So you're talking about the ability to have type constructors as generic parameters, a feature usually referred to as "higher-kinded types". Indeed, Rust canno

So you're talking about the ability to have type constructors as generic parameters, a feature usually referred to as "higher-kinded types". Indeed, Rust cannot do this yet, although it will be able to do something like it (but uglier) soon using associated type constructors (something like Haskell's type families). However, I doubt this will have much impact on error handling. For example, from your earlier post: > PS And things from this comment [1] would be very much explainable through "follow the types". > [1] https://news.ycombinator.com/item?id=24526604 https://news.ycombinator.com/item?id=24526604 They already are explainable that way. I went through and mapped the bullets there to the actual language/library features being explained in the corresponding blog post: - A method on Result - A method on Result - A method on Result - The ? operator - Existential (boxed) types - The Any trait - API design tips - How to create an ADT and implement some traits for it - The ? operator uses the From trait - Pattern matching on ADTs In short, most of it is explaining either standard library functionality, or general-purpose language features as applied to the error-handling use case. The exception is the one language feature specific to error handling, the ? operator.