Issue 52176. Support for ojbect pattern in 'Create Getter' and 'CCreate Field'.

Bug: https://github.com/dart-lang/sdk/issues/52176
Change-Id: Ic9c97bec1981c5613b23206e872f6f708d53792d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/298920
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>

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

@@ -2,16 +2,17 @@
 // 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:analysis_server/src/services/correction/dart/abstract_producer.dart';
+import 'package:analysis_server/src/services/correction/dart/create_getter.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/correction/util.dart';
 import 'package:analysis_server/src/utilities/extensions/ast.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
+import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 
-class CreateField extends CorrectionProducer {
+class CreateField extends CreateFieldOrGetter {
   /// The name of the field to be created.
   String _fieldName = '';
 
@@ -21,8 +22,29 @@ class CreateField extends CorrectionProducer {
   @override
   FixKind get fixKind => DartFixKind.CREATE_FIELD;
 
+  @override
+  Future<void> addForObjectPattern({
+    required ChangeBuilder builder,
+    required InterfaceElement? targetElement,
+    required String fieldName,
+    required DartType? fieldType,
+  }) async {
+    _fieldName = fieldName;
+
+    await _addDeclaration(
+      builder: builder,
+      staticModifier: false,
+      targetElement: targetElement,
+      fieldType: fieldType,
+    );
+  }
+
   @override
   Future<void> compute(ChangeBuilder builder) async {
+    if (await compute0(builder)) {
+      return;
+    }
+
     var parameter = node.thisOrAncestorOfType<FieldFormalParameter>();
     if (parameter != null) {
       await _proposeFromFieldFormalParameter(builder, parameter);
@@ -31,6 +53,58 @@ class CreateField extends CorrectionProducer {
     }
   }
 
+  Future<void> _addDeclaration({
+    required ChangeBuilder builder,
+    required bool staticModifier,
+    required InterfaceElement? targetElement,
+    required DartType? fieldType,
+  }) async {
+    if (targetElement == null) {
+      return;
+    }
+    if (targetElement.library.isInSdk) {
+      return;
+    }
+    utils.targetClassElement = targetElement;
+    // prepare target ClassDeclaration
+    var targetDeclarationResult =
+        await sessionHelper.getElementDeclaration(targetElement);
+    if (targetDeclarationResult == null) {
+      return;
+    }
+    var targetNode = targetDeclarationResult.node;
+    if (targetNode is! CompilationUnitMember) {
+      return;
+    }
+    if (!(targetNode is ClassDeclaration || targetNode is MixinDeclaration)) {
+      return;
+    }
+    // prepare location
+    var targetUnit = targetDeclarationResult.resolvedUnit;
+    if (targetUnit == null) {
+      return;
+    }
+    var targetLocation =
+        CorrectionUtils(targetUnit).prepareNewFieldLocation(targetNode);
+    if (targetLocation == null) {
+      return;
+    }
+    // build field source
+    var targetSource = targetElement.source;
+    var targetFile = targetSource.fullName;
+    await builder.addDartFileEdit(targetFile, (builder) {
+      builder.addInsertion(targetLocation.offset, (builder) {
+        builder.write(targetLocation.prefix);
+        builder.writeFieldDeclaration(_fieldName,
+            isStatic: staticModifier,
+            nameGroupName: 'NAME',
+            type: fieldType,
+            typeGroupName: 'TYPE');
+        builder.write(targetLocation.suffix);
+      });
+    });
+  }
+
   Future<void> _proposeFromFieldFormalParameter(
       ChangeBuilder builder, FieldFormalParameter parameter) async {
     var targetClassNode = parameter.thisOrAncestorOfType<ClassDeclaration>();
@@ -93,51 +167,15 @@ class CreateField extends CorrectionProducer {
       targetClassElement = node.enclosingInterfaceElement;
       staticModifier = inStaticContext;
     }
-    if (targetClassElement == null) {
-      return;
-    }
-    if (targetClassElement.library.isInSdk) {
-      return;
-    }
-    utils.targetClassElement = targetClassElement;
-    // prepare target ClassDeclaration
-    var targetDeclarationResult =
-        await sessionHelper.getElementDeclaration(targetClassElement);
-    if (targetDeclarationResult == null) {
-      return;
-    }
-    var targetNode = targetDeclarationResult.node;
-    if (targetNode is! CompilationUnitMember) {
-      return;
-    }
-    if (!(targetNode is ClassDeclaration || targetNode is MixinDeclaration)) {
-      return;
-    }
-    // prepare location
-    var targetUnit = targetDeclarationResult.resolvedUnit;
-    if (targetUnit == null) {
-      return;
-    }
-    var targetLocation =
-        CorrectionUtils(targetUnit).prepareNewFieldLocation(targetNode);
-    if (targetLocation == null) {
-      return;
-    }
-    // build field source
-    var targetSource = targetClassElement.source;
-    var targetFile = targetSource.fullName;
-    await builder.addDartFileEdit(targetFile, (builder) {
-      var fieldTypeNode = climbPropertyAccess(nameNode);
-      var fieldType = inferUndefinedExpressionType(fieldTypeNode);
-      builder.addInsertion(targetLocation.offset, (builder) {
-        builder.write(targetLocation.prefix);
-        builder.writeFieldDeclaration(_fieldName,
-            isStatic: staticModifier,
-            nameGroupName: 'NAME',
-            type: fieldType,
-            typeGroupName: 'TYPE');
-        builder.write(targetLocation.suffix);
-      });
-    });
+
+    var fieldTypeNode = climbPropertyAccess(nameNode);
+    var fieldType = inferUndefinedExpressionType(fieldTypeNode);
+
+    await _addDeclaration(
+      builder: builder,
+      staticModifier: staticModifier,
+      targetElement: targetClassElement,
+      fieldType: fieldType,
+    );
   }
 }

