Safe conversions between Array and [T; N]
#24
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Simply bounding on `ArrayType<T> = [T; N]` is enough to accomplish this. I've verified this change against a few of our repos (e.g. `block-ciphers`, `elliptic-curve`) and it does not seem to cause any inference problems. When this bound is in place there's no need for `ArrayOps<T, N>` either.
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I guess I was worried that this bound might be viral and it would require downstream bounds, but now that I can actually integration test it against large repos it doesn't seem to be causing any problems. Perhaps we could even get rid of |
tarcieri
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Jan 25, 2024
Continuation of the approach from #24 which replaces `ArrayOps<T, N>` bounds with `ArraySize<ArrayType<T> = [T; N]>`. Though a bit more verbose, this makes the inner type of `Array` explicit and therefore allows more safe conversions as well as making `unsafe` code easier to reason about, since the inner type is no longer implicit. This doesn't go as far as to remove the `ArrayOps` (and `SliceOps) trait(s) yet, but that should now be possible.
tarcieri
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Jan 25, 2024
Continuation of the approach from #24 which replaces `ArrayOps<T, N>` bounds with `ArraySize<ArrayType<T> = [T; N]>`. Though a bit more verbose, this makes the inner type of `Array` explicit and therefore allows more safe conversions as well as making `unsafe` code easier to reason about, since the inner type is no longer implicit. This doesn't go as far as to remove the `ArrayOps` (and `SliceOps`) trait(s) yet, but that should now be possible.
tarcieri
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Jan 27, 2024
After #24, #25, and #26, these traits don't really need to exist and have largely been replaced by safe type conversions with appropriate bounds. In lieu of `ArrayOps<T, N>` we instead can use `U: ArraySize<ArrayType<T> = [T; N]>>` as a bound, which albeit a bit more verbose concretely describes the inner type of `Array` to the compiler. The `cast_slice_(to|from)_core(_mut)` methods previously defined on the trait have been preserved, but as static methods of `Array`, making the change largely a drop in replacement. Places where they were being called as e.g. `ArrayOps::cast_slice_to_core` just need to be called as `Array::cast_slice_to_core` instead.
tarcieri
added a commit
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this pull request
Jan 27, 2024
After #24, #25, and #26, these traits don't really need to exist and have largely been replaced by safe type conversions with appropriate bounds. In lieu of `ArrayOps<T, N>` we instead can use `U: ArraySize<ArrayType<T> = [T; N]>>` as a bound, which albeit a bit more verbose concretely describes the inner type of `Array` to the compiler. The `cast_slice_(to|from)_core(_mut)` methods previously defined on the trait have been preserved, but as static methods of `Array`, making the change largely a drop in replacement. Places where they were being called as e.g. `ArrayOps::cast_slice_to_core` just need to be called as `Array::cast_slice_to_core` instead.
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Simply bounding on
ArrayType<T> = [T; N]is enough to accomplish this.I've verified this change against a few of our repos (e.g.
block-ciphers,elliptic-curve) and it does not seem to cause any inference problems.When this bound is in place there's no need for
ArrayOps<T, N>either.