[Bug fortran/109076] New: class extending abstract type with deferred procedures, with another unrelated procedure interface, crashes on valid code

["federico.perini at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109076

            Bug ID: 109076
           Summary: class extending abstract type with deferred
                    procedures, with another unrelated procedure
                    interface, crashes on valid code
           Product: gcc
           Version: 12.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: federico.perini at gmail dot com
  Target Milestone: ---

Hello gfortran/gcc team,

I've reduced my issue to the following minimum viable example. 
Please note I haven't shortened the names because changing them sometimes
solves this issue. 

- The abstract class has deferred procedures, with their abstract interface
- The extended type implements them, AND it has another unrelated subroutine
that contains a procedure interface
- A casual solution is found by either shortening the unrelated subroutine
name, or 
removing some imports from the abstract interface

==> With all gfortran versions from 12.2.0 down to 4.9, I get an "interface
mismatch" issue: 

/app/example.f90:13:15:

   13 |       procedure :: expand => i_expand
      |               1
Error: Argument mismatch for the overriding procedure 'expand' at (1): Shape
mismatch in argument 'array'

The code can be found to play with here: https://godbolt.org/z/GfKGE1cYa 

And is also here:

module my_mod
    use iso_fortran_env, only: real64
    implicit none
    private

    type, abstract, public :: parallel_class
        contains
        procedure(par_expand_r64), pass(this), deferred :: expand
    end type parallel_class

    type, public, extends(parallel_class) :: interpolator
      contains
      procedure :: expand => i_expand
    end type interpolator

    abstract interface
       pure subroutine par_expand_r64(this,array)
          import parallel_class,real64
          class(parallel_class), intent(inout) :: this
          real(real64), intent(in) :: array(:)
       end subroutine par_expand_r64

        pure function interp_fun(ndim,x) result(fun_values)
           ! ****** SOLUTION #1 *******
           !import real64  ! works with this
           import real64,interpolator  ! this crashes gfortran-12
           integer         , intent(in)      :: ndim
           real(real64)    , intent(in)      :: x
           real(real64)    , dimension(ndim) :: fun_values
        end function interp_fun
    end interface

    contains

    !****** SOLUTION #2 ******
    !subroutine create_object(this,fun) ! works with this name
    subroutine interpolator_create_fromfun_fixedstep(this,fun) ! crashes with
this name
      class(interpolator) , intent(inout) :: this
      procedure(interp_fun)                  :: fun
      print *, 'hello world'
     end subroutine

    ! Get comm size
    pure subroutine i_expand(this,array)
       class(interpolator), intent(inout) :: this
       real(real64), intent(in) :: array(:)
    end subroutine i_expand

end module my_mod

Thank you,
Federico