[Bug fortran/67539] New: Segmentation fault with elemental defined assignment and scalar function at the RHS

["mrestelli at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67539

            Bug ID: 67539
           Summary: Segmentation fault with elemental defined assignment
                    and scalar function at the RHS
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mrestelli at gmail dot com
  Target Milestone: ---

The attached code produces a segmentation fault:

$ gfortran --version
GNU Fortran (GCC) 6.0.0 20150910 (experimental)

$ ./test 

Program received signal SIGSEGV: Segmentation fault - invalid memory reference.

Backtrace for this error:
#0  0x7FD288EF6757
#1  0x7FD288EF6D5E
#2  0x7FD28842EE8F
#3  0x400B69 in __m_MOD_copy_t_a at test.f90:17 (discriminator 3)
#4  0x400D15 in p at test.f90:40 (discriminator 2)


Notice that both workarounds a) using a scalar temporary tmp and b)
assigning to each element separately work.




module m
 implicit none

 type :: t_a
  real, allocatable :: x
 end type t_a

 interface assignment(=)
  module procedure copy_t_a
 end interface

contains

 elemental subroutine copy_t_a(y,x)
  type(t_a), intent(in)  :: x
  type(t_a), intent(out) :: y
   allocate( y%x , source=x%x )
 end subroutine copy_t_a

 elemental function new_t_a(x) result(res)
  real, intent(in) :: x
  type(t_a) :: res
   allocate( res%x )
   res%x = x
 end function new_t_a

end module m


program p
 use m
 implicit none

 integer :: i
 type(t_a) :: tmp
 type(t_a), allocatable :: v(:)

 allocate( v(2) )

 v = new_t_a(1.5)   ! -> segmentation fault

 !tmp = new_t_a(1.5) ! -> OK
 !v = tmp

 !do i=1,size(v)     ! -> also OK
 !  v(i) = new_t_a(1.5)
 !enddo

 do i=1,size(v)
   write(*,*) " i = ",i
   write(*,*) allocated(v(i)%x)
   write(*,*) v(i)%x
 enddo

end program p