diff --git a/src/eval.c b/src/eval.c
index 79c5488..9b9b7f4 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -1055,7 +1055,8 @@
 	    }
 	    // existing variable, need to check if it can be changed
 	    else if ((flags & GLV_READ_ONLY) == 0
-			     && var_check_ro(lp->ll_di->di_flags, name, FALSE))
+			&& (var_check_ro(lp->ll_di->di_flags, name, FALSE)
+			  || var_check_lock(lp->ll_di->di_flags, name, FALSE)))
 	    {
 		clear_tv(&var1);
 		return NULL;
@@ -1220,7 +1221,7 @@
 		semsg(_(e_letwrong), op);
 		return;
 	    }
-	    if (var_check_lock(lp->ll_blob->bv_lock, lp->ll_name, FALSE))
+	    if (value_check_lock(lp->ll_blob->bv_lock, lp->ll_name, FALSE))
 		return;
 
 	    if (lp->ll_range && rettv->v_type == VAR_BLOB)
@@ -1297,7 +1298,7 @@
 	}
 	*endp = cc;
     }
-    else if (var_check_lock(lp->ll_newkey == NULL
+    else if (value_check_lock(lp->ll_newkey == NULL
 		? lp->ll_tv->v_lock
 		: lp->ll_tv->vval.v_dict->dv_lock, lp->ll_name, FALSE))
 	;
@@ -1317,7 +1318,7 @@
 	 */
 	for (ri = rettv->vval.v_list->lv_first; ri != NULL && ll_li != NULL; )
 	{
-	    if (var_check_lock(ll_li->li_tv.v_lock, lp->ll_name, FALSE))
+	    if (value_check_lock(ll_li->li_tv.v_lock, lp->ll_name, FALSE))
 		return;
 	    ri = ri->li_next;
 	    if (ri == NULL || (!lp->ll_empty2 && lp->ll_n2 == ll_n1))