[Assignment ?][11/13 Lecture Question] "Is it possible to define a generic closure in Rust?"

[Jeong-jin-Han]

Related Issue

https://github.com/nrc/r4cppp/blob/master/closures.md

Googling Result

https://users.rust-lang.org/t/use-generics-in-closure/86679

ChatGPT Result

https://chatgpt.com/c/

Your question here

I tried defining a generic closure in Rust like this:

let example_closure<T> = |x: T| x;

However, this produces a compiler error: expected one of ':' , ';', '=', '@', or '|'. I understand that closures in Rust infer types based on their first use, but is there a way to explicitly make a closure generic without wrapping it in a function or struct? If not, could you explain why this limitation exists?

[Lee-Janggun]

There isn't. I'm not sure why it isn't supported, but my guess is that closures are typically single-use functions, so there is no real point on making it generic in the most case.
Also, generic code needs to be monomorphized at compile time, and it would be very difficult to account to do that for arbitrary let statements.

[Jeong-jin-Han]

Thank you!!