Stop emitting kSloppyLexical errors when --harmony-sloppy-let is enabled

src/preparser.cc

 // Copyright 2011 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.
 
 #include <cmath>
 
 #include "src/allocation.h"
 #include "src/base/logging.h"
 #include "src/conversions-inl.h"
 #include "src/conversions.h"
@@ skipping 682 matching lines @@
            !IsFutureStrictReserved(expr.AsIdentifier()));
     Consume(Token::COLON);
     Statement statement = ParseStatement(ok);
     return statement.IsJumpStatement() ? Statement::Default() : statement;
     // Preparsing is disabled for extensions (because the extension details
     // aren't passed to lazily compiled functions), so we don't
     // accept "native function" in the preparser.
   }
   // Parsed expression statement.
   // Detect attempts at 'let' declarations in sloppy mode.
-  if (peek() == Token::IDENTIFIER && is_sloppy(language_mode()) &&
-      expr.IsIdentifier() && expr.AsIdentifier().IsLet()) {
+  if (!allow_harmony_sloppy_let() && peek() == Token::IDENTIFIER &&
+      is_sloppy(language_mode()) && expr.IsIdentifier() &&
+      expr.AsIdentifier().IsLet()) {
     ReportMessage(MessageTemplate::kSloppyLexical, NULL);
     *ok = false;
     return Statement::Default();
   }
   ExpectSemicolon(CHECK_OK);
   return Statement::ExpressionStatement(expr);
 }
 
 
 PreParser::Statement PreParser::ParseIfStatement(bool* ok) {
@@ skipping 238 matching lines @@
         ParseExpression(true, CHECK_OK);
         Expect(Token::RPAREN, CHECK_OK);
         ParseSubStatement(CHECK_OK);
         return Statement::Default();
       }
     }
   }
 
   // Parsed initializer at this point.
   // Detect attempts at 'let' declarations in sloppy mode.
-  if (peek() == Token::IDENTIFIER && is_sloppy(language_mode()) &&
-      is_let_identifier_expression) {
+  if (!allow_harmony_sloppy_let() && peek() == Token::IDENTIFIER &&
+      is_sloppy(language_mode()) && is_let_identifier_expression) {
     ReportMessage(MessageTemplate::kSloppyLexical, NULL);
     *ok = false;
     return Statement::Default();
   }
   Expect(Token::SEMICOLON, CHECK_OK);
 
   if (peek() != Token::SEMICOLON) {
     ParseExpression(true, CHECK_OK);
   }
   Expect(Token::SEMICOLON, CHECK_OK);
@@ skipping 256 matching lines @@
 
   DCHECK(!spread_pos.IsValid());
 
   return Expression::Default();
 }
 
 #undef CHECK_OK
 
 
 } }  // v8::internal