diff --git a/include/boost/multiprecision/float128.hpp b/include/boost/multiprecision/float128.hpp
index 5610d213..e7dd074e 100644
--- a/include/boost/multiprecision/float128.hpp
+++ b/include/boost/multiprecision/float128.hpp
@@ -632,7 +632,7 @@ inline int eval_signbit BOOST_PREVENT_MACRO_SUBSTITUTION(const float128_backend&
 
 inline std::size_t hash_value(const float128_backend& val)
 {
-   return hash_value(static_cast<double>(val.value()));
+   return boost::multiprecision::detail::hash_value(static_cast<double>(val.value()));
 }
 
 } // namespace backends
diff --git a/test/test_hash.cpp b/test/test_hash.cpp
index 3bfc1331..0dc9224c 100644
--- a/test/test_hash.cpp
+++ b/test/test_hash.cpp
@@ -34,6 +34,7 @@
 #include <boost/functional/hash.hpp>
 
 #include "test.hpp"
+#include <functional> // std::hash
 #include <iostream>
 #include <iomanip>