diff --git a/libcxx/test/std/input.output/filesystems/fs.enum/enum.perm_options.pass.cpp b/libcxx/test/std/input.output/filesystems/fs.enum/enum.perm_options.pass.cpp
--- a/libcxx/test/std/input.output/filesystems/fs.enum/enum.perm_options.pass.cpp
+++ b/libcxx/test/std/input.output/filesystems/fs.enum/enum.perm_options.pass.cpp
@@ -33,7 +33,7 @@
   typedef std::underlying_type<E>::type UT;
   static_assert(!std::is_convertible<E, UT>::value, "");
 
-  static_assert(std::is_same<UT, unsigned char >::value, ""); // Implementation detail
+  LIBCPP_ONLY(static_assert(std::is_same<UT, unsigned char >::value, "")); // Implementation detail
 
   typedef check_bitmask_type<E, E::replace, E::nofollow> BitmaskTester;
   assert(BitmaskTester::check());