This is the most intuitive thing I could come up with: since the
problem is mainly due to the order in which we try declaring the
aliases, then it suffices to simply try as much as we can, and retry
on failure until there's no more failure.
Note that it's important to detect cycles if we do such thing (which
we can by noticing that a given iteration didn't make any progress).
It works pretty well in the end and even allow us to define a new kind
of type error should there be a cyclic definition.
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