I'd like to see them expand it the way Rust did: Rust lifted `if let` from Swift (I believe) but made it a more general-purpose refutable pattern matcher, it's just one step below match and works with any enum type not just Option. So you can write:
enum Foo {
Bar,
Baz(i32),
Qux(f64)
}
if let Bar = item {
// do something
} else if let Baz(val) = other {
// do something with val
}
which is oft shorter than a full-blown `match`, and more convenient when alternating on different "source" items.
That's putting it a bit mildly. Speaking as the author of that RFC, Rust's "if let" would never have existed if it were not for Swift. When I saw Swift's "if let" I immediately knew I wanted it in Rust. I also generalized it to arbitrary patterns at that time, since Rust doesn't fetishize Option the way Swift fetishizes Optional.
I am glad to see Swift 1.2 expanding "if let" to multiple clauses. But I do wish it supported arbitrary values instead of just Optional.
