# Replace in `recv` the value of the attribute `mproperty` by `value`
	redef fun write_attribute(mproperty: MAttribute, recv: Instance, value: Instance)
	do
		assert recv isa MutableInstance

		# Replace the old value of mproperty in recv
		var position = recv.mtype.as(MClassType).mclass.get_position_attributes(mproperty.intro_mclassdef.mclass)
		if position > -1 then
			# if this attribute class has an unique position for this receiver, then use direct access
			write_attribute_sst(recv.internal_attributes, position + mproperty.offset, value)
		else
			# Otherwise, use perfect hashing to replace the old value
			var id = mproperty.intro_mclassdef.mclass.vtable.id

			write_attribute_ph(recv.internal_attributes, recv.vtable.internal_vtable,
					recv.vtable.mask, id, mproperty.offset, value)
		end
	end