Set::SubclassCompatible#==

# File tmp/rubies/ruby-4.0.0/lib/set/subclass_compatible.rb, line 283
def ==(other)
  if self.equal?(other)
    true
  elsif other.instance_of?(self.class)
    super
  elsif other.is_a?(Set) && self.size == other.size
    other.all? { |o| include?(o) }
  else
    false
  end
end