diff --git a/src/nvim/cmdexpand.c b/src/nvim/cmdexpand.c
index cf15e4dcef..339379d8fd 100644
--- a/src/nvim/cmdexpand.c
+++ b/src/nvim/cmdexpand.c
@@ -4363,8 +4363,8 @@ static int expand_pattern_in_buf(char *pat, Direction dir, char ***matches, int
     }
 
     // Extract the matching text prepended to completed word
-    if (!copy_substring_from_pos(&cur_match_pos, &end_match_pos, &full_match,
-                                 &word_end_pos)) {
+    if (copy_substring_from_pos(&cur_match_pos, &end_match_pos, &full_match,
+                                &word_end_pos) == FAIL) {
       break;
     }