diff --git a/src/eval.c b/src/eval.c
index 06c6ada..496e208 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -1049,7 +1049,7 @@
 		wrong = (lp->ll_dict->dv_scope == VAR_DEF_SCOPE
 			       && rettv->v_type == VAR_FUNC
 			       && var_wrong_func_name(key, lp->ll_di == NULL))
-			|| !valid_varname(key);
+			|| !valid_varname(key, TRUE);
 		if (len != -1)
 		    key[len] = prevval;
 		if (wrong)