diff --git a/src/vim9.h b/src/vim9.h
index 60699f9..9685b9d 100644
--- a/src/vim9.h
+++ b/src/vim9.h
@@ -82,6 +82,7 @@
     ISN_RETURN,	    // return, result is on top of stack
     ISN_FUNCREF,    // push a function ref to dfunc isn_arg.funcref
     ISN_NEWFUNC,    // create a global function from a lambda function
+    ISN_DEF,	    // list functions
 
     // expression operations
     ISN_JUMP,	    // jump if condition is matched isn_arg.jump