[Bug fortran/84218] New: [8 Regression] ICE in free_expr0, at fortran/expr.c:451

[gscfq@t-online.de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84218

            Bug ID: 84218
           Summary: [8 Regression] ICE in free_expr0, at
                    fortran/expr.c:451
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gscfq@t-online.de
  Target Milestone: ---

Another testcase (from scratch) with undefined variable "j".
Changed between 20170820 and 20170910 :


$ cat z1.f90
program p
   integer :: i
   character(3) :: x
   data (x(j:i), i=1,2,2) /'a'/
   print *, x
end


$ gfortran-8-20170820 -c z1.f90
z1.f90:4:28:

    data (x(j:i), i=1,2,2) /'a'/
                            1
Warning: Unused initialization string at (1) because variable has zero length


$ gfortran-8-20180204 -c z1.f90
*** Error in `.../x86_64-pc-linux-gnu/8.0.1/f951': double free or corruption
(out): 0x0000000003f1fdd0 ***
...
z1.f90:6:0:

 end

internal compiler error: Aborted
0xb953ff crash_signal
        ../../gcc/toplev.c:325
0x6a70c7 free_expr0
        ../../gcc/fortran/expr.c:451
0x6a717d gfc_free_expr(gfc_expr*)
        ../../gcc/fortran/expr.c:520
0x738566 gfc_free_symbol(gfc_symbol*)
        ../../gcc/fortran/symbol.c:3042
0x7386f3 free_sym_tree
        ../../gcc/fortran/symbol.c:3890
0x7386ea free_sym_tree
        ../../gcc/fortran/symbol.c:3888
0x738391 gfc_free_namespace(gfc_namespace*)
        ../../gcc/fortran/symbol.c:4045
0x73897c gfc_symbol_done_2()
        ../../gcc/fortran/symbol.c:4089
0x6dca58 gfc_done_2()
        ../../gcc/fortran/misc.c:267
0x6fffc6 translate_all_program_units
        ../../gcc/fortran/parse.c:6140
0x6fffc6 gfc_parse_file()
        ../../gcc/fortran/parse.c:6324
0x74686f gfc_be_parse_file
        ../../gcc/fortran/f95-lang.c:204