[WIP] Transmute #2335
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[WIP] Transmute #2335
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We already have the merge queue; running on push is redundant.
Upgrade our MSRV to 1.65 and remove version detection logic prior to that version.
* Release 0.9.0-alpha.0 Upgrade our MSRV to 1.65 and remove version detection logic prior to that version. * Enable clippy::missing_const_for_fn While we're here, remove defensive programming against bug in `Layout::from_size_align` which is no longer needed on our new MSRV.
Now that our MSRV is 1.65, we can clean up some code. Makes progress on #67
Also clean up some code for 0.9.
* Upgrade some code for MSRV 1.65 Now that our MSRV is 1.65, we can clean up some code. Makes progress on #67 * Upgrade versions of some dependencies Now that our MSRV is 1.65, it unlocks upgrading some dependencies' versions.
Bumps [github/codeql-action](https://github.com/github/codeql-action) from 3.26.12 to 3.26.13. - [Release notes](https://github.com/github/codeql-action/releases) - [Changelog](https://github.com/github/codeql-action/blob/main/CHANGELOG.md) - [Commits](github/codeql-action@c36620d...f779452) --- updated-dependencies: - dependency-name: github/codeql-action dependency-type: direct:production update-type: version-update:semver-patch ... Signed-off-by: dependabot[bot] <support@github.com> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Bumps [Swatinem/rust-cache](https://github.com/swatinem/rust-cache) from 2.7.3 to 2.7.5. - [Release notes](https://github.com/swatinem/rust-cache/releases) - [Changelog](https://github.com/Swatinem/rust-cache/blob/master/CHANGELOG.md) - [Commits](Swatinem/rust-cache@23bce25...82a92a6) --- updated-dependencies: - dependency-name: Swatinem/rust-cache dependency-type: direct:production update-type: version-update:semver-patch ... Signed-off-by: dependabot[bot] <support@github.com> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Previously, we supported the `AtLeast` bound, which was used to describe a subset relationship in which `I: AtLeast<J>` implied that `I` as at least as restrictive as `J`. However, as described in #1866, this incorrectly models invariants as monotonic. In reality, invariants both provide guarantees but also *require* guarantees. This commit takes a step in the direction of resolving #1866 by removing `AtLeast`. Uses of `AtLeast<Shared>` are replaced by a new `Reference` trait, which is implemented for `Shared` and `Exclusive`. This serves two purposes: First, it makes it explicit what this bound means. Previously, `AtLeast<Shared>` had an ambiguous meaning, while `Reference` means precisely that an invariant is either `Shared` or `Exclusive` and nothing else. Second, it paves the way for #1183, in which we may add new aliasing invariants which convey ownership. In that case, it will be important for existing methods to add `Reference` bounds when those methods would not be sound in the face of ownership semantics. We also inline the items in the `invariant` module, which were previously generated by macro. The addition of the `Reference` trait did not play nicely with that macro, and we will likely need to go further from the macro in order to fix #1839 – this fix will likely require making aliasing invariants meaningfully different than other invariants, for example by adding an associated type. Makes progress on #1866
Explain why we only support concrete types so that future authors won't spuriously add support for them.
`PtrInner` carries all invariants which are not controlled by type parameters. Since `PtrInner` does not promise to uphold aliasing, alignment, or validity, we can move some utility methods to `PtrInner` which previously were responsible for maintaining invariants orthogonal to their purpose. Makes progress on #1892 (still needs to be fixed on v0.8.x) Closes #1890
This prepares us for future changes which will significantly increase the amount of code in the `invariant` module. Also merge `aliasing_safety` into this new file.
When the aliasing mode is `Any`, `Ptr<'a, T>` is invariant in `'a` and `T`. When the aliasing mode is `Shared` or `Exclusive`, `Ptr` has the same variance as `&'a T` and `&'a mut T` respectively. Makes progress on #1839
`AliasingSafe` is really about whether a pointer permits unsynchronized reads - either because the referent contains no `UnsafeCell`s or because the aliasing mode is `Exclusive`. Previously, `AliasingSafe` was not named consistent with this meaning, and was a function of a *pair* of types rather than of a single type. This commit fixes both oversights. While we're here, we also add `Read` bounds in some places, allowing us to simplify many safety comments.
For aliasing, use `Inaccessible`. For alignment and validity, use `Unknown`.
This commit adds a framework which supports encoding in the type system any `I -> I` mapping where `I` is any `Invariant` type. This permits us to make `cast_unsized`'s return value smarter, and as a result, allows us to remove a lot of `unsafe` code. Makes progress on #1122
gherrit-pr-id: I003d5360d1b7f7882a71490813eca50b39025f14
We eventually hope to make use of `#[marker]` traits once they're stable. This permits us to test to make sure the feature is as we expect and that our intended usage works. gherrit-pr-id: I3a111bf5647fdcc9805cbadf36f729ac69b28509
And allow `non_local_definitions`.
We eventually hope to make use of `#[marker]` traits once they're stable. This permits us to test to make sure the feature is as we expect and that our intended usage works. gherrit-pr-id: I3a111bf5647fdcc9805cbadf36f729ac69b28509
Co-authored-by: Joshua Liebow-Feeser <joshlf@users.noreply.github.com>
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Previously, validity was stored as part of the `I: Invariants` type parameter on a `Ptr<T, I>`. In this commit, we migrate the validity to being stored as the `V` in `Ptr<V, I>`; `I` now only stores aliasing and alignment. Bit validity is subtle, in that the pair of referent type and validity invariant define a set of bit patterns which may appear in the `Ptr`'s referent. By encoding the validity in the referent type instead of in the `I` parameter, we ensure that the validity of the referent is captured entirely by a single type parameter rather than by a pair of two separate type parameters. This makes future changes (e.g. #1359) easier to model. This idea was originally proposed in #1866 (comment) Makes progress on #1866 gherrit-pr-id: Ia73ca4e5dfb3b20f71ed72ffda24dd7450c427ba
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Previously, `Ptr<'a, T>` and `PtrInner<'a, T>` documented themselves to be covariant in both `'a` and `T`. This was true for `PtrInner`, but not for `Ptr`, which used GATs, which are invariant. This is also not the desired variance: for `Exclusive` aliasing, the desired variance matches that of `&mut` references - namely, covariant in `'a` but invariant in `T`. This commit fixes this by making `Ptr<'a, T>` and `PtrInner<'a, T>` unconditionally covariant in `'a` and invariant in `T`. gherrit-pr-id: I29f8429d9d7b14026313f030f8dc1e895a98ad56
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See #2319. Includes a Miri test confirming the previous unsoundness. gherrit-pr-id: Iede94c196c710c74d970c93935f1539e07446e50
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Co-authored-by: Jack Wrenn <jswrenn@amazon.com> gherrit-pr-id: I8d5d162c1b6fe43e3dcb90a6dc5bf58a7a203bf8
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Co-authored-by: Jack Wrenn jswrenn@amazon.com
This PR is on branch transmute-from.