Codable synthesis for enums with associated values

Swift 4 introduced support for automatically synthesizing conformance to the Encodable and Decodable protocols. It's a useful feature, most likely used by any application which handles JSON-based network requests. This Swift evolution pitch from Dario Rexin proposes extending auto-synthesis of these conformances to enums with associated values. I'm sure we will see this in an upcoming Swift version.

Standard library behavior change for LazyMapCollection prefix to act as a Sequence

The Swift standard library provides lazy variations of its Sequence and Collection types, on which operations such as map and filter are implemented lazily. This means that the actual computations will only occur when the results are needed. In this Swift evolution pitch, Greg Titus proposes an addition to the standard library that improves the behavior of the LazyMapCollection type.