diff --git a/src/vim9.h b/src/vim9.h
index 49103ba..440de27 100644
--- a/src/vim9.h
+++ b/src/vim9.h
@@ -84,6 +84,7 @@
     ISN_PCALL,	    // call partial, use isn_arg.pfunc
     ISN_PCALL_END,  // cleanup after ISN_PCALL with cpf_top set
     ISN_RETURN,	    // return, result is on top of stack
+    ISN_RETURN_ZERO, // Push zero, then return
     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