Provide blanket implementations for &T, &mut T, Box<T> and IntoIterator, Deref for ergonomics

When you define a new trait, you’ll usually want to provide blanket implementations for that trait for:

• &T, no dereferencing with shared references
• &mut T, same as above
• Box<T>, for heap-allocated types

For ergonomics, also consider:

• IntoIterator for both &T and &mut T to have for loops
• Deref if you provide a transparent type (like Arc) allows calling methods on the inner type via .. Avoid it on types in which you don’t know in advance the inner type

See also

• Principle of Least Astonishment
• Every Rust type should implement Debug, Send, Sync, Clone and Default - the parent: first focus on standard traits
• OCP - software should be open for extension and closed for modification - blanket implementations are open for extension

References

• J. Gjengset, Rust for Rustaceans: Idiomatic Programming for Experienced Developers. No Starch Press, 2021.