Bunched CanThrows

[odersky]

One problem with the saferException scheme is that so far each CanThrow capability has to be passed separately. It's not yet possible to bunch several exceptions in a single CanThrow capability.

It looks like we could use dependency injection scheme explained here and here to aggregate CanThrow. Using this scheme, a capability to enable throwing an IOException and an SQLExcecption would be

  CanThrow[(IoException, SQLException)]

The discussion on dependency injection shows why & would not work for aggregating exceptions (it would lead to given search ambiguities) but tupling is a good alternative.

[odersky]

This would have ramifications on the translation of throws clauses.

def f(): T throws E1 | E2

should now translate to

def f()(using CanThrow[(E1, E2)]): T