https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107429
Patrick Palka <ppalka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
CC| |ppalka at gcc dot gnu.org
Resolution|--- |DUPLICATE
--- Comment #1 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Thanks for the bug report. This is a consequence of CWG2369, and the
constraint recursion diagnosis is strictly speaking correct correct. I think
other compilers accept it because they don't fully implement
https://wg21.link/cwg2369 which moved the constraint satisfaction check during
template argument deduction to _before_ the checking non-dependent conversions.
A workaround (that should be valid pre- and post-CWG2369) is to encode the
non-dependent conversion in the constrained overload of f as an additional
constraint that's checked before the fooable constraint:
template<std::convertible_to<tag_bar> U, typename... T> requires
(fooable<T...>)
auto f(U, T... x)
see PR99599 and its dups for more info
*** This bug has been marked as a duplicate of bug 99599 ***
