[strong] Deprecate for-in

src/preparser.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_PREPARSER_H
 #define V8_PREPARSER_H
 
 #include "src/v8.h"
 
 #include "src/bailout-reason.h"
@@ skipping 402 matching lines @@
 
   void ExpectContextualKeyword(Vector<const char> keyword, bool* ok) {
     Expect(Token::IDENTIFIER, ok);
     if (!*ok) return;
     if (!scanner()->is_literal_contextual_keyword(keyword)) {
       ReportUnexpectedToken(scanner()->current_token());
       *ok = false;
     }
   }
 
+  bool CheckInOrOf(
+      bool accept_OF, ForEachStatement::VisitMode* visit_mode, bool* ok) {
+    if (Check(Token::IN)) {
+      if (is_strong(language_mode())) {
+        ReportMessageAt(scanner()->location(), "strong_for_in");
+        *ok = false;
+      } else {
+        *visit_mode = ForEachStatement::ENUMERATE;
+      }
+      return true;
+    } else if (accept_OF && CheckContextualKeyword(CStrVector("of"))) {
+      *visit_mode = ForEachStatement::ITERATE;
+      return true;
+    }
+    return false;
+  }
+
   // Checks whether an octal literal was last seen between beg_pos and end_pos.
   // If so, reports an error. Only called for strict mode and template strings.
   void CheckOctalLiteral(int beg_pos, int end_pos, const char* error,
                          bool* ok) {
     Scanner::Location octal = scanner()->octal_position();
     if (octal.IsValid() && beg_pos <= octal.beg_pos &&
         octal.end_pos <= end_pos) {
       ReportMessageAt(octal, error);
       scanner()->clear_octal_position();
       *ok = false;
@@ skipping 1173 matching lines @@
       Identifier name, Scanner::Location function_name_location,
       bool name_is_strict_reserved, FunctionKind kind, int function_token_pos,
       FunctionLiteral::FunctionType function_type,
       FunctionLiteral::ArityRestriction arity_restriction, bool* ok);
   void ParseLazyFunctionLiteralBody(bool* ok);
 
   PreParserExpression ParseClassLiteral(PreParserIdentifier name,
                                         Scanner::Location class_name_location,
                                         bool name_is_strict_reserved, int pos,
                                         bool* ok);
-
-  bool CheckInOrOf(bool accept_OF);
 };
 
 
 void PreParserTraits::MaterializeTemplateCallsiteLiterals() {
   pre_parser_->function_state_->NextMaterializedLiteralIndex();
   pre_parser_->function_state_->NextMaterializedLiteralIndex();
 }
 
 
 PreParserStatementList PreParser::ParseEagerFunctionBody(
@@ skipping 1455 matching lines @@
       *ok = false;
       return;
     }
     has_seen_constructor_ = true;
     return;
   }
 }
 } }  // v8::internal
 
 #endif  // V8_PREPARSER_H