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 57089fad85dc25abaa994ae3ea84179548858bad..46884859f68067e72f0f416b3bb0f4a3a52957d1 100644
--- a/src/parser.cc
+++ b/src/parser.cc
@@ -3969,6 +3969,8 @@ 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;