Update the minimum external LLVM to 12
With this change, we'll have stable support for LLVM 12 and 13.
For reference, the previous increase to LLVM 10 was #83387,
and this replaces the pending increase to LLVM 11 in #90062.
r? `@nagisa` `@nikic`
Particularly for ctfe-stress-4, the hashing of byte slices as part of the
MIR Allocation is quite hot. Previously, we were falling back on byte-by-byte
copying of the slice into the SipHash buffer (64 bytes long) before hashing a 64
byte chunk, and then doing that again and again.
This should hopefully be an improvement for that code.
Rollup of 5 pull requests
Successful merges:
- #85833 (Scrape code examples from examples/ directory for Rustdoc)
- #88041 (Make all proc-macro back-compat lints deny-by-default)
- #89829 (Consider types appearing in const expressions to be invariant)
- #90168 (Reset qualifs when a storage of a local ends)
- #90198 (Add caveat about changing parallelism and function call overhead)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Reset qualifs when a storage of a local ends
Reset qualifs when a storage of a local ends to ensure that the local qualifs
are affected by the state from previous loop iterations only if the local is
kept alive.
The change should be forward compatible with a stricter handling of indirect
assignments, since storage dead invalidates all existing pointers to the local.
Consider types appearing in const expressions to be invariant
This is an approach to fix#80977.
Currently, a type parameter which is only used in a constant expression is considered bivariant and will trigger error E0392 *"parameter T is never used"*.
Here is a short example:
```rust
pub trait Foo {
const N: usize;
}
struct Bar<T: Foo>([u8; T::N])
where [(); T::N]:;
```
([playgound](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2015&gist=b51a272853f75925e72efc1597478aa5))
While it is possible to silence this error by adding a `PhantomData<T>` field, I think the better solution would be to make `T` invariant.
This would be analogous to the invariance constraints added for associated types.
However, I'm quite new to the compiler and unsure whether this is the right approach.
r? ``@varkor`` (since you authored #60058)
Make all proc-macro back-compat lints deny-by-default
The affected crates have had plenty of time to update.
By keeping these as lints rather than making them hard errors,
we ensure that downstream crates will still be able to compile,
even if they transitive depend on broken versions of the affected
crates.
This should hopefully discourage anyone from writing any
new code which relies on the backwards-compatibility behavior.
Implement coherence checks for negative trait impls
The main purpose of this PR is to be able to [move Error trait to core](https://github.com/rust-lang/project-error-handling/issues/3).
This feature is necessary to handle the following from impl on box.
```rust
impl From<&str> for Box<dyn Error> { ... }
```
Without having negative traits affect coherence moving the error trait into `core` and moving that `From` impl to `alloc` will cause the from impl to no longer compiler because of a potential future incompatibility. The compiler indicates that `&str` _could_ introduce an `Error` impl in the future, and thus prevents the `From` impl in `alloc` that would cause overlap with `From<E: Error> for Box<dyn Error>`. Adding `impl !Error for &str {}` with the negative trait coherence feature will disable this error by encoding a stability guarantee that `&str` will never implement `Error`, making the `From` impl compile.
We would have this in `alloc`:
```rust
impl From<&str> for Box<dyn Error> {} // A
impl<E> From<E> for Box<dyn Error> where E: Error {} // B
```
and this in `core`:
```rust
trait Error {}
impl !Error for &str {}
```
r? `@nikomatsakis`
This PR was built on top of `@yaahc` PR #85764.
Language team proposal: to https://github.com/rust-lang/lang-team/issues/96
Do not depend on the stored value when trying to cache on disk.
Having different criteria for loading and saving of query results can lead to saved results that may never be loaded.
Since the on-disk cache is discarded as soon as a compilation error is issued, there should not be any need for an exclusion mecanism based on errors.
As a result, the possibility to condition the storage on the value itself does not appear useful.
to ensure that the local qualifs are affected by the state from previous
loop iterations only if the local is kept alive.
The change should be forward compatible with a stricter handling of
indirect assignments, since storage dead invalidates all existing
pointers to the local.
Implement -Z location-detail flag
This PR implements the `-Z location-detail` flag as described in https://github.com/rust-lang/rfcs/pull/2091 .
`-Z location-detail=val` controls what location details are tracked when using `caller_location`. This allows users to control what location details are printed as part of panic messages, by allowing them to exclude any combination of filenames, line numbers, and column numbers. This option is intended to provide users with a way to mitigate the size impact of `#[track_caller]`.
Some measurements of the savings of this approach on an embedded binary can be found here: https://github.com/rust-lang/rust/issues/70579#issuecomment-942556822 .
Closes#70580 (unless people want to leave that open as a place for discussion of further improvements).
