Implement simple effect typing for variables

src/ast.h

 // Copyright 2012 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 371 matching lines @@
 
   // TODO(rossberg): this should move to its own AST node eventually.
   virtual void RecordToBooleanTypeFeedback(TypeFeedbackOracle* oracle);
   byte to_boolean_types() const { return to_boolean_types_; }
 
   BailoutId id() const { return id_; }
   TypeFeedbackId test_id() const { return test_id_; }
 
  protected:
   explicit Expression(Isolate* isolate)
-      : bounds_(Type::None(), Type::Any(), isolate),
+      : bounds_(Bounds::Unbounded(isolate)),
         id_(GetNextId(isolate)),
         test_id_(GetNextId(isolate)) {}
   void set_to_boolean_types(byte types) { to_boolean_types_ = types; }
 
  private:
   Bounds bounds_;
   byte to_boolean_types_;
 
   const BailoutId id_;
   const TypeFeedbackId test_id_;
@@ skipping 2806 matching lines @@
  private:
   Isolate* isolate_;
   Zone* zone_;
   Visitor visitor_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_