Add debug names to scopes.

pkg/front_end/lib/src/fasta/kernel/kernel_library_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_library_builder;
 
 import 'package:front_end/src/fasta/combinator.dart' as fasta;
 import 'package:front_end/src/fasta/export.dart';
 import 'package:front_end/src/fasta/import.dart';
 import 'package:kernel/ast.dart';
@@ skipping 116 matching lines @@
       List<KernelTypeBuilder> interfaces,
       int charOffset) {
     // Nested declaration began in `OutlineBuilder.beginClassDeclaration`.
     var declaration = endNestedDeclaration(className)
       ..resolveTypes(typeVariables, this);
     assert(declaration.parent == libraryDeclaration);
     Map<String, MemberBuilder> members = declaration.members;
     Map<String, MemberBuilder> constructors = declaration.constructors;
     Map<String, MemberBuilder> setters = declaration.setters;
 
-    Scope classScope = new Scope(
-        members, setters, scope.withTypeVariables(typeVariables),
+    Scope classScope = new Scope(members, setters,
+        scope.withTypeVariables(typeVariables), "class $className",
         isModifiable: false);
 
     // When looking up a constructor, we don't consider type variables or the
     // library scope.
-    Scope constructorScope =
-        new Scope(constructors, null, null, isModifiable: false);
+    Scope constructorScope = new Scope(constructors, null, null, "constructors",
+        isModifiable: false);
     ClassBuilder cls = new SourceClassBuilder(
         documentationComment,
         metadata,
         modifiers,
         className,
         typeVariables,
         applyMixins(supertype,
             isSyntheticMixinImplementation: true,
             subclassName: className,
             typeVariables: typeVariables),
@@ skipping 92 matching lines @@
       builder = new SourceClassBuilder(
           documentationComment,
           metadata,
           modifiers,
           name,
           typeVariables,
           supertype,
           interfaces,
           new Scope(<String, MemberBuilder>{}, <String, MemberBuilder>{},
               scope.withTypeVariables(typeVariables),
+              "mixin $name", isModifiable: false),
+          new Scope(constructors, null, null, "constructors",
               isModifiable: false),
-          new Scope(constructors, null, null, isModifiable: false),
           this,
           <ConstructorReferenceBuilder>[],
           charOffset,
           null,
           mixin);
       builder.cls.isSyntheticMixinImplementation =
           isSyntheticMixinImplementation;
       addBuilder(name, builder, charOffset);
       if (!isNamed) {
         mixinApplicationClasses[name] = builder;
@@ skipping 675 matching lines @@
           mixinApplicationClasses.putIfAbsent(name, () => builder);
       if (existing != builder) {
         part.scope.local.remove(name);
       }
     });
     super.includePart(part);
     nativeMethods.addAll(part.nativeMethods);
     boundlessTypeVariables.addAll(part.boundlessTypeVariables);
   }
 }