Warning not filtered by regex

[dantswain]

Precheck

• Take a look at the open issues and be sure that your issue is not already covered. ✅
• Be sure your versions of Dialyxir and Erlex are up to date. ✅

Environment

• Elixir & Erlang/OTP versions (elixir --version): Elixir 1.11.0, Erlang/OTP 23

• Which version of Dialyxir are you using? (cat mix.lock | grep dialyxir): 1.1.0 (erlex is 0.2.6)

Current behavior

I'm getting a warning that doesn't make sense (an else clause from a with construct, but that's a separate issue) that I'd like to ignore. I have tried adding a regex to my dialyzer ignore file and I'm seeing weird behavior wrt that regex actually filtering the warning.

Here is the warning (somewhat redacted):

# --format dialyzer
lib/foo_server.ex:49: The pattern {'error', 'not_found'} can never match the type {'error','some_error1' | 'some_error2'}
# --format raw
{:warn_matching, {'lib/foo_server.ex', 49}, {:pattern_match, ['pattern {\'error\', \'not_found\'}', '{\'error\',\'some_error1\' | \'some_error2\'}']}}

It seems whenever I include any subset of not_found in the regex, it does not work ("work" == "ignores the warning"). Here are some regexes that do/do not work:

• ~r/foo_server\.ex/ - works
• ~r/foo_server\.ex.*pattern/ - works
• ~r/foo_server\.ex.*pattern.*never match/ - works
• ~r/foo_server\.ex.*pattern.*not/ - does not work
• ~r/foo_server\.ex.*pattern.*not_found/ - does not work

Expected behavior

I would have expected all of these regexes to work.