Forward more Iterator methods #43074
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alexcrichton
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Is anyone going to be reviewing this? ping @aturon. |
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@bors: r+ Thanks @SimonSapin! |
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📌 Commit 758ddeb has been approved by |
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🔒 Merge conflict |
These are overridden by slice::Iter
`position` could not be implemented because calling `rposition` on the inner iterator would require more trait bounds.
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@bors: r=aturon |
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📌 Commit 2007987 has been approved by |
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@bors rollup |
Forward more Iterator methods This allows in more cases to take advantage of specific (possibly more optimized) impls of these methods, rather than the default one defined for all `Iterator`s. I also wanted to do this for `&mut I` and `Box<I>`, but that didn’t compile for two reasons: * To make the trait object-safe, generic methods (e.g. that take a closure parameter) have a `where Self: Sized` bound. But e.g. `Box<I>: Sized` does not imply `I: Sized`, and adding an additional bound in the impl is not allowed. Some for of specialization would be needed here. * With e.g. a `F: FnMut(Self::Item) -> bool` bound and a `type Item = I::Item` associated types, I got errors like `F does not implement FnMut(I::Item) -> bool`. This looks like a limitation in the trait resolution system not recognizing that `Self::Item == I::Item` or "propagating" that fact to `FnMut` bounds.
Rev::rposition counts from the wrong end Introduced in rust-lang#43074. cc @SimonSapin
Rev::rposition counts from the wrong end Introduced in rust-lang#43074. cc @SimonSapin
This allows in more cases to take advantage of specific (possibly more optimized) impls of these methods, rather than the default one defined for all
Iterators.I also wanted to do this for
&mut IandBox<I>, but that didn’t compile for two reasons:where Self: Sizedbound. But e.g.Box<I>: Sizeddoes not implyI: Sized, and adding an additional bound in the impl is not allowed. Some for of specialization would be needed here.F: FnMut(Self::Item) -> boolbound and atype Item = I::Itemassociated types, I got errors likeF does not implement FnMut(I::Item) -> bool. This looks like a limitation in the trait resolution system not recognizing thatSelf::Item == I::Itemor "propagating" that fact toFnMutbounds.