---

yaml
---
r: 361503
b: refs/heads/main
c: 5ef329c
h: refs/heads/main
i:
  361501: 839d9d3
  361499: d23cacc
  361495: 959e2e1
  361487: 657680d
  361471: 8e858a6

Author: scheglov

[refs]

@@ -1988,7 +1988,7 @@ refs/tags/2.14.0-96.0.dev: 1eee24e50fc3028754d9a8e98852b949c04da4e4
 refs/tags/2.14.0-97.0.dev: ba9c1636e87fbdcc02b8bc4a584455c32f8378b4
 refs/tags/2.14.0-98.0.dev: f2d370c93582bbf4da42b5dd4c906d6145b01ea9
 refs/tags/2.14.0-99.0.dev: e722f62b48fb382534efc1f20735def68848006f
-refs/heads/main: 79b66e79bad9dc88c893e001ffed26dc6ef8cdf6
+refs/heads/main: 5ef329cf747f38d6196fed180c9689af1369e69b
 refs/heads/TedSander-patch-1: 739563c962fea6f5e2883a8d84f8638c48f2aa40
 refs/tags/2.13.1: 53a67a7b0650edb435535a50b5c430abbc68bc60
 refs/tags/2.13.3: a77223333944631f8f48a76e7f4697a4877e29d7

trunk/pkg/analysis_server/lib/src/services/correction/error_fix_status.yaml

@@ -354,6 +354,8 @@ CompileTimeErrorCode.DUPLICATE_NAMED_ARGUMENT:
   status: needsEvaluation
 CompileTimeErrorCode.DUPLICATE_PART:
   status: needsEvaluation
+CompileTimeErrorCode.DUPLICATE_VARIABLE_PATTERN:
+  status: needsEvaluation
 CompileTimeErrorCode.ENUM_CONSTANT_SAME_NAME_AS_ENCLOSING:
   status: noFix
   notes: |-

trunk/pkg/analyzer/lib/error/error.dart

@@ -162,6 +162,7 @@ const List<ErrorCode> errorCodeValues = [
   CompileTimeErrorCode.DUPLICATE_FIELD_FORMAL_PARAMETER,
   CompileTimeErrorCode.DUPLICATE_NAMED_ARGUMENT,
   CompileTimeErrorCode.DUPLICATE_PART,
+  CompileTimeErrorCode.DUPLICATE_VARIABLE_PATTERN,
   CompileTimeErrorCode.ENUM_CONSTANT_SAME_NAME_AS_ENCLOSING,
   CompileTimeErrorCode.ENUM_CONSTANT_WITH_NON_CONST_CONSTRUCTOR,
   CompileTimeErrorCode.ENUM_INSTANTIATED_TO_BOUNDS_IS_NOT_WELL_BOUNDED,

trunk/pkg/analyzer/lib/src/dart/resolver/resolution_visitor.dart

@@ -23,6 +23,7 @@ import 'package:analyzer/src/dart/resolver/ast_rewrite.dart';
 import 'package:analyzer/src/dart/resolver/named_type_resolver.dart';
 import 'package:analyzer/src/dart/resolver/record_type_annotation_resolver.dart';
 import 'package:analyzer/src/dart/resolver/scope.dart';
+import 'package:analyzer/src/diagnostic/diagnostic_factory.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer/src/generated/element_walker.dart';
 import 'package:analyzer/src/generated/utilities_dart.dart';
@@ -1621,8 +1622,16 @@ class _PatternContext
     required DartPatternImpl pattern,
     required DartPatternImpl previousPattern,
   }) {
-    // TODO: implement matchVarOverlap
-    throw UnimplementedError();
+    pattern as VariablePatternImpl;
+    visitor._errorReporter.reportError(
+      DiagnosticFactory().duplicateDefinitionForNodes(
+        visitor._errorReporter.source,
+        CompileTimeErrorCode.DUPLICATE_VARIABLE_PATTERN,
+        pattern,
+        previousPattern,
+        [pattern.name.lexeme],
+      ),
+    );
   }
 
   @override

trunk/pkg/analyzer/lib/src/error/codes.g.dart

@@ -1170,6 +1170,15 @@ class CompileTimeErrorCode extends AnalyzerErrorCode {
     hasPublishedDocs: true,
   );
 
