Range<u64> implements ExactSizeIterator #22047
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I checked the code and it turns out the impl is conditional -- only on 64-bit platforms. So that's correct and for me it turned into a different question of whether that kind of platform dependence is good. I've started a discussion about that here. |
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Reopened, got some voices backing that this is a bug. Soft solution would be to warn on using that particular impl of ExactSizeIterator for Range and i64, but I don't know if we can even do that. Otherwise we can just remove the impls. |
bluss
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Feb 13, 2015
Fixes rust-lang#22047 Range<u64> and Range<i64> may be longer than usize::MAX on 32-bit platforms, and thus they cannot fulfill the protocol for ExactSizeIterator. We don't want a nonobvious platform dependency in basic iterator traits, so the trait impl is removed. The logic of this change assumes that usize is at least 32-bit. This is technically a breaking change; note that Range<usize> and Range<isize> are always ExactSizeIterators. [breaking-change]
steveklabnik
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Feb 14, 2015
…=alexcrichton Fixes rust-lang#22047 Range<u64> and Range<i64> may be longer than usize::MAX on 32-bit platforms, and thus they cannot fulfill the protocol for ExactSizeIterator. We don't want a nonobvious platform dependency in basic iterator traits, so the trait impl is removed. The logic of this change assumes that usize is at least 32-bit. This is technically a breaking change; note that Range<usize> and Range<isize> are always ExactSizeIterators. [breaking-change]
steveklabnik
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Feb 15, 2015
…=alexcrichton Fixes rust-lang#22047 `Range<u64>` and `Range<i64>` may be longer than usize::MAX on 32-bit platforms, and thus they cannot fulfill the protocol for ExactSizeIterator. We don't want a nonobvious platform dependency in basic iterator traits, so the trait impl is removed. The logic of this change assumes that usize is at least 32-bit. This is technically a breaking change; note that `Range<usize>` and `Range<isize>` are always ExactSizeIterators. [breaking-change]
Manishearth
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Feb 15, 2015
…=alexcrichton Fixes rust-lang#22047 `Range<u64>` and `Range<i64>` may be longer than usize::MAX on 32-bit platforms, and thus they cannot fulfill the protocol for ExactSizeIterator. We don't want a nonobvious platform dependency in basic iterator traits, so the trait impl is removed. The logic of this change assumes that usize is at least 32-bit. This is technically a breaking change; note that `Range<usize>` and `Range<isize>` are always ExactSizeIterators. [breaking-change]
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What does
(0..std::u64::MAX).size_hint()return on a 32-bit build?Range<u64>andRange<i64>cannot fulfill the requirements of the ExactSizeIterator trait, and the implementations must be removed.The text was updated successfully, but these errors were encountered: