[Bug libstdc++/71098] New: uniform initialization for nested tuples work in c++11/14 mode but should only work >=c++17

[lts-rudolph at gmx dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71098

            Bug ID: 71098
           Summary: uniform initialization for nested tuples work in
                    c++11/14 mode but should only work >=c++17
           Product: gcc
           Version: 6.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: lts-rudolph at gmx dot de
  Target Milestone: ---

uniform initialization for nested std::tuple works in c++11/14 mode but should
work not before c++17.

The following line compiles without warning/error in --std=c++11/14

std::tuple<std::tuple<int,float> > t2{{ 1,2.2}};