diff --git a/src/insexpand.c b/src/insexpand.c
index 259acb9..0278522 100644
--- a/src/insexpand.c
+++ b/src/insexpand.c
@@ -2313,7 +2313,7 @@
     else
     {
 	word = tv_get_string_chk(tv);
-	vim_memset(cptext, 0, sizeof(cptext));
+	CLEAR_FIELD(cptext);
     }
     if (word == NULL || (!empty && *word == NUL))
 	return FAIL;