This patch enables support for references in Safe Transmute, by generating
nested obligations during trait selection. Specifically, when we call
`confirm_transmutability_candidate(...)`, we now recursively traverse the
`rustc_transmute::Answer` tree and create obligations for all the `Answer`
variants, some of which include multiple nested `Answer`s.
Also, to handle recursive types, enable support for coinduction for the Safe
Transmute trait (`BikeshedIntrinsicFrom`) by adding the `#[rustc_coinduction]`
annotation.
Also fix some small logic issues when reducing the `or` and `and` combinations
in `rustc_transmute`, so that we don't end up with additional redundant
`Answer`s in the tree.
Co-authored-by: Jack Wrenn <jack@wrenn.fyi>
Preprocess and cache dominator tree
Preprocessing dominators has a very strong effect for https://github.com/rust-lang/rust/pull/111344.
That pass checks that assignments dominate their uses repeatedly. Using the unprocessed dominator tree caused a quadratic runtime (number of bbs x depth of the dominator tree).
This PR also caches the dominator tree and the pre-processed dominators in the MIR cfg cache.
Rebase of https://github.com/rust-lang/rust/pull/107157
cc `@tmiasko`
Don't assume that `-Bdynamic` is the default linker mode
In particular this is false when passing `-static` or `-static-pie` to the linker, which changes the default to `-Bstatic`. This PR ensures we explicitly initialize the correct mode when we first need it.
Rollup of 5 pull requests
Successful merges:
- #111861 (Don't ICE on return-type notation when promoting trait preds to associated type bounds)
- #111864 (Always require closure parameters to be `Sized`)
- #111870 (Rename `traits_in_crate` query to `traits`)
- #111880 (Don't ICE when computing PointerLike trait when region vars are in param-env)
- #111887 (Add regression tests for pretty-printing inherent projections)
r? `@ghost`
`@rustbot` modify labels: rollup
Always require closure parameters to be `Sized`
The `rust-call` ABI isn't compatible with `#![feature(unsized_fn_params)]`, so trying to use that feature with closures leads to an ICE (#67981). This turns that ICE into a type-check error.
`@rustbot` label A-closures F-unsized_fn_params
Update cargo
10 commits in 09276c703a473ab33daaeb94917232e80eefd628..64fb38c97ac4d3a327fc9032c862dd28c8833b17
2023-05-16 21:43:35 +0000 to 2023-05-23 18:53:23 +0000
- Consider rust-version when selecting packages for cargo add (rust-lang/cargo#12078)
- fix(lints): Switch to -Zlints so stable projects can experiment (rust-lang/cargo#12168)
- Automatically inherit workspace fields when running cargo new/init (rust-lang/cargo#12069)
- ci: check if any version bump needed for member crates (rust-lang/cargo#12126)
- feat: `lints` feature (rust-lang/cargo#12148)
- fix: pass `-C debuginfo` after weakening if explicitly set (rust-lang/cargo#12165)
- Tweak build help to clarify role of --bin (rust-lang/cargo#12157)
- fix: Pass CI on nightly (rust-lang/cargo#12160)
- docs(source): doc comments for Source and its impls (rust-lang/cargo#12159)
- docs(source): doc comments for `Source` and friends (rust-lang/cargo#12153)
r? `@ghost`
CFI: Fix encode_region: unexpected ReEarlyBound(0, 'a)
Fixes#111515 and complements #106547 by adding support for encoding early bound regions and also excluding projections when transforming trait objects' traits into their identities before emitting type checks.
Update books
## rust-embedded/book
1 commits in d9eb4c3f75435b008881062ffa77bf0d1527b37d..f2aed2fe8e9f55508c86ba3aa4b6789b18a08a22
2023-05-12 12:26:37 UTC to 2023-05-12 12:26:37 UTC
- Add link to Comprehensive Rust 🦀 (rust-embedded/book#354)
## rust-lang/nomicon
2 commits in b5f7500fc40775096c2bbd204eae096612cf9047..b5f018fb5930cb733b0a8aaf2eed975d4771e74d
2023-05-19 18:10:25 UTC to 2023-05-14 20:22:16 UTC
- Expand unbounded lifetime example code and improve wording (rust-lang/nomicon#408)
- Update to 2021 edition (rust-lang/nomicon#410)
## rust-lang/reference
5 commits in 28dc0f3576b55f5e57c5d6e65cd68ba3161e9fd5..553d99b02a53b4133a40d5bd2e19958c67487c00
2023-05-22 10:50:07 UTC to 2023-05-10 01:54:07 UTC
- Update raw-dylib documentation for stabilization (rust-lang/reference#1345)
- fix a typo (rust-lang/reference#1359)
- fixed minor error in a comment that annotated output of a proc macro (rust-lang/reference#1358)
- Fix example code in `impl` docs (rust-lang/reference#1360)
- Add documentation for debugger_visualizer attribute (rust-lang/reference#1335)
## rust-lang/rustc-dev-guide
4 commits in 28dbeaf5c44bc7f5111ad412e99f2d7c5cec6c90..f1e637883fafeb83bdd5906ee7f467e4d35b7337
2023-05-18 02:44:05 UTC to 2023-05-11 09:59:23 UTC
- Add note about shell completion scripts (rust-lang/rustc-dev-guide#1686)
- filter out S-blocked issues in the "Getting Started" search (rust-lang/rustc-dev-guide#1687)
- Rename InstCombine to InstSimplify (rust-lang/rustc-dev-guide#1684)
- Use unpretty for debugging Hir (rust-lang/rustc-dev-guide#1685)
