Lint/UnusedMethodArgument offense ignored with comment body

[garettarrowood]

Expected behavior

I expect to see a Lint/UnusedMethodArgument offense in the following code snippet:

# frozen_string_literal: true

# A Fooy example
class Foo
  def unused_arg(arg)
    # Fooy comment
  end
end

Interestingly, when the method is called on self, the offense is correctly raised.

# frozen_string_literal: true

# A Fooy example
class Foo
  def self.unused_arg(arg)
    # Fooy comment
  end
end

This may be related to #4677 , simply because it deals with the same cop.

Actual behavior

No offense is raised by first example.

Steps to reproduce the problem

Run rubocop on this snippet:

# frozen_string_literal: true

# A Fooy example
class Foo
  def unused_arg(arg)
    # Fooy comment
  end
end

RuboCop version

0.50.0 (using Parser 2.4.0.0, running on ruby 2.3.3 x86_64-darwin15)

[Drenmi]

There's a configuration option, IgnoreEmptyMethods, which defaults to true. If you set this to false, it will report an offense on the method definition.

The disparity between an instance method- and class method definition looks like a bug though.