diff -r 9962f5d98764 -r bde99d803caf src/chess/rook.c
--- a/src/chess/rook.c	Thu Aug 06 14:45:55 2026 +0200
+++ b/src/chess/rook.c	Thu Aug 06 16:11:37 2026 +0200
@@ -59,7 +59,8 @@
     return false;
 }
 
-size_t rook_moves(GameState *gamestate, Color c, Row r, File f, Move *moves) {
+size_t rook_moves(const GameState *gamestate,
+        Color c, Row r, File f, Move *moves) {
     size_t count = 0;
     const int directions[4][2] = {
         { 1,  0},