Additional case, switched between 20190630 and 20190728 :


$ cat z1.f90
program p
   type t
   end type
   type t2
      class(t), allocatable :: a(:)
   end type
   type(t2) :: z
   z%a = [z%a]
end


$ gfortran-10-20190630 -c z1.f90
$
$ gfortran-10-20191201 -c z1.f90
z1.f90:8:0:

    8 |    z%a = [z%a]
      |
internal compiler error: in gfc_dep_resolver, at fortran/dependency.c:2123
0x6c9416 gfc_dep_resolver(gfc_ref*, gfc_ref*, gfc_reverse*, bool)
        ../../gcc/fortran/dependency.c:2123
0x6c98ac gfc_check_dependency(gfc_expr*, gfc_expr*, bool)
        ../../gcc/fortran/dependency.c:1394
0x6e2c8e gfc_conv_resolve_dependencies(gfc_loopinfo*, gfc_ss*, gfc_ss*)
        ../../gcc/fortran/trans-array.c:4851
0x714bc5 gfc_trans_assignment_1
        ../../gcc/fortran/trans-expr.c:10806
0x6d4617 trans_code
        ../../gcc/fortran/trans.c:1852
0x6fda64 gfc_generate_function_code(gfc_namespace*)
        ../../gcc/fortran/trans-decl.c:6798
0x686c26 translate_all_program_units
        ../../gcc/fortran/parse.c:6302
0x686c26 gfc_parse_file()
        ../../gcc/fortran/parse.c:6541
0x6d10bf gfc_be_parse_file
        ../../gcc/fortran/f95-lang.c:210