[parser] disallow language mode directive in body of function with non-simple parameters

src/parser.h

Index: src/parser.h
diff --git a/src/parser.h b/src/parser.h
index 602b5278ea813cb20083df5e99465c7466975abd..26a4b66a08d966f0246e866e8331d2671c7019ba 100644
--- a/src/parser.h
+++ b/src/parser.h
@@ -783,11 +783,11 @@ class ParserTraits {
       Expression* initializer, bool is_rest);
   V8_INLINE void DeclareFormalParameter(
       Scope* scope, const ParserFormalParameters::Parameter& parameter,
-      bool is_simple, ExpressionClassifier* classifier);
-  void ParseArrowFunctionFormalParameters(
-      ParserFormalParameters* parameters, Expression* params,
-      const Scanner::Location& params_loc,
-      Scanner::Location* duplicate_loc, bool* ok);
+      ExpressionClassifier* classifier);
+  void ParseArrowFunctionFormalParameters(ParserFormalParameters* parameters,
+                                          Expression* params,
+                                          const Scanner::Location& params_loc,
+                                          bool* ok);
   void ParseArrowFunctionFormalParameterList(
       ParserFormalParameters* parameters, Expression* params,
       const Scanner::Location& params_loc,
@@ -1332,12 +1332,14 @@ void ParserTraits::AddFormalParameter(
 
 void ParserTraits::DeclareFormalParameter(
     Scope* scope, const ParserFormalParameters::Parameter& parameter,
-    bool is_simple, ExpressionClassifier* classifier) {
+    ExpressionClassifier* classifier) {
   bool is_duplicate = false;
+  bool is_simple = classifier->is_simple_parameter_list();
   // TODO(caitp): Remove special handling for rest once desugaring is in.
   auto name = is_simple || parameter.is_rest
       ? parameter.name : parser_->ast_value_factory()->empty_string();
   auto mode = is_simple || parameter.is_rest ? VAR : TEMPORARY;
+  if (!is_simple) scope->SetHasNonSimpleParameters();
   Variable* var =
       scope->DeclareParameter(name, mode, parameter.is_rest, &is_duplicate);
   if (is_duplicate) {