind.MIXIN;
       }

pkg/analysis_server/lib/src/services/correction/dart/create_method_or_function.dart

@@ -36,6 +36,7 @@ class CreateMethodOrFunction extends ResolvedCorrectionProducer {
 
   @override
   Future<void> compute(ChangeBuilder builder) async {
+    var isStatic = false;
     var nameNode = node;
     if (nameNode is SimpleIdentifier) {
       // prepare argument expression (to get parameter)
@@ -47,6 +48,13 @@ class CreateMethodOrFunction extends ResolvedCorrectionProducer {
         if (targetType is InterfaceType) {
           targetElement = targetType.element3;
           argument = target.parent as Expression;
+        } else if (target case SimpleIdentifier(
+          :InterfaceElement2? element,
+          :Expression parent,
+        )) {
+          isStatic = true;
+          targetElement = element;
+          argument = parent;
         } else {
           return;
         }
@@ -107,7 +115,12 @@ class CreateMethodOrFunction extends ResolvedCorrectionProducer {
       }
       // add proposal
       if (targetElement != null) {
-        await _createMethod(builder, targetElement, parameterType);
+        await _createMethod(
+          builder,
+          targetElement,
+          parameterType,
+          isStatic: isStatic,
+        );
       } else {
         await _createFunction(builder, parameterType);
       }
@@ -195,8 +208,9 @@ class CreateMethodOrFunction extends ResolvedCorrectionProducer {
   Future<void> _createMethod(
     ChangeBuilder builder,
     InterfaceElement2 targetClassElement,
-    FunctionType functionType,
-  ) async {
+    FunctionType functionType, {
+    required bool isStatic,
+  }) async {
     var name = (node as SimpleIdentifier).name;
     // prepare environment
     var targetSource = targetClassElement.firstFragment.libraryFragment.source;
@@ -211,6 +225,14 @@ class CreateMethodOrFunction extends ResolvedCorrectionProducer {
       var fragment = targetClassElement.firstFragment;
       var node = targetNode = await getClassDeclaration(fragment);
       classMembers = node?.members;
+    } else if (targetClassElement is ExtensionTypeElement2) {
+      var fragment = targetClassElement.firstFragment;
+      var node = targetNode = await getExtensionTypeDeclaration(fragment);
+      classMembers = node?.members;
+    } else if (targetClassElement is EnumElement2) {
+      var fragment = targetClassElement.firstFragment;
+      var node = targetNode = await getEnumDeclaration(fragment);
+      classMembers = node?.members;
     }
     if (targetNode == null || classMembers == null) {
       return;
@@ -231,7 +253,7 @@ class CreateMethodOrFunction extends ResolvedCorrectionProducer {
       name,
       targetSource.fullName,
       insertOffset,
-      inStaticContext,
+      isStatic || inStaticContext,
       prefix,
       sourcePrefix,
       sourceSuffix,

pkg/analysis_server/lib/src/services/correction/fix_internal.dart

@@ -965,6 +965,7 @@ final _builtInNonLintGenerators = <ErrorCode, List<ProducerGenerator>>{
   CompileTimeErrorCode.UNDEFINED_ENUM_CONSTANT: [
     AddEnumConstant.new,
     ChangeTo.getterOrSetter,
+    CreateMethodOrFunction.new,
   ],
   CompileTimeErrorCode.UNDEFINED_ENUM_CONSTRUCTOR_NAMED: [
     CreateConstructor.new,

pkg/analysis_server/test/src/services/correction/fix/create_method_test.dart

@@ -728,6 +728,164 @@ class A {
 ''');
   }
 
+  Future<void> test_enum_invocation() async {
+    await resolveTestCode('''
+enum E {
+  e1,
+  e2;
+}
+
+void test(E e) {
+  e.bar();
+}
+''');
+    await assertHasFix('''
+enum E {
+  e1,
+  e2;
+
+  void bar() {}
+}
+
+void test(E e) {
+  e.bar();
+}
+''');
+  }
+
+  Future<void> test_enum_invocation_static() async {
+    await resolveTestCode('''
+enum E {
+  e1,
+  e2;
+}
+
+void test() {
+  E.bar();
+}
+''');
+    await assertHasFix('''
+enum E {
+  e1,
+  e2;
+
+  static void bar() {}
+}
+
+void test() {
+  E.bar();
+}
+''');
+  }
+
+  Future<void> test_enum_tearoff() async {
+    await resolveTestCode('''
+enum E {
+  e1,
+  e2;
+}
+
+void g(int Function() f) {}
+
+void test(E e) {
+  g(e.bar);
+}
+''');
+    await assertHasFix('''
+enum E {
+  e1,
+  e2;
+  int bar() {
+  }
+}
+
+void g(int Function() f) {}
+
+void test(E e) {
+  g(e.bar);
+}
+''');
+  }
+
+  Future<void> test_enum_tearoff_static() async {
+    await resolveTestCode('''
+enum E {
+  e1,
+  e2;
+}
+
+void g(int Function() f) {}
+
+void test() {
+  g(E.bar);
+}
+''');
+    await assertHasFix('''
+enum E {
+  e1,
+  e2;
+  static int bar() {
+  }
+}
+
+void g(int Function() f) {}
+
+void test() {
+  g(E.bar);
+}
+''');
+  }
+
+  Future<void> test_extensionType_tearoff() async {
+    await resolveTestCode('''
+extension type E(int i) {
+}
+
+void g(int Function() f) {}
+
+void test(E e) {
+  g(e.bar);
+}
+''');
+    await assertHasFix('''
+extension type E(int i) {
+  int bar() {
+  }
+}
+
+void g(int Function() f) {}
+
+void test(E e) {
+  g(e.bar);
+}
+''');
+  }
+
+  Future<void> test_extensionType_tearoff_static() async {
+    await resolveTestCode('''
+extension type E(int i) {
+}
+
+void g(int Function() f) {}
+
+void test() {
+  g(E.bar);
+}
+''');
+    await assertHasFix('''
+extension type E(int i) {
+  static int bar() {
+  }
+}
+
+void g(int Function() f) {}
+
+void test() {
+  g(E.bar);
+}
+''');
+  }
+
   Future<void> test_functionType_argument() async {
     await resolveTestCode('''
 class A {
@@ -1465,14 +1623,4 @@ void f() {
 }
 ''');
   }
-
-  Future<void> test_targetIsEnum() async {
-    await resolveTestCode('''
-enum MyEnum {A, B}
-void f() {
-  MyEnum.foo();
-}
-''');
-    await assertNoFix();
-  }
 }

pkg/analysis_server_plugin/lib/edit/dart/correction_producer.dart

@@ -429,6 +429,17 @@ abstract class ResolvedCorrectionProducer
     return null;
   }
 
+  /// Returns the class declaration for the given [fragment], or `null` if there
+  /// is no such class.
+  Future<EnumDeclaration?> getEnumDeclaration(EnumFragment fragment) async {
+    var result = await sessionHelper.getFragmentDeclaration(fragment);
+    var node = result?.node;
+    if (node is EnumDeclaration) {
+      return node;
+    }
+    return null;
+  }
+
   /// Returns the extension declaration for the given [fragment], or `null` if
   /// there is no such extension.
   Future<ExtensionDeclaration?> getExtensionDeclaration(