[m-dev.] Does dynamic_cast/2 preserve typeclass info?

[Ralph Becket]

If I have

	func f(t(T)) = u <= tc(T)

and do

	if dynamic_cast(X, Y) then f(Y) else ...

should I expect this to work if X is an existentially quantified type
that may indeed be a t(T) <= tc(T)?

Rats!  It won't because dynamic_cast/2 uses univ_value/1 whose
signature is not sufficient to report such information.

Any ideas how I might work around this one?

Cheers,

Ralph
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