Rollup of 6 pull requests
Successful merges:
- #129838 (uefi: process: Add args support)
- #130800 (Mark `get_mut` and `set_position` in `std::io::Cursor` as const.)
- #132708 (Point at `const` definition when used instead of a binding in a `let` statement)
- #133226 (Make `PointerLike` opt-in instead of built-in)
- #133244 (Account for `wasm32v1-none` when exporting TLS symbols)
- #133257 (Add `UnordMap::clear` method)
r? `@ghost`
`@rustbot` modify labels: rollup
Make `PointerLike` opt-in instead of built-in
The `PointerLike` trait currently is a built-in trait that computes the layout of the type. This is a bit problematic, because types implement this trait automatically. Since this can be broken due to semver-compatible changes to a type's layout, this is undesirable. Also, calling `layout_of` in the trait system also causes cycles.
This PR makes the trait implemented via regular impls, and adds additional validation on top to make sure that those impls are valid. This could eventually be `derive()`d for custom smart pointers, and we can trust *that* as a semver promise rather than risking library authors accidentally breaking it.
On the other hand, we may never expose `PointerLike`, but at least now the implementation doesn't invoke `layout_of` which could cause ICEs or cause cycles.
Right now for a `PointerLike` impl to be valid, it must be an ADT that is `repr(transparent)` and the non-1zst field needs to implement `PointerLike`. There are also some primitive impls for `&T`/ `&mut T`/`*const T`/`*mut T`/`Box<T>`.
Point at `const` definition when used instead of a binding in a `let` statement
Modify `PatKind::InlineConstant` to be `ExpandedConstant` standing in not only for inline `const` blocks but also for `const` items. This allows us to track named `const`s used in patterns when the pattern is a single binding. When we detect that there is a refutable pattern involving a `const` that could have been a binding instead, we point at the `const` item, and suggest renaming. We do this for both `let` bindings and `match` expressions missing a catch-all arm if there's at least one single binding pattern referenced.
After:
```
error[E0005]: refutable pattern in local binding
--> $DIR/bad-pattern.rs:19:13
|
LL | const PAT: u32 = 0;
| -------------- missing patterns are not covered because `PAT` is interpreted as a constant pattern, not a new variable
...
LL | let PAT = v1;
| ^^^ pattern `1_u32..=u32::MAX` not covered
|
= note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
= note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
= note: the matched value is of type `u32`
help: introduce a variable instead
|
LL | let PAT_var = v1;
| ~~~~~~~
```
Before:
```
error[E0005]: refutable pattern in local binding
--> $DIR/bad-pattern.rs:19:13
|
LL | let PAT = v1;
| ^^^
| |
| pattern `1_u32..=u32::MAX` not covered
| missing patterns are not covered because `PAT` is interpreted as a constant pattern, not a new variable
| help: introduce a variable instead: `PAT_var`
|
= note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
= note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
= note: the matched value is of type `u32`
```
CC #132582.
Reduce false positives of tail-expr-drop-order from consumed values (attempt #2)
r? `@nikomatsakis`
Tracked by #123739.
Related to #129864 but not replacing, yet.
Related to #130836.
This is an implementation of the approach suggested in the [Zulip stream](https://rust-lang.zulipchat.com/#narrow/stream/213817-t-lang/topic/temporary.20drop.20order.20changes). A new MIR statement `BackwardsIncompatibleDrop` is added to the MIR syntax. The lint now works by inspecting possibly live move paths before at the `BackwardsIncompatibleDrop` location and the actual drop under the current edition, which should be one before Edition 2024 in practice.
take 2
open up coroutines
tweak the wordings
the lint works up until 2021
We were missing one case, for ADTs, which was
causing `Result` to yield incorrect results.
