[Bug c++/102721] out-of-line member function definition fails to allow lambda in unevaluated-context of new feature in c++20

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102721

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2021-10-12
     Ever confirmed|0                           |1

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed,
Here is a better example of what is going wrong:
template<class T>
struct A
{    
    void foo(const T){}
};

using t = decltype(+[]{})[3];
using t1 = const decltype(+[]{})[3];

template<>
void A<t>::foo(t1)
{}

template<>
void A<decltype(+[]{})[4]>::foo(const decltype(+[]{})[4])
{}

The first template specialization is accepted but the second one is not.