get rid of OptionSquare

src/board.rs

@@ -434,52 +434,6 @@ impl core::str::FromStr for Square {
     }
 }
 
-#[rustfmt::skip]
-#[allow(unused)]
-#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
-#[repr(u8)]
-pub(crate) enum OptionSquare {
-    A1, B1, C1, D1, E1, F1, G1, H1,
-    A2, B2, C2, D2, E2, F2, G2, H2,
-    A3, B3, C3, D3, E3, F3, G3, H3,
-    A4, B4, C4, D4, E4, F4, G4, H4,
-    A5, B5, C5, D5, E5, F5, G5, H5,
-    A6, B6, C6, D6, E6, F6, G6, H6,
-    A7, B7, C7, D7, E7, F7, G7, H7,
-    A8, B8, C8, D8, E8, F8, G8, H8,
-    None,
-}
-
-impl OptionSquare {
-    #[inline]
-    pub(crate) fn new(square: Option<Square>) -> OptionSquare {
-        match square {
-            Some(square) => Self::from_square(square),
-            None => Self::None,
-        }
-    }
-
-    #[inline]
-    pub(crate) fn try_into_square(self) -> Option<Square> {
-        unsafe {
-            match self {
-                Self::None => None,
-                _ => Some(Square::new_unchecked(self as u8)),
-            }
-        }
-    }
-
-    #[inline]
-    pub(crate) fn from_square(square: Square) -> Self {
-        unsafe { core::mem::transmute(square) }
-    }
-
-    #[inline]
-    pub(crate) fn bitboard(&self) -> Bitboard {
-        Bitboard(1 << (*self as u8))
-    }
-}
-
 /// A type of piece.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 #[repr(u8)]