[Bug c++/99683] New: Deduction failure when using CTAD of CNTTP inside a deduction guide

[omer.rosler at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99683

            Bug ID: 99683
           Summary: Deduction failure when using CTAD of CNTTP inside a
                    deduction guide
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: omer.rosler at gmail dot com
  Target Milestone: ---

The following code causes a deduction failure on gcc and is accepted by clang.
It happens when using a CTAD for a CNTTP inside an explicit deduction guide.
I'm pretty sure it is legal C++20.

https://godbolt.org/z/Y49T6P