hybrid-array: make ArraySize an unsafe trait
#914
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
tarcieri
force-pushed
the
hybrid-array/make-array-size-unsafe-trait
branch
2 times, most recently
from
beb2b92 to
cf96416
Compare
It's used when checking the lengths of slices match an array size prior to using a pointer cast to convert types. If someone were to make their own `typenum::Unsigned` type and impl `ArraySize` for it with an `ArrayType` whose size does not match `Unsigned::USIZE`, that would be UB. Really `ArraySize` is not intended for downstream crates to impl anyway, but making it an `unsafe trait` at least captures the UB potential. Additionally this adds more debug checks to `check_slice_length` to ensure that if there is a length mismatch, it's at least caught in debug builds.
tarcieri
force-pushed
the
hybrid-array/make-array-size-unsafe-trait
branch
from
cf96416 to
6ef5edf
Compare
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
It's used when checking the lengths of slices match an array size prior to using a pointer cast to convert types.
If someone were to make their own
typenum::Unsignedtype and implArraySizefor it with anArrayTypewhose size does not matchUnsigned::USIZE, that would be UB.Really
ArraySizeis not intended for downstream crates to impl anyway, but making it anunsafe traitat least captures the UB potential.Additionally this adds more debug checks to
check_slice_lengthto ensure that if there is a length mismatch, it's at least caught in debug builds.