Use better names for captured variables in closures.

pkg/compiler/lib/src/closure.dart

 // Copyright (c) 2012, 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 closureToClassMapper;
 
 import 'common.dart';
 import 'common/names.dart' show
     Identifiers;
 import 'common/resolution.dart' show
@@ skipping 85 matching lines @@
   }
 }
 
 /// Common interface for [BoxFieldElement] and [ClosureFieldElement] as
 /// non-elements.
 abstract class CapturedVariable implements Element {}
 
 // TODO(ahe): These classes continuously cause problems.  We need to
 // find a more general solution.
 class ClosureFieldElement extends ElementX
-    implements FieldElement, CapturedVariable {
+    implements FieldElement, CapturedVariable, PrivatelyNamedJSEntity {
   /// The [BoxLocal] or [LocalElement] being accessed through the field.
   final Local local;
 
   ClosureFieldElement(String name,
                       this.local,
                       ClosureClassElement enclosing)
       : super(name, ElementKind.FIELD, enclosing);
 
   /// Use [closureClass] instead.
   @deprecated
   get enclosingElement => super.enclosingElement;
 
   ClosureClassElement get closureClass => super.enclosingElement;
 
   MemberElement get memberContext => closureClass.methodElement.memberContext;
 
+  @override
+  Entity get declaredEntity => local;
+  @override
+  Entity get rootOfScope => closureClass;
+
   bool get hasNode => false;
 
   Node get node {
     throw new SpannableAssertionFailure(local,
         'Should not access node of ClosureFieldElement.');
   }
 
   bool get hasResolvedAst => hasTreeElements;
 
   ResolvedAst get resolvedAst {
@@ skipping 106 matching lines @@
 class BoxLocal extends Local {
   final String name;
   final ExecutableElement executableContext;
 
   BoxLocal(this.name, this.executableContext);
 }
 
 // TODO(ngeoffray, ahe): These classes continuously cause problems.  We need to
 // find a more general solution.
 class BoxFieldElement extends ElementX
-    implements TypedElement, CapturedVariable, FieldElement {
+    implements TypedElement, CapturedVariable, FieldElement,
+        PrivatelyNamedJSEntity {
   final BoxLocal box;
 
-  BoxFieldElement(String name, this.variableElement, BoxLocal box)
+  BoxFieldElement(String name, this.variableElement,
+      BoxLocal box)
       : this.box = box,
         super(name, ElementKind.FIELD, box.executableContext);
 
   DartType computeType(Resolution resolution) => type;
 
   DartType get type => variableElement.type;
 
+  @override
+  Entity get declaredEntity => variableElement;
+  @override
+  Entity get rootOfScope => box;
+
   final VariableElement variableElement;
 
   accept(ElementVisitor visitor, arg) {
     return visitor.visitBoxFieldElement(this, arg);
   }
 
   @override
   bool get hasNode => false;
 
   @override
@@ skipping 242 matching lines @@
 
   /// Generate a unique name for the [id]th closure field, with proposed name
   /// [name].
   ///
   /// The result is used as the name of [ClosureFieldElement]s, and must
   /// therefore be unique to avoid breaking an invariant in the element model
   /// (classes cannot declare multiple fields with the same name).
   ///
   /// Also, the names should be distinct from real field names to prevent
   /// clashes with selectors for those fields.
+  ///
+  /// These names are not used in generated code, just as element name.
   String getClosureVariableName(String name, int id) {
     return "_captured_${name}_$id";
   }
 
   /// Generate a unique name for the [id]th box field, with proposed name
   /// [name].
   ///
   /// The result is used as the name of [BoxFieldElement]s, and must
   /// therefore be unique to avoid breaking an invariant in the element model
   /// (classes cannot declare multiple fields with the same name).
   ///
   /// Also, the names should be distinct from real field names to prevent
   /// clashes with selectors for those fields.
+  ///
+  /// These names are not used in generated code, just as element name.
   String getBoxFieldName(int id) {
     return "_box_$id";
   }
 
   bool isCapturedVariable(Local element) {
     return _capturedVariableMapping.containsKey(element);
   }
 
   void addCapturedVariable(Node node, Local variable) {
     if (_capturedVariableMapping[variable] != null) {
@@ skipping 582 matching lines @@
 
   String get name => typeVariable.name;
 
   int get hashCode => typeVariable.hashCode;
 
   bool operator ==(other) {
     if (other is! TypeVariableLocal) return false;
     return typeVariable == other.typeVariable;
   }
 }
+
+///
+/// Move the below classes to a JS model eventually.
+///
+abstract class JSEntity implements Entity {
+  Entity get declaredEntity;
+}
+
+abstract class PrivatelyNamedJSEntity implements JSEntity {
+  Entity get rootOfScope;
+}