fix(allocator): remove Clone impl from Vec
#13040
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CodSpeed Instrumentation Performance ReportMerging #13040 will not alter performanceComparing Summary
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Dunqing
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`Vec::clone` method is unsound, for the same reasons as `Vec::bump` is (#13039). `clone` only takes a `&self` and then uses it to access the `&Bump` contained in `Vec`, and allocates into that arena. Because `Vec` is `Sync`, that can result in 2 threads allocating into same `Bump` simultaneously, which is UB. `Clone` is of limited use, because usually usually the contents of the `Vec` aren't `Clone`. We have `CloneIn` trait for this purpose. We don't currently use `Clone` anywhere, so we can remove it.
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Vec::clonemethod is unsound, for the same reasons asVec::bumpis (#13039).cloneonly takes a&selfand then uses it to access the&Bumpcontained inVec, and allocates into that arena. BecauseVecisSync, that can result in 2 threads allocating into sameBumpsimultaneously, which is UB.Cloneis of limited use, because usually usually the contents of theVecaren'tClone. We haveCloneIntrait for this purpose.We don't currently use
Cloneanywhere, so we can remove it.