False positive in Style/TrivialAccessors with inline private

[fujimura]

Expected behavior

Not an offense. In this case, private / protected clause needs symbol returned from def but attr_reader returns nil, which causes TypeError.

Actual behavior

# a.rb
class A
  private def foo
    @foo
  end
end

$ rubocop -a a.rb
Inspecting 1 file
C

Offenses:

a.rb:2:11: C: [Corrected] Style/TrivialAccessors: Use attr_reader to define trivial reader methods.
  private def foo
          ^^^

1 file inspected, 1 offense detected, 1 offense corrected

# Corrected a.rb
class A
  private attr_reader :foo
end

$ ruby a.rb
a.rb:2:in `private': nil is not a symbol nor a string (TypeError)
        from a.rb:2:in `<class:A>'
        from a.rb:1:in `<main>'

Steps to reproduce the problem

Described in actual behavour.

RuboCop version

$ rubocop -V
0.53.0 (using Parser 2.5.0.2, running on ruby 2.4.2 x86_64-darwin16)

[Drenmi]

You can still define private readers using attr_reader, which is what RuboCop is suggesting:

private

attr_reader :foo

although not using the new inline syntax.

[pocke]

I don't think it is a false positive for the same reason as the @Drenmi comment.
But the auto-correction behaviour is a bug. So we should disable the auto-correction on private.

BTW, maybe we can add an option to ignore this case, i.e. this cop ignores private def foo ... with this option. But I'm not sure the option is necessary as I think the private; attr_reader :foo is better style.

[fujimura]

I don't think it is a false positive for the same reason as the @Drenmi comment.
But the auto-correction behaviour is a bug. So we should disable the auto-correction on private.

Agreed. Thanks for fixing this!

[Darhazer]

Fixed in 0.54. Can we close this?