Ruby

Object#respond_to? seems to ignore active refinements.

Take for instance the following code:

module R1
  refine String do
    def foobar
      'foobar'
    end
  end
end

puts 'string'.respond_to?(:foobar) # Returns false

using R1

puts 'string'.foobar # Returns 'foobar'
puts 'string'.respond_to?(:foobar) # Is still false

Also seems to equally fail at ruby 2.1.5