Comment on Common Rust Lifetime Misconceptions (2020)parentComments−almost_usual2yMind expanding on this? The nomicon describes &’a T where both ‘a’ and ‘T’ are covariant. I thought I had a clear picture but now I’m confused.https://doc.rust-lang.org/nomicon/subtyping.html#variance−cwzwarich2yHere is the original GitHub issue on the question:https://github.com/rust-lang/rust/issues/15699And an RFC by some people that felt frustrated by this arguably implementation-centric view that kind of lost steam:https://github.com/rust-lang/rfcs/issues/391Intuitively, the bottom lifetime should the one that is uninhabited, which would be a lifetime with no extent rather than 'static.−almost_usual2yInteresting, thanks for sharing!−Georgelemental2y`rustc` used to use different terminology than the nomicom, but this is no longer the case: https://github.com/rust-lang/rust/pull/107339
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Mind expanding on this? The nomicon describes &’a T where both ‘a’ and ‘T’ are covariant. I thought I had a clear picture but now I’m confused.
https://doc.rust-lang.org/nomicon/subtyping.html#variance
Here is the original GitHub issue on the question:
https://github.com/rust-lang/rust/issues/15699
And an RFC by some people that felt frustrated by this arguably implementation-centric view that kind of lost steam:
https://github.com/rust-lang/rfcs/issues/391
Intuitively, the bottom lifetime should the one that is uninhabited, which would be a lifetime with no extent rather than 'static.
Interesting, thanks for sharing!
`rustc` used to use different terminology than the nomicom, but this is no longer the case: https://github.com/rust-lang/rust/pull/107339