This issue is split from EWG Issue 9.

http://open-std.org/JTC1/SC22/WG21/docs/papers/2013/n3602.html

Bristol 2013: Reviewed and accepted by EWG, needs redrafting before ready for core.

Core pointed out problems in Bristol. Gregor summarized in Chicago 2013 that The primary template might not be the right place to pick constructors from. (Partial) specializations might have completely different constructors. Stroustrup thought that there's only two ways: all specializations have to be in scope, and you look at all of those, or look only at the primary and give an error if that doesn't work. Spertus is encouraged to write a follow-up paper.