Compute expected type for variables

src/typing.h

 // Copyright 2013 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 40 matching lines @@
   void operator delete(void* pointer, Zone* zone) { }
   void operator delete(void* pointer) { }
 
   DEFINE_AST_VISITOR_SUBCLASS_MEMBERS();
 
  private:
   explicit AstTyper(CompilationInfo* info);
 
   CompilationInfo* info_;
   TypeFeedbackOracle oracle_;
+  Handle<Type> expected_type_;
 
   TypeFeedbackOracle* oracle() { return &oracle_; }
   Zone* zone() const { return info_->zone(); }
 
   void MergeLowerType(Expression* e, Handle<Type> t) {
     e->set_lower_type(handle(Type::Union(e->lower_type(), t), isolate_));
   }
   void MergeUpperType(Expression* e, Handle<Type> t) {
     e->set_upper_type(handle(Type::Intersect(e->upper_type(), t), isolate_));
   }
@@ skipping 10 matching lines @@
 #define DECLARE_VISIT(type) virtual void Visit##type(type* node);
   AST_NODE_LIST(DECLARE_VISIT)
 #undef DECLARE_VISIT
 
   DISALLOW_COPY_AND_ASSIGN(AstTyper);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_TYPING_H_