[cfe] Report more errors on forbidden enum constructor calls

This CL also adds support for redirecting enum factories.

Part of #47453

Change-Id: Idd16598316a52ac6122a47f4c12f82ab5750d8f3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/230661
Auto-Submit: Chloe Stefantsova <[email protected]>
Reviewed-by: Johnni Winther <[email protected]>
Commit-Queue: Johnni Winther <[email protected]>

Author: chloestefantsova

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

@@ -2778,6 +2778,14 @@ const MessageCode messageEnumConstructorSuperInitializer = const MessageCode(
     "EnumConstructorSuperInitializer",
     problemMessage: r"""Enum constructors can't contain super-initializers.""");
 
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Null> codeEnumConstructorTearoff = messageEnumConstructorTearoff;
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+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> codeEnumDeclarationEmpty = messageEnumDeclarationEmpty;
 
@@ -2807,6 +2815,16 @@ const MessageCode messageEnumEntryWithTypeArgumentsWithoutArguments =
         problemMessage:
             r"""Missing arguments in enum constructor invocation.""");
 
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Null> codeEnumFactoryRedirectsToConstructor =
+    messageEnumFactoryRedirectsToConstructor;
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const MessageCode messageEnumFactoryRedirectsToConstructor = const MessageCode(
+    "EnumFactoryRedirectsToConstructor",
+    problemMessage:
+        r"""Enum factory constructors can't redirect to generative constructors.""");
+
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
 const Code<Null> codeEnumInClass = messageEnumInClass;
 

pkg/front_end/lib/src/fasta/kernel/expression_generator.dart

@@ -3219,6 +3219,9 @@ class TypeUseGenerator extends AbstractReadOnlyAccessGenerator {
                     messageAbstractClassConstructorTearOff,
                     nameOffset,
                     name.text.length);
+              } else if (declarationBuilder.cls.isEnum) {
+                return _helper.buildProblem(messageEnumConstructorTearoff,
+                    nameOffset, name.text.length);
               }
               tearOffExpression = _helper.forest
                   .createConstructorTearOff(token.charOffset, tearOff);

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

@@ -952,24 +952,29 @@ class SourceClassBuilder extends ClassBuilderImpl
       return;
     }
 
-    // Check whether [redirecteeType] <: [factoryType].
-    if (!typeEnvironment.isSubtypeOf(
-        redirecteeType, factoryType, SubtypeCheckMode.ignoringNullabilities)) {
-      _addProblemForRedirectingFactory(
-          factory,
-          templateIncompatibleRedirecteeFunctionType.withArguments(
-              redirecteeType, factoryType, library.isNonNullableByDefault),
-          factory.redirectionTarget.charOffset,
-          noLength);
-    } else if (library.isNonNullableByDefault) {
-      if (!typeEnvironment.isSubtypeOf(
-          redirecteeType, factoryType, SubtypeCheckMode.withNullabilities)) {
+    // Redirection to generative enum constructors is forbidden and is reported
+    // as an error elsewhere.
+    if (!(cls.isEnum &&
+        (factory.redirectionTarget.target?.isConstructor ?? false))) {
+      // Check whether [redirecteeType] <: [factoryType].
+      if (!typeEnvironment.isSubtypeOf(redirecteeType, factoryType,
+          SubtypeCheckMode.ignoringNullabilities)) {
         _addProblemForRedirectingFactory(
             factory,
             templateIncompatibleRedirecteeFunctionType.withArguments(
                 redirecteeType, factoryType, library.isNonNullableByDefault),
             factory.redirectionTarget.charOffset,
             noLength);
+      } else if (library.isNonNullableByDefault) {
+        if (!typeEnvironment.isSubtypeOf(
+            redirecteeType, factoryType, SubtypeCheckMode.withNullabilities)) {
+          _addProblemForRedirectingFactory(
+              factory,
+              templateIncompatibleRedirecteeFunctionType.withArguments(
+                  redirecteeType, factoryType, library.isNonNullableByDefault),
+              factory.redirectionTarget.charOffset,
+              noLength);
+        }
       }
     }
   }
@@ -1690,6 +1695,16 @@ class SourceClassBuilder extends ClassBuilderImpl
                     noLength);
                 targetNode = null;
               }
+              if (targetNode != null &&
+                  targetNode is Constructor &&
+                  targetNode.enclosingClass.isEnum) {
+                _addProblemForRedirectingFactory(
+                    declaration,
+                    messageEnumFactoryRedirectsToConstructor,
+                    redirectionTarget.charOffset,
+                    noLength);
+                targetNode = null;
+              }
               if (targetNode != null) {
                 List<DartType> typeArguments = declaration.typeArguments ??
                     new List<DartType>.filled(

