[cfe] Report errors on declared 'values' member in enums

Part of #47453

Closes #48389
Closes #48387

Change-Id: I8313e3f63122c85c91a9647ddaa53346591d7238
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/232841
Reviewed-by: Johnni Winther <[email protected]>
Commit-Queue: Chloe Stefantsova <[email protected]>

Author: chloestefantsova

pkg/_fe_analyzer_shared/lib/src/messages/codes_generated.dart

@@ -2786,6 +2786,16 @@ const MessageCode messageEnumConstructorTearoff = const MessageCode(
     "EnumConstructorTearoff",
     problemMessage: r"""Enum constructors can't be torn off.""");
 
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Null> codeEnumContainsValuesDeclaration =
+    messageEnumContainsValuesDeclaration;
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const MessageCode messageEnumContainsValuesDeclaration = const MessageCode(
+    "EnumContainsValuesDeclaration",
+    problemMessage:
+        r"""Enums can't contain declarations of members with the name 'values'.""");
+
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
 const Code<Null> codeEnumDeclarationEmpty = messageEnumDeclarationEmpty;
 

pkg/front_end/lib/src/fasta/source/diet_listener.dart

@@ -722,8 +722,18 @@ class DietListener extends StackListenerImpl {
       builder =
           lookupConstructor(beginToken, name!) as SourceFunctionBuilderImpl;
     } else {
-      builder = lookupBuilder(beginToken, getOrSet, name as String)
-          as SourceFunctionBuilderImpl;
+      Builder? memberBuilder =
+          lookupBuilder(beginToken, getOrSet, name as String);
+      if (currentClass?.isEnum == true &&
+          memberBuilder is SourceFieldBuilder &&
+          memberBuilder.name == "values") {
+        // This is the case of a method with the name 'values' declared in an
+        // Enum. In that case the method is replaced with the synthesized field
+        // in the outline building phase, and the error is reported there. At
+        // this point we skip the member.
+        return;
+      }
+      builder = memberBuilder as SourceFunctionBuilderImpl;
     }
     buildFunctionBody(
         createFunctionListener(builder),

pkg/front_end/lib/src/fasta/source/source_enum_builder.dart

@@ -27,6 +27,7 @@ import '../builder/type_variable_builder.dart';
 import '../fasta_codes.dart'
     show
         LocatedMessage,
+        messageEnumContainsValuesDeclaration,
         messageEnumEntryWithTypeArgumentsWithoutArguments,
         messageEnumNonConstConstructor,
         messageNoUnnamedConstructorInObject,
@@ -242,6 +243,20 @@ class SourceEnumBuilder extends SourceClassBuilder {
           referencesFromIndexed.lookupSetterReference(valuesName);
     }
 
+    Builder? customValuesDeclaration =
+        scope.lookupLocalMember("values", setter: false);
+    if (customValuesDeclaration != null) {
+      // Retrieve the earliest declaration for error reporting.
+      while (customValuesDeclaration?.next != null) {
+        customValuesDeclaration = customValuesDeclaration?.next;
+      }
+      parent.addProblem(
+          messageEnumContainsValuesDeclaration,
+          customValuesDeclaration!.charOffset,
+          customValuesDeclaration.fullNameForErrors.length,
+          fileUri);
+    }
+
     SourceFieldBuilder valuesBuilder = new SourceFieldBuilder(
         /* metadata = */ null,
         listType,
@@ -338,7 +353,9 @@ class SourceEnumBuilder extends SourceClassBuilder {
     final int startCharOffsetComputed =
         metadata == null ? startCharOffset : metadata.first.charOffset;
     scope.forEachLocalMember((name, member) {
-      members[name] = member as MemberBuilder;
+      if (name != "values") {
+        members[name] = member as MemberBuilder;
+      }
     });
     scope.forEachLocalSetter((name, member) {
       setters[name] = member;

pkg/front_end/messages.status

@@ -5,6 +5,8 @@
 # Note that test/spelling: Status will have no effect. Spelling errors can
 # always be fixed by either spelling correctly or updating the dictionary.
 
