Re: gen_statem:start_monitor dialyzer warning
Kostis Sagonas <[email protected]>
| Newsgroups | gmane.comp.lang.erlang.general |
|---|---|
| Message-ID | <[email protected]> |
On 1/24/21 2:14 PM, Matt Kowalczyk wrote:
> Having a hard time understanding why the following sample code generates
> a dialyzer warning,
Either because somebody added wrong specs to 'gen_statem' or forgot to
update the specs of 'gen'.
===== gen_statem has these types and specs =====
-type start_mon_ret() ::
{'ok', {pid(),reference()}}
| 'ignore'
| {'error', term()}.
-spec start_monitor(
Module :: module(), Args :: term(), Opts :: [start_opt()]) ->
start_mon_ret().
start_monitor(Module, Args, Opts) ->
gen:start(?MODULE, monitor, Module, Args, Opts).
===== gen:start/5's return type is: ======
-type start_ret() :: {'ok', pid()} | 'ignore' | {'error', term()}.
Their intersection is: 'ignore' | {'error', term()}.
Dialyzer is never wrong (C), but wrong specs can cause confusion.
Kostis