Remove generic_const_exprs
#368
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| /// The length of the bitmask array. | ||
| const BYTES: usize; | ||
| /// The bitmask array. | ||
| type BitMaskArray; |
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this should have some useful bounds, such as Copy + Unpin + Send + Sync + 'static + AsRef<[u8]> + AsMut<[u8]> + BorrowMut<[u8]> and maybe more
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Would adding more bounds in the future be backwards compatible?
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No, bounds can only be relaxed backwards-compatibly, and only sometimes. They cannot be added, so forward-compatibility requires maximum bounds.
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Is that still true when the trait is sealed?
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...that does change things a bit, since the major compat hazard is people referencing the type generically.
crates/core_simd/src/to_bytes.rs
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| /// Convert SIMD vectors to vectors of bytes | ||
| pub trait ToBytes: Sealed { | ||
| /// This type, reinterpreted as bytes. | ||
| type Bytes; |
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could use some bounds here too.
Inspired by the errors in #367 (caused by rust-lang/rust#116320) I've removed all instances of
generic_const_exprs.For
ToBitMaskArray, this was straightforward, simply use an associated type instead of an associated const. For the variousto_bytesfunctions, this was more complicated. I now implemented aToBytestrait over every individual vector type. In the future when const generics are more powerful, I'd hope this can be implemented generically.This effectively upgrades these functions to nightly, as they're currently disabled on core.