[Bug c++/58089] expanding empty parameter pack as constructor arguments requires accessible copy constructor

[aaz@q-fu.com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58089

Andrey Zholos <aaz@q-fu.com> changed:

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--- Comment #2 from Andrey Zholos <aaz@q-fu.com> ---
I also stumbled onto this bug, and bug 59141 is a duplicate.

It appears the empty parameter pack is expanded as t({}) rather than t().

There is a similar example in 14.5.3p6 that indicates obj should be value-
initialized (not copy-constructed), and clang accepts this code.