--- a/src/cargotype.h	Mon Mar 19 12:40:51 2007 +0000
+++ b/src/cargotype.h	Mon Mar 19 12:58:43 2007 +0000
@@ -59,7 +59,7 @@
 
 static inline bool IsCargoInClass(CargoID c, uint16 cc)
 {
-	return GetCargo(c)->classes & cc;
+	return (GetCargo(c)->classes & cc) != 0;
 }