diff --git a/include/boost/unordered/detail/foa.hpp b/include/boost/unordered/detail/foa.hpp
index dfa99753..614654a3 100644
--- a/include/boost/unordered/detail/foa.hpp
+++ b/include/boost/unordered/detail/foa.hpp
@@ -1381,7 +1381,7 @@ private:
         prefetch_elements(p);
         do{
           auto n=unchecked_countr_zero(mask);
-          if(BOOST_LIKELY(pred()(x,key_from(p[n])))){
+          if(BOOST_LIKELY(static_cast<bool>(pred()(x,key_from(p[n]))))){
             return {pg,n,p+n};
           }
           mask&=mask-1;