[Bug c++/100589] New: function with trailing return type must specify return type 'auto' instead of 'concept auto'

[stanislaw.w.morawski at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100589

            Bug ID: 100589
           Summary: function with trailing return type must specify return
                    type 'auto' instead of 'concept auto'
           Product: gcc
           Version: 11.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: stanislaw.w.morawski at gmail dot com
  Target Milestone: ---

https://godbolt.org/z/jnahsxrnq

Behaviour:
Concept is being ignored when used with auto keyword preceding function with
trailing return type.

Expected Behaviour:
Syntax error: improper use of concept.