# An internal hash code for the object based on its identity.
	#
	# Unless specific code, you should not use this method but
	# use `hash` instead.
	#
	# As its name hints it, the internal hash code, is used internally
	# to provide a hash value.
	# It is also used by the `inspect` method to loosely identify objects
	# and helps debugging.
	#
	# ~~~
	# var a = "Hello"
	# var b = a
	# assert a.object_id == b.object_id
	# ~~~
	#
	# The specific details of the internal hash code it let to the specific
	# engine. The rules are the following:
	#
	# * The `object_id` MUST be invariant for the whole life of the object.
	# * Two living instances of the same classes SHOULD NOT share the same `object_id`.
	# * Two instances of different classes MIGHT share the same `object_id`.
	# * The `object_id` of a garbage-collected instance MIGHT be reused by new instances.
	# * The `object_id` of an object MIGHT be non constant across different executions.
	#
	# For instance, the `nitc` compiler uses the address of the object in memory
	# as its `object_id`.
	#
	# TODO rename in something like `internal_hash_code`
	fun object_id: Int is intern