[Bug fortran/44131] New: Using polymorfism in modules unware of derived types fails at run-time

["klaas_giesbertz at hotmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

This problem is best illustrated by the following piece of code

module BaseModule
  type, abstract :: BaseType
  contains
    procedure (DoAbstract), deferred, pass :: DoIt
  end type

  abstract interface
    subroutine DoAbstract(self)
!      import :: BaseType
      class(BaseType) :: self
    end subroutine
  end interface
end module

module DerivedModule
  use BaseModule
! use DerivedModule

  type, extends(BaseType) :: DerivedType
  contains
    procedure :: DoIt => DoDerived
  end type

contains

  subroutine DoDerived(self)
    class(DerivedType) :: self
    print *, "Derived DoIt"
  end subroutine
end module

module UseTypes
  use BaseModule
contains

  subroutine UseBaseOrDerived(someType)
    class(BaseType) :: someType

    call someType%DoIt()
  end subroutine
end module

program Test
  use BaseModule
  use DerivedModule
  use UseTypes

  class(BaseType), allocatable :: someType

  allocate(DerivedType :: someType)

  call UseBaseOrDerived(someType)
end program

The subroutine useTypes should only need to know about the BaseType. The code
compiles perfectly without warning. However, at run-time, I get the following
error message:

At line 38 of file test.f03
Fortran runtime error: internal error: bad hash value in dynamic dispatch

However, if I uncomment use DerivedModule in the UseTypes module, everything
works fine. I also tried to compile this code with the xlf compiler 11.1. In
that case I need to uncomment the import statement in the abstract interface to
make it compile. However, it compiles and runs without the explicit declaration
of the DerivedType in the UseTypes module.


-- 
           Summary: Using polymorfism in modules unware of derived types
                    fails at run-time
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: klaas_giesbertz at hotmail dot com
  GCC host triplet: x86_64-apple-darwin10


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44131