diff --git a/libcxx/test/std/numerics/bit/bit.endian/endian.pass.cpp b/libcxx/test/std/numerics/bit/bit.endian/endian.pass.cpp
--- a/libcxx/test/std/numerics/bit/bit.endian/endian.pass.cpp
+++ b/libcxx/test/std/numerics/bit/bit.endian/endian.pass.cpp
@@ -15,6 +15,7 @@
 #include <cstring>
 #include <cassert>
 #include <cstdint>
+#include <type_traits>
 
 #include "test_macros.h"