fix: black not having close castling rights removed after B pawn moves

Author: dechristopher

move_test.go

@@ -21,10 +21,10 @@ type perfTest struct {
 // https://www.chessprogramming.org/Perft_Results
 var perfResults = []perfTest{
 {pos: unsafeOFEN("ppkn/4/4/NKPP w NCFncf - 0 1"), nodesPerDepth: []int{
-10, 84, 642, 4348, 29171, 183118,
+10, 84, 642, 4373, 29389, 185151,
 }},
 {pos: unsafeOFEN("ppkn/4/2P1/NK1P w NCFncf - 0 1"), nodesPerDepth: []int{
-10, 75, 538, 3407,
+10, 75, 538, 3432,
 }},
 }
 

position.go

@@ -367,7 +367,7 @@ func (pos *Position) updateCastleRights(m *Move) CastleRights {
 if didPieceMove(pos, m, BlackKing, D4) {
 removeCastlingRight(&cr, "n")
 }
-if didPieceMove(pos, m, BlackKing, D4) {
+if didPieceMove(pos, m, BlackKing, B4) {
 removeCastlingRight(&cr, "c")
 }
 if didPieceMove(pos, m, BlackKing, A4) {