[cfe] Report error on instantiation of enums from .dill

Closes #48350

Change-Id: I0cedf8a5a12e1a8dee546eec73e012519a054e13
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/232384
Reviewed-by: Chloe Stefantsova <cstefantsova@google.com>
Commit-Queue: Johnni Winther <johnniwinther@google.com>

Author: johnniwinther

pkg/front_end/lib/src/fasta/builder/type_declaration_builder.dart

@@ -28,6 +28,9 @@ abstract class TypeDeclarationBuilder implements ModifierBuilder {
   @override
   TypeDeclarationBuilder get origin;
 
+  /// Return `true` if this type declaration is an enum.
+  bool get isEnum;
+
   /// Creates the [DartType] corresponding to this declaration applied with
   /// [arguments] in [library] with the syntactical nullability defined by
   /// [nullabilityBuilder].
@@ -74,6 +77,9 @@ abstract class TypeDeclarationBuilderImpl extends ModifierBuilderImpl
   @override
   bool get isTypeDeclaration => true;
 
+  @override
+  bool get isEnum => false;
+
   @override
   String get fullNameForErrors => name;
 

pkg/front_end/lib/src/fasta/dill/dill_class_builder.dart

@@ -46,6 +46,9 @@ class DillClassBuilder extends ClassBuilderImpl {
             parent,
             cls.fileOffset);
 
+  @override
+  bool get isEnum => cls.isEnum;
+
   @override
   DillClassBuilder get origin => this;
 

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

@@ -5371,7 +5371,7 @@ class BodyBuilder extends ScopeListener<JumpTarget>
       } else {
         target = b.member;
       }
-      if (type is SourceEnumBuilder &&
+      if (type.isEnum &&
           !(libraryBuilder.enableEnhancedEnumsInLibrary &&
               target is Procedure &&
               target.kind == ProcedureKind.Factory)) {

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

@@ -455,6 +455,9 @@ class SourceEnumBuilder extends SourceClassBuilder {
     return enumBuilder;
   }
 
+  @override
+  bool get isEnum => true;
+
   @override
   TypeBuilder? get mixedInTypeBuilder => null;
 

pkg/front_end/testcases/expression/instantiate_enum.expression.yaml

@@ -0,0 +1,9 @@
+# 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.
+
+entry_point: "main.dart"
+definitions: []
+position: "main.dart"
+expression: |
+  En(123, 'foo')

pkg/front_end/testcases/expression/instantiate_enum.expression.yaml.expect

@@ -0,0 +1,7 @@
+Errors: {
+  org-dartlang-debug:synthetic_debug_expression:1:1: Error: Enums can't be instantiated.
+  En(123, 'foo')
+  ^^
+}
+method /* from org-dartlang-debug:synthetic_debug_expression */ debugExpr() → dynamic
+  return invalid-expression "org-dartlang-debug:synthetic_debug_expression:1:1: Error: Enums can't be instantiated.\nEn(123, 'foo')\n^^";

pkg/front_end/testcases/expression/main.dart

@@ -127,3 +127,5 @@ void hasClosure() {
       .fold<int>(0, (previousValue, element) => previousValue + element.length);
   print("xCombinedLength = $xCombinedLength");
 }
+
+enum En { a, b, c }

pkg/front_end/testcases/general/instantiate_enum/main.dart

@@ -0,0 +1,18 @@
+// 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 'main_lib.dart';
+
+enum Enum1 { a, b, c }
+
+typedef Alias1 = Enum1;
+
+test() {
+  Enum1(123, 'foo');
+  Enum2(123, 'foo');
+  Alias1(123, 'foo');
+  Alias2(123, 'foo');
+}
+
+main() {}

pkg/front_end/testcases/general/instantiate_enum/main.dart.textual_outline.expect

@@ -0,0 +1,6 @@
+import 'main_lib.dart';
+
+enum Enum1 { a, b, c }
+typedef Alias1 = Enum1;
+test() {}
+main() {}

pkg/front_end/testcases/general/instantiate_enum/main.dart.textual_outline_modelled.expect

@@ -0,0 +1,6 @@
+import 'main_lib.dart';
+
+enum Enum1 { a, b, c }
+main() {}
+test() {}
+typedef Alias1 = Enum1;