enhanced enum support for hash_and_equals (#3202)

* enhanced enum support for `hash_and_equals`

* rename

* fmt

Author: pq

lib/src/rules/hash_and_equals.dart

@@ -63,6 +63,7 @@ class HashAndEquals extends LintRule {
       NodeLintRegistry registry, LinterContext context) {
     var visitor = _Visitor(this);
     registry.addClassDeclaration(this, visitor);
+    registry.addEnumDeclaration(this, visitor);
   }
 }
 
@@ -80,9 +81,18 @@ class _Visitor extends SimpleAstVisitor<void> {
 
   @override
   void visitClassDeclaration(ClassDeclaration node) {
+    _check(node.members);
+  }
+
+  @override
+  void visitEnumDeclaration(EnumDeclaration node) {
+    _check(node.members);
+  }
+
+  void _check(NodeList<ClassMember> members) {
     MethodDeclaration? eq;
     ClassMember? hash;
-    for (var member in node.members) {
+    for (var member in members) {
       if (isEquals(member)) {
         eq = member as MethodDeclaration;
       } else if (isHashCode(member)) {

test/rules/all.dart

@@ -18,6 +18,7 @@ import 'avoid_unused_constructor_parameters.dart'
 import 'conditional_uri_does_not_exist.dart' as conditional_uri_does_not_exist;
 import 'deprecated_consistency.dart' as deprecated_consistency;
 import 'file_names.dart' as file_names;
+import 'hash_and_equals.dart' as hash_and_equals;
 import 'literal_only_boolean_expressions.dart'
     as literal_only_boolean_expressions;
 import 'missing_whitespace_between_adjacent_strings.dart'
@@ -63,6 +64,7 @@ void main() {
   conditional_uri_does_not_exist.main();
   deprecated_consistency.main();
   file_names.main();
+  hash_and_equals.main();
   literal_only_boolean_expressions.main();
   missing_whitespace_between_adjacent_strings.main();
   non_constant_identifier_names.main();

test/rules/hash_and_equals.dart

@@ -0,0 +1,37 @@
+// 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:test_reflective_loader/test_reflective_loader.dart';
+
+import '../rule_test_support.dart';
+
+main() {
+  defineReflectiveSuite(() {
+    defineReflectiveTests(HashAndEqualsTest);
+  });
+}
+
+@reflectiveTest
+class HashAndEqualsTest extends LintRuleTest {
+  @override
+  List<String> get experiments => [
+        EnableString.enhanced_enums,
+      ];
+
+  @override
+  String get lintRule => 'hash_and_equals';
+
+  @FailingTest(issue: 'https://github.com/dart-lang/linter/issues/3195')
+  test_enum_missingHash() async {
+    await assertDiagnostics(r'''
+enum A {
+  a,b,c;
+  @override
+  bool operator ==(Object other) => false;
+}
+''', [
+      lint('hash_and_equals', 46, 2), // todo(pq): fix index
+    ]);
+  }
+}