I know what is a callback.
Regardless of being able to use $v1 (or any local $identifiers as you noted) or not, there's no reason to expect /filter to use a seperate call chain (I don't see any).
The fact that it might not be possible because of some limit is irrelevant, if it's true we will know at some point and then I will see the reason.
$dllcall and $comcall are different from this case, you cannot expect them to call the alias in the same call chain.
I don't need this behavior nor I'm expecting an alias to be called in the same call chain even though I don't call it myself, it's about consistency only.
