Fix missing pawn color check in move_is_legal()

[stockfish] / src / movegen.cpp

diff --git a/src/movegen.cpp b/src/movegen.cpp
index 0f2f6b4e0fd37d94187eeb05cfde1d6179e1b412..9a6b902bb3efc8b66d2b08a52f63bbad7419a0d5 100644 (file)
--- a/src/movegen.cpp
+++ b/src/movegen.cpp
@@ -73,9 +73,8 @@ namespace {
         return Us == WHITE ? p << 9 : p >> 7;
     else if (Direction == DELTA_NW)
         return Us == WHITE ? p << 7 : p >> 9;
-
-    assert(false);
-    return p;
+    else
+        return p;
   }
 
   // Template generate_piece_checks() with specializations
@@ -177,10 +176,10 @@ int generate_noncaptures(const Position& pos, MoveStack* mlist) {
 }
 
 
-/// generate_checks() generates all pseudo-legal non-capturing, non-promoting
-/// checks. It returns the number of generated moves.
+/// generate_non_capture_checks() generates all pseudo-legal non-capturing,
+/// non-promoting checks. It returns the number of generated moves.
 
-int generate_checks(const Position& pos, MoveStack* mlist, Bitboard dc) {
+int generate_non_capture_checks(const Position& pos, MoveStack* mlist, Bitboard dc) {
 
   assert(pos.is_ok());
   assert(!pos.is_check());
@@ -497,6 +496,11 @@ bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) {
   // Proceed according to the type of the moving piece.
   if (type_of_piece(pc) == PAWN)
   {
+      // Move direction must be compatible with pawn color
+      int direction = to - from;
+      if ((us == WHITE) != (direction > 0))
+          return false;
+
       // If the destination square is on the 8/1th rank, the move must
       // be a promotion.
       if (   (  (square_rank(to) == RANK_8 && us == WHITE)
@@ -506,7 +510,7 @@ bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) {
 
       // Proceed according to the square delta between the source and
       // destionation squares.
-      switch (to - from)
+      switch (direction)
       {
       case DELTA_NW:
       case DELTA_NE:
@@ -815,9 +819,17 @@ namespace {
         return mlist;
 
     Bitboard checkSqs = pos.piece_attacks<Piece>(ksq) & pos.empty_squares();
+    if (!checkSqs)
+        return mlist;
+
     while (b)
     {
         Square from = pop_1st_bit(&b);
+        if (   (Piece == QUEEN  && !(QueenPseudoAttacks[from]  & checkSqs))
+            || (Piece == ROOK   && !(RookPseudoAttacks[from]   & checkSqs))
+            || (Piece == BISHOP && !(BishopPseudoAttacks[from] & checkSqs)))
+            continue;
+
         Bitboard bb = pos.piece_attacks<Piece>(from) & checkSqs;
         SERIALIZE_MOVES(bb);
     }