Bug report: public generic type bound procedure resolves to private

Compilation fails for a generic type bound procedure in Fortran, when it aliases an aliased private type bound procedure.

Operating system is a Manjaro Linux.
Compiler used

pgfortran -V

pgfortran 19.10-0 LLVM 64-bit target on x86-64 Linux -tp sandybridge 
PGI Compilers and Tools
Copyright (c) 2019, NVIDIA CORPORATION.  All rights reserved.

A minimal working example is provided with:

module a_module
   implicit none
   public :: a_type

   type :: a_type
      generic :: proc => proc1
      procedure, private :: proc1 => proc1_impl
   end type a_type


subroutine proc1_impl(self)
   class(a_type) :: self
end subroutine proc1_impl

end module a_module

program mwe
   use a_module
   implicit none
   type(a_type) :: obj
   call obj%proc
end program mwe

Invoking the PGI compiler results in an error

pgfortran mwe.f90
PGF90-S-0155-cannot access PRIVATE type bound procedure proc1$tbp (bug1.f90: 24)
  0 inform,   0 warnings,   1 severes, 0 fatal for mwe

Expected behaviour is compiling the program.

A workaround is possible by not aliasing the private procedure, which seem to cause the issue in the first place.

Thanks awvwgk. I’ve replicated the issue here and filed TPR #28452.