- paths can now take region parameters, replacing the dirty hack
I was doing before of abusing vstores. vstores are now a bit
of a hack though.
- fix various small bugs:
- we never checked that iface types were compatible when casting
to an iface with `as`
- we allowed nonsense like int<int>
- and more! (actually that may be it)
Adds a new kind of pattern C(*) where C is a constructor that may
have any number of fields. This pattern matches any value
constructed with C, without binding names for any of the fields.
Closes#1701.
