Cleanups needed for this-scoping in arrow functions

src/ast.h

Index: src/ast.h
diff --git a/src/ast.h b/src/ast.h
index 661b5f962d86723482c0f08b2c574413787b4f21..184f3365026c7b8ad1604e565799e0f7d362bcc1 100644
--- a/src/ast.h
+++ b/src/ast.h
@@ -1623,9 +1623,7 @@ class VariableProxy FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(VariableProxy)
 
-  bool IsValidReferenceExpression() const OVERRIDE {
-    return !is_resolved() || var()->IsValidReference();
-  }
+  bool IsValidReferenceExpression() const OVERRIDE { return !is_this(); }
 
   bool IsArguments() const { return is_resolved() && var()->is_arguments(); }
 
@@ -1680,8 +1678,9 @@ class VariableProxy FINAL : public Expression {
   VariableProxy(Zone* zone, Variable* var, int start_position,
                 int end_position);
 
-  VariableProxy(Zone* zone, const AstRawString* name, bool is_this,
-                int start_position, int end_position);
+  VariableProxy(Zone* zone, const AstRawString* name,
+                Variable::Kind variable_kind, int start_position,
+                int end_position);
 
   class IsThisField : public BitField8<bool, 0, 1> {};
   class IsAssignedField : public BitField8<bool, 1, 1> {};
@@ -3395,11 +3394,12 @@ class AstNodeFactory FINAL BASE_EMBEDDED {
     return new (zone_) VariableProxy(zone_, var, start_position, end_position);
   }
 
-  VariableProxy* NewVariableProxy(const AstRawString* name, bool is_this,
+  VariableProxy* NewVariableProxy(const AstRawString* name,
+                                  Variable::Kind variable_kind,
                                   int start_position = RelocInfo::kNoPosition,
                                   int end_position = RelocInfo::kNoPosition) {
     return new (zone_)
-        VariableProxy(zone_, name, is_this, start_position, end_position);
+        VariableProxy(zone_, name, variable_kind, start_position, end_position);
   }
 
   Property* NewProperty(Expression* obj, Expression* key, int pos) {