That's just a weird and unrealistic example, though. Like, why is process_handler taking an owned, boxed reference to something it only needs shared access to? Why is there an unnecessary 'a bound on handler?
In the places where you need to add lifetime annotations, it's certainly useful to be able to see them in the types, rather than relegate them to the documentation like in C++; cf. all the places where C++'s STL has to mention iterator and reference invalidation.
LLMs LOVE to write Rust like this. They add smart pointers, options and lifetimes everywhere when none of those things are necessary. I don’t know what it is, but they love over-engineering it.
As a first guess, they're trained on lots of social media and Q&A content. The former has lots of complaints about "look how complex rust is!" while the latter has lots of "help I've written very complex rust".
I agree that the signature for process_handler is weird, but you could steelman it to take a borrowed trait object instead, which would have an extra sigil.
The handler function isn't actually unnecessary, or at least, it isn't superfluous: by default, the signature would include 'a on self as well, and that's probably not what you actually want.
I do think that the example basically boils down to the lifetime syntax though, and yes, while it's a bit odd at first, every other thing that was tried was worse.
> The handler function isn't actually unnecessary, or at least, it isn't superfluous: by default, the signature would include 'a on self as well, and that's probably not what you actually want.
To clarify, I meant the 'a in `Box<dyn Handler + 'a>` in the definition of `process_handler` is unnecessary. I'm not saying that the <'a> parameter in the definition of Handler::handle is unnecessary, which seems to be what you think I said, unless I misunderstood.
In the places where you need to add lifetime annotations, it's certainly useful to be able to see them in the types, rather than relegate them to the documentation like in C++; cf. all the places where C++'s STL has to mention iterator and reference invalidation.