Support ~Copyable, ~Escapable in simple standard library protocols

[x-sheep (Lennard Sprong)]

Conceptually, I think LosslessStringConvertible is similar to Decodable. Are the Codable protocols also considered to support ~Copyable?

[jackhax0r (Jack Hacker)]

@ben-cohen

I have yet to run into any real-world scenario where a LosslessStringConvertible type has been useful in practice, so uses of it with non-Copyable types is a subset of that. I mostly did it for completeness sake.

I found a use for it once — transferring complex data types across an FFI boundary in a compact parsable format (faster to parse than JSON).