Explain the difference between Once(Lock|Cell) and Lazy(Lock|Cell) in the docs

[panstromek]

Location

https://doc.rust-lang.org/std/sync/struct.LazyLock.html
https://doc.rust-lang.org/std/sync/struct.OnceLock.html

https://doc.rust-lang.org/std/cell/struct.OnceCell.html
https://doc.rust-lang.org/std/cell/struct.LazyCell.html

Summary

Today I realized these are separate types. I used the experimental LazyLock before without realizing I can actually use stable OnceLock. These types are so similar that I never realized there are two of them.

Still, I don't think I quite understand the difference and the tradeoff (e.g. is some of them faster or not?). It would be useful if the docs pages linked to each other and explained the difference.

[workingjubilee]

LazyLock is an API you can build on top of OnceLock, and is the "obvious one" to use in many cases. OnceLock permits more potential use-cases, being the more basic form, but also often is additional complication if you wanted LazyLock.

[workingjubilee]

...so it should probably say something like that, yes.