diff --git a/card.cpp b/card.cpp
index f7c5649c3..ca27625e7 100644
--- a/card.cpp
+++ b/card.cpp
@@ -26,7 +26,7 @@ const std::unordered_map<uint32, uint32> card::second_code = {
 bool card_sort::operator()(card* const& c1, card* const& c2) const {
 	return c1->cardid < c2->cardid;
 }
-bool card_state::is_location(int32 loc) const {
+bool card_state::is_location(uint32 loc) const {
 	if((loc & LOCATION_FZONE) && location == LOCATION_SZONE && sequence == 5)
 		return true;
 	if((loc & LOCATION_PZONE) && location == LOCATION_SZONE && pzone)
diff --git a/card.h b/card.h
index fbf3cde1d..f73c30f95 100644
--- a/card.h
+++ b/card.h
@@ -56,7 +56,7 @@ struct card_state {
 	uint8 reason_player{ PLAYER_NONE };
 	effect* reason_effect{ nullptr };
 
-	bool is_location(int32 loc) const;
+	bool is_location(uint32 loc) const;
 	bool is_main_mzone() const {
 		return location == LOCATION_MZONE && sequence >= 0 && sequence <= 4;
 	}