Commits
Joe Groff committed 35c85c50179
Implement 'x is T' runtime type checks. Implement type-checking and IRGen for 'x is T', and fix a bug in 'x as! T' typechecking when the operand is an lvalue. For IRGen I'm reusing the checked swift_dynamicCastClass runtime function and testing the result against null. Swift SVN r4515