[Pre-RFC]: Unnamed struct types

language design
64

If the trait fields RFC gets accepted, impls for anonymous structs feel like a natural extension, just like impls for tuples, e.g.


impl<A, B> Foo for (A, B) { /*...*/ }

// maybe use (a :A, b :B) if the grammar doesn't play nicely.
impl<A, B> Bar for { a: A, b: B } {
     a = a;
     b = b;
}

If the generic tuples RFC gets accepted maybe it should apply to structs too so that many procedural macro style impl can be written generically.

impl<A: Clone, ...Tail: Clone> for (A, ...Tail) {
   /* ... */
}

You’d probably still need macros for things that need field names, e.g. Serialize and it might be too magical anyway.

Pre-RFC: Catching Functions