This is my first real PR to rust, so any help correcting mistakes / understanding side effects / improving my tests is appreciated :)
I have one question: RFC 2091 specified this as a debugging option (I think that is what -Z implies?). Does that mean this can never be stabilized without a separate MCP? If so, do I need to submit an MCP now, or is the initial RFC specifying this option sufficient for this to be merged as is, and then an MCP would be needed for eventual stabilization?
add feature flag for `type_changing_struct_update`
This implements the PR0 part of the mentoring notes within #86618.
overrides the previous inactive #86646 pr.
r? ```@nikomatsakis```
Report fatal lexer errors in `--cfg` command line arguments
Fixes#89358. The erroneous behavior was apparently introduced by `@Mark-Simulacrum` in a678e31911; the idea is to silence individual parser errors and instead emit one catch-all error message after parsing. However, for the example in #89358, a fatal lexer error is created here:
edebf77e00/compiler/rustc_parse/src/lexer/mod.rs (L340-L349)
This fatal error aborts the compilation, and so the call to `new_parser_from_source_str()` never returns and the catch-all error message is never emitted. I have therefore changed the `SilentEmitter` to silence only non-fatal errors; with my changes, for the rustc invocation described in #89358:
```sh
rustc --cfg "abc\""
```
I get the following output:
```
error[E0765]: unterminated double quote string
|
= note: this error occurred on the command line: `--cfg=abc"`
```
This doesn't work properly yet, we would probably need to implement an
`assembly_neg_candidates` and consider things like `T: !AB` as `T: !A`
|| `T: !B`
Fix const qualification when executed after promotion
The const qualification was so far performed before the promotion and
the implementation assumed that it will never encounter a promoted.
With `const_precise_live_drops` feature, checking for live drops is
delayed until after drop elaboration, which in turn runs after
promotion. so the assumption is no longer true. When evaluating
`NeedsNonConstDrop` it is now possible to encounter promoteds.
Use type base qualification for the promoted. It is a sound
approximation in general, and in the specific case of promoteds and
`NeedsNonConstDrop` it is precise.
Fixes#89938.
rustc_ast: Turn `MutVisitor::token_visiting_enabled` into a constant
It's a visitor property rather than something that needs to be determined at runtime
Update E0637 description to mention `&` w/o an explicit lifetime name
Deal with https://github.com/rust-lang/rust/issues/89824#issuecomment-941598647. Another solution would be splitting the error code into two as (I think) it's a bit unclear to users why they have the same error code.
Don't mark for loop iter expression as desugared
We typically don't mark spans of lowered things as desugared. This helps Clippy rightly discern when code is (not) from expansion. This was discovered by ``@flip1995`` at https://github.com/rust-lang/rust-clippy/pull/7789#issuecomment-939289501.
Rollup of 14 pull requests
Successful merges:
- #86984 (Reject octal zeros in IPv4 addresses)
- #87440 (Remove unnecessary condition in Barrier::wait())
- #88644 (`AbstractConst` private fields)
- #89292 (Stabilize CString::from_vec_with_nul[_unchecked])
- #90010 (Avoid overflow in `VecDeque::with_capacity_in()`.)
- #90029 (Add test for debug logging during incremental compilation)
- #90031 (config: add the option to enable LLVM tests)
- #90048 (Add test for line-number setting)
- #90071 (Remove hir::map::blocks and use FnKind instead)
- #90074 (2229 migrations small cleanup)
- #90077 (Make `From` impls of NonZero integer const.)
- #90097 (Add test for duplicated sidebar entries for reexported macro)
- #90098 (Add test to ensure that the missing_doc_code_examples is not triggered on foreign trait implementations)
- #90099 (Fix MIRI UB in `Vec::swap_remove`)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Remove hir::map::blocks and use FnKind instead
The principal tool is `FnLikeNode`, which is not often used and can be easily implemented using `rustc_hir::intravisit::FnKind`.
Don't emit a warning for empty rmeta files.
This avoids displaying a warning when attempting to load an empty rmeta file. Warnings were enabled via #89634 which can cause a lot of noise (for example, running `./x.py check`). rustc generates empty rmeta files for things like binaries, which can happen when checking libraries as unittests.
Closes#89795
Merge the two depkind vtables
Knowledge of `DepKind`s is managed using two arrays containing flags (is_anon, eval_always, fingerprint_style), and function pointers (forcing and loading code).
This PR aims at merging the two arrays so as to reduce unneeded indirect calls and (hopefully) increase code locality.
r? `@ghost`
Erase late-bound regions before computing vtable debuginfo name.
Fixes#90019.
The `msvc_enum_fallback()` for computing enum type names needs to access the memory layout of niche enums in order to determine the type name. `compute_debuginfo_vtable_name()` did not properly erase regions before computing type names which made memory layout computation ICE when encountering un-erased regions.
r? `@wesleywiser`
resolve: Use `NameBinding` for local variables and generic parameters
`NameBinding` is a structure used for representing any name introduction (an item, or import, or even a built-in).
Except that local variables and generic parameters weren't represented as `NameBinding`s, for this reason they requires separate paths in name resolution code in several places.
This PR introduces `NameBinding`s for local variables as well and simplifies all the code working with them leaving only the `NameBinding` paths.