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

@@ -85,6 +85,7 @@ class SourceEnumBuilder extends SourceClassBuilder {
       this.objectType,
       this.stringType,
       SourceLibraryBuilder parent,
+      List<ConstructorReferenceBuilder> constructorReferences,
       int startCharOffset,
       int charOffset,
       int charEndOffset,
@@ -100,7 +101,7 @@ class SourceEnumBuilder extends SourceClassBuilder {
             scope,
             constructors,
             parent,
-            /* constructorReferences = */ null,
+            constructorReferences,
             startCharOffset,
             charOffset,
             charEndOffset,
@@ -115,6 +116,7 @@ class SourceEnumBuilder extends SourceClassBuilder {
       List<TypeBuilder>? interfaceBuilders,
       List<EnumConstantInfo?>? enumConstantInfos,
       SourceLibraryBuilder parent,
+      List<ConstructorReferenceBuilder> constructorReferences,
       int startCharOffset,
       int charOffset,
       int charEndOffset,
@@ -422,6 +424,7 @@ class SourceEnumBuilder extends SourceClassBuilder {
         objectType,
         stringType,
         parent,
+        constructorReferences,
         startCharOffsetComputed,
         charOffset,
         charEndOffset,

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

@@ -2820,6 +2820,7 @@ class SourceLibraryBuilder extends LibraryBuilderImpl {
         interfaceBuilders,
         enumConstantInfos,
         this,
+        new List<ConstructorReferenceBuilder>.of(constructorReferences),
         startCharOffset,
         charOffset,
         charEndOffset,
@@ -2831,6 +2832,7 @@ class SourceLibraryBuilder extends LibraryBuilderImpl {
             debugName: "enum $name",
             isModifiable: false),
         new ConstructorScope(name, constructors));
+    constructorReferences.clear();
 
     Map<String, TypeVariableBuilder>? typeVariablesByName =
         checkTypeVariables(typeVariables, enumBuilder);

pkg/front_end/messages.status

@@ -215,12 +215,16 @@ Encoding/analyzerCode: Fail
 EnumConstantSameNameAsEnclosing/example: Fail
 EnumConstructorSuperInitializer/analyzerCode: Fail
 EnumConstructorSuperInitializer/example: Fail
+EnumConstructorTearoff/analyzerCode: Fail
+EnumConstructorTearoff/example: Fail
 EnumDeclaresConstFactory/analyzerCode: Fail
 EnumDeclaresConstFactory/example: Fail
 EnumDeclaresFactory/analyzerCode: Fail
 EnumDeclaresFactory/example: Fail
 EnumEntryWithTypeArgumentsWithoutArguments/analyzerCode: Fail
 EnumEntryWithTypeArgumentsWithoutArguments/example: Fail
+EnumFactoryRedirectsToConstructor/analyzerCode: Fail
+EnumFactoryRedirectsToConstructor/example: Fail
 EnumInstantiation/example: Fail
 EnumNonConstConstructor/analyzerCode: Fail
 EnumNonConstConstructor/example: Fail

pkg/front_end/messages.yaml

@@ -5467,3 +5467,9 @@ EnumNonConstConstructor:
 
