[es6] Handle conflicts for sloppy let

src/parser.cc

 // 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.
 
 #include "src/v8.h"
 
 #include "src/api.h"
 #include "src/ast.h"
 #include "src/ast-literal-reindexer.h"
 #include "src/bailout-reason.h"
@@ skipping 1044 matching lines @@
     } else {
       ParseStatementList(body, Token::EOS, &ok);
     }
 
     // The parser will peek but not consume EOS.  Our scope logically goes all
     // the way to the EOS, though.
     scope->set_end_position(scanner()->peek_location().beg_pos);
 
     if (ok && is_strict(language_mode())) {
       CheckStrictOctalLiteral(beg_pos, scanner()->location().end_pos, &ok);
+    }
+    if (ok && (is_strict(language_mode()) || allow_harmony_sloppy())) {
       CheckConflictingVarDeclarations(scope_, &ok);
     }
 
     if (ok && info->parse_restriction() == ONLY_SINGLE_FUNCTION_LITERAL) {
       if (body->length() != 1 ||
           !body->at(0)->IsExpressionStatement() ||
           !body->at(0)->AsExpressionStatement()->
               expression()->IsFunctionLiteral()) {
         ReportMessage(MessageTemplate::kSingleFunctionLiteral);
         ok = false;
@@ skipping 3059 matching lines @@
     const bool use_strict_params =
         !parsing_state.is_simple_parameter_list || IsConciseMethod(kind);
     const bool allow_duplicate_parameters =
         is_sloppy(language_mode()) && !use_strict_params;
     ValidateFormalParameters(&formals_classifier, language_mode(),
                              allow_duplicate_parameters, CHECK_OK);
 
     if (is_strict(language_mode())) {
       CheckStrictOctalLiteral(scope->start_position(), scope->end_position(),
                               CHECK_OK);
+    }
+    if (is_strict(language_mode()) || allow_harmony_sloppy()) {
       CheckConflictingVarDeclarations(scope, CHECK_OK);
     }
   }
 
   bool has_duplicate_parameters =
       !formals_classifier.is_valid_formal_parameter_list_without_duplicates();
   FunctionLiteral::ParameterFlag duplicate_parameters =
       has_duplicate_parameters ? FunctionLiteral::kHasDuplicateParameters
                                : FunctionLiteral::kNoDuplicateParameters;
 
@@ skipping 1790 matching lines @@
 Expression* Parser::SpreadCallNew(Expression* function,
                                   ZoneList<v8::internal::Expression*>* args,
                                   int pos) {
   args->InsertAt(0, function, zone());
 
   return factory()->NewCallRuntime(
       ast_value_factory()->reflect_construct_string(), NULL, args, pos);
 }
 }  // namespace internal
 }  // namespace v8