Add offset_of! macro (RFC 3308)
Implements https://github.com/rust-lang/rfcs/pull/3308 (tracking issue #106655) by adding the built in macro `core::mem::offset_of`. Two of the future possibilities are also implemented:
* Nested field accesses (without array indexing)
* DST support (for `Sized` fields)
I wrote this a few months ago, before the RFC merged. Now that it's merged, I decided to rebase and finish it.
cc `@thomcc` (RFC author)
This code was added in 9dc5dfb97504c538bc72f367a77bb9f714c30097
and 704050da2334c465784954d81c8990c4bc7a92c5 because the browser-
native checkbox was `display: none`, breaking native keyboard
accessibility.
The native checkbox is now merely `appearance: none`, which does
not turn off [behavior semantics], so JavaScript to
reimplement it isn't needed any more.
[behavior semantics]: https://w3c.github.io/csswg-drafts/css-ui/#appearance-semantics
Rollup of 5 pull requests
Successful merges:
- #110333 (rustc_metadata: Split `children` into multiple tables)
- #110501 (rustdoc: fix ICE from rustc_resolve and librustdoc parse divergence)
- #110608 (Specialize some `io::Read` and `io::Write` methods for `VecDeque<u8>` and `&[u8]`)
- #110632 (Panic instead of truncating if the incremental on-disk cache is too big)
- #110633 (More `mem::take` in `library`)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Ensure mir_drops_elaborated_and_const_checked when requiring codegen.
mir_drops_elaborated_and_const_checked may emit errors while codegen has started, and the compiler would exit leaving object code files around.
Found by `@cuviper` in https://github.com/rust-lang/rust/issues/109731
Deduplicate unreachable blocks, for real this time
In https://github.com/rust-lang/rust/pull/106428 (in particular 41eda69516) we noticed that inlining `unreachable_unchecked` can produce duplicate unreachable blocks. So we improved two MIR optimizations: `SimplifyCfg` was given a simplify to deduplicate unreachable blocks, then `InstCombine` was given a combiner to deduplicate switch targets that point at the same block. The problem is that change doesn't actually work.
Our current pass order is
```
SimplifyCfg (does nothing relevant to this situation)
Inline (produces multiple unreachable blocks)
InstCombine (doesn't do anything here, oops)
SimplifyCfg (produces the duplicate SwitchTargets that InstCombine is looking for)
```
So in here, I have factored out the specific function from `InstCombine` and placed it inside the simplify that produces the case it is looking for. This should ensure that it runs in the scenario it was designed for.
Fixes https://github.com/rust-lang/rust/issues/110551
r? `@cjgillot`
Allow to feed a value in another query's cache and remove `WithOptConstParam`
I used it to remove `WithOptConstParam` queries, as an example.
The idea is that a query (here `typeck(function)`) can write into another query's cache (here `type_of(anon const)`). The dependency node for `type_of` would depend on all the current dependencies of `typeck`.
There is still an issue with cycles: if `type_of(anon const)` is accessed before `typeck(function)`, we will still have the usual cycle. The way around this issue is to `ensure` that `typeck(function)` is called before accessing `type_of(anon const)`.
When replayed, we may the following cases:
- `typeck` is green, in that case `type_of` is green too, and all is right;
- `type_of` is green, `typeck` may still be marked as red (it depends on strictly more things than `type_of`) -> we verify that the saved value and the re-computed value of `type_of` have the same hash;
- `type_of` is red, then `typeck` is red -> it's the caller responsibility to ensure `typeck` is recomputed *before* `type_of`.
As `anon consts` have their own `DefPathData`, it's not possible to have the def-id of the anon-const point to something outside the original function, but the general case may have to be resolved before using this device more broadly.
There is an open question about loading from the on-disk cache. If `typeck` is loaded from the on-disk cache, the side-effect does not happen. The regular `type_of` implementation can go and fetch the correct value from the decoded `typeck` results, and the dep-graph will check that the hashes match, but I'm not sure we want to rely on this behaviour.
I specifically allowed to feed the value to `type_of` from inside a call to `type_of`. In that case, the dep-graph will check that the fingerprints of both values match.
This implementation is still very sensitive to cycles, and requires that we call `typeck(function)` before `typeck(anon const)`. The reason is that `typeck(anon const)` calls `type_of(anon const)`, which calls `typeck(function)`, which feeds `type_of(anon const)`, and needs to build the MIR so needs `typeck(anon const)`. The latter call would not cycle, since `type_of(anon const)` has been set, but I'd rather not remove the cycle check.
Add regression test for #46506Fixes#46506.
This issue was fixed very likely alongside the others when we cleaned up the re-exports code.
r? `@notriddle`
Substitute missing trait items suggestion correctly
Properly substitute missing item suggestions, so that when they reference generics from their parent trait they actually have the right time for the impl.
Also, some other minor tweaks like using `/* Type */` to signify a GAT's type is actually missing, and fixing generic arg suggestions for GATs in general.
fix lint regression in `non_upper_case_globals`
Fixes#110573
The issue also exists for inherent associated types (where I copied my impl from). `EarlyContext` is more involved to fix in this way, so I'll leave it be for now (note it's unstable so that's not urgent).
r? `@compiler-errors`
Implement `Neg` for signed non-zero integers.
Negating a non-zero integer currently requires unpacking to a primitive and re-wrapping. Since negation of non-zero signed integers always produces a non-zero result, it is safe to implement `Neg` for `NonZeroI{N}`.
The new `impl` is marked as stable because trait impls for two stable types can't be marked unstable.
See discussion on https://github.com/rust-lang/libs-team/issues/105 for additional context.
Negating a non-zero integer currently requires unpacking to a
primitive and re-wrapping. Since negation of non-zero signed
integers always produces a non-zero result, it is safe to
implement `Neg` for `NonZeroI{N}`.
The new `impl` is marked as stable because trait implementations
for two stable types can't be marked unstable.
