[bitboard,core,position] Address a bunch of clippy warnings

core/src/colors.rs

@@ -3,8 +3,9 @@
 use crate::{errors::TryFromCharError, try_from_string};
 use std::fmt;
 
-#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+#[derive(Clone, Copy, Debug, Default, Eq, Hash, PartialEq)]
 pub enum Color {
+    #[default]
     White = 0,
     Black = 1,
 }
@@ -16,7 +17,9 @@ impl Color {
         Color::ALL.iter()
     }
 
-    pub fn other(&self) -> Color {
+    /// The other color
+    #[must_use]
+    pub const fn other(&self) -> Color {
         match self {
             Color::White => Color::Black,
             Color::Black => Color::White,
@@ -24,12 +27,6 @@ impl Color {
     }
 }
 
-impl Default for Color {
-    fn default() -> Self {
-        Color::White
-    }
-}
-
 impl fmt::Display for Color {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(

core/src/pieces.rs

@@ -34,7 +34,7 @@ impl Shape {
         PROMOTABLE_SHAPES.iter()
     }
 
-    const fn to_ascii(&self) -> char {
+    const fn to_ascii(self) -> char {
         match self {
             Shape::Pawn => 'P',
             Shape::Knight => 'N',
@@ -79,7 +79,7 @@ impl Into<char> for Shape {
 impl fmt::Display for Shape {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let self_char: char = self.into();
-        write!(f, "{}", self_char)
+        write!(f, "{self_char}")
     }
 }
 
@@ -91,6 +91,7 @@ pub struct Piece {
 
 macro_rules! piece_constructor {
     ($func_name:ident, $type:tt) => {
+        #[must_use]
         pub fn $func_name(color: Color) -> Piece {
             Piece {
                 color,
@@ -102,6 +103,7 @@ macro_rules! piece_constructor {
 
 macro_rules! is_shape {
     ($func_name:ident, $shape:ident) => {
+        #[must_use]
         pub fn $func_name(&self) -> bool {
             self.shape == Shape::$shape
         }
@@ -109,6 +111,7 @@ macro_rules! is_shape {
 }
 
 impl Piece {
+    #[must_use]
     pub fn new(color: Color, shape: Shape) -> Piece {
         Piece { color, shape }
     }
@@ -120,10 +123,12 @@ impl Piece {
     piece_constructor!(queen, Queen);
     piece_constructor!(king, King);
 
+    #[must_use]
     pub fn color(&self) -> Color {
         self.color
     }
 
+    #[must_use]
     pub fn shape(&self) -> Shape {
         self.shape
     }
@@ -135,7 +140,8 @@ impl Piece {
     is_shape!(is_queen, Queen);
     is_shape!(is_king, King);
 
-    pub fn to_ascii(&self) -> char {
+    #[must_use]
+    pub fn to_ascii(self) -> char {
         let ch = self.shape.to_ascii();
         match self.color {
             Color::White => ch,
@@ -143,7 +149,8 @@ impl Piece {
         }
     }
 
-    fn to_unicode(&self) -> char {
+    #[must_use]
+    fn to_unicode(self) -> char {
         match (self.color, self.shape) {
             (Color::Black, Shape::Pawn) => '♟',
             (Color::Black, Shape::Knight) => '♞',
@@ -175,6 +182,7 @@ pub struct PlacedPiece {
 
 macro_rules! is_shape {
     ($func_name:ident, $shape:ident) => {
+        #[must_use]
         pub fn $func_name(&self) -> bool {
             self.piece().shape == Shape::$shape
         }
@@ -182,26 +190,35 @@ macro_rules! is_shape {
 }
 
 impl PlacedPiece {
+    #[must_use]
     pub const fn new(piece: Piece, square: Square) -> PlacedPiece {
         PlacedPiece { piece, square }
     }
 
+    /// The [Piece] itself
     #[inline]
+    #[must_use]
     pub fn piece(&self) -> &Piece {
         &self.piece
     }
 
+    /// The square the piece is on
     #[inline]
+    #[must_use]
     pub fn square(&self) -> Square {
         self.square
     }
 
+    /// The piece's [Color]
     #[inline]
+    #[must_use]
     pub fn color(&self) -> Color {
         self.piece.color
     }
 
+    /// The piece's [Shape]
     #[inline]
+    #[must_use]
     pub fn shape(&self) -> Shape {
         self.piece.shape
     }
@@ -213,6 +230,7 @@ impl PlacedPiece {
     is_shape!(is_queen, Queen);
     is_shape!(is_king, King);
 
+    #[must_use]
     pub fn is_kingside_rook(&self) -> bool {
         self.is_rook()
             && match self.color() {
@@ -221,6 +239,7 @@ impl PlacedPiece {
             }
     }
 
+    #[must_use]
     pub fn is_queenside_rook(&self) -> bool {
         self.is_rook()
             && match self.color() {