Implement proper scoping for "this" in arrow functions

src/ast.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_AST_H_
 #define V8_AST_H_
 
 #include "src/v8.h"
 
 #include "src/assembler.h"
@@ skipping 1581 matching lines @@
   Handle<FixedArray> constant_elements_;
   ZoneList<Expression*>* values_;
 };
 
 
 class VariableProxy FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(VariableProxy)
 
   bool IsValidReferenceExpression() const OVERRIDE {
-    return !is_resolved() || var()->IsValidReference();
+    return !is_this() && !is_new_target();
   }
 
   bool IsArguments() const { return is_resolved() && var()->is_arguments(); }
 
   Handle<String> name() const { return raw_name()->string(); }
   const AstRawString* raw_name() const {
     return is_resolved() ? var_->raw_name() : raw_name_;
   }
 
   Variable* var() const {
     DCHECK(is_resolved());
     return var_;
   }
   void set_var(Variable* v) {
     DCHECK(!is_resolved());
     DCHECK_NOT_NULL(v);
     var_ = v;
   }
 
   bool is_this() const { return IsThisField::decode(bit_field_); }
 
+  bool is_new_target() const { return IsNewTargetField::decode(bit_field_); }
+
   bool is_assigned() const { return IsAssignedField::decode(bit_field_); }
   void set_is_assigned() {
     bit_field_ = IsAssignedField::update(bit_field_, true);
   }
 
   bool is_resolved() const { return IsResolvedField::decode(bit_field_); }
   void set_is_resolved() {
     bit_field_ = IsResolvedField::update(bit_field_, true);
   }
 
@@ skipping 14 matching lines @@
   }
   Code::Kind FeedbackICSlotKind(int index) OVERRIDE { return Code::LOAD_IC; }
   FeedbackVectorICSlot VariableFeedbackSlot() {
     DCHECK(!UsesVariableFeedbackSlot() || !variable_feedback_slot_.IsInvalid());
     return variable_feedback_slot_;
   }
 
  protected:
   VariableProxy(Zone* zone, Variable* var, int position);
 
-  VariableProxy(Zone* zone, const AstRawString* name, bool is_this,
-                int position);
+  VariableProxy(Zone* zone, const AstRawString* name,
+                Variable::Kind variable_kind, int position);
 
   class IsThisField : public BitField8<bool, 0, 1> {};
   class IsAssignedField : public BitField8<bool, 1, 1> {};
   class IsResolvedField : public BitField8<bool, 2, 1> {};
+  class IsNewTargetField : public BitField8<bool, 3, 1> {};
 
   // Start with 16-bit (or smaller) field, which should get packed together
   // with Expression's trailing 16-bit field.
   uint8_t bit_field_;
   FeedbackVectorICSlot variable_feedback_slot_;
   union {
     const AstRawString* raw_name_;  // if !is_resolved_
     Variable* var_;                 // if is_resolved_
   };
 };
@@ skipping 1677 matching lines @@
                                 int pos) {
     return new (zone_) ArrayLiteral(zone_, values, literal_index, pos);
   }
 
   VariableProxy* NewVariableProxy(Variable* var,
                                   int pos = RelocInfo::kNoPosition) {
     return new (zone_) VariableProxy(zone_, var, pos);
   }
 
   VariableProxy* NewVariableProxy(const AstRawString* name,
-                                  bool is_this,
+                                  Variable::Kind variable_kind,
                                   int position = RelocInfo::kNoPosition) {
-    return new (zone_) VariableProxy(zone_, name, is_this, position);
+    return new (zone_) VariableProxy(zone_, name, variable_kind, position);
   }
 
   Property* NewProperty(Expression* obj, Expression* key, int pos) {
     return new (zone_) Property(zone_, obj, key, pos);
   }
 
   Call* NewCall(Expression* expression,
                 ZoneList<Expression*>* arguments,
                 int pos) {
     return new (zone_) Call(zone_, expression, arguments, pos);
@@ skipping 116 matching lines @@
 
  private:
   Zone* zone_;
   AstValueFactory* ast_value_factory_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_