Fix for use_key_in_widget_constructors to add key at the end

Fixes #48917

Change-Id: Ie9a1e06188ad958ba89cd7b37081878211b3e90b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/243905
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Brian Wilkerson <brianwilkerson@google.com>

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

@@ -175,15 +175,26 @@ class AddKeyToConstructors extends CorrectionProducer {
           argument is NamedExpression && argument.name.label.name == 'key');
       if (existing == null) {
         // There is no 'key' argument, so add it.
-        if (arguments.isEmpty) {
-          builder.addSimpleInsertion(
-              argumentList.leftParenthesis.end, 'key: key');
-        } else {
-          // This case should never happen because 'key' is the only parameter
-          // in the constructors for both `StatelessWidget` and `StatefulWidget`.
-          builder.addSimpleInsertion(
-              argumentList.leftParenthesis.end, 'key: key, ');
-        }
+        var namedArguments = arguments.whereType<NamedExpression>();
+        var firstNamed = namedArguments.firstOrNull;
+        var token = firstNamed?.beginToken ?? argumentList.endToken;
+        var comma = token.previous?.type == TokenType.COMMA;
+
+        builder.addInsertion(token.offset, (builder) {
+          if (arguments.length != namedArguments.length) {
+            // there are unnamed arguments
+            if (!comma) {
+              builder.write(',');
+            }
+            builder.write(' ');
+          }
+          builder.write('key: key');
+          if (firstNamed != null) {
+            builder.write(', ');
+          } else if (comma) {
+            builder.write(',');
+          }
+        });
       } else {
         // There is an existing 'key' argument, so we leave it alone.
       }

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

@@ -13,6 +13,8 @@ import 'fix_processor.dart';
 void main() {
   defineReflectiveSuite(() {
     defineReflectiveTests(AddKeyToConstructorsTest);
+    defineReflectiveTests(
+        AddKeyToConstructorsWithoutNamedArgumentsAnywhereTest);
   });
 }
 
@@ -169,19 +171,93 @@ class MyWidget extends StatelessWidget {
     await resolveTestCode('''
 import 'package:flutter/material.dart';
 
-class MyWidget extends StatelessWidget {
+class A extends StatelessWidget {
+  const A({required this.text, Key? key}) : super(key: key);
+
+  final String text;
+}
+
+class MyWidget extends A {
   MyWidget() : super(text: '');
 }
 ''');
     await assertHasFix('''
 import 'package:flutter/material.dart';
 
-class MyWidget extends StatelessWidget {
+class A extends StatelessWidget {
+  const A({required this.text, Key? key}) : super(key: key);
+
+  final String text;
+}
+
+class MyWidget extends A {
   MyWidget({Key? key}) : super(key: key, text: '');
 }
 ''', errorFilter: (error) => error.errorCode is LintCode);
   }
 
+  Future<void>
+      test_constructor_noParameters_withSuper_nonEmpty_tailingComma() async {
+    await resolveTestCode('''
+import 'package:flutter/material.dart';
+
+class A extends StatelessWidget {
+  const A({required this.text, Key? key}) : super(key: key);
+
+  final String text;
+}
+
+class MyWidget extends A {
+  MyWidget() : super(text: '',);
+}
+''');
+    await assertHasFix('''
+import 'package:flutter/material.dart';
+
+class A extends StatelessWidget {
+  const A({required this.text, Key? key}) : super(key: key);
+
+  final String text;
+}
+
+class MyWidget extends A {
+  MyWidget({Key? key}) : super(key: key, text: '',);
+}
+''', errorFilter: (error) => error.errorCode is LintCode);
+  }
+
+  Future<void>
+      test_constructor_noParameters_withSuper_nonNamed_trailingComma() async {
+    await resolveTestCode('''
+import 'package:flutter/material.dart';
+
+class A extends StatelessWidget {
+  const A(this.widget, {Key? key}) : super(key: key);
+
+  final Widget widget;
+}
+
+class B extends A {
+  B() : super(const Text(''),);
+}
+''');
+    await assertHasFix('''
+import 'package:flutter/material.dart';
+
+class A extends StatelessWidget {
+  const A(this.widget, {Key? key}) : super(key: key);
+
+  final Widget widget;
+}
+
+class B extends A {
+  B({Key? key}) : super(const Text(''), key: key,);
+}
+''',
+        //TODO(asashour) there should be no other errors
+        errorFilter: (error) => error.errorCode is LintCode);
+  }
+
   Future<void> test_initializer_final_constant() async {
     await resolveTestCode('''
 import 'package:flutter/material.dart';
@@ -311,3 +387,55 @@ class MyWidget extends ParentWidget {
 ''', errorFilter: (error) => error.errorCode is LintCode);
   }
 }
+
+@reflectiveTest
+class AddKeyToConstructorsWithoutNamedArgumentsAnywhereTest
+    extends FixProcessorLintTest {
+  @override
+  FixKind get kind => DartFixKind.ADD_KEY_TO_CONSTRUCTORS;
+
+  @override
+  String get lintCode => LintNames.use_key_in_widget_constructors;
+
+  @override
+  String get testPackageLanguageVersion => '2.16';
+
+  @override
+  void setUp() {
+    super.setUp();
+    writeTestPackageConfig(
+      flutter: true,
+    );
+  }
+
+  Future<void> test_constructor_noParameters_withSuper_nonEmpty() async {
+    await resolveTestCode('''
+import 'package:flutter/material.dart';
+
+class A extends StatelessWidget {
+  const A(this.widget, {Key? key}) : super(key: key);
+
+  final Widget widget;
+}
+
+class B extends A {
+  B() : super(const Text(''));
+}
+''');
+    await assertHasFix('''
+import 'package:flutter/material.dart';
+
+class A extends StatelessWidget {
+  const A(this.widget, {Key? key}) : super(key: key);
+
+  final Widget widget;
+}
+
+class B extends A {
+  B({Key? key}) : super(const Text(''), key: key);
+}
+''',
+        //TODO(asashour) there should be no other errors
+        errorFilter: (error) => error.errorCode is LintCode);
+  }
+}