[Bug c++/80736] New: Wrong overload picked with uniform initialization

["d.frey at gmx dot de" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80736

            Bug ID: 80736
           Summary: Wrong overload picked with uniform initialization
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: d.frey at gmx dot de
  Target Milestone: ---

The following program leads to an infinite recursion:

#include <initializer_list>

template< typename T >
struct vector
{
   vector() = default;
   vector( const vector& ) = default; // 1

   vector( std::initializer_list< T > ) {} // 2
};

template< typename T >
struct model
{
   T data;

   model( const T& v )
   // : data( v )  // chooses 1
      : data{ v }  // chooses 2 over 1, creating an infinite recursion
   {
   }
};

struct drawable
{
   template< typename T >
   drawable( const T& v )
   {
      model< T >{ v };
   }
};

int main()
{
   vector< drawable > v;
   drawable d = v;
   (void)d;
}

The problem is that the ctor with the initializer_list is preferred over the
copy-ctor. This should be fixed by DR 1467 (AFAICT), but GCC still gets it
wrong in the above program.

Tested with GCC 4.9.3, 5.4, 6.3, and 7.1.

Clang 3.7+ gets it right, previous versions of Clang have the same problem as
GCC.

Link: https://wandbox.org/permlink/MiS6pzVbGOO8Hxaw