Reducing generics bloat

[Fylwind]

An idea I had a while back closely related to this:

[Idea] Type erasure in Rust through parametricity

Summary: This post proposes a mechanism for type-erased generics by restoring parametricity of types in a limited fashion. Rust’s primary mechanism for generics is through monomorphization, following the same path as C++. This is generally good for performance and optimization, but can be bad for binary size, but more importantly it does not offer the full expressiveness of higher-rank types (not to be confused with higher-kinded types nor higher-rank trait bounds). It’s also worse for compil…