Check for redundant visibility modifiers

[agrimm]

The following code doesn't generate any RuboCop offenses, even though it has a redundant visibility modifier, in that there's a second private call.

# Example of a class with repeated private visibility modifiers
class MyClass
  def foo
    # This is public
    bar
    baz
  end

  private

  def bar
    # This is private
    puts 'bar called'
  end

  # Redundant visibility modifier

  private

  def baz
    # This is also private
    puts 'baz called'
  end
end

MyClass.new.foo

There should be a cop that generates an offense for the second private.

[bbatsov]

Yeah, we should definitely generate some offence in such situations.