diff --git a/src/board/bitboard/mod.rs b/src/board/bitboard/mod.rs
index 092dba7..8b716be 100644
--- a/src/board/bitboard/mod.rs
+++ b/src/board/bitboard/mod.rs
@@ -1,4 +1,6 @@
 use super::Square;
+use crate::utils::static_assert;
+
 mod iterator;
 use iterator::*;
 
@@ -63,6 +65,9 @@ impl Bitboard {
     }
 }
 
+// Ensure zero-cost (at least size-wise) wrapping.
+static_assert!(std::mem::size_of::<Bitboard>() == std::mem::size_of::<u64>());
+
 impl Default for Bitboard {
     fn default() -> Self {
         Self::EMPTY
diff --git a/src/board/file.rs b/src/board/file.rs
index 3dac5c8..fa7ba15 100644
--- a/src/board/file.rs
+++ b/src/board/file.rs
@@ -1,4 +1,5 @@
 use super::Bitboard;
+use crate::utils::static_assert;
 
 /// An enum representing a singular file on a chess board (i.e: the columns).
 #[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
@@ -74,6 +75,9 @@ impl File {
     }
 }
 
+// Ensure that niche-optimization is in effect.
+static_assert!(std::mem::size_of::<Option<File>>() == std::mem::size_of::<File>());
+
 #[cfg(test)]
 mod test {
     use super::*;
diff --git a/src/board/rank.rs b/src/board/rank.rs
index c2499d7..59374c7 100644
--- a/src/board/rank.rs
+++ b/src/board/rank.rs
@@ -1,4 +1,5 @@
 use super::Bitboard;
+use crate::utils::static_assert;
 
 /// An enum representing a singular rank on a chess board (i.e: the rows).
 #[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
@@ -74,6 +75,9 @@ impl Rank {
     }
 }
 
+// Ensure that niche-optimization is in effect.
+static_assert!(std::mem::size_of::<Option<Rank>>() == std::mem::size_of::<Rank>());
+
 #[cfg(test)]
 mod test {
     use super::*;
diff --git a/src/board/square.rs b/src/board/square.rs
index 0079bbb..69d8167 100644
--- a/src/board/square.rs
+++ b/src/board/square.rs
@@ -1,4 +1,5 @@
 use super::{Bitboard, File, Rank};
+use crate::utils::static_assert;
 
 /// Represent a square on a chessboard. Defined in the same order as the
 /// [Bitboard](crate::board::Bitboard) squares.
@@ -185,6 +186,9 @@ impl std::ops::Sub<Bitboard> for Square {
     }
 }
 
+// Ensure that niche-optimization is in effect.
+static_assert!(std::mem::size_of::<Option<Square>>() == std::mem::size_of::<Square>());
+
 #[cfg(test)]
 mod test {
     use super::*;