diff --git a/src/runtime-js.ts b/src/runtime-js.ts
index e7e96b1..63d2ffe 100644
--- a/src/runtime-js.ts
+++ b/src/runtime-js.ts
@@ -137,7 +137,7 @@ export const _rt = {
 
         return { _tag: 'Rebind', _0: name, _1: path, _2: value };
     },
-    "undefine": (name: string) => {
+    "undefine!": (name: string) => {
         delete store[name];
         definitions.delete(name);
         dependencies.delete(name);