CREATE_MISSING_OVERRIDES to create brackets if missing

Fixes #37903

Change-Id: I13ed4e1bf34bf7d5cfd0bdc78d6191c6964cc28a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/210961
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Brian Wilkerson <brianwilkerson@google.com>

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

@@ -2,6 +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.
 
+import 'package:_fe_analyzer_shared/src/scanner/token.dart';
 import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/utilities/strings.dart';
@@ -27,8 +28,7 @@ class CreateMissingOverrides extends CorrectionProducer {
       return;
     }
     var targetClass = node.parent as ClassDeclaration;
-    var targetClassElement = targetClass.declaredElement;
-    utils.targetClassElement = targetClassElement;
+    utils.targetClassElement = targetClass.declaredElement;
     var signatures =
         InheritanceOverrideVerifier.missingOverrides(targetClass).toList();
     // sort by name, getters before setters
@@ -52,12 +52,22 @@ class CreateMissingOverrides extends CorrectionProducer {
 
     var prefix = utils.getIndent(1);
     await builder.addDartFileEdit(file, (builder) {
+      final syntheticLeftBracket = targetClass.leftBracket.isSynthetic;
+      if (syntheticLeftBracket) {
+        var previousToLeftBracket = targetClass.leftBracket.previous;
+        builder.addSimpleInsertion(previousToLeftBracket!.end, ' {');
+      }
+
       builder.addInsertion(location.offset, (builder) {
         // Separator management.
         var numOfMembersWritten = 0;
         void addSeparatorBetweenDeclarations() {
           if (numOfMembersWritten == 0) {
-            builder.write(location.prefix);
+            var locationPrefix = location.prefix;
+            if (syntheticLeftBracket && locationPrefix.startsWith(eol)) {
+              locationPrefix = locationPrefix.substring(eol.length);
+            }
+            builder.write(locationPrefix);
           } else {
             builder.write(eol); // after the previous member
             builder.write(eol); // empty line separator
@@ -97,6 +107,19 @@ class CreateMissingOverrides extends CorrectionProducer {
           builder.writeOverride(element);
         }
         builder.write(location.suffix);
+
+        if (targetClass.rightBracket.isSynthetic) {
+          var next = targetClass.rightBracket.next;
+          if (next!.type != TokenType.CLOSE_CURLY_BRACKET) {
+            if (!syntheticLeftBracket) {
+              builder.write(eol);
+            }
+            builder.write('}');
+            if (syntheticLeftBracket) {
+              builder.write(eol);
+            }
+          }
+        }
       });
     });
     builder.setSelection(Position(file, location.offset));

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

@@ -3,6 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:analysis_server/src/services/correction/fix.dart';
+import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
@@ -22,6 +23,82 @@ class CreateMissingOverridesTest extends FixProcessorTest {
   @override
   FixKind get kind => DartFixKind.CREATE_MISSING_OVERRIDES;
 
+  Future<void> test_brackets_both() async {
+    await resolveTestCode('''
+class A {
+  void m() {};
+}
+
+class B implements A
+''');
+    await assertHasFix('''
+class A {
+  void m() {};
+}
+
+class B implements A {
+  @override
+  void m() {
+    // TODO: implement m
+  }
+}
+''', errorFilter: (error) {
+      return error.errorCode ==
+          CompileTimeErrorCode.NON_ABSTRACT_CLASS_INHERITS_ABSTRACT_MEMBER_ONE;
+    });
+  }
+
+  Future<void> test_brackets_left() async {
+    await resolveTestCode('''
+class A {
+  void m() {};
+}
+
+class B implements A
+}
+''');
+    await assertHasFix('''
+class A {
+  void m() {};
+}
+
+class B implements A {
+  @override
+  void m() {
+    // TODO: implement m
+  }
+}
+''', errorFilter: (error) {
+      return error.errorCode ==
+          CompileTimeErrorCode.NON_ABSTRACT_CLASS_INHERITS_ABSTRACT_MEMBER_ONE;
+    });
+  }
+
+  Future<void> test_brackets_right() async {
+    await resolveTestCode('''
+class A {
+  void m() {};
+}
+
+class B implements A {
+''');
+    await assertHasFix('''
+class A {
+  void m() {};
+}
+
+class B implements A {
+  @override
+  void m() {
+    // TODO: implement m
+  }
+}
+''', errorFilter: (error) {
+      return error.errorCode ==
+          CompileTimeErrorCode.NON_ABSTRACT_CLASS_INHERITS_ABSTRACT_MEMBER_ONE;
+    });
+  }
+
   Future<void> test_field_untyped() async {
     await resolveTestCode('''
 class A {