prelude: |
  class Range
    unless method_defined?(:overlap?)
      def overlap?(other)
        other.begin == self.begin || cover?(other.begin) || other.cover?(self.begin)
      end
    end
  end

benchmark:
  - (2..3).overlap?(1..1)
  - (2..3).overlap?(2..4)
  - (2..3).overlap?(4..5)
  - (2..3).overlap?(2..1)
  - (2..3).overlap?(0..1)
  - (2..3).overlap?(...1)
  - (2...3).overlap?(..2)
  - (2...3).overlap?(3...)
  - (2..3).overlap?('a'..'d')
