[Bug c++/91911] Strange interaction between CTAD and decltype

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91911

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
                 CC|                            |ppalka at gcc dot gnu.org
           Assignee|unassigned at gcc dot gnu.org      |ppalka at gcc dot 
gnu.org
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2021-06-24

--- Comment #1 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Confirmed, this never worked.  More reduced:

template<typename T>
struct span {
  using value_type = T;
  span(T);
};

template<typename X>
using SpanType = decltype(span(X()));

template<typename X>
using ConstSpanType = span<const typename SpanType<X>::value_type>;

using type = ConstSpanType<int>;
using type = span<const int>;