diff --git a/position/src/check.rs b/position/src/check.rs
index 218ef58..05e34b7 100644
--- a/position/src/check.rs
+++ b/position/src/check.rs
@@ -5,6 +5,7 @@ use chessfriend_core::{Color, Direction, Shape, Square};
 
 use crate::sight::SliderRayToSquareExt;
 
+#[derive(Clone, Debug, Eq, PartialEq)]
 pub struct CheckingPieces {
     bitboards: [BitBoard; 5],
 }
@@ -23,7 +24,7 @@ impl CheckingPieces {
     }
 
     pub fn count(&self) -> u32 {
-        self.bitboards.iter().map(|b| b.population_count()).sum()
+        self.bitboards.iter().map(BitBoard::population_count).sum()
     }
 
     /// A BitBoard representing the set of pieces that must be captured to