From ea63c58ce7e9dbc0e1c0e1cb679a89c038e2edd3 Mon Sep 17 00:00:00 2001
From: eug-vs <eugene@eug-vs.xyz>
Date: Thu, 31 Aug 2023 14:58:40 +0300
Subject: fix: consider promotion a tactical move

---
 src/board/move_generation.rs | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

(limited to 'src/board')

diff --git a/src/board/move_generation.rs b/src/board/move_generation.rs
index 7669b85..abc603a 100644
--- a/src/board/move_generation.rs
+++ b/src/board/move_generation.rs
@@ -55,9 +55,15 @@ impl Board {
                 // Generalized attack/move pattern for all pieces
                 for target in (move_targets & targets).serialize() {
                     moves.push(Move { source, target, kind });
+                }
+
+                // Promotions
+                if piece_type == Piece::Pawn && tactical_only {
+                    // All promotions are tactical, but target square can be empty
+                    let iter_captures = (move_targets & targets).serialize();
+                    let iter_pushes = (self.attacks.pawn_pushes[color as usize][source as usize] & empty).serialize();
 
-                    // Promotions
-                    if piece_type == Piece::Pawn {
+                    for target in iter_pushes.chain(iter_captures) {
                         if target.rank() == 7 {
                             for promo_type in [Piece::Bishop, Piece::Knight, Piece::Rook, Piece::Queen] {
                                 moves.push(Move { source, target, kind: MoveKind::Promotion(promo_type)})
@@ -152,6 +158,7 @@ impl Board {
                 }
             }
         }
+
         moves
     }
 }
@@ -164,7 +171,7 @@ mod tests {
 
     #[test]
     fn generate_pseudolegal_moves_starting_position() {
-        let mut board = Board::new();
+        let board = Board::new();
         let moves = board.generate_pseudolegal_moves();
         let black_moves = board.generate_pseudolegal_moves();
 
@@ -212,6 +219,7 @@ mod tests {
         // Make sure tactical_only and true_tactical are identical sets
         for mov in tactical_only.iter() {
             assert!(true_tactical.iter().any(|m| *m == *mov));
+            assert!(mov.is_tactical());
         }
         for mov in true_tactical {
             assert!(tactical_only.iter().any(|m| *m == mov));
@@ -219,6 +227,7 @@ mod tests {
 
         // Make sure quiet_only and true_quiet are identical sets
         for mov in quiet_only.iter() {
+            assert!(!mov.is_tactical());
             assert!(true_quiet.iter().any(|m| *m == *mov));
         }
         for mov in true_quiet {
-- 
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