diff --git a/lib/6to5/generators/expressions.js b/lib/6to5/generators/expressions.js
index c7df89f842..84204c133b 100644
--- a/lib/6to5/generators/expressions.js
+++ b/lib/6to5/generators/expressions.js
@@ -96,10 +96,6 @@ exports.MemberExpression = function (node, print) {
   }
 };
 
-exports.ParenthesizedExpression = function (node, print) {
-  throw new Error("ParenthesizedExpression");
-};
-
 exports.TaggedTemplateExpression = function (node, print) {
   print(node.tag);
   print(node.quasi);
diff --git a/lib/6to5/traverse/visitor-keys.json b/lib/6to5/traverse/visitor-keys.json
index fe3396a904..7a5ccb1ea0 100644
--- a/lib/6to5/traverse/visitor-keys.json
+++ b/lib/6to5/traverse/visitor-keys.json
@@ -41,7 +41,6 @@
   "NewExpression":            ["callee", "arguments"],
   "ObjectExpression":         ["properties"],
   "ObjectPattern":            ["properties"],
-  "ParenthesizedExpression":  ["expression"],
   "Program":                  ["body"],
   "Property":                 ["key", "value"],
   "ReturnStatement":          ["argument"],