Unreachable code warning compiling under MSVC with LTO

[jcmoyer]

In my setup I'm compiling Lua as part of my project, and when I turn on LTO via CMAKE_INTERPROCEDURAL_OPTIMIZATION, the return listed below is considered unreachable by MSVC. I guess MSVC can analyze through multiple Lua calls and determine that luaL_error eventually calls a function marked noreturn. I'm compiling with /W4 /WX and this becomes an error during linking, so marking the library as SYSTEM in cmake doesn't suppress the error. Commenting out the return fixes the issue in MSVC, but I don't know if it'll break other compilers.

Tested with Sol 3.3.0, Lua 5.4.4, cl 19.36.32532 x64.

Sol config: SOL_USING_CXX_LUA, SOL_ALL_SAFETIES_ON, SOL_CHECK_ARGUMENTS

sol2/include/sol/stack_core.hpp

Lines 335 to 343 in eab1430

	if (!result) {
	if (pointer_adjusted == nullptr) {
	luaL_error(L, "aligned allocation of userdata block (pointer section) for '%s' failed", detail::demangle<T>().c_str());
	}
	else {
	luaL_error(L, "aligned allocation of userdata block (data section) for '%s' failed", detail::demangle<T>().c_str());
	}
	return nullptr;
	}

I can try to provide a complete test case if necessary.