[Bug c++/102479] segfault when deducing class template arguments for tuple with libc++-14

[ppalka at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102479

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |ppalka at gcc dot 
gnu.org
             Status|UNCONFIRMED                 |ASSIGNED
     Ever confirmed|0                           |1
                 CC|                            |ppalka at gcc dot gnu.org
   Last reconfirmed|                            |2021-09-27

--- Comment #2 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Confirmed, not a regression AFAICT.  Reduced rejects-valid testcase:

template<class T> struct A;

template<class T>
struct tuple {
  tuple(T);

  template<template<class> class Tmpl, typename A<Tmpl<char>>::type = 0>
  tuple(Tmpl<T>);

  template<template<class> class Tmpl, typename A<Tmpl<long>>::type = 0>
  tuple(Tmpl<T>);
};

auto r = tuple(0);

We should also make sure the alias CTAD case works too:

template<class T> using const_tuple = tuple<const T>;
auto s = const_tuple(0);