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Date: Tue, 15 Dec 2009 23:01:00 -0000
Subject: [Bug fortran/42385]  New: [OOP] poylmorphic operators do not work
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Spin-off from PR 42144 (comment #6). As the following code demonstrates,
polymorphic type-bound operators are buggy:


module foo_module
 implicit none
 private
 public :: foo

 type :: foo
 contains
   procedure :: times => times_foo
   procedure :: assign => assign_foo
   generic :: operator(*) => times
   generic :: assignment(=) => assign
 end type

contains

   function times_foo(this,factor) result(product)
     class(foo) ,intent(in) :: this
     class(foo) ,allocatable :: product
     real, intent(in) :: factor
   end function

   subroutine assign_foo(lhs,rhs)
     class(foo) ,intent(inout) :: lhs
     class(foo) ,intent(in) :: rhs
   end subroutine

end module

module bar_module
 use foo_module ,only : foo
 implicit none
 private
 public :: bar

 type ,extends(foo) :: bar
   private
   real :: x=1.
 contains
   procedure :: times => times_bar
   procedure :: assign => assign_bar
 end type

contains
 subroutine assign_bar(lhs,rhs)
   class(bar) ,intent(inout) :: lhs
   class(foo) ,intent(in) :: rhs
   select type(rhs)
     type is (bar)
       lhs%x = rhs%x
   end select
 end subroutine
 function times_bar(this,factor) result(product)
   class(bar) ,intent(in) :: this
   real, intent(in) :: factor
   class(foo), allocatable :: product
   select type(this)
     type is (bar)
       allocate(product,source=this)
       select type(product)
         type is(bar)
           product%x = this%x*factor
       end select
   end select
 end function
end module

program main
 use foo_module ,only : foo
 use bar_module ,only : bar
 implicit none
 type(bar) :: unit
 call rescale(unit,3.141592654)
contains
 subroutine rescale(this,scale)
   class(foo) ,intent(inout) :: this
   real, intent(in) :: scale
   this = this*scale
 end subroutine
end program


This test case is compiled flawlessly, but the generated code is wrong:

rescale (struct .class.foo & restrict this, real(kind=4) & restrict scale)
{
  {
    struct .class.foo.a D.1631;

    D.1631 = times_foo ((struct .class.foo *) this, (real(kind=4) *) scale);
    assign_foo ((struct .class.foo *) this, &D.1631);
  }
}

The operators are always resolved to the base-class procedures. Polymorphic
treatment is missing.


-- 
           Summary: [OOP] poylmorphic operators do not work
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: janus at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42385