diff --git a/src/types.h b/src/types.h
index d270384e..34369388 100644
--- a/src/types.h
+++ b/src/types.h
@@ -388,11 +388,13 @@ constexpr CastlingRights operator&(Color c, CastlingRights cr) {
 }
 
 constexpr Value mate_in(int ply) {
-  return VALUE_MATE - ply;
+  Value zero = Value(0);
+  return zero - (VALUE_MATE - ply);
 }
 
 constexpr Value mated_in(int ply) {
-  return -VALUE_MATE + ply;
+  Value zero = Value(0);
+  return zero - (-VALUE_MATE + ply);
 }
 
 constexpr Square make_square(File f, Rank r) {