This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21 Core Issues List revision 115d. See http://www.open-std.org/jtc1/sc22/wg21/ for the official list.

2024-10-26

2686. Pack expansion into a non-pack parameter of a concept

Section: 13.5.2  [temp.constr.constr]     Status: open     Submitter: Michał Dominiak     Date: 2021-10-15

Consider:

  template<typename T>  concept A = true;
  template<typename... T> concept B = A<T...>;

Is this valid? MSVC accepts; gcc and clang reject. See also issue 1430 for the equivalent question for alias templates.