[Bug libstdc++/100577] [11/12 Regression] Unhelpful diagnostics for ill-formed call to partially applied range adaptor object

["ppalka at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100577

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |10.1.0, 10.2.0, 10.3.0
           Keywords|                            |diagnostic
   Target Milestone|---                         |11.2
      Known to fail|                            |11.1.0

--- Comment #1 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Diagnostics for ill-formed calls to adaptor pipelines regress similarly:

#include <ranges>

int main() {
  extern int x[100];
  (std::views::join | std::views::join)(x);
}

<stdin>: In function ‘int main()’:
<stdin>:5:40: error: use of deleted function ‘constexpr auto
std::ranges::views::__adaptor::_Pipe<_Lhs, _Rhs>::operator()(_Range&&) const &&
[with _Range = int (&)[100]; _Lhs = std::ranges::views::_Join; _Rhs = 
std::ranges::views::_Join]’
In file included from <stdin>:1:
/home/patrick/code/gcc-master/libstdc++-v3/include/std/ranges:901:9: note:
declared here
  901 |         operator()(_Range&& __r) const && = delete;
      |         ^~~~~~~~