1 files changed, 3 insertions, 0 deletions
diff --git a/lib/transform.js b/lib/transform.js
index b84bf0b9..ede6e254 100644
--- a/lib/transform.js
+++ b/lib/transform.js
@@ -157,6 +157,9 @@ TreeTransformer.prototype = new TreeWalker;
     DEF(AST_Await, function(self, tw) {
         self.expression = self.expression.transform(tw);
     });
+    DEF(AST_Yield, function(self, tw) {
+        if (self.expression) self.expression = self.expression.transform(tw);
+    });
     DEF(AST_Dot, function(self, tw) {
         self.expression = self.expression.transform(tw);
     });