X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=b57cc3c7468d83f24fca51883ca6d83e07a5c05e;hp=8a902502acbee50006dfdd4016272b7a4f4fd032;hb=31a0d2200c7e8b1db653ba0c033783787259f1e6;hpb=e0a00c499654850108749ca6fd686f79188ac1f9

diff --git a/src/position.cpp b/src/position.cpp
index 8a902502..b57cc3c7 100644
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -245,7 +245,7 @@ void Position::set_castling_rights(char token) {
     Square sqH = relative_square(c, SQ_H1);
     Square rsq, ksq = king_square(c);
 
-    token = toupper(token);
+    token = char(toupper(token));
 
     if (token == 'K')
         for (rsq = sqH; piece_on(rsq) != make_piece(c, ROOK); rsq--) {}