parametric-vm / section other upcalls

[Remi Forax]

In the sub-section "other upcalls",
for type-testing, the VM does an upcall to the method "isAssignableFrom" of the Species but it's not clear for me how a user can creates such "Species" given that it seems that the way to configure a species is to return a ParameterBinding properly configured.

It looks like a vestige of an old behavior ? right ?

Rémi