[PATCH] D38216: [C++17] Fix class template argument deduction for default constructors without an initializer

[Zhihao Yuan via Phabricator via cfe-commits]

lichray added a comment.

In https://reviews.llvm.org/D38216#923580, @rsmith wrote:

> That's almost right, but not all `extern` declarations are disallowed. (An `extern` declaration is still a defining declaration if it has an initializer.)


Good to know, thanks.

So gcc got this wrong?

https://wandbox.org/permlink/RVApvaca1ebUfInn


https://reviews.llvm.org/D38216