Rubocop: RescueWithoutErrorClass gives false positive

[perlun]

After upgrading to RuboCop 0.50, we are seeing RescueWithoutErrorClass being raised for code that _does_ actually provide an error class:

lib/ecraft/sequel_library/sequel_session_store.rb:148:105: W: Lint/RescueWithoutErrorClass: Avoid rescuing without specifying an error class.

Ecraft::WebApi::SessionManager.register_store(:postgres, Ecraft::SequelLibrary::SequelSessionStore) rescue NameError # rubocop:disable RescueModifier, LineLength

---

Expected behavior

Rubocop should accept this code, since it provides an error class (NameError).

Actual behavior

Rubocop produced a Lint/RescueWithoutErrorClass warning.

Steps to reproduce the problem

Probably the following will do, if not, the exact example above:

puts 'hello' rescue NameError

RuboCop version

Include the output of rubocop -V. Here's an example:

Fetching rubocop 0.50.0

(don't have rubocop -V output since this was running on Travis.)

[Drenmi]

Looks like the parsed AST is different when using a rescue modifier. Working on a fix.

[ctm]

I don't think rescue as a modifier works the way @perlun thinks it works.

irb(main):018:0> 3 / 0 rescue NameError
=> NameError

I don't know of a syntax that allows the modifier form of rescue to be restricted to a particular class. If there isn't one, then it might make sense to simply not have rubocop complain about the error class when using the modifier form.

[Drenmi]

You're right @ctm. This cop should just ignore modifier form rescue. (It is handled by the RescueModifier cop.) PR incoming.

[perlun]

@ctm Hehe, very good point! 😆 Thanks for pointing that out. I need to fix my code...