Refactored treatment of closure variables in dart2js CPS.

pkg/compiler/lib/src/cps_ir/constant_propagation.dart

 // Copyright (c) 2014, 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.
 
 part of dart2js.optimizers;
 
 /**
  * Propagates constants throughout the IR, and replaces branches with fixed
  * jumps as well as side-effect free expressions with known constant results.
  * Should be followed by the [ShrinkingReducer] pass.
@@ skipping 290 matching lines @@
   }
 
   // -------------------------- Visitor overrides ------------------------------
 
   void visitNode(Node node) {
     compiler.internalError(NO_LOCATION_SPANNABLE,
         "_ConstPropagationVisitor is stale, add missing visit overrides");
   }
 
   void visitFunctionDefinition(FunctionDefinition node) {
-    node.parameters.forEach(visitParameter);
+    node.parameters.forEach(visit);
     setReachable(node.body);
   }
 
   void visitFieldDefinition(FieldDefinition node) {
     if (node.hasInitializer) {
       setReachable(node.body);
     }
   }
 
   // Expressions.
@@ skipping 257 matching lines @@
     setReachable(node.definition);
     ConstantValue constant =
         new FunctionConstantValue(node.definition.element);
     setValue(node, new _ConstnessLattice(constant));
   }
 
   void visitGetClosureVariable(GetClosureVariable node) {
     setValue(node, _ConstnessLattice.NonConst);
   }
 
+  void visitClosureVariable(ClosureVariable node) {
+  }
+
   void visitParameter(Parameter node) {
     if (node.parent is FunctionDefinition) {
       // Functions may escape and thus their parameters must be initialized to
       // NonConst.
       setValue(node, _ConstnessLattice.NonConst);
     } else if (node.parent is Continuation) {
       // Continuations on the other hand are local, and parameters are
       // initialized to Unknown.
       setValue(node, _ConstnessLattice.Unknown);
     } else {
@@ skipping 94 matching lines @@
       return that;
     }
 
     if (this.constant == that.constant) {
       return this;
     }
 
     return NonConst;
   }
 }