Synthesizing Equatable and Hashable conformance

Following in the footsteps of the well received Swift 4 Codable protocols, this Swift evolution proposal outlines the motivation for, and proposed implementation of, synthesized conformance to the Equatable and Hashable protocols. This is a really good proposal which would reduce the need for common boilerplate code. The idea is that if a types members all conform to Equatable or Hashable, then the entire type can simply opt-in to automatic synthesis by declaring itself as conforming.