Block castling when rook is frozen by potion

Author: Belzedar94

src/position.cpp

@@ -1347,7 +1347,9 @@ bool Position::legal(Move m) const {
 
       // Will the gate be blocked by king or rook?
       Square rto = to + (to_sq(m) > from_sq(m) ? WEST : EAST);
-      if (is_gating(m) && (gating_square(m) == to || gating_square(m) == rto))
+      if (is_gating(m) && (gating_square(m) == to || gating_square(m) == rto))  
+          return false;
+      if (freeze_squares() & to_sq(m))
           return false;
 
       // Non-royal pieces can not be impeded from castling

tests/perft.sh

@@ -156,6 +156,7 @@ if [[ $1 == "all" || $1 == "variant" ]]; then
   expect perft.exp atomic "fen 1R4kr/4K3/8/8/8/8/8/8 b k - 0 1" 4 17915 true > /dev/null
   expect perft.exp extinction "fen rnbqb1kr/pppppppp/8/8/8/8/PPPPPPPP/RNBQB1KR w AHah - 0 1" 4 195286 true > /dev/null
   expect perft.exp seirawan "fen qbbrnkrn/pppppppp/8/8/8/8/PPPPPPPP/QBBRNKRN[HEhe] w ABCDEFGHabcdefgh - 0 1" 3 21170 true > /dev/null
+  expect perft.exp spell-chess "fen 4k3/p7/8/8/8/8/8/4K2R[f] b K - 0 1 moves f@h1,a7a6" 1 5 > /dev/null
 fi
 
 # large-board variants