[Bug c++/63628] [c++1y] cannot use decltype on captured arg-pack

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63628

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2014-10-23
            Summary|[c++1y] cannot use decltype |[c++1y] cannot use decltype
                   |on captured variable in     |on captured arg-pack
                   |generic lambda              |
     Ever confirmed|0                           |1

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This still fails on trunk, reduced from the original code in PR 61814

    auto const pack = [](auto... t)
    {
        [&]
        {
           int a[] = { static_cast<decltype(t)>(t)... };
        };
    };

    int main() {
        pack(1);
    }

ll.cc: In instantiation of ‘<lambda(auto:1 ...)>::<lambda()> [with auto:1 =
{int}]’:
ll.cc:5:49:   required from ‘struct<lambda(auto:1 ...)> [with auto:1 =
{int}]::<lambda()>’
ll.cc:3:9:   required from ‘<lambda(auto:1 ...)> [with auto:1 = {int}]’
ll.cc:10:15:   required from here
ll.cc:5:55: error: cannot convert ‘decltype (t)’ to ‘int’ in initialization
            int a[] = { static_cast<decltype(t)>(t)... };
                                                       ^
ll.cc:5:55: error: storage size of ‘a’ isn’t known