diff --git a/src/vim9compile.c b/src/vim9compile.c
index 6ed166d..5d0ccb6 100644
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -277,9 +277,12 @@
 lookup_script(char_u *name, size_t len, int vim9script)
 {
     int		    cc;
-    hashtab_T	    *ht = &SCRIPT_VARS(current_sctx.sc_sid);
+    hashtab_T	    *ht;
     dictitem_T	    *di;
 
+    if (current_sctx.sc_sid <= 0)
+	return FAIL;
+    ht = &SCRIPT_VARS(current_sctx.sc_sid);
     if (vim9script && !script_is_vim9())
 	return FAIL;
     cc = name[len];