[Bug c++/109782] New: erroneous error "'auto' parameter not permitted in this context" for generic lambda in tparam list

[eric.niebler at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109782

            Bug ID: 109782
           Summary: erroneous error "'auto' parameter not permitted in
                    this context" for generic lambda in tparam list
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: eric.niebler at gmail dot com
  Target Milestone: ---

template <auto A = [](auto x){}>
struct C {};


...compiled with `-std=c++20` results in:

<source>:1:23: error: 'auto' parameter not permitted in this context
    1 | template <auto A = [](auto x){}>
      |                       ^~~~
Compiler returned: 1