Only call the closure parameter of Iterator::is_sorted_by_key once per item #62473
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r? @aidanhs (rust_highfive has picked a reviewer for you, use r? to override) |
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r? @scottmcm |
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Well, this seems reasonable to me and the signature change is unstable so if libs is unhappy with it we can always revert it 🙃, so @bors r+ |
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Only call the closure parameter of Iterator::is_sorted_by_key once per item See #53485 (comment). This changes `Iterator::is_sorted_by_key` to only call the given closure once for each item, which allows us to pass the items to the closure by value instead of by reference. **Important**: `is_sorted_by_key` for slices and slice iterators is now no longer implemented in terms of the custom `slice::Iter::is_sorted_by` implementation. It's a trade-off: we could forward `slice::Iter::is_sorted_by_key` to it directly for potential SIMD benefits, but that would mean that the closure is potentially called twice for (almost) every element of the slice.
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See #53485 (comment).
This changes
Iterator::is_sorted_by_keyto only call the given closure once for each item, which allows us to pass the items to the closure by value instead of by reference.Important:
is_sorted_by_keyfor slices and slice iterators is now no longer implemented in terms of the customslice::Iter::is_sorted_byimplementation. It's a trade-off: we could forwardslice::Iter::is_sorted_by_keyto it directly for potential SIMD benefits, but that would mean that the closure is potentially called twice for (almost) every element of the slice.