only include field spans with significant types
deduplicate and eliminate field spans
switch to emit spans to impl Drops
Co-authored-by: Niko Matsakis <nikomat@amazon.com>
collect drops instead of taking liveness diff
apply some suggestions and add explantory notes
small fix on the cache
let the query recurse through coroutine
new suggestion format with extracted variable name
fine-tune the drop span and messages
bugfix on runtime borrows
tweak message wording
filter out ecosystem types earlier
apply suggestions
clippy
check lint level at session level
further restrict applicability of the lint
translate bid into nop for stable mir
detect cycle in type structure
lints_that_dont_need_to_run: never skip future-compat-reported lints
Follow-up to https://github.com/rust-lang/rust/pull/125116: future-compat lints show up with `--json=future-incompat` even if they are otherwise allowed in the crate. So let's ensure we do not skip those as part of the `lints_that_dont_need_to_run` logic.
I could not find a current future compat lint that is emitted by a lint pass, so there's no clear way to add a test for this.
Cc `@blyxyas` `@cjgillot`
Rollup of 4 pull requests
Successful merges:
- #131081 (Use `ConstArgKind::Path` for all single-segment paths, not just params under `min_generic_const_args`)
- #132577 (Report the `unexpected_cfgs` lint in external macros)
- #133023 (Merge `-Zhir-stats` into `-Zinput-stats`)
- #133200 (ignore an occasionally-failing test in Miri)
r? `@ghost`
`@rustbot` modify labels: rollup
Use `ConstArgKind::Path` for all single-segment paths, not just params under `min_generic_const_args`
r? `@BoxyUwU`
edit by `@BoxyUwU:`
This PR introduces a `min_generic_const_args` feature gate and implements some preliminary work for it, representing all const arguments that are single segment paths as `ConstArg::Path` instead of only those that resolve to a const generic parameter. There are a few bits of follow up work after this lands:
- Figure out how to represent `Foo<{ STATIC }>`
- Figure out how to evaluate `Foo<{ EnumVariantConstructor }>`
- Make param env normalization handle non-anon-consts
- Move `try_from_lit` and `from_anon_const` to hir ty lowering too
Improve VecCache under parallel frontend
This replaces the single Vec allocation with a series of progressively larger buckets. With the cfg for parallel enabled but with -Zthreads=1, this looks like a slight regression in i-count and cycle counts (~1%).
With the parallel frontend at -Zthreads=4, this is an improvement (-5% wall-time from 5.788 to 5.4688 on libcore) than our current Lock-based approach, likely due to reducing the bouncing of the cache line holding the lock. At -Zthreads=32 it's a huge improvement (-46%: 8.829 -> 4.7319 seconds).
try-job: i686-gnu-nopt
try-job: dist-x86_64-linux
Use `TypingMode` throughout the compiler instead of `ParamEnv`
Hopefully the biggest single PR as part of https://github.com/rust-lang/types-team/issues/128.
## `infcx.typing_env` while defining opaque types
I don't know how'll be able to correctly handle opaque types when using something taking a `TypingEnv` while defining opaque types. To correctly handle the opaques we need to be able to pass in the current `opaque_type_storage` and return constraints, i.e. we need to use a proper canonical query. We should migrate all the queries used during HIR typeck and borrowck where this matters to proper canonical queries. This is
## `layout_of` and `Reveal::All`
We convert the `ParamEnv` to `Reveal::All` right at the start of the `layout_of` query, so I've changed callers of `layout_of` to already use a post analysis `TypingEnv` when encountering it.
ca87b535a0/compiler/rustc_ty_utils/src/layout.rs (L51)
## `Ty::is_[unpin|sized|whatever]`
I haven't migrated `fn is_item_raw` to use `TypingEnv`, will do so in a followup PR, this should significantly reduce the amount of `typing_env.param_env`. At some point there will probably be zero such uses as using the type system while ignoring the `typing_mode` is incorrect.