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

@@ -9,10 +9,86 @@ import 'package:analysis_server/src/utilities/extensions/ast.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
+import 'package:analyzer/src/dart/ast/ast.dart';
+import 'package:analyzer/src/dart/ast/extensions.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
+import 'package:meta/meta.dart';
 
-class CreateGetter extends CorrectionProducer {
+/// Shared implementation that identifies what getter should be added,
+/// but delegates to the subtypes to produce the fix code.
+abstract class CreateFieldOrGetter extends CorrectionProducer {
+  /// Adds the declaration that makes a [fieldName] available.
+  Future<void> addForObjectPattern({
+    required ChangeBuilder builder,
+    required InterfaceElement? targetElement,
+    required String fieldName,
+    required DartType? fieldType,
+  });
+
+  @protected
+  Future<bool> compute0(ChangeBuilder builder) async {
+    final node = this.node;
+
+    if (node is DeclaredVariablePatternImpl) {
+      final fieldName = node.fieldNameWithImplicitName;
+      if (fieldName != null) {
+        await _patternFieldName(
+          builder: builder,
+          fieldName: fieldName,
+        );
+        return true;
+      }
+    }
+
+    if (node is PatternFieldName) {
+      await _patternFieldName(
+        builder: builder,
+        fieldName: node,
+      );
+      return true;
+    }
+
+    return false;
+  }
+
+  Future<void> _patternFieldName({
+    required ChangeBuilder builder,
+    required PatternFieldName fieldName,
+  }) async {
+    final patternField = node.parent;
+    if (patternField is! PatternField) {
+      return;
+    }
+
+    final effectiveName = patternField.effectiveName;
+    if (effectiveName == null) {
+      return;
+    }
+
+    final objectPattern = patternField.parent;
+    if (objectPattern is! ObjectPattern) {
+      return;
+    }
+
+    final matchedType = objectPattern.type.typeOrThrow;
+    if (matchedType is! InterfaceType) {
+      return;
+    }
+
+    var fieldType = patternField.pattern.requiredType;
+    fieldType ??= typeProvider.objectQuestionType;
+
+    await addForObjectPattern(
+      builder: builder,
+      targetElement: matchedType.element,
+      fieldName: effectiveName,
+      fieldType: fieldType,
+    );
+  }
+}
+
+class CreateGetter extends CreateFieldOrGetter {
   String _getterName = '';
 
   @override
@@ -21,8 +97,28 @@ class CreateGetter extends CorrectionProducer {
   @override
   FixKind get fixKind => DartFixKind.CREATE_GETTER;
 
