this post was submitted on 26 Jul 2023
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Rust Programming
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@calcopiritus @hatchet That way you can pass a reference or anything that can be turned into a reference as an argument. So the caller can supply a &T, Box, Rc, Arc, … (I dont’t know if there is a blanket impl so that even T itself will work.
Well, actually I would tend to agree that &[T] is preferable to AsRef in most cases; all of the smart pointers you mentioned can also easily be turned into plain references. I probably could have chosen a better example.
@hatchet That is true and I mostly agree with you. AsRef makes function signatures more complex and you effectively change a simple function into a generic function.
That said, when using some crates that make heavy use of this construction (especially when working with owned values in call chains) is sometimes significantly more ergonomic.
So AsRef definitely had it’s uses, but I agree that it probably shouldn’t be the recommended “best practice” for all crates.