 EnumConstructorSuperInitializer:
   problemMessage: "Enum constructors can't contain super-initializers."
+
+EnumConstructorTearoff:
+  problemMessage: "Enum constructors can't be torn off."
+
+EnumFactoryRedirectsToConstructor:
+  problemMessage: "Enum factory constructors can't redirect to generative constructors."

pkg/front_end/test/spell_checking_list_common.txt

@@ -1249,6 +1249,7 @@ following
 follows
 food
 for
+forbidden
 force
 forced
 forest

pkg/front_end/testcases/enhanced_enums/constructor_calls.dart

@@ -0,0 +1,45 @@
+// 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 E {
+  one, // Ok.
+  two.named(), // Ok.
+  three.f(), // Error.
+  four.f2(); // Error.
+
+  const E();
+
+  const E.named()
+    : this(); // Ok.
+
+  factory E.f() => values.first;
+
+  factory E.f2() {
+    return const E(); // Error.
+  }
+
+  const factory E.f3() = E; // Error.
+
+  factory E.f4() = E; // Error.
+
+  factory E.f5() = E.f; // Ok.
+
+  factory E.f6(int value) = E.f; // Error.
+}
+
+test() {
+  new E(); // Error.
+  const E(); // Error.
+  E.new; // Error.
+
+  new E.named(); // Error.
+  const E().named(); // Error.
+  E.named; // Error.
+
+  new E.f(); // Ok.
+  const E.f(); // Error.
+  E.f; // Ok.
+}
+
+main() {}