Add support for artifact size profiling
This adds support for profiling artifact file sizes (incremental compilation artifacts and query cache to begin with).
Eventually we want to track this in perf.rlo so we can ensure that file sizes do not change dramatically on each pull request.
This relies on support in measureme: https://github.com/rust-lang/measureme/pull/169. Once that lands we can update this PR to not point to a git dependency.
This was worked on together with `@michaelwoerister.`
r? `@wesleywiser`
Adopt let_else across the compiler
This performs a substitution of code following the pattern:
```
let <id> = if let <pat> = ... { identity } else { ... : ! };
```
To simplify it to:
```
let <pat> = ... { identity } else { ... : ! };
```
By adopting the `let_else` feature (cc #87335).
The PR also updates the syn crate because the currently used version of the crate doesn't support `let_else` syntax yet.
Note: Generally I'm the person who *removes* usages of unstable features from the compiler, not adds more usages of them, but in this instance I think it hopefully helps the feature get stabilized sooner and in a better state. I have written a [comment](https://github.com/rust-lang/rust/issues/87335#issuecomment-944846205) on the tracking issue about my experience and what I feel could be improved before stabilization of `let_else`.
Fix wrong niche calculation when 2+ niches are placed at the start
When the niche is at the start, existing code incorrectly uses 1 instead of count for subtraction.
Fix#90038
`@rustbot` label: T-compiler
Rollup of 8 pull requests
Successful merges:
- #89766 (RustWrapper: adapt for an LLVM API change)
- #89867 (Fix macro_rules! duplication when reexported in the same module)
- #89941 (removing TLS support in x86_64-unknown-none-hermitkernel)
- #89956 (Suggest a case insensitive match name regardless of levenshtein distance)
- #89988 (Do not promote values with const drop that need to be dropped)
- #89997 (Add test for issue #84957 - `str.as_bytes()` in a `const` expression)
- #90002 (⬆️ rust-analyzer)
- #90034 (Tiny tweak to Iterator::unzip() doc comment example.)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Do not promote values with const drop that need to be dropped
Changes from #88558 allowed using `~const Drop` in constants by
introducing a new `NeedsNonConstDrop` qualif.
The new qualif was also used for promotion purposes, and allowed
promotion to happen for values that needs to be dropped but which
do have a const drop impl.
Since for promoted the drop implementation is never executed,
this lead to observable change in behaviour. For example:
```rust
struct Panic();
impl const Drop for Panic {
fn drop(&mut self) {
panic!();
}
}
fn main() {
let _ = &Panic();
}
```
Restore the use of `NeedsDrop` qualif during promotion to avoid the issue.
Suggest a case insensitive match name regardless of levenshtein distance
Fixes#86170
Currently, `find_best_match_for_name` only returns a case insensitive match name depending on a Levenshtein distance. It's a bit unfortunate that that hides some suggestions for typos like `Bar` -> `BAR`. That idea is from https://github.com/rust-lang/rust/pull/46347#discussion_r153701834, but I think it still makes some sense to show a candidate when we find a case insensitive match name as it's more like a typo.
Skipped the `candidate != lookup` check because the current (i.e, `levenshtein_match`) returns the exact same `Symbol` anyway but it doesn't seem to confuse anything on UI tests.
r? ``@estebank``
removing TLS support in x86_64-unknown-none-hermitkernel
HermitCore's kernel itself doesn't support TLS. Consequently, the entries in x86_64-unknown-none-hermitkernel should be removed. This commit should help to finalize #89062.
RustWrapper: adapt for an LLVM API change
No functional changes intended.
The LLVM commit
89b57061f7
moved TargetRegistry.(h|cpp) from Support to MC.
This adapts RustWrapper accordingly.
Revert "Auto merge of #89709 - clemenswasser:apply_clippy_suggestions…
…_2, r=petrochenkov"
The PR had some unforseen perf regressions that are not as easy to find.
Revert the PR for now.
This reverts commit 6ae8912a3e, reversing
changes made to 86d6d2b738.
The const qualification was so far performed before the promotion and
the implementation assumed that it will never encounter a promoted.
With `const_precise_live_drops` feature, checking for live drops is
delayed until after drop elaboration, which in turn runs after
promotion. so the assumption is no longer true. When evaluating
`NeedsNonConstDrop` it is now possible to encounter promoteds.
Use type base qualification for the promoted. It is a sound
approximation in general, and in the specific case of promoteds and
`NeedsNonConstDrop` it is precise.
Remove redundant member-constraint check
impl trait will, for each lifetime in the hidden type, register a "member constraint" that says the lifetime must be equal or outlive one of the lifetimes of the impl trait. These member constraints will be solved by borrowck
But, as you can see in the big red block of removed code, there was an ad-hoc check for member constraints happening at the site where they get registered. This check had some minor effects on diagnostics, but will fall down on its feet with my big type alias impl trait refactor. So we removed it and I pulled the removal out into a (hopefully) reviewable PR that works on master directly.
