diff --git a/src/blackmisc/tuple_private.h b/src/blackmisc/tuple_private.h
index 2d8b5b163..f8306b4e6 100644
--- a/src/blackmisc/tuple_private.h
+++ b/src/blackmisc/tuple_private.h
@@ -168,7 +168,7 @@ namespace BlackMisc
 
         // A tuple element with attached metadata.
         template <class T, qint64 Flags = 0>
-        struct Attribute : public AttributeComparable<Attribute<T, Flags>, Flags & DisabledForComparison, Flags & CaseInsensitiveComparison>
+        struct Attribute : public AttributeComparable<Attribute<T, Flags>, bool(Flags & DisabledForComparison), bool(Flags & CaseInsensitiveComparison)>
         {
             typedef T type;
             static const qint64 flags = Flags;