+EnumContainsValuesDeclaration/analyzerCode: Fail
+EnumContainsValuesDeclaration/example: Fail
 AbstractClassConstructorTearOff/analyzerCode: Fail
 AbstractClassInstantiation/example: Fail
 AbstractExtensionField/analyzerCode: Fail

pkg/front_end/messages.yaml

@@ -5473,3 +5473,6 @@ EnumConstructorTearoff:
 
 EnumFactoryRedirectsToConstructor:
   problemMessage: "Enum factory constructors can't redirect to generative constructors."
+
+EnumContainsValuesDeclaration:
+  problemMessage: "Enums can't contain declarations of members with the name 'values'."

pkg/front_end/testcases/enhanced_enums/declared_values.dart

@@ -0,0 +1,48 @@
+// 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.
+
+enum E1 {
+  element;
+
+  static const List<E1> values = [E1.element]; // Error in E1.
+}
+
+enum E2 {
+  element;
+
+  int values = 42; // Error in E2.
+}
+
+enum E3 {
+  element;
+
+  static const List<E3> values = [E3.element]; // Error in E3.
+  int values = 42; // Duplicate.
+}
+
+enum E4 {
+  element;
+
+  static void set values(List<E4> x) {} // Ok.
+}
+
+enum E5 {
+  element;
+
+  static void set values(dynamic x) {} // Ok.
+}
+
+enum E6 {
+  element;
+
+  static void set values(Never x) {} // Error in E6.
+}
+
+enum E7 {
+  element;
+
+  void values() {} // Error in E7.
+}
+
+main() {}