fix(resolve): not defined `extern crate shadow_name`
Fixes https://github.com/rust-lang/rust/issues/109148
## Why does #109148 panic?
When resolving `use std::xx` it enters `visit_scopes` from `early_resolve_ident_in_lexical_scope`, and iters twice during the loop:
|iter| `scope` | `break_result` | result |
|-|-|-|-|
| 0 | `Module` pointed to root | binding pointed to `Undetermined`, so result is `None` | scope changed to `ExternPrelude` |
| 1 | `ExternPrelude` | binding pointed to `std` | - |
Then, the result of `maybe_resolve_path` is `Module(std)`, so `import.imported_module.set` is executed.
Finally, during the `finalize_import` of `use std::xx`, `resolve_path` returns `NonModule` because `Binding(Ident(std), Module(root)`'s binding points to `extern crate blah as std`, which causes the assertion to fail at `assert!(import.imported_module.get().is_none());`.
## Investigation
The question is why `#[a] extern crate blah as std` is not defined as a binding of `std::xxx`, which causes the iteration twice during `visit_scopes` when resolving `std::xxx`. Ideally, the value of `break_result.is_some()` should have been valid in the first iteration.
After debugging, I found that because `#[a] extern crate blah as std` had been dummied by `placeholder` during `collect_invocations`, so it had lost its attrs, span, etc..., so it will not be defined. However, `expand_invoc` added them back, then the next `build_reduced_graph`, `#[a] extern crate blah as std` would have been defined, so it makes the result of `resolved_path` unexpected, and the program panics.
## Try to solve
I think there has two-way to solve this issue:
- Expand invocations before the first `resolve_imports` during `fully_expand_fragment`. However, I do not think this is a good idea because it would mess up the current design.
- As my PR described: do not define to `extern crate blah as std` during the second `build_reduced_graph`, which is very easy and more reasonable.
r? `@petrochenkov`
Document stack-protector option
Only updated `exploit-mitigations.md` to reflect that the option exists. Removed the alternatives mentioned as they are not actually implemented yet.
As this is an unstable feature, should it be added to `unstable-book` also? [Example](https://doc.rust-lang.org/beta/unstable-book/compiler-flags/sanitizer.html). I didn't do that because I couldn't find the tracking issue for stack-protector. (There should be one to track stabilization of the feature, I think?)
cc `@rcvalle`
Pretty-print inherent projections correctly
Previously, we were trying to pretty-print inherent projections with `Printer::print_def_path` which is incorrect since
it expects the substitutions to be of a certain format (parents substs followed by own substs) which doesn't hold for
inherent projections (self type subst followed by own substs).
Now we print inherent projections manually.
Fixes#111390.
Fixes#111397.
Lacking tests! Is there a test suite / compiletest flags for the pretty-printer? In most if not all cases,
inherent projections are normalized away before they get the chance to appear in diagnostics.
If I were to create regression tests for linked issues, they would need to be `mir-opt` tests to exercise
`-Zdump-mir=all` (right?) which doesn't feel quite adequate to me.
`@rustbot` label F-inherent_associated_types
The `rust-call` ABI isn't compatible with
`#![feature(unsized_fn_params)]`, so trying to use that feature with
closures leads to an ICE (#67981). This turns that ICE into a
type-check error.
Fixes#111515 and complements #106547 by adding support for encoding
early bound regions and also excluding projections when transforming
trait objects' traits into their identities before emitting type checks.
Fix some issues with folded AArch64 features
In #91608 the `fp` feature was removed for AArch64 and folded into the `neon` feature, however disabling the `neon` feature doesn't actually disable the `fp` feature. If my understanding on that thread is correct it should do.
