diff --git a/builtin/checkout.c b/builtin/checkout.c
index 8013a1b8b4..9941abc3ac 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -154,8 +154,8 @@ static int check_stages(unsigned stages, const struct cache_entry *ce, int pos)
 	return 0;
 }
 
-static int checkout_stage(int stage, struct cache_entry *ce, int pos,
-			  struct checkout *state)
+static int checkout_stage(int stage, const struct cache_entry *ce, int pos,
+			  const struct checkout *state)
 {
 	while (pos < active_nr &&
 	       !strcmp(active_cache[pos]->name, ce->name)) {
@@ -169,7 +169,7 @@ static int checkout_stage(int stage, struct cache_entry *ce, int pos,
 		return error(_("path '%s' does not have their version"), ce->name);
 }
 
-static int checkout_merged(int pos, struct checkout *state)
+static int checkout_merged(int pos, const struct checkout *state)
 {
 	struct cache_entry *ce = active_cache[pos];
 	const char *path = ce->name;