+  @override
+  Future<void> addForObjectPattern({
+    required ChangeBuilder builder,
+    required InterfaceElement? targetElement,
+    required String fieldName,
+    required DartType? fieldType,
+  }) async {
+    _getterName = fieldName;
+
+    await _addDeclaration(
+      builder: builder,
+      staticModifier: false,
+      targetElement: targetElement,
+      fieldType: fieldType,
+    );
+  }
+
   @override
   Future<void> compute(ChangeBuilder builder) async {
+    if (await compute0(builder)) {
+      return;
+    }
     var nameNode = node;
     if (nameNode is! SimpleIdentifier) {
       return;
@@ -64,16 +160,35 @@ class CreateGetter extends CorrectionProducer {
         staticModifier = targetElement?.kind == ElementKind.CLASS;
       }
     } else {
-      targetElement =
-          node.enclosingInterfaceElement ?? node.enclosingExtensionElement;
+      targetElement = nameNode.enclosingInterfaceElement ??
+          nameNode.enclosingExtensionElement;
       if (targetElement == null) {
         return;
       }
       staticModifier = inStaticContext;
     }
+
+    var fieldTypeNode = climbPropertyAccess(nameNode);
+    var fieldType = inferUndefinedExpressionType(fieldTypeNode);
+
+    await _addDeclaration(
+      builder: builder,
+      staticModifier: staticModifier,
+      targetElement: targetElement,
+      fieldType: fieldType,
+    );
+  }
+
+  Future<void> _addDeclaration({
+    required ChangeBuilder builder,
+    required bool staticModifier,
+    required Element? targetElement,
+    required DartType? fieldType,
+  }) async {
     if (targetElement == null) {
       return;
     }
+
     var targetSource = targetElement.source;
     if (targetSource == null || targetElement.library?.isInSdk == true) {
       return;
@@ -108,8 +223,6 @@ class CreateGetter extends CorrectionProducer {
     var targetFile = targetSource.fullName;
     await builder.addDartFileEdit(targetFile, (builder) {
       builder.addInsertion(targetLocation.offset, (builder) {
-        var fieldTypeNode = climbPropertyAccess(nameNode);
-        var fieldType = inferUndefinedExpressionType(fieldTypeNode);
         builder.write(targetLocation.prefix);
         builder.writeGetterDeclaration(_getterName,
             isStatic: staticModifier,

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

@@ -415,6 +415,98 @@ class C {
 ''');
   }
 
+  Future<void> test_objectPattern_explicitName_variablePattern_typed() async {
+    await resolveTestCode('''
+void f(Object? x) {
+  if (x case A(test: int y)) {
+    y;
+  }
+}
+
+class A {
+}
+''');
+    await assertHasFix('''
+void f(Object? x) {
+  if (x case A(test: int y)) {
+    y;
+  }
+}
+
+class A {
+  int test;
+}
+''');
+  }
+
+  Future<void> test_objectPattern_explicitName_variablePattern_untyped() async {
+    await resolveTestCode('''
+void f(Object? x) {
+  if (x case A(test: var y)) {
+    y;
+  }
+}
+
+class A {
+}
+''');
+    await assertHasFix('''
+void f(Object? x) {
+  if (x case A(test: var y)) {
+    y;
+  }
+}
+
+class A {
+  Object? test;
+}
+''');
+  }
+
+  Future<void> test_objectPattern_explicitName_wildcardPattern_typed() async {
+    await resolveTestCode('''
+void f(Object? x) {
+  if (x case A(test: int _)) {}
+}
+
+class A {
+}
+''');
+    await assertHasFix('''
+void f(Object? x) {
+  if (x case A(test: int _)) {}
+}
+
+class A {
+  int test;
+}
+''');
+  }
+
+  Future<void> test_objectPattern_implicitName_variablePattern_typed() async {
+    await resolveTestCode('''
+void f(Object? x) {
+  if (x case A(:int test)) {
+    test;
+  }
+}
+
+class A {
+}
+''');
+    await assertHasFix('''
+void f(Object? x) {
+  if (x case A(:int test)) {
+    test;
+  }
+}
+
+class A {
+  int test;
+}
+''');
+  }
+
   Future<void> test_setter_generic_BAD() async {
     await resolveTestCode('''
 class A {