While doing this, I also noticed that disabling some features would disable features that it shouldn't. For instance enabling `sve` will enable `neon`, however, when disabling `sve` it would then also disable `neon`, I wouldn't expect disabling `sve` to also disable `neon`.
cc `@workingjubilee`
Rollup of 6 pull requests
Successful merges:
- #111461 (Fix symbol conflict diagnostic mistakenly being shown instead of missing crate diagnostic)
- #111579 (Also assume wrap-around discriminants in `as` MIR building)
- #111704 (Remove return type sized check hack from hir typeck)
- #111853 (Check opaques for mismatch during writeback)
- #111854 (rustdoc: clean up `settings.css`)
- #111860 (Don't ICE if method receiver fails to unify with `arbitrary_self_types`)
r? `@ghost`
`@rustbot` modify labels: rollup
Don't ICE if method receiver fails to unify with `arbitrary_self_types`
Consider:
```rust
struct Foo(u32);
impl Foo {
fn get<R: Deref<Target=Self>>(self: R) -> u32 {
self.0
}
}
fn main() {
let mut foo = Foo(1);
foo.get::<&Foo>();
}
```
The problem here is that with `arbitrary_self_types`, we're allowed to have a method receiver that mentions generics from the method itself (`fn get<R: Deref<Target=Self>>(self: R)`). Since we don't actually take into account the user-written turbofish generics when doing method lookup (nor do we check that method predicates hold), method probing will happily infer `R = Foo` during the probe. When we later confirm the method, we do use the turbofish'd subst and instead now have that `R = &Foo`. This doesn't unify with the self type we chose during the probe, causing an ICE.
Getting this to work correctly will be difficult. Specifically, we'll need to actually pass in the turbofish generics for the method being probed for and check that the self type unifies considering those generics. This seems like a lot of work, and I'm not actually familiar with the restrictions originally called out for `#![feature(arbitrary_self_types)]`, but I think we should probably instead just deny having receivers that mention (type/const) generics that come from the method itself.
But I mostly just want to turn this ICE into an error, so I'll leave that up for later PRs.
Fixes#111838
Check opaques for mismatch during writeback
Revive #111705.
I realized that we don't need to put any substs in the writeback results since all of the hidden types have already been remapped. See the comment in `compiler/rustc_middle/src/ty/typeck_results.rs`, which should make that clear for other explorers of the codebase.
Additionally, we need to do some diagnostic stashing because the diagnostics we produce during HIR typeck is very poor and we should prefer the diagnostic that comes from MIR, if we have one.
r? `@oli-obk`
Remove return type sized check hack from hir typeck
Remove a bunch of special-cased suggestions when someone returns `-> dyn Trait` that checks for type equality, etc.
This was a pretty complex piece of code that also relied on a hack in hir typeck (see changes to `compiler/rustc_hir_typeck/src/check.rs`), and I'm not convinced that it's necessary to maintain, when all we really need to tell the user is that they should return `-> impl Trait` or `-> Box<dyn Trait>`, depending on their specific use-case.
This is necessary because we may need to move the "return type is sized" check from hir typeck to wfcheck, which does not have access to typeck results. This is a prerequisite for that, and I'm fairly confident that the diagnostics "regressions" here are not a big deal.
[rustc_ty_utils] Treat `drop_in_place`'s *mut argument like &mut when adding LLVM attributes
This resurrects PR #103614, which has sat idle for a while.
This could probably use a new perf run, since we're on a new LLVM version now.
r? `@oli-obk`
cc `@RalfJung`
---
LLVM can make use of the `noalias` parameter attribute on the parameter to `drop_in_place` in areas like argument promotion. Because the Rust compiler fully controls the code for `drop_in_place`, it can soundly deduce parameter attributes on it.
In #103957, Miri was changed to retag `drop_in_place`'s argument as if it was `&mut`, matching this change.
Deal with unnormalized projections when structurally resolving types with new solver
1. Normalize types in `structurally_resolved_type` when the new solver is enabled
2. Normalize built-in autoderef targets in `Autoderef` when the new solver is enabled
3. Normalize-erasing-regions in `resolve_type` in writeback
This is motivated by the UI test provided, which currently fails with:
```
error[E0609]: no field `x` on type `<usize as SliceIndex<[Foo]>>::Output`
--> <source>:9:11
|
9 | xs[0].x = 1;
| ^
```
I'm pretty happy with the approach in (1.) and (2.) and think we'll inevitably need something like this in the long-term, but (3.) seems like a hack to me. It's a *lot* of work to add tons of new calls to every user of these typeck results though (mir build, late lints, etc). Happy to discuss further.
r? `@lcnr`
