diff --git a/lib/6to5/patch.js b/lib/6to5/patch.js
index be867989b9..4bc79909c5 100644
--- a/lib/6to5/patch.js
+++ b/lib/6to5/patch.js
@@ -34,7 +34,7 @@ def("ImportBatchSpecifier")
 def("RestElement")
   .bases("Node")
   .build("argument")
-  .field("argument", def("Expression"));
+  .field("argument", def("Pattern"));
 
 // Abstract references
 def("VirtualPropertyExpression")