Nobody knows if there are users of libc++ with MSVC. Let's try to find that out and encourage them to upstream their changes to make that configuration work.
Reviewed By: ldionne, #libc
Spies: libcxx-commits
Differential Revision: https://reviews.llvm.org/D129055
# error "libc++ only supports C++03 with Clang-based compilers. Please enable C++11"
# endif
+# ifdef _LIBCPP_COMPILER_MSVC
+# error If you successfully use libc++ with MSVC please tell the libc++ developers and consider upstreaming your \
+changes. We are not aware of anybody using this configuration and know that at least some code is currently broken. \
+If there are users of this configuration we are happy to provide support.
+# endif
+
// FIXME: ABI detection should be done via compiler builtin macros. This
// is just a placeholder until Clang implements such macros. For now assume
// that Windows compilers pretending to be MSVC++ target the Microsoft ABI,