Parse arrow functions at proper precedence level

src/parser.cc

Index: src/parser.cc
diff --git a/src/parser.cc b/src/parser.cc
index ecc65301350c9e61805e5bb7ca71aae054704961..23ea714a75052b4c940dcad745d351b6390e31bf 100644
--- a/src/parser.cc
+++ b/src/parser.cc
@@ -3931,6 +3931,8 @@ void ParserTraits::ParseArrowFunctionFormalParameterList(
     ParserFormalParameters* parameters, Expression* expr,
     const Scanner::Location& params_loc,
     Scanner::Location* duplicate_loc, bool* ok) {
+  if (expr->IsEmptyParentheses()) return;
+
   ParseArrowFunctionFormalParameters(parameters, expr, params_loc,
                                      duplicate_loc, ok);
   if (!*ok) return;