diff --git a/plugins/sudoers/regress/parser/check_fill.c b/plugins/sudoers/regress/parser/check_fill.c
index 6ff807628..ce7c3ca4d 100644
--- a/plugins/sudoers/regress/parser/check_fill.c
+++ b/plugins/sudoers/regress/parser/check_fill.c
@@ -133,8 +133,8 @@ static int
 do_tests(int (*checker)(const char *, int, int, const char *, char **),
     struct fill_test *data, size_t ntests)
 {
-    int i, len;
-    int errors = 0;
+    int len, errors = 0;
+    unsigned int i;
     char *result;
 
     for (i = 0; i < ntests; i++) {