Pick over the standard libraries for types that don't (but can) implement common traits

[huonw]

... and implement/derive them.

Traits like Eq, Hash, Ord, Clone are sometimes forgotten (or have been missed, in the various library changes that have happened), and this is annoying for downstream users. To paper over the deeper issue (how to make adding these impls more natural/harder to forget), impls for all the various traits can be added to types.

List of types missing things just from a basic scan:

• many types in collections (only implement the Partial comparison traits, and pretty much none of them implement Hash)
• semver::Version
• all types in num are missing Hash
• url::Path, url::UserInfo
• uuid::UuidVariant, uuid::UuidVersion

[aturon]

cc me

[wycats]

Also things like Path, Command, etc. It's common to want to be able to create sets of even somewhat exotic objects.

[chris-morgan]

I’m imagining a tool which produces a massive table where each column is a trait and each row is a struct or enum, with each cell shaded appropriately for whether there is an implementation (under any constraints) of the trait for the type.