740668dbd9
Implementation of RFC 2289 (associated_type_bounds) This PR implements the [`asociated_type_bounds` feature](https://github.com/rust-lang/rfcs/blob/master/text/2289-associated-type-bounds.md). Associated type bounds are implemented in: - function/method arguments and return types - structs, enums, unions - associated items in traits - type aliases - type parameter defaults - trait objects - let bindings CC @nikomatsakis @centril