[Bug fortran/57639] New: ICE with polymorphism (and illegal code)

[w6ws at earthlink dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57639

            Bug ID: 57639
           Summary: ICE with polymorphism (and illegal code)
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: w6ws at earthlink dot net

Bug encountered with a snapshot of todays (June 17, 2013) trunk.  The example
compiles ok with 'allocatable' attribute specified (and the related allocate
statement used) for variables t1 and t2.  However if the allocatable attribute
is omitted, (and allocate statement removed), gfortran gives a correct error
message and then ICEs.

module class_mod
  implicit none

contains

  function compare (a, b)
    class(*), intent(in), allocatable :: a, b
    logical :: compare

    compare = SAME_TYPE_AS (a, b)

  end function

end module

program unlimited_test
  use class_mod
  implicit none

  type wws
    integer :: a, b
  end type

! When t1 and t2 are given the 'allocatable' attribute,
! and the allocate statement is used, this example compiles
! and runs correctly.  However if the 'allocatable' attribute
! and the allocate statement are removed, the compiler issues
! the correct error message and then ICEs.
  class(*) :: t1, t2
!  allocate (wws::t1, t2)

  print *, 'main: compare = ', compare (t1, t2)

end program


wws@w6ws-4:~/fortran/f2008$ gfortran --version
GNU Fortran (GCC) 4.9.0 20130617 (experimental)
Copyright (C) 2013 Free Software Foundation, Inc.

GNU Fortran comes with NO WARRANTY, to the extent permitted by law.
You may redistribute copies of GNU Fortran
under the terms of the GNU General Public License.
For more information about these matters, see the file named COPYING

wws@w6ws-4:~/fortran/f2008$ gfortran -c unlimited_test.f90
unlimited_test.f90:29.16:

  class(*) :: t1, t2
                1
Error: CLASS variable 't1' at (1) must be dummy, allocatable or pointer
unlimited_test.f90:29.20:

  class(*) :: t1, t2
                    1
Error: CLASS variable 't2' at (1) must be dummy, allocatable or pointer
f951: internal compiler error: Segmentation fault
0x96fcaf crash_signal
    ../../gcc-trunk/gcc/toplev.c:333
0x53a009 compare_parameter
    ../../gcc-trunk/gcc/fortran/interface.c:1982
0x53a009 compare_actual_formal
    ../../gcc-trunk/gcc/fortran/interface.c:2567
0x53ad33 gfc_procedure_use(gfc_symbol*, gfc_actual_arglist**, locus*)
    ../../gcc-trunk/gcc/fortran/interface.c:3269
0x585fe0 resolve_specific_f0
    ../../gcc-trunk/gcc/fortran/resolve.c:2612
0x585fe0 resolve_specific_f
    ../../gcc-trunk/gcc/fortran/resolve.c:2637
0x585fe0 resolve_function
    ../../gcc-trunk/gcc/fortran/resolve.c:2905
0x585fe0 gfc_resolve_expr(gfc_expr*)
    ../../gcc-trunk/gcc/fortran/resolve.c:6083
0x58bd2b resolve_code
    ../../gcc-trunk/gcc/fortran/resolve.c:9685
0x58ba7b gfc_resolve_blocks(gfc_code*, gfc_namespace*)
    ../../gcc-trunk/gcc/fortran/resolve.c:8998
0x58bd09 resolve_code
    ../../gcc-trunk/gcc/fortran/resolve.c:9675
0x58e8be resolve_codes
    ../../gcc-trunk/gcc/fortran/resolve.c:14464
0x57fe82 gfc_resolve
    ../../gcc-trunk/gcc/fortran/resolve.c:14492
0x5749aa resolve_all_program_units
    ../../gcc-trunk/gcc/fortran/parse.c:4442
0x5749aa gfc_parse_file()
    ../../gcc-trunk/gcc/fortran/parse.c:4691
0x5b0a45 gfc_be_parse_file
    ../../gcc-trunk/gcc/fortran/f95-lang.c:189
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.
wws@w6ws-4:~/fortran/f2008$