Handle use of constant constructors with default values.

pkg/compiler/lib/src/elements/modelx.dart

 // Copyright (c) 2013, 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 elements.modelx;
 
 import '../common.dart';
 import '../common/resolution.dart' show Resolution, ParsingContext;
 import '../compiler.dart' show Compiler;
 import '../constants/constant_constructors.dart';
@@ skipping 1375 matching lines @@
   VariableDefinitions parseNode(Element element, ParsingContext parsing) {
     return definitions;
   }
 
   DartType computeType(Element element, Resolution resolution) => type;
 }
 
 abstract class ConstantVariableMixin implements VariableElement {
   ConstantExpression constantCache;
 
+  // TODO(johnniwinther): Update the on `constant = ...` when evaluation of
+  // constant expression can handle references to unanalyzed constant variables.
+  @override
+  bool get hasConstant => false;
+
   ConstantExpression get constant {
     if (isPatch) {
       ConstantVariableMixin originVariable = origin;
       return originVariable.constant;
     }
     assert(invariant(this, !isConst || constantCache != null,
         message: "Constant has not been computed for $this."));
     return constantCache;
   }
 
@@ skipping 1882 matching lines @@
       body = node.asFunctionExpression().body;
     }
     return new ParsedResolvedAst(
         declaration,
         node,
         body,
         definingElement.treeElements,
         definingElement.compilationUnit.script.resourceUri);
   }
 }