+  ///  Parameters:
+  ///  0: the name of the variable
+  static const CompileTimeErrorCode DUPLICATE_VARIABLE_PATTERN =
+      CompileTimeErrorCode(
+    'DUPLICATE_VARIABLE_PATTERN',
+    "The variable '{0}' is already defined in this pattern.",
+    correctionMessage: "Try renaming the variable.",
+  );
+
   static const CompileTimeErrorCode ENUM_CONSTANT_SAME_NAME_AS_ENCLOSING =
       CompileTimeErrorCode(
     'ENUM_CONSTANT_SAME_NAME_AS_ENCLOSING',

trunk/pkg/analyzer/messages.yaml

@@ -3518,6 +3518,12 @@ CompileTimeErrorCode:
 
       part 'part.dart';
       ```
+  DUPLICATE_VARIABLE_PATTERN:
+    problemMessage: The variable '{0}' is already defined in this pattern.
+    correctionMessage: Try renaming the variable.
+    comment: |-
+      Parameters:
+      0: the name of the variable
   ENUM_CONSTANT_SAME_NAME_AS_ENCLOSING:
     problemMessage: "The name of the enum constant can't be the same as the enum's name."
     correctionMessage: Try renaming the constant.

trunk/pkg/analyzer/test/src/diagnostics/duplicate_variable_pattern_test.dart

@@ -0,0 +1,70 @@
+// Copyright (c) 2022, the Dart project authors. Please see the AUTHORS file
+// 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:analyzer/src/error/codes.dart';
+import 'package:test_reflective_loader/test_reflective_loader.dart';
+
+import '../dart/resolution/context_collection_resolution.dart';
+
+main() {
+  defineReflectiveSuite(() {
+    defineReflectiveTests(DuplicateVariablePatternTest);
+  });
+}
+
+@reflectiveTest
+class DuplicateVariablePatternTest extends PatternsResolutionTest {
+  test_ifCase() async {
+    await assertErrorsInCode(r'''
+void f(int x) {
+  if (x case var a & var a) {}
+}
+''', [
+      error(CompileTimeErrorCode.DUPLICATE_VARIABLE_PATTERN, 41, 1,
+          contextMessages: [message('/home/test/lib/test.dart', 33, 1)]),
+    ]);
+    final node = findNode.caseClause('case').pattern;
+    assertResolvedNodeText(node, r'''
+BinaryPattern
+  leftOperand: VariablePattern
+    keyword: var
+    name: a
+    declaredElement: hasImplicitType a@33
+      type: int
+  operator: &
+  rightOperand: VariablePattern
+    keyword: var
+    name: a
+    declaredElement: a@33
+''');
+  }
+
+  test_switchStatement() async {
+    await assertErrorsInCode(r'''
+void f(int x) {
+  switch (x) {
+    case var a & var a:
+      break;
+  }
+}
+''', [
+      error(CompileTimeErrorCode.DUPLICATE_VARIABLE_PATTERN, 52, 1,
+          contextMessages: [message('/home/test/lib/test.dart', 44, 1)]),
+    ]);
+    final node = findNode.switchPatternCase('case').pattern;
+    assertResolvedNodeText(node, r'''
+BinaryPattern
+  leftOperand: VariablePattern
+    keyword: var
+    name: a
+    declaredElement: hasImplicitType a@44
+      type: int
+  operator: &
+  rightOperand: VariablePattern
+    keyword: var
+    name: a
+    declaredElement: a@44
+''');
+  }
+}

trunk/pkg/analyzer/test/src/diagnostics/test_all.dart

@@ -160,6 +160,7 @@ import 'duplicate_import_test.dart' as duplicate_import;
 import 'duplicate_named_argument_test.dart' as duplicate_named_argument;
 import 'duplicate_part_test.dart' as duplicate_part;
 import 'duplicate_shown_name_test.dart' as duplicate_shown_name;
+import 'duplicate_variable_pattern_test.dart' as duplicate_variable_pattern;
 import 'enum_constant_same_name_as_enclosing_test.dart'
     as enum_constant_same_name_as_enclosing;
 import 'enum_constant_with_non_const_constructor_test.dart'
@@ -913,6 +914,7 @@ main() {
     duplicate_named_argument.main();
     duplicate_part.main();
     duplicate_shown_name.main();
+    duplicate_variable_pattern.main();
     enum_constant_same_name_as_enclosing.main();
     enum_constant_with_non_const_constructor.main();
     enum_instantiated_to_bounds_is_not_well_bounded.main();