[Bug fortran/71883] New: ICE in identical_array_ref, at fortran/dependency.c:104

["gerhard dot steinmetz dot fortran at t-online dot de" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71883

            Bug ID: 71883
           Summary: ICE in identical_array_ref, at
                    fortran/dependency.c:104
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gerhard.steinmetz.fortran@t-online.de
  Target Milestone: ---

ICE on rank mismatch or typo with experimental (--enable-checking=yes)
versions 7, 6, and maybe older. No ICE for release versions 4.9, 5, 6.


$ cat z1.f90
program p
   character(3), allocatable :: z(:,:)
   z(1:2,1:2) = 'abc'
   z(2,1) = z(12)
   z(21) = z(1,2)
end


$ gfortran-6 z1.f90            # release
z1.f90:4:13:

    z(2,1) = z(12)
             1
Error: Rank mismatch in array reference at (1) (1/2)
z1.f90:5:4:

    z(21) = z(1,2)
    1
Error: Rank mismatch in array reference at (1) (1/2)



$ gfortran-7-20160710 z1.f90   # experimental
z1.f90:4:13:

    z(2,1) = z(12)
             1
Error: Rank mismatch in array reference at (1) (1/2)
z1.f90:5:4:

    z(21) = z(1,2)
    1
Error: Rank mismatch in array reference at (1) (1/2)
f951: internal compiler error: in identical_array_ref, at
fortran/dependency.c:104
0x70fdee identical_array_ref
        ../../gcc/fortran/dependency.c:104
0x70fdee are_identical_variables
        ../../gcc/fortran/dependency.c:164
0x70fdee gfc_dep_compare_expr(gfc_expr*, gfc_expr*)
        ../../gcc/fortran/dependency.c:462
0x7ac7a6 realloc_string_callback
        ../../gcc/fortran/frontend-passes.c:182
0x7af779 gfc_code_walker(gfc_code**, int (*)(gfc_code**, int*, void*), int
(*)(gfc_expr**, int*, void*), void*)
        ../../gcc/fortran/frontend-passes.c:3376
0x7b08c2 realloc_strings
        ../../gcc/fortran/frontend-passes.c:1015
0x6eb38a gfc_resolve(gfc_namespace*)
        ../../gcc/fortran/resolve.c:15707
0x6d668a resolve_all_program_units
        ../../gcc/fortran/parse.c:5853
0x6d668a gfc_parse_file()
        ../../gcc/fortran/parse.c:6105
0x718d12 gfc_be_parse_file
        ../../gcc/fortran/f95-lang.c:198