[position] For non-King move generators, only generate moves if the push and captures masks aren't empty

Always generate King moves.

position/src/move_generator.rs

@@ -51,10 +51,15 @@ macro_rules! move_generator_declaration {
                 capture_mask: chessfriend_bitboard::BitBoard,
                 push_mask: chessfriend_bitboard::BitBoard,
             ) -> $name {
-                $name {
-                    color,
-                    move_sets: Self::move_sets(position, color, capture_mask, push_mask),
-                }
+                let move_sets = if Self::shape() == chessfriend_core::Shape::King
+                    || (!capture_mask.is_empty() && !push_mask.is_empty())
+                {
+                    Self::move_sets(position, color, capture_mask, push_mask)
+                } else {
+                    std::collections::BTreeMap::new()
+                };
+
+                $name { color, move_sets }
             }
         }
     };
@@ -84,7 +89,11 @@ macro_rules! move_generator_declaration {
 pub(self) use move_generator_declaration;
 
 trait MoveGeneratorInternal {
-    fn piece(color: Color) -> Piece;
+    fn shape() -> Shape;
+
+    fn piece(color: Color) -> Piece {
+        Piece::new(color, Self::shape())
+    }
 
     fn move_sets(
         position: &Position,

position/src/move_generator/bishop.rs

@@ -3,13 +3,13 @@
 use super::{move_generator_declaration, MoveGeneratorInternal, MoveSet};
 use crate::Position;
 use chessfriend_bitboard::BitBoard;
-use chessfriend_core::{Color, Direction, Piece, PlacedPiece};
+use chessfriend_core::{Direction, PlacedPiece, Shape};
 
 move_generator_declaration!(ClassicalMoveGenerator);
 
 impl MoveGeneratorInternal for ClassicalMoveGenerator {
-    fn piece(color: Color) -> Piece {
-        Piece::bishop(color)
+    fn shape() -> Shape {
+        Shape::Bishop
     }
 
     fn move_set_for_piece(

position/src/move_generator/king.rs

@@ -6,15 +6,15 @@
 use super::{move_generator_declaration, MoveGeneratorInternal, MoveSet};
 use crate::{r#move::Castle, Position};
 use chessfriend_bitboard::BitBoard;
-use chessfriend_core::{Color, Piece, PlacedPiece};
+use chessfriend_core::{PlacedPiece, Shape};
 
 move_generator_declaration!(KingMoveGenerator, struct);
 move_generator_declaration!(KingMoveGenerator, new);
 move_generator_declaration!(KingMoveGenerator, getters);
 
 impl MoveGeneratorInternal for KingMoveGenerator {
-    fn piece(color: Color) -> Piece {
-        Piece::king(color)
+    fn shape() -> Shape {
+        Shape::King
     }
 
     fn move_set_for_piece(
@@ -59,7 +59,7 @@ mod tests {
     use super::*;
     use crate::{assert_move_list, position, test_position, Move, MoveBuilder, PositionBuilder};
     use chessfriend_bitboard::bitboard;
-    use chessfriend_core::{piece, Square};
+    use chessfriend_core::{piece, Color, Square};
     use std::collections::HashSet;
 
     #[test]

position/src/move_generator/knight.rs

@@ -3,13 +3,13 @@
 use super::{move_generator_declaration, MoveGeneratorInternal, MoveSet};
 use crate::Position;
 use chessfriend_bitboard::BitBoard;
-use chessfriend_core::{Color, Piece, PlacedPiece};
+use chessfriend_core::{PlacedPiece, Shape};
 
 move_generator_declaration!(KnightMoveGenerator);
 
 impl MoveGeneratorInternal for KnightMoveGenerator {
-    fn piece(color: Color) -> Piece {
-        Piece::knight(color)
+    fn shape() -> Shape {
+        Shape::Knight
     }
 
     fn move_set_for_piece(
@@ -35,7 +35,7 @@ impl MoveGeneratorInternal for KnightMoveGenerator {
 mod tests {
     use super::*;
     use crate::{position, Move, MoveBuilder};
-    use chessfriend_core::{piece, Square};
+    use chessfriend_core::{piece, Color, Square};
     use std::collections::HashSet;
 
     #[test]

position/src/move_generator/pawn.rs

@@ -3,7 +3,7 @@
 use super::{move_generator_declaration, MoveGeneratorInternal, MoveSet};
 use crate::Position;
 use chessfriend_bitboard::BitBoard;
-use chessfriend_core::{Color, Piece, PlacedPiece, Rank, Square};
+use chessfriend_core::{Piece, PlacedPiece, Rank, Shape, Square};
 
 #[derive(Debug)]
 struct MoveIterator(usize, usize);
@@ -11,8 +11,8 @@ struct MoveIterator(usize, usize);
 move_generator_declaration!(PawnMoveGenerator);
 
 impl MoveGeneratorInternal for PawnMoveGenerator {
-    fn piece(color: Color) -> Piece {
-        Piece::pawn(color)
+    fn shape() -> Shape {
+        Shape::Pawn
     }
 
     fn move_set_for_piece(
@@ -63,7 +63,7 @@ impl PawnMoveGenerator {
 mod tests {
     use super::*;
     use crate::{assert_move_list, position::DiagramFormatter, test_position, Move, MoveBuilder};
-    use chessfriend_core::{piece, Square};
+    use chessfriend_core::{piece, Color, Square};
     use std::collections::HashSet;
 
     #[test]

position/src/move_generator/queen.rs

@@ -3,13 +3,13 @@
 use super::{move_generator_declaration, MoveGeneratorInternal, MoveSet};
 use crate::Position;
 use chessfriend_bitboard::BitBoard;
-use chessfriend_core::{Color, Direction, Piece, PlacedPiece};
+use chessfriend_core::{Direction, PlacedPiece, Shape};
 
 move_generator_declaration!(ClassicalMoveGenerator);
 
 impl MoveGeneratorInternal for ClassicalMoveGenerator {
-    fn piece(color: Color) -> Piece {
-        Piece::queen(color)
+    fn shape() -> Shape {
+        Shape::Queen
     }
 
     fn move_set_for_piece(

position/src/move_generator/rook.rs

@@ -3,13 +3,13 @@
 use super::{move_generator_declaration, MoveGeneratorInternal, MoveSet};
 use crate::Position;
 use chessfriend_bitboard::BitBoard;
-use chessfriend_core::{Color, Direction, Piece, PlacedPiece};
+use chessfriend_core::{Direction, PlacedPiece, Shape};
 
 move_generator_declaration!(ClassicalMoveGenerator);
 
 impl MoveGeneratorInternal for ClassicalMoveGenerator {
-    fn piece(color: Color) -> Piece {
-        Piece::rook(color)
+    fn shape() -> Shape {
+        Shape::Rook
     }
 
     fn move_set_for_piece(