1 files changed, 1 insertions, 1 deletions
diff --git a/pathfind.h b/pathfind.h
index ee05661d1..e2ee50d18 100644
--- a/pathfind.h
+++ b/pathfind.h
@@ -64,7 +64,7 @@ typedef struct {
 	TileIndex tile;
 	int length;
 } FindLengthOfTunnelResult;
-FindLengthOfTunnelResult FindLengthOfTunnel(TileIndex tile, int direction);
+FindLengthOfTunnelResult FindLengthOfTunnel(TileIndex tile, uint direction);
 
 void NewTrainPathfind(TileIndex tile, TileIndex dest, byte direction, NTPEnumProc *enum_proc, void *data);