| Index: src/parser.cc | 
| diff --git a/src/parser.cc b/src/parser.cc | 
| index 2e6e0ad1cfab6aebc322c3cf930eb178fb370ec1..7ddd0fce0c804b2924ce422307c0e0b12110ed07 100644 | 
| --- a/src/parser.cc | 
| +++ b/src/parser.cc | 
| @@ -1198,9 +1198,8 @@ FunctionLiteral* Parser::ParseLazy(Isolate* isolate, ParseInfo* info, | 
| // BindingIdentifier | 
| ParseFormalParameter(&formals, &formals_classifier, &ok); | 
| if (ok) { | 
| -            DeclareFormalParameter( | 
| -                formals.scope, formals.at(0), formals.is_simple, | 
| -                &formals_classifier); | 
| +            DeclareFormalParameter(formals.scope, formals.at(0), | 
| +                                   &formals_classifier); | 
| } | 
| } | 
| } | 
| @@ -1322,6 +1321,20 @@ void* Parser::ParseStatementList(ZoneList<Statement*>* body, int end_token, | 
| token_loc.end_pos - token_loc.beg_pos == | 
| ast_value_factory()->use_strong_string()->length() + 2; | 
| if (use_strict_found || use_strong_found) { | 
| +          if (!scope_->HasSimpleParameters()) { | 
| +            // TC39 deemed "use strict" directives to be an error when occurring | 
| +            // in the body of a function with non-simple parameter list, on | 
| +            // 29/7/2015. https://goo.gl/ueA7Ln | 
| +            // | 
| +            // In V8, this also applies to "use strong " directives. | 
| +            const AstRawString* string = literal->raw_value()->AsString(); | 
| +            ParserTraits::ReportMessageAt( | 
| +                token_loc, MessageTemplate::kIllegalLanguageModeDirective, | 
| +                string); | 
| +            *ok = false; | 
| +            return nullptr; | 
| +          } | 
| + | 
| // Strong mode implies strict mode. If there are several "use strict" | 
| // / "use strong" directives, do the strict mode changes only once. | 
| if (is_sloppy(scope_->language_mode())) { | 
| @@ -3889,8 +3902,7 @@ Handle<FixedArray> CompileTimeValue::GetElements(Handle<FixedArray> value) { | 
|  | 
| void ParserTraits::ParseArrowFunctionFormalParameters( | 
| ParserFormalParameters* parameters, Expression* expr, | 
| -    const Scanner::Location& params_loc, | 
| -    Scanner::Location* duplicate_loc, bool* ok) { | 
| +    const Scanner::Location& params_loc, bool* ok) { | 
| if (parameters->Arity() >= Code::kMaxArguments) { | 
| ReportMessageAt(params_loc, MessageTemplate::kMalformedArrowFunParamList); | 
| *ok = false; | 
| @@ -3917,8 +3929,7 @@ void ParserTraits::ParseArrowFunctionFormalParameters( | 
| DCHECK_EQ(binop->op(), Token::COMMA); | 
| Expression* left = binop->left(); | 
| Expression* right = binop->right(); | 
| -    ParseArrowFunctionFormalParameters(parameters, left, params_loc, | 
| -                                       duplicate_loc, ok); | 
| +    ParseArrowFunctionFormalParameters(parameters, left, params_loc, ok); | 
| if (!*ok) return; | 
| // LHS of comma expression should be unparenthesized. | 
| expr = right; | 
| @@ -3962,15 +3973,16 @@ void ParserTraits::ParseArrowFunctionFormalParameterList( | 
| Scanner::Location* duplicate_loc, bool* ok) { | 
| if (expr->IsEmptyParentheses()) return; | 
|  | 
| -  ParseArrowFunctionFormalParameters(parameters, expr, params_loc, | 
| -                                     duplicate_loc, ok); | 
| +  ParseArrowFunctionFormalParameters(parameters, expr, params_loc, ok); | 
| if (!*ok) return; | 
|  | 
| +  ExpressionClassifier classifier; | 
| +  if (!parameters->is_simple) { | 
| +    classifier.RecordNonSimpleParameter(); | 
| +  } | 
| for (int i = 0; i < parameters->Arity(); ++i) { | 
| auto parameter = parameters->at(i); | 
| -    ExpressionClassifier classifier; | 
| -    DeclareFormalParameter( | 
| -        parameters->scope, parameter, parameters->is_simple, &classifier); | 
| +    DeclareFormalParameter(parameters->scope, parameter, &classifier); | 
| if (!duplicate_loc->IsValid()) { | 
| *duplicate_loc = classifier.duplicate_formal_parameter_error().location; | 
| } | 
| @@ -4585,7 +4597,8 @@ PreParser::PreParseResult Parser::ParseLazyFunctionBodyWithPreParser( | 
| #undef SET_ALLOW | 
| } | 
| PreParser::PreParseResult result = reusable_preparser_->PreParseLazyFunction( | 
| -      language_mode(), function_state_->kind(), logger, bookmark); | 
| +      language_mode(), function_state_->kind(), scope_->has_simple_parameters(), | 
| +      logger, bookmark); | 
| if (pre_parse_timer_ != NULL) { | 
| pre_parse_timer_->Stop(); | 
| } | 
|  |