A Stable Modular ABI for Rust

[zicklag]

@kornel

Generics are not a problem as long as all types are known in the interface exposed through the ABI. So it wouldn't be a problem to return Result<i32, String> or even Result<(), Box<dyn Error>> (assuming trait objects have defined ABI).

That's nice!

@kornel

Just forbid them. Library interfaces would have to use dyn Trait or concrete types instead. IMHO this is quite sensible limitation, especially for an MVP.

I think that is rather reasonable.

@kornel

Do what Swift does and compile a universal version of the generic function that uses run time type information to support arbitrary types. It's a very clever approach from ABI perspective, but it's equivalent of changing everything into dyn Trait , so it may be a poor fit for Rust.

Maybe this could be optional behavior?