Progress on list type inferencing

gistfile1.txt

list_test_() ->
    [?_assertMatch({{t_list, t_float}, _},
                   top_typ_of("1.0 : []")),
     ?_assertMatch({{t_list, t_int}, _},
                   top_typ_of("1 : 2 : []")),
     ?_assertMatch({error, _}, top_typ_of("1 : 2.0 : []")),
     ?_assertMatch({{t_arrow, 
                     [{unbound, A, _}, {t_list, {unbound, A, _}}],
                     {t_list, {unbound, A, _}}}, _},
                   top_typ_of("f x y = x : y")),
     ?_assertMatch({{t_arrow, [{t_list, t_int}], t_int}, _},
                   top_typ_of(
                     "f list = match list with\n"
                     "| h : t -> h + 1")),
     %% Ensure that a '_' in a list nested in a tuple is renamed properly
     %% so that one does NOT get unified with the other when they're 
     %% potentially different types:
     ?_assertMatch({{t_arrow,
                    [{t_tuple, [{t_list, t_int}, {unbound, _, _}, t_float]}],
                    {t_tuple, [t_int, t_float]}}, _},
                   top_typ_of(
                     "f list_in_tuple =\n"
                     "  match list_in_tuple with\n"
                     "  | (h : 1 : _ : t, _, f) -> (h, f +. 3.0)"))
    ].