Hi,
comparing diagnostics behavior between clang on Linux and clang on Windows in MSVC compat mode, I noticed that the deprecated copy warning (enabled via -Wdeprecated-copy) is not raised in the latter case.
Judging by this comment in clang’s source, this is a deliberate choice, though I do not fully understand the reasoning behind it.
Can anyone shed some light here? 
Thanks,
Julius
Good question! We hit a bug in Chromium a while ago which I think this warning would catch on Windows.
I don’t understand the comment in the code. Perhaps we should try removing the special casing for Windows and see if it breaks something?
It seems to come from here: 
D26868 Sema: As of MSVC 2015, a user-declared move operation causes the deletion of both copy operations. (llvm.org)
But maybe it’s no longer true in newer versions of MSVC?
I think it’s from the warning was originally added: C++11: If a class has a user-declared copy operation or destructor, the · llvm/llvm-project@d577fbb · GitHub
I found the following SemaCXX test cases dealing with the deprecated copy warning (though the list may be incomplete):
None of these seem to cover the MSVC specific behavior.
I also did not find any reference to the deprecated copy warning in the compatibility related test cases (MicrosoftCompatibility.cpp), though the quirks mentioned by @tobiashieta seem to be covered there.
I submitted a patch that causes the deprecated copy warning to be also raised in MSVC compatibility mode:
https://reviews.llvm.org/D133354