Remove a pair of problematic uses of the Reference utility class from...

src/ast.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 629 matching lines @@
 
  private:
   Block* try_block_;
   ZoneList<BreakTarget*>* escaping_targets_;
 };
 
 
 class TryCatchStatement: public TryStatement {
  public:
   TryCatchStatement(Block* try_block,
-                    Expression* catch_var,
+                    VariableProxy* catch_var,
                     Block* catch_block)
       : TryStatement(try_block),
         catch_var_(catch_var),
         catch_block_(catch_block) {
     ASSERT(catch_var->AsVariableProxy() != NULL);
   }
 
   virtual void Accept(AstVisitor* v);
 
-  Expression* catch_var() const  { return catch_var_; }
+  VariableProxy* catch_var() const  { return catch_var_; }
   Block* catch_block() const  { return catch_block_; }
 
  private:
-  Expression* catch_var_;
+  VariableProxy* catch_var_;
   Block* catch_block_;
 };
 
 
 class TryFinallyStatement: public TryStatement {
  public:
   TryFinallyStatement(Block* try_block, Block* finally_block)
       : TryStatement(try_block),
         finally_block_(finally_block) { }
 
@@ skipping 1134 matching lines @@
 #undef DEF_VISIT
 
  private:
   bool stack_overflow_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_