diff --git a/src/bitboard.h b/src/bitboard.h
index 7dbd5329be8..8b9c291807a 100644
--- a/src/bitboard.h
+++ b/src/bitboard.h
@@ -89,7 +89,7 @@ struct Magic {
 extern Magic RookMagics[SQUARE_NB];
 extern Magic BishopMagics[SQUARE_NB];
 
-inline Bitboard square_bb(Square s) {
+constexpr Bitboard square_bb(Square s) {
     assert(is_ok(s));
     return (1ULL << s);
 }