RUST-1358 Remove most type constraints on cursor values #891
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isabelatkinson
approved these changes
Jun 12, 2023
| drop_address: Option<ServerAddress>, | ||
| #[cfg(test)] | ||
| kill_watcher: Option<oneshot::Sender<()>>, | ||
| _phantom: std::marker::PhantomData<T>, | ||
| _phantom: std::marker::PhantomData<fn() -> T>, |
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out of curiosity, why was this change needed?
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This is a gnarly little corner of the Rust typesystem: https://doc.rust-lang.org/nomicon/phantom-data.html
TL;DR changing it from PhantomData<T> to PhantomData<fn() -> T> means the compiler will no longer consider dropping Cursor<T> to drop a T, which can relax restrictions in some hypothetical situations.
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RUST-1358
Now that we're internally passing around
RawDocumentrather than the deserialized type, we don't need to carry around the final type for our internal cursor implementation bits, and in turn we don't need theSync + Send + Unpinconstraints on that type.I think there's further opportunity for cleaning up the implementation, but that won't have any user-facing benefit, so I've filed RUST-1676 to track that.