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

@@ -0,0 +1,156 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:22:26: Error: Enum factory constructors can't redirect to generative constructors.
+//   const factory E.f3() = E; // Error.
+//                          ^
+//
+// pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:24:20: Error: Enum factory constructors can't redirect to generative constructors.
+//   factory E.f4() = E; // Error.
+//                    ^
+//
+// pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:8:8: Error: Couldn't find constructor 'E.f'.
+//   three.f(), // Error.
+//        ^
+//
+// pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:9:7: Error: Couldn't find constructor 'E.f2'.
+//   four.f2(); // Error.
+//       ^^
+//
+// pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:28:29: Error: The constructor function type 'E Function()' isn't a subtype of 'E Function(int)'.
+//  - 'E' is from 'pkg/front_end/testcases/enhanced_enums/constructor_calls.dart'.
+//   factory E.f6(int value) = E.f; // Error.
+//                             ^
+//
+// pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:19:18: Error: Enums can't be instantiated.
+//     return const E(); // Error.
+//                  ^
+//
+// pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:32:7: Error: Enums can't be instantiated.
+//   new E(); // Error.
+//       ^
+//
+// pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:33:9: Error: Enums can't be instantiated.
+//   const E(); // Error.
+//         ^
+//
+// pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:34:5: Error: Enum constructors can't be torn off.
+//   E.new; // Error.
+//     ^^^
+//
+// pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:36:7: Error: Enums can't be instantiated.
+//   new E.named(); // Error.
+//       ^
+//
+// pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:37:9: Error: Enums can't be instantiated.
+//   const E().named(); // Error.
+//         ^
+//
+// pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:38:5: Error: Enum constructors can't be torn off.
+//   E.named; // Error.
+//     ^^^^^
+//
+// pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:41:9: Error: Cannot invoke a non-'const' factory where a const expression is expected.
+// Try using a constructor or factory that is 'const'.
+//   const E.f(); // Error.
+//         ^
+//
+import self as self;
+import "dart:core" as core;
+
+class E extends core::_Enum /*isEnum*/  {
+  static const field core::List<self::E> values = invalid-expression "pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:8:8: Error: Couldn't find constructor 'E.f'.
+  three.f(), // Error.
+       ^";
+  static const field self::E one = #C3;
+  static const field self::E two = #C6;
+  static const field self::E three = invalid-expression "pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:8:8: Error: Couldn't find constructor 'E.f'.
+  three.f(), // Error.
+       ^";
+  static const field self::E four = invalid-expression "pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:9:7: Error: Couldn't find constructor 'E.f2'.
+  four.f2(); // Error.
+      ^^";
+  static final field dynamic _redirecting# = <dynamic>[#C7, #C8, #C9, #C10]/*isLegacy*/;
+  const constructor •(core::int index, core::String name) → self::E
+    : super core::_Enum::•(index, name)
+    ;
+  const constructor named(core::int index, core::String name) → self::E
+    : this self::E::•(index, name)
+    ;
+  method toString() → core::String
+    return "E.${this.{core::_Enum::_name}{core::String}}";
+  static factory f() → self::E
+    return invalid-expression "pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:8:8: Error: Couldn't find constructor 'E.f'.
+  three.f(), // Error.
+       ^".{core::Iterable::first}{self::E};
+  static factory f2() → self::E {
+    return invalid-expression "pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:19:18: Error: Enums can't be instantiated.
+    return const E(); // Error.
+                 ^";
+  }
+  static factory f3() → self::E
+    return invalid-expression "pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:22:26: Error: Enum factory constructors can't redirect to generative constructors.
+  const factory E.f3() = E; // Error.
+                         ^";
+  static factory f4() → self::E
+    return invalid-expression "pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:24:20: Error: Enum factory constructors can't redirect to generative constructors.
+  factory E.f4() = E; // Error.
+                   ^";
+  static factory f5() → self::E
+    return self::E::f();
+  static factory f6(core::int value) → self::E
+    return invalid-expression "pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:28:29: Error: The constructor function type 'E Function()' isn't a subtype of 'E Function(int)'.
+ - 'E' is from 'pkg/front_end/testcases/enhanced_enums/constructor_calls.dart'.
+  factory E.f6(int value) = E.f; // Error.
+                            ^";
+}
+static method test() → dynamic {
+  invalid-expression "pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:32:7: Error: Enums can't be instantiated.
+  new E(); // Error.
+      ^";
+  invalid-expression "pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:33:9: Error: Enums can't be instantiated.
+  const E(); // Error.
+        ^";
+  invalid-expression "pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:34:5: Error: Enum constructors can't be torn off.
+  E.new; // Error.
+    ^^^";
+  invalid-expression "pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:36:7: Error: Enums can't be instantiated.
+  new E.named(); // Error.
+      ^";
+  invalid-expression "pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:37:9: Error: Enums can't be instantiated.
+  const E().named(); // Error.
+        ^"{dynamic}.named();
+  invalid-expression "pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:38:5: Error: Enum constructors can't be torn off.
+  E.named; // Error.
+    ^^^^^";
+  self::E::f();
+  invalid-expression "pkg/front_end/testcases/enhanced_enums/constructor_calls.dart:41:9: Error: Cannot invoke a non-'const' factory where a const expression is expected.
+Try using a constructor or factory that is 'const'.
+  const E.f(); // Error.
+        ^";
+  #C11;
+}
+static method main() → dynamic {}
+
+constants  {
+  #C1 = 0
+  #C2 = "one"
+  #C3 = self::E {index:#C1, _name:#C2}
+  #C4 = 1
+  #C5 = "two"
+  #C6 = self::E {index:#C4, _name:#C5}
+  #C7 = constructor-tearoff self::E::f3
+  #C8 = constructor-tearoff self::E::f4
+  #C9 = constructor-tearoff self::E::f5
+  #C10 = constructor-tearoff self::E::f6
+  #C11 = constructor-tearoff self::E::f
+}
+
+
+Constructor coverage from constants:
+org-dartlang-testcase:///constructor_calls.dart:
+- E. (from org-dartlang-testcase:///constructor_calls.dart:11:9)
+- _Enum. (from org-dartlang-sdk:///sdk/lib/core/enum.dart:76:9)
+- Object. (from org-dartlang-sdk:///sdk/lib/core/object.dart:25:9)
+- E.named (from org-dartlang-testcase:///constructor_calls.dart:13:9)