tree-ir: Do not merge captured parameters with other variables.

pkg/compiler/lib/src/tree_ir/tree_ir_builder.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.
 
 library tree_ir_builder;
 
 import '../dart2jslib.dart' as dart2js;
 import '../dart_types.dart';
 import '../elements/elements.dart';
 import '../cps_ir/cps_ir_nodes.dart' as cps_ir;
@@ skipping 138 matching lines @@
 
       body = visit(node.body);
     }
     return new FieldDefinition(node.element, body);
   }
 
   Variable addFunctionParameter(cps_ir.Definition variable) {
     if (variable is cps_ir.Parameter) {
       return getVariable(variable);
     } else {
-      return addMutableVariable(variable as cps_ir.MutableVariable);
+      return addMutableVariable(variable as cps_ir.MutableVariable)
+              ..isCaptured = true;

[asgerf, 2015/04/15 10:43:39]

This is for parameters accessed by initializers.

     }
   }
 
   FunctionDefinition buildFunction(cps_ir.FunctionDefinition node) {
     currentElement = node.element;
     if (parent != null) {
       // Local function's 'this' refers to enclosing method's 'this'
       thisParameter = parent.thisParameter;
     } else {
       thisParameter = node.thisParameter;
@@ skipping 480 matching lines @@
   }
 
   @override
   Node visitTypeExpression(cps_ir.TypeExpression node) {
     return new TypeExpression(
         node.dartType,
         node.arguments.map(getVariableUse).toList());
   }
 }