pkg/front_end/testcases/enhanced_enums/declared_values.dart.strong.expect

@@ -0,0 +1,138 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/enhanced_enums/declared_values.dart:8:25: Error: Enums can't contain declarations of members with the name 'values'.
+//   static const List<E1> values = [E1.element]; // Error in E1.
+//                         ^^^^^^
+//
+// pkg/front_end/testcases/enhanced_enums/declared_values.dart:14:7: Error: Enums can't contain declarations of members with the name 'values'.
+//   int values = 42; // Error in E2.
+//       ^^^^^^
+//
+// pkg/front_end/testcases/enhanced_enums/declared_values.dart:21:7: Error: 'values' is already declared in this scope.
+//   int values = 42; // Duplicate.
+//       ^^^^^^
+// pkg/front_end/testcases/enhanced_enums/declared_values.dart:20:25: Context: Previous declaration of 'values'.
+//   static const List<E3> values = [E3.element]; // Error in E3.
+//                         ^^^^^^
+//
+// pkg/front_end/testcases/enhanced_enums/declared_values.dart:20:25: Error: Enums can't contain declarations of members with the name 'values'.
+//   static const List<E3> values = [E3.element]; // Error in E3.
+//                         ^^^^^^
+//
+// pkg/front_end/testcases/enhanced_enums/declared_values.dart:45:8: Error: Enums can't contain declarations of members with the name 'values'.
+//   void values() {} // Error in E7.
+//        ^^^^^^
+//
+// pkg/front_end/testcases/enhanced_enums/declared_values.dart:36:6: Error: The type 'List<E6>' of the getter 'E6.values' is not a subtype of the type 'Never' of the setter 'E6.values'.
+//  - 'List' is from 'dart:core'.
+//  - 'E6' is from 'pkg/front_end/testcases/enhanced_enums/declared_values.dart'.
+// enum E6 {
+//      ^^^^^...
+// pkg/front_end/testcases/enhanced_enums/declared_values.dart:39:19: Context: This is the declaration of the setter 'E6.values'.
+//   static void set values(Never x) {} // Error in E6.
+//                   ^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+
+class E1 extends core::_Enum /*isEnum*/  {
+  static const field core::List<self::E1> values = #C4;
+  static const field self::E1 element = #C3;
+  const constructor •(core::int index, core::String name) → self::E1
+    : super core::_Enum::•(index, name)
+    ;
+  method toString() → core::String
+    return "E1.${this.{core::_Enum::_name}{core::String}}";
+}
+class E2 extends core::_Enum /*isEnum*/  {
+  static const field core::List<self::E2> values = #C6;
+  static const field self::E2 element = #C5;
+  const constructor •(core::int index, core::String name) → self::E2
+    : super core::_Enum::•(index, name)
+    ;
+  method toString() → core::String
+    return "E2.${this.{core::_Enum::_name}{core::String}}";
+}
+class E3 extends core::_Enum /*isEnum*/  {
+  static const field core::List<self::E3> values = #C8;
+  static const field self::E3 element = #C7;
+  const constructor •(core::int index, core::String name) → self::E3
+    : super core::_Enum::•(index, name)
+    ;
+  method toString() → core::String
+    return "E3.${this.{core::_Enum::_name}{core::String}}";
+}
+class E4 extends core::_Enum /*isEnum*/  {
+  static const field core::List<self::E4> values = #C10;
+  static const field self::E4 element = #C9;
+  const constructor •(core::int index, core::String name) → self::E4
+    : super core::_Enum::•(index, name)
+    ;
+  method toString() → core::String
+    return "E4.${this.{core::_Enum::_name}{core::String}}";
+  static set values(core::List<self::E4> x) → void {}
+}
+class E5 extends core::_Enum /*isEnum*/  {
+  static const field core::List<self::E5> values = #C12;
+  static const field self::E5 element = #C11;
+  const constructor •(core::int index, core::String name) → self::E5
+    : super core::_Enum::•(index, name)
+    ;
+  method toString() → core::String
+    return "E5.${this.{core::_Enum::_name}{core::String}}";
+  static set values(dynamic x) → void {}
+}
+class E6 extends core::_Enum /*isEnum*/  {
+  static const field core::List<self::E6> values = #C14;
+  static const field self::E6 element = #C13;
+  const constructor •(core::int index, core::String name) → self::E6
+    : super core::_Enum::•(index, name)
+    ;
+  method toString() → core::String
+    return "E6.${this.{core::_Enum::_name}{core::String}}";
+  static set values(Never x) → void {}
+}
+class E7 extends core::_Enum /*isEnum*/  {
+  static const field core::List<self::E7> values = #C16;
+  static const field self::E7 element = #C15;
+  const constructor •(core::int index, core::String name) → self::E7
+    : super core::_Enum::•(index, name)
+    ;
+  method toString() → core::String
+    return "E7.${this.{core::_Enum::_name}{core::String}}";
+}
+static method main() → dynamic {}
+
+constants  {
+  #C1 = 0
+  #C2 = "element"
+  #C3 = self::E1 {index:#C1, _name:#C2}
+  #C4 = <self::E1>[#C3]
+  #C5 = self::E2 {index:#C1, _name:#C2}
+  #C6 = <self::E2>[#C5]
+  #C7 = self::E3 {index:#C1, _name:#C2}
+  #C8 = <self::E3>[#C7]
+  #C9 = self::E4 {index:#C1, _name:#C2}
+  #C10 = <self::E4>[#C9]
+  #C11 = self::E5 {index:#C1, _name:#C2}
+  #C12 = <self::E5>[#C11]
+  #C13 = self::E6 {index:#C1, _name:#C2}
+  #C14 = <self::E6>[#C13]
+  #C15 = self::E7 {index:#C1, _name:#C2}
+  #C16 = <self::E7>[#C15]
+}
+
+
+Constructor coverage from constants:
+org-dartlang-testcase:///declared_values.dart:
+- E1. (from org-dartlang-testcase:///declared_values.dart:5:6)
+- _Enum. (from org-dartlang-sdk:///sdk/lib/core/enum.dart:103:9)
+- Object. (from org-dartlang-sdk:///sdk/lib/core/object.dart:25:9)
+- E2. (from org-dartlang-testcase:///declared_values.dart:11:6)
+- E3. (from org-dartlang-testcase:///declared_values.dart:17:6)
+- E4. (from org-dartlang-testcase:///declared_values.dart:24:6)
+- E5. (from org-dartlang-testcase:///declared_values.dart:30:6)
+- E6. (from org-dartlang-testcase:///declared_values.dart:36:6)
+- E7. (from org-dartlang-testcase:///declared_values.dart:42:6)