Setup correct scope for initializers and complain about fields initialized more than once.

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

 // Copyright (c) 2016, 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.
 
 library fasta.kernel_enum_builder;
 
 import 'package:kernel/ast.dart'
     show
         Arguments,
         Class,
@@ skipping 10 matching lines @@
         MapLiteral,
         MethodInvocation,
         ProcedureKind,
         ReturnStatement,
         StaticGet,
         StringLiteral,
         SuperInitializer,
         ThisExpression,
         VariableGet;
 
+import 'package:front_end/src/scanner/token.dart' show Token;
+
 import '../errors.dart' show inputError;
 
 import '../modifier.dart' show constMask, finalMask, staticMask;
 
 import '../names.dart' show indexGetName;
 
 import '../source/source_class_builder.dart' show SourceClassBuilder;
 
 import 'kernel_builder.dart'
     show
@@ skipping 71 matching lines @@
     /// From Dart Programming Language Specification 4th Edition/December 2015:
     ///     metadata class E {
     ///       final int index;
     ///       const E(this.index);
     ///       static const E id0 = const E(0);
     ///       ...
     ///       static const E idn-1 = const E(n - 1);
     ///       static const List<E> values = const <E>[id0, ..., idn-1];
     ///       String toString() => { 0: ‘E.id0’, . . ., n-1: ‘E.idn-1’}[index]
     ///     }
-    members["index"] = new KernelFieldBuilder(
-        null, intType, "index", finalMask, parent, charOffset, null);
+    members["index"] = new KernelFieldBuilder(null, intType, "index", finalMask,
+        parent, charOffset, new Token.eof(charOffset));

[Johnni Winther, 2017/06/06 10:35:08]

Document why you pass `new Token.eof(...)`

[ahe, 2017/06/06 15:08:24]

Done.

     KernelConstructorBuilder constructorBuilder = new KernelConstructorBuilder(
         null,
         constMask,
         null,
         "",
         null,
         <FormalParameterBuilder>[
           new KernelFormalParameterBuilder(
               null, 0, intType, "index", true, parent, charOffset)
         ],
         parent,
         charOffset,
         charOffset,
         charEndOffset);
     constructors[""] = constructorBuilder;
     int index = 0;
     List<MapEntry> toStringEntries = <MapEntry>[];
-    KernelFieldBuilder valuesBuilder = new KernelFieldBuilder(null, listType,
-        "values", constMask | staticMask, parent, charOffset, null);
+    KernelFieldBuilder valuesBuilder = new KernelFieldBuilder(
+        null,
+        listType,
+        "values",
+        constMask | staticMask,
+        parent,
+        charOffset,
+        new Token.eof(charOffset));
     members["values"] = valuesBuilder;
     KernelProcedureBuilder toStringBuilder = new KernelProcedureBuilder(
         null,
         0,
         stringType,
         "toString",
         null,
         null,
         ProcedureKind.Method,
         parent,
         charOffset,
         charOffset,
         charEndOffset);
     members["toString"] = toStringBuilder;
     String className = name;
     for (int i = 0; i < constantNamesAndOffsets.length; i += 2) {
       String name = constantNamesAndOffsets[i];
       int charOffset = constantNamesAndOffsets[i + 1];
       if (members.containsKey(name)) {
         inputError(null, null, "Duplicated name: $name");
         continue;
       }
-      KernelFieldBuilder fieldBuilder = new KernelFieldBuilder(null, selfType,
-          name, constMask | staticMask, parent, charOffset, null);
+      KernelFieldBuilder fieldBuilder = new KernelFieldBuilder(
+          null,
+          selfType,
+          name,
+          constMask | staticMask,
+          parent,
+          charOffset,
+          new Token.eof(charOffset));
       members[name] = fieldBuilder;
       toStringEntries.add(new MapEntry(
           new IntLiteral(index), new StringLiteral("$className.$name")));
       index++;
     }
     MapLiteral toStringMap = new MapLiteral(toStringEntries, isConst: true);
     KernelEnumBuilder enumBuilder = new KernelEnumBuilder.internal(
         metadata,
         name,
         new Scope(members, null, parent.scope, isModifiable: false),
@@ skipping 90 matching lines @@
     }
     return super.build(libraryBuilder, coreLibrary);
   }
 
   @override
   Builder findConstructorOrFactory(
       String name, int charOffset, Uri uri, LibraryBuilder library) {
     return null;
   }
 }