Add ConstantConstructor to ConstantExpression system.

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 "elements/elements.dart";
-import "dart2jslib.dart";
-import "dart_types.dart";
-import "js_backend/js_backend.dart" show JavaScriptBackend;
-import "scanner/scannerlib.dart" show Token;
-import "tree/tree.dart";
-import "util/util.dart";
-import "elements/modelx.dart"
+import 'constants/expressions.dart';
+import 'dart2jslib.dart';
+import 'dart_types.dart';
+import 'elements/elements.dart';
+import 'elements/modelx.dart'
     show BaseFunctionElementX,
          ClassElementX,
          ElementX,
          LocalFunctionElementX;
-import "elements/visitor.dart" show ElementVisitor;
-
+import 'elements/visitor.dart' show ElementVisitor;
+import 'js_backend/js_backend.dart' show JavaScriptBackend;
+import 'scanner/scannerlib.dart' show Token;
+import 'tree/tree.dart';
+import 'util/util.dart';
 import 'universe/universe.dart' show
     Universe;
 
 class ClosureTask extends CompilerTask {
   Map<Node, ClosureClassMap> closureMappingCache;
   ClosureTask(Compiler compiler)
       : closureMappingCache = new Map<Node, ClosureClassMap>(),
         super(compiler);
 
   String get name => "Closure Simplifier";
@@ skipping 113 matching lines @@
   String toString() => "ClosureFieldElement($name)";
 
   accept(ElementVisitor visitor, arg) {
     return visitor.visitClosureFieldElement(this, arg);
   }
 
   Element get analyzableElement => closureClass.methodElement.analyzableElement;
 
   @override
   List<FunctionElement> get nestedClosures => const <FunctionElement>[];
+
+  @override
+  ConstantExpression get constant => null;
 }
 
 // TODO(ahe): These classes continuously cause problems.  We need to find
 // a more general solution.
 class ClosureClassElement extends ClassElementX {
   DartType rawType;
   DartType thisType;
   FunctionType callType;
   /// Node that corresponds to this closure, used for source position.
   final FunctionExpression node;
@@ skipping 105 matching lines @@
 
   @override
   Node get node {
     throw new UnsupportedError("BoxFieldElement.node");
   }
 
   @override
   ResolvedAst get resolvedAst {
     throw new UnsupportedError("BoxFieldElement.resolvedAst");
   }
+
+  @override
+  ConstantExpression get constant => null;
 }
 
 /// A local variable used encode the direct (uncaptured) references to [this].
 class ThisLocal extends Local {
   final ExecutableElement executableContext;
 
   ThisLocal(this.executableContext);
 
   String get name => 'this';
 
@@ skipping 804 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;
   }
 }