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

@@ -205,6 +205,98 @@ void f(C c) {
 ''');
   }
 
+  Future<void> test_objectPattern_explicitName_variablePattern_typed() async {
+    await resolveTestCode('''
+void f(Object? x) {
+  if (x case A(test: int y)) {
+    y;
+  }
+}
+
+class A {
+}
+''');
+    await assertHasFix('''
+void f(Object? x) {
+  if (x case A(test: int y)) {
+    y;
+  }
+}
+
+class A {
+  int get test => null;
+}
+''');
+  }
+
+  Future<void> test_objectPattern_explicitName_variablePattern_untyped() async {
+    await resolveTestCode('''
+void f(Object? x) {
+  if (x case A(test: var y)) {
+    y;
+  }
+}
+
+class A {
+}
+''');
+    await assertHasFix('''
+void f(Object? x) {
+  if (x case A(test: var y)) {
+    y;
+  }
+}
+
+class A {
+  Object? get test => null;
+}
+''');
+  }
+
+  Future<void> test_objectPattern_explicitName_wildcardPattern() async {
+    await resolveTestCode('''
+void f(Object? x) {
+  if (x case A(test: int _)) {}
+}
+
+class A {
+}
+''');
+    await assertHasFix('''
+void f(Object? x) {
+  if (x case A(test: int _)) {}
+}
+
+class A {
+  int get test => null;
+}
+''');
+  }
+
+  Future<void> test_objectPattern_implicitName_variablePattern() async {
+    await resolveTestCode('''
+void f(Object? x) {
+  if (x case A(:int test)) {
+    test;
+  }
+}
+
+class A {
+}
+''');
+    await assertHasFix('''
+void f(Object? x) {
+  if (x case A(:int test)) {
+    test;
+  }
+}
+
+class A {
+  int get test => null;
+}
+''');
+  }
+
   Future<void> test_override() async {
     await resolveTestCode('''
 extension E on String {

pkg/analyzer/lib/dart/element/type_provider.dart

@@ -96,6 +96,12 @@ abstract class TypeProvider {
   /// Return the type representing the built-in type `num`.
   InterfaceType get numType;
 
+  /// Return the element representing the built-in class `Object`.
+  ClassElement get objectElement;
+
+  /// Return the type representing the built-in type `Object?`.
+  InterfaceType get objectQuestionType;
+
   /// Return the type representing the built-in type `Object`.
   InterfaceType get objectType;
 

pkg/analyzer/lib/src/dart/ast/extensions.dart

@@ -124,6 +124,20 @@ extension DartPatternExtension on DartPattern {
     }
     return type;
   }
+
+  DartType? get requiredType {
+    final self = this;
+    if (self is DeclaredVariablePattern) {
+      return self.type?.typeOrThrow;
+    } else if (self is ListPattern) {
+      return self.requiredType;
+    } else if (self is MapPattern) {
+      return self.requiredType;
+    } else if (self is WildcardPattern) {
+      return self.type?.typeOrThrow;
+    }
+    return null;
+  }
 }
 
 extension ExpressionExtension on Expression {

pkg/analyzer/lib/src/dart/element/type_provider.dart

@@ -143,6 +143,7 @@ class TypeProviderImpl extends TypeProviderBase {
   InterfaceType? _numType;
   InterfaceType? _numTypeQuestion;
   InterfaceType? _objectType;
+  InterfaceType? _objectQuestionType;
   InterfaceType? _recordType;
   InterfaceType? _stackTraceType;
   InterfaceType? _streamDynamicType;
@@ -384,13 +385,25 @@ class TypeProviderImpl extends TypeProviderBase {
       _numTypeQuestion ??= (numType as InterfaceTypeImpl)
           .withNullability(NullabilitySuffix.question);
 
+  @override
   ClassElement get objectElement {
     return _objectElement ??= _getClassElement(_coreLibrary, 'Object');
   }
 
+  @override
+  InterfaceType get objectQuestionType {
+    return _objectQuestionType ??= objectElement.instantiate(
+      typeArguments: const [],
+      nullabilitySuffix: NullabilitySuffix.question,
+    );
+  }
+
   @override
   InterfaceType get objectType {
-    return _objectType ??= _getType(_coreLibrary, "Object");
+    return _objectType ??= objectElement.instantiate(
+      typeArguments: const [],
+      nullabilitySuffix: _nullabilitySuffix,
+    );
   }
 
   @override