diff --git a/src/evalfunc.c b/src/evalfunc.c
index d53dda4..6e1eb03 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -4458,7 +4458,7 @@
 f_expand(typval_T *argvars, typval_T *rettv)
 {
     char_u	*s;
-    int		len;
+    size_t	len;
     int		options = WILD_SILENT|WILD_USE_NL|WILD_LIST_NOTFOUND;
     expand_T	xpc;
     int		error = FALSE;