Handle constant function references.

pkg/compiler/lib/src/compile_time_constants.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 dart2js.compile_time_constant_evaluator;
 
 import 'common.dart';
 import 'common/resolution.dart' show Resolution;
 import 'common/tasks.dart' show CompilerTask;
 import 'compiler.dart' show Compiler;
@@ skipping 171 matching lines @@
   /// Compile [element] into a constant expression. If [isConst] is true,
   /// then [element] is a constant variable. If [checkType] is true, then
   /// report an error if [element] does not typecheck.
   ConstantExpression internalCompileVariable(
       VariableElement element, bool isConst, bool checkType) {
     if (initialVariableValues.containsKey(element.declaration)) {
       ConstantExpression result = initialVariableValues[element.declaration];
       return result;
     }
     if (element.hasConstant) {
-      if (element.constant != null &&
-          compiler.serialization.supportsDeserialization) {
-        evaluate(element.constant);
+      if (element.constant != null) {
+        if (compiler.serialization.supportsDeserialization) {
+          evaluate(element.constant);
+        }
+        assert(invariant(element, hasConstantValue(element.constant),
+            message: "Constant expression has not been evaluated: "
+                "${element.constant.toStructuredText()}."));
       }
       return element.constant;
     }
     AstElement currentElement = element.analyzableElement;
     return reporter.withCurrentElement(element, () {
       // TODO(johnniwinther): Avoid this eager analysis.
       compiler.resolution.ensureResolved(currentElement.declaration);
 
       ConstantExpression constant = compileVariableWithDefinitions(
           element, currentElement.resolvedAst.elements,
@@ skipping 380 matching lines @@
     }
     return signalNotCompileTimeConstant(node);
   }
 
   // TODO(floitsch): provide better error-messages.
   AstConstant visitSend(Send send) {
     Element element = elements[send];
     if (send.isPropertyAccess) {
       AstConstant result;
       if (Elements.isStaticOrTopLevelFunction(element)) {
-        FunctionElementX function = element;
+        FunctionElement function = element;
         function.computeType(resolution);
         result = new AstConstant(
             context,
             send,
             new FunctionConstantExpression(function),
             new FunctionConstantValue(function));
       } else if (Elements.isStaticOrTopLevelField(element)) {
         ConstantExpression elementExpression;
         if (element.isConst) {
           elementExpression = handler.compileConstant(element);
@@ skipping 745 matching lines @@
 class _CompilerEnvironment implements Environment {
   final Compiler compiler;
 
   _CompilerEnvironment(this.compiler);
 
   @override
   String readFromEnvironment(String name) {
     return compiler.fromEnvironment(name);
   }
 }