Introduce a quick fix for prefer_final_parameters

Change-Id: I63bd7b37325a44fbb6066d19ac4e358b675c58e9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/206160
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Brian Wilkerson <brianwilkerson@google.com>

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

@@ -43,6 +43,35 @@ class MakeFinal extends CorrectionProducer {
       return;
     }
 
+    if (node is SimpleFormalParameter) {
+      await builder.addDartFileEdit(file, (builder) {
+        final keyword = node.keyword;
+        if (keyword != null && keyword.keyword == Keyword.VAR) {
+          builder.addSimpleReplacement(range.token(keyword), 'final');
+        } else {
+          final type = node.type;
+          if (type != null) {
+            builder.addSimpleInsertion(type.offset, 'final ');
+            return;
+          }
+          final identifier = node.identifier;
+          if (identifier != null) {
+            builder.addSimpleInsertion(identifier.offset, 'final ');
+          } else {
+            builder.addSimpleInsertion(node.offset, 'final ');
+          }
+        }
+      });
+      return;
+    }
+
+    if (node is SimpleIdentifier && parent is SimpleFormalParameter) {
+      await builder.addDartFileEdit(file, (builder) {
+        builder.addSimpleInsertion(node.offset, 'final ');
+      });
+      return;
+    }
+
     VariableDeclarationList list;
     if (node is SimpleIdentifier &&
         parent is VariableDeclaration &&

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

@@ -96,6 +96,7 @@ bool hasFix(ErrorCode errorCode) =>
             errorCode.name == LintNames.prefer_equal_for_default_values ||
             errorCode.name == LintNames.prefer_final_fields ||
             errorCode.name == LintNames.prefer_final_locals ||
+            errorCode.name == LintNames.prefer_final_parameters ||
             errorCode.name == LintNames.prefer_is_not_empty ||
             errorCode.name == LintNames.type_init_formals ||
             errorCode.name == LintNames.unawaited_futures ||

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

@@ -456,6 +456,9 @@ class FixProcessor extends BaseProcessor {
     LintNames.prefer_final_locals: [
       MakeFinal.newInstance,
     ],
+    LintNames.prefer_final_parameters: [
+      MakeFinal.newInstance,
+    ],
     LintNames.prefer_for_elements_to_map_fromIterable: [
       ConvertMapFromIterableToForLiteral.newInstance,
     ],

pkg/analysis_server/lib/src/services/linter/lint_names.dart

@@ -68,6 +68,7 @@ class LintNames {
   static const String prefer_final_fields = 'prefer_final_fields';
   static const String prefer_final_in_for_each = 'prefer_final_in_for_each';
   static const String prefer_final_locals = 'prefer_final_locals';
+  static const String prefer_final_parameters = 'prefer_final_parameters';
   static const String prefer_for_elements_to_map_fromIterable =
       'prefer_for_elements_to_map_fromIterable';
   static const String prefer_generic_function_type_aliases =

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

@@ -16,6 +16,8 @@ void main() {
     defineReflectiveTests(PreferFinalFieldsWithNullSafetyTest);
     defineReflectiveTests(PreferFinalInForEachTest);
     defineReflectiveTests(PreferFinalLocalsBulkTest);
+    defineReflectiveTests(PreferFinalParametersTest);
+    defineReflectiveTests(PreferFinalParametersBulkTest);
   });
 }
 
@@ -186,3 +188,199 @@ f() {
 ''');
   }
 }
+
+@reflectiveTest
+class PreferFinalParametersBulkTest extends BulkFixProcessorTest {
+  @override
+  String get lintCode => LintNames.prefer_final_parameters;
+
+  Future<void> test_singleFile() async {
+    await resolveTestCode('''
+void fn(String test, int other) {
+  print(test);
+  print(other);
+}
+''');
+    await assertHasFix('''
+void fn(final String test, final int other) {
+  print(test);
+  print(other);
+}
+''');
+  }
+}
+
+@reflectiveTest
+class PreferFinalParametersTest extends FixProcessorLintTest {
+  @override
+  FixKind get kind => DartFixKind.MAKE_FINAL;
+
+  @override
+  String get lintCode => LintNames.prefer_final_parameters;
+
+  Future<void> test_class_constructor() async {
+    await resolveTestCode('''
+class C {
+  C(String content) {
+    print(content);
+  }
+}
+''');
+    await assertHasFix('''
+class C {
+  C(final String content) {
+    print(content);
+  }
+}
+''');
+  }
+
+  Future<void> test_class_requiredCovariant() async {
+    await resolveTestCode('''
+class C {
+  void fn({required covariant String test}) {
+    print(test);
+  }
+}
+''');
+    await assertHasFix('''
+class C {
+  void fn({required covariant final String test}) {
+    print(test);
+  }
+}
+''');
+  }
+
+  Future<void> test_closure_hasType() async {
+    await resolveTestCode('''
+void fn() {
+  ['1', '2', '3'].forEach((String string) => print(string));
+}
+''');
+    await assertHasFix('''
+void fn() {
+  ['1', '2', '3'].forEach((final String string) => print(string));
+}
+''');
+  }
+
+  Future<void> test_closure_noType() async {
+    await resolveTestCode('''
+void fn() {
+  ['1', '2', '3'].forEach((string) => print(string));
+}
+''');
+    await assertHasFix('''
+void fn() {
+  ['1', '2', '3'].forEach((final string) => print(string));
+}
+''');
+  }
+
+  Future<void> test_functionLiteral() async {
+    await resolveTestCode('''
+var fn = (String test) {
+  print(test);
+};
+''');
+    await assertHasFix('''
+var fn = (final String test) {
+  print(test);
+};
+''');
+  }
+
+  Future<void> test_named_optional() async {
+    await resolveTestCode('''
+void fn({String? test}) {
+  print(test);
+}
+''');
+    await assertHasFix('''
+void fn({final String? test}) {
+  print(test);
+}
+''');
+  }
+
+  Future<void> test_named_required() async {
+    await resolveTestCode('''
+void fn({required String test}) {
+  print(test);
+}
+''');
+    await assertHasFix('''
+void fn({required final String test}) {
+  print(test);
+}
+''');
+  }
+
+  Future<void> test_positional_optional() async {
+    await resolveTestCode('''
+void fn([String? test]) {
+  print(test);
+}
+''');
+    await assertHasFix('''
+void fn([final String? test]) {
+  print(test);
+}
+''');
+  }
+
+  Future<void> test_simple_hasType() async {
+    await resolveTestCode('''
+void fn(String test) {
+  print(test);
+}
+''');
+    await assertHasFix('''
+void fn(final String test) {
+  print(test);
+}
+''');
+  }
+
+  Future<void> test_simple_noType() async {
+    await resolveTestCode('''
+void fn(test) {
+  print(test);
+}
+''');
+    await assertHasFix('''
+void fn(final test) {
+  print(test);
+}
+''');
+  }
+
+  Future<void> test_simple_second() async {
+    await resolveTestCode('''
+void fn(final String test, String other) {
+  print(test);
+  print(other);
+}
+''');
+    await assertHasFix('''
+void fn(final String test, final String other) {
+  print(test);
+  print(other);
+}
+''');
+  }
+
+  Future<void> test_simple_var() async {
+    await resolveTestCode('''
+void fn(var test) {
+  print(test);
+}
+''');
+    await assertHasFix('''
+void fn(final test) {
+  print(test);
+}
+''');
+  }
+}