[analysis_server] In "Encapsulate Field", update references to renamed parameters in initializers

Fixes https://github.com/dart-lang/sdk/issues/63145

Change-Id: I6dd672e5ae189a023419d2c41157fa7cdc43e46b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/494141
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Reviewed-by: Keerti Parthasarathy <keertip@google.com>
Commit-Queue: Keerti Parthasarathy <keertip@google.com>

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

@@ -7,6 +7,7 @@ import 'package:analysis_server/src/utilities/extensions/ast.dart';
 import 'package:analysis_server_plugin/edit/dart/correction_producer.dart';
 import 'package:analyzer/dart/analysis/features.dart';
 import 'package:analyzer/dart/ast/token.dart';
+import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/dart/ast/ast.dart';
 import 'package:analyzer/src/dart/ast/extensions.dart';
@@ -305,6 +306,10 @@ class EncapsulateField extends ResolvedCorrectionProducer {
     required Token? separator,
     required NodeList<ConstructorInitializer>? initializers,
   }) {
+    // If we rename a parameter, keep track of it so we can update any
+    // references in initializers.
+    FieldFormalParameterElement? renamedParameterElement;
+
     // Update any field formal parameter that refers to the field.
     for (var parameter in parameters.parameters) {
       var identifier = parameter.name;
@@ -340,6 +345,7 @@ class EncapsulateField extends ResolvedCorrectionProducer {
       } else {
         // Rename the parameter.
         builder.addSimpleReplacement(range.token(identifier), '_$name');
+        renamedParameterElement = parameterElement;
       }
 
       // Change `final` to `var` in declaring parameters.
@@ -361,6 +367,17 @@ class EncapsulateField extends ResolvedCorrectionProducer {
             '_$name',
           );
         }
+
+        // Update any references to the renamed parameter in initializers.
+        if (renamedParameterElement != null) {
+          initializer.accept(
+            _InitializerReferenceUpdater(
+              builder,
+              renamedParameterElement,
+              '_$name',
+            ),
+          );
+        }
       }
     }
   }
@@ -402,3 +419,23 @@ class EncapsulateField extends ResolvedCorrectionProducer {
     }
   }
 }
+
+/// Updates references to [parameterElement] to use [newName].
+class _InitializerReferenceUpdater extends RecursiveAstVisitor<void> {
+  final DartFileEditBuilder builder;
+  final FieldFormalParameterElement parameterElement;
+  final String newName;
+
+  _InitializerReferenceUpdater(
+    this.builder,
+    this.parameterElement,
+    this.newName,
+  );
+
+  @override
+  void visitSimpleIdentifier(SimpleIdentifier node) {
+    if (node.element == parameterElement) {
+      builder.addSimpleReplacement(range.token(node.token), newName);
+    }
+  }
+}

pkg/analysis_server/test/src/services/correction/assist/encapsulate_field_test.dart

@@ -335,6 +335,73 @@ void f(A a) {
 ''');
   }
 
+  Future<void> test_initializer_reference() async {
+    await resolveTestCode('''
+class Foo {
+  final int ^a;
+  final int b;
+
+  Foo(this.a) : b = a + 1 {}
+}
+''');
+    await assertHasAssist('''
+class Foo {
+  int _a;
+
+  int get a => _a;
+  final int b;
+
+  Foo(this._a) : b = _a + 1 {}
+}
+''');
+  }
+
+  Future<void> test_initializer_reference_noPrivateNamedParameters() async {
+    await resolveTestCode('''
+// @dart=3.10
+
+class Foo {
+  final int ^a;
+  final int b;
+
+  Foo({required this.a}) : b = a + 1 {}
+}
+''');
+    await assertHasAssist('''
+// @dart=3.10
+
+class Foo {
+  int _a;
+
+  int get a => _a;
+  final int b;
+
+  Foo({required int a}) : _a = a, b = a + 1 {}
+}
+''');
+  }
+
+  Future<void> test_initializer_reference_privateNamedParameters() async {
+    await resolveTestCode('''
+class Foo {
+  final int ^a;
+  final int b;
+
+  Foo({required this.a}) : b = a + 1 {}
+}
+''');
+    await assertHasAssist('''
+class Foo {
+  int _a;
+
+  int get a => _a;
+  final int b;
+
+  Foo({required this._a}) : b = _a + 1 {}
+}
+''');
+  }
+
   Future<void> test_mixin_hasType() async {
     await resolveTestCode('''
 mixin M {