Re: Compilation error

[David Car <david dot car7 at gmail dot com>]

Hi Janus,

Thanks so much for the info (and thank you to the other postings too).

> help you, but hopefully we will get this nasty bug fixed soon. If you
> want to help, it might be useful if you could isolate this bug in your
> code and construct a minimal test case. We already have a test case in
> PR 44064/65, but having another one might help us nail down the
> specific conditions under which this occurs.

Definitely would like to help.  I've tried to construct a minimal test
case that duplicates the build error but was unsuccessful.  Listed
below is the case I tried that basically implements the same pattern:

!====================================================
module test1
  implicit none

  type foo
     integer :: i1
     integer :: i2
  end type foo

contains

  subroutine caller( this, callback )
    class (foo) :: this
    interface
       subroutine callback( this )
         import foo
         class (foo) :: this
       end subroutine callback
    end interface

    print *, this % i1
    call callback( this )
    print *, this % i2
    this % i1 = 77

  end subroutine caller

end module test1

!=========================================================
module test2
  use test1
  implicit none

  type, extends( foo ) :: foo2
    real :: r1
    real :: r2
  end type foo2

contains

  subroutine callback( this )
    class (foo) :: this

    print *, 'In callback'

    select type( this )
    type is ( foo2 )
       print *, this % r1
       this % i2 = 50
       this % r2 = 76.
    end select

  end subroutine callback

end module test2

!=============================================
program main
  use test1
  use test2

  type (foo2) :: this

  this % r1 = 55.
  call caller( this, callback )
  print *, this % i1
  print *, this % i2
  print *, this % r1

end program main
!=============================
When I build this, the resultant symbols in the object code are:

000001ec t MAIN__
00000000 T __test1_MOD_caller
00000000 D __test1_MOD_vtab$foo
000000ea T __test2_MOD_callback
         U _gfortran_set_args
         U _gfortran_set_options
         U _gfortran_st_write
         U _gfortran_st_write_done
         U _gfortran_transfer_character
         U _gfortran_transfer_integer
         U _gfortran_transfer_real
000003ad T main
00000020 r options.9.1576
00000018 d vtab$foo.1565
0000000c d vtab$foo2.1564

Both 'vtab$foo' and 'vtab$foo2' show up in a data section.  Is that
correct?  This code compiles though and works just fine.  I could tar
up the code that is not compiling with a makefile and attach it.  It's
not to terribly much.  Let me know if you want me to do that.

> Do you have any "use, only: ..." clauses in your code? If yes, does
> removing the "only" help? This might be a possible workaround ...

No.  The code that does not compile has no 'use, only:' clauses at
all.  Let me know if there is anything that you would like me try.
I'd love to help you track this down.  Thanks again.

Regards,

David