[Bug c++/93140] New: Segfault in cc1plus on incorrect decltype among function args

[gcc at lxlz dot space]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93140

            Bug ID: 93140
           Summary: Segfault in cc1plus on incorrect decltype among
                    function args
           Product: gcc
           Version: 9.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gcc at lxlz dot space
  Target Milestone: ---

Created attachment 47583
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=47583&action=edit
mcve

Failure happens when variadic template function args used inside decltype.

Minimal example is in attachment. Failure happens whether function Bar declared
or not.