Parse arrow functions at proper precedence level

src/pattern-rewriter.cc

Index: src/pattern-rewriter.cc
diff --git a/src/pattern-rewriter.cc b/src/pattern-rewriter.cc
index f3ecf7f1542dd658f3f2bbfc789f7d19381b4efc..431b2acf8ff5cd7823238eeb23df7695c0e6784d 100644
--- a/src/pattern-rewriter.cc
+++ b/src/pattern-rewriter.cc
@@ -368,6 +368,11 @@ void Parser::PatternRewriter::VisitSpread(Spread* node) {
 }
 
 
+void Parser::PatternRewriter::VisitEmptyParentheses(EmptyParentheses* node) {
+  UNREACHABLE();
+}
+
+
 // =============== UNREACHABLE =============================
 
 void Parser::PatternRewriter::Visit(AstNode* node) { UNREACHABLE(); }