anchor.diff:  types(erlang, 'list_to_bitstring', [_]) ->
       %% As list_to_binary but with bitstrings rather than binaries.
       sub_unsafe(#t_bitstring{}, [proper_list()]);
  +types(erlang, list_to_integer, [_]) ->
  +    sub_unsafe(#t_integer{}, [proper_cons()]);
  +types(erlang, list_to_integer, [_, _]) ->
  +    sub_unsafe(#t_integer{}, [proper_cons(), #t_integer{}]);
   
   %% Process operations
   types(erlang, alias, []) ->
  
positive.code: %% make it impossible to reach in the foreseeable future.
  %%
  -define(SIZE_UPPER_LIMIT, ((1 bsl 58) - 1)).
  
  %%
  %% Returns whether a call will succeed or not.
  
negative.code:     RetType = copy_list(LHS, new_length, proper),
      sub_unsafe(RetType, [proper_list(), proper_list()]);
  
  types(erlang, atom_to_list, [_]) ->
      sub_unsafe(proper_list(?UNICODE_TYPE), [#t_atom{}]);
  types(erlang, 'iolist_to_binary', [_]) ->
      %% Arg is an iodata(), despite its name.
      ArgType = join(#t_list{}, #t_bitstring{size_unit=8}),
  