C++ VS when making template class a friend of any instantiation of itself gets this error "cannot access private member declared in class"

[Matthew Heyn]

If anyone else is having the same issues with Studio that I am having this seems to be the best workaround that I have found.

Avoid constexpr initialization of the 'kek' variable (by removing the 'constexpr' specifier on the variable and the 'constexpr' specifier from the Test:perator+() function).
Compile in C++14 mode (guaranteed copy elision is enabled only in C++17 mode and later).
Alternatively, compile with the (undocumented and unpublished) /d1gce- option, which will disable guaranteed copy

Hope that helps.