[Bug c++/105583] New: Syntax error when alias template in requires-clause

[hewillk at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105583

            Bug ID: 105583
           Summary: Syntax error when alias template in requires-clause
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hewillk at gmail dot com
  Target Milestone: ---

template<class>
constexpr bool v = true;

template<class>
using A = decltype([] { return 0; }());

template<class T>
using B = decltype([] {
  if (requires { v<A<T>&>; }) { }
}());

https://godbolt.org/z/WseWqKMcG

gcc rejects the above legal syntax.