[Bug c++/102881] New: gcc totally broken when trailing return type combine with decltype lambda

[hewillk at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102881

            Bug ID: 102881
           Summary: gcc totally broken when trailing return type combine
                    with decltype lambda
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hewillk at gmail dot com
  Target Milestone: ---

template<int N>
using R = decltype([] { return 0; }());

template <int N>
auto you_can_see_me() -> R<N> {
  return {};
}

int main() {
  you_can_see_me<0>();
}

GCC rejects with:

<source>:10:3: error: 'you_can_see_me' was not declared in this scope
   10 |   you_can_see_me<0>();
      |   ^~~~~~~~~~~~~~~~~

https://godbolt.org/z/7WEsjjscT