add note for future type-system adventurers #26439
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| @@ -512,6 +512,8 @@ impl<T: ?Sized> PartialOrd for *mut T { | |||
| #[unstable(feature = "unique", reason = "needs an RFC to flesh out design")] | |||
| pub struct Unique<T: ?Sized> { | |||
| pointer: NonZero<*const T>, | |||
| // NOTE: this marker has no consequences for variance, but is necessary | |||
| // for dropck to understand that we logically contain a `T`. | |||
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I'm actually not sure which dropck really cares about.
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Ownership (i.e. when destructors run).
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(Well, maybe that's not precisely right, since Unique doesn't actually drop its T. I guess @pnkfelix will have to clarify.)
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Ownership is right; it doesn't matter that Unique doesn't drop its T itself -- dropck thinks it does.
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(having said that, I have no problem with using the word "contain" here. The one thing you might do is link to the relevant part of RFC, namely: https://github.com/rust-lang/rfcs/blob/master/text/0769-sound-generic-drop.md#phantom-data )
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Updated text |
r? @pnkfelix