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 10702d65cee6a49c1db4aa0029cff66a868d496e..4bf4bf20f25006ca77f57f0df0680c9bc01353ef 100644
--- a/src/pattern-rewriter.cc
+++ b/src/pattern-rewriter.cc
@@ -367,6 +367,11 @@ void Parser::PatternRewriter::VisitSpread(Spread* node) {
 }
 
 
+void Parser::PatternRewriter::VisitEmptyParentheses(EmptyParentheses* node) {
+  UNREACHABLE();
+}
+
+
 // =============== UNREACHABLE =============================
 
 void Parser::PatternRewriter::Visit(AstNode* node) { UNREACHABLE(); }