anchor.diff:  uniq([]) -> [].
   
   -ifdef(TEST).
  --dialyzer({[no_match, no_fail_call, no_improper_lists], uniq_test_/0}).
  +-dialyzer({[no_fail_call, no_improper_lists], uniq_test_/0}).
   uniq_test_() ->
       {"uniq",
        [?_assertError(function_clause, uniq(ok)),
  
positive.code: is_nonempty_string(Cs) -> is_string(Cs).
  
  -ifdef(TEST).
  -dialyzer({no_match, is_string_test_/0}).
  is_string_test_() ->
      {"is_string",
       [{"no non-lists", ?_assert(not is_string($A))},
  
negative.code: 
  -ifdef(TEST).
  
  trie_test_() ->
      [{"basic representation",
        [?_assert(trie_new() =:= gb_trees:empty()),
  