diff --git a/src/vim9script.c b/src/vim9script.c
index a72ef55..2f2f2dc 100644
--- a/src/vim9script.c
+++ b/src/vim9script.c
@@ -31,6 +31,7 @@
 		|| (cmdmod.cmod_flags & CMOD_VIM9CMD);
 }
 
+#if defined(FEAT_EVAL) || defined(PROTO)
 /*
  * Return TRUE if the current script is Vim9 script.
  * This also returns TRUE in a legacy function in a Vim9 script.
@@ -42,6 +43,7 @@
 	    && SCRIPT_ITEM(current_sctx.sc_sid)->sn_version
 						       == SCRIPT_VERSION_VIM9;
 }
+#endif
 
 /*
  * ":vim9script".