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Changes between Version 2 and Version 3 of Ticket #36051, comment 3

v2	v3
5	5	To me #36042 and and this ticket should be addressed by introducing a `BaseExpression.allows_composite_expressions: bool = False` that we set to `True` on `Count` and `TupleLookupMixin` and make `BaseExpression.resolve_expression` raise a `ValueError` when it's set to `False` and any of its source expression is an instance of `ColPairs`.
6	6
7		Don't get me wrong I think we should define `arity` for `Aggregate` subclasses to guard against improper calls but I don't think that making `Func.resolve_expression` unpack composite expressions is something we should do for the aforementioned reasons. In essence this is the same problem as `model_instance.pk` now returning a `tuple` and requiring some special care but at the field resolving level.
	7	Don't get me wrong I think we should define `arity` for `Aggregate` subclasses to guard against improper calls but I don't think that making `Func.resolve_expression` unpack composite expressions to trigger arity check failures is something we should do for the aforementioned reasons. In essence this is the same problem as `model_instance.pk` now returning a `tuple` and requiring some special care but at the field resolving level.