class Foo

	var _x as int
	
	cue init
		base.init
		this._x = 5  # .warning. explicit
		.check(this)

	def run
		.check(this)  # passing this

	def check(other as Foo)
		assert other is this  # comparing this
		assert this is other
		assert other == this
		assert this == other

	def main is shared
		Foo().run