## `MirPhase` and phase-transitions
When inside of a MIR-body, we can mostly use its `MirPhase` to figure out the right `typing_mode`. This does not work during phase transitions, most notably when transitioning from `Analysis` to `Runtime`:
dae7ac133b/compiler/rustc_mir_transform/src/lib.rs (L606-L625)
All these passes still run with `MirPhase::Analysis`, but we should only use `Reveal::All` once we're run the `RevealAll` pass. This required me to manually construct the right `TypingEnv` in all these passes. Given that it feels somewhat easy to accidentally miss this going forward, I would maybe like to change `Body::phase` to an `Option` and replace it at the start of phase transitions. This then makes it clear that the MIR is currently in a weird state.
r? `@ghost`
stability: remove skip_stability_check_due_to_privacy
This was added in https://github.com/rust-lang/rust/pull/38689 to deal with https://github.com/rust-lang/rust/issues/38412. However, even after removing the check, the relevant tests still pass. Let's see if CI finds any other tests that rely on this. If not, it seems like logic elsewhere in the compiler changed so this is not required any more.
the behavior of the type system not only depends on the current
assumptions, but also the currentnphase of the compiler. This is
mostly necessary as we need to decide whether and how to reveal
opaque types. We track this via the `TypingMode`.
After:
```
error[E0005]: refutable pattern in local binding
--> $DIR/bad-pattern.rs:19:13
|
LL | const PAT: u32 = 0;
| -------------- missing patterns are not covered because `PAT` is interpreted as a constant pattern, not a new variable
...
LL | let PAT = v1;
| ^^^
| |
| pattern `1_u32..=u32::MAX` not covered
| help: introduce a variable instead: `PAT_var`
|
= note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
= note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
= note: the matched value is of type `u32`
```
Before:
```
error[E0005]: refutable pattern in local binding
--> $DIR/bad-pattern.rs:19:13
|
LL | let PAT = v1;
| ^^^
| |
| pattern `1_u32..=u32::MAX` not covered
| missing patterns are not covered because `PAT` is interpreted as a constant pattern, not a new variable
| help: introduce a variable instead: `PAT_var`
|
= note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
= note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
= note: the matched value is of type `u32`
```
Querify MonoItem collection
Factored out of https://github.com/rust-lang/rust/pull/131650. These changes are required for post-mono MIR opts, because the previous implementation would load the MIR for every Instance that we traverse (as well as invoke queries on it). The cost of that would grow massively with post-mono MIR opts because we'll need to load new MIR for every Instance, instead of re-using the `optimized_mir` for every Instance with the same DefId.
So the approach here is to add two new queries, `items_of_instance` and `size_estimate`, which contain the specific information about an Instance's MIR that MirUsedCollector and CGU partitioning need, respectively. Caching these significantly increases the size of the query cache, but that's justified by our improved incrementality (I'm sure walking all the MIR for a huge crate scales quite poorly).
This also changes `MonoItems` into a type that will retain the traversal order (otherwise we perturb a bunch of diagnostics), and will also eliminate duplicate findings. Eliminating duplicates removes about a quarter of the query cache size growth.
The perf improvements in this PR are inflated because rustc-perf uses `-Zincremental-verify-ich`, which makes loading MIR a lot slower because MIR contains a lot of Spans and computing the stable hash of a Span is slow. And the primary goal of this PR is to load less MIR. Some squinting at `collector profile_local perf-record +stage1` runs suggests the magnitude of the improvements in this PR would be decreased by between a third and a half if that flag weren't being used. Though this effect may apply to the regressions too since most are incr-full and this change also causes such builds to encode more Spans.
This replaces the single Vec allocation with a series of progressively
larger buckets. With the cfg for parallel enabled but with -Zthreads=1,
this looks like a slight regression in i-count and cycle counts (<0.1%).
With the parallel frontend at -Zthreads=4, this is an improvement (-5%
wall-time from 5.788 to 5.4688 on libcore) than our current Lock-based
approach, likely due to reducing the bouncing of the cache line holding
the lock. At -Zthreads=32 it's a huge improvement (-46%: 8.829 -> 4.7319
seconds).
Mention both release *and* edition breakage for never type lints
This PR makes ~~two changes~~ a change to the never type lints (`dependency_on_unit_never_type_fallback` and `never_type_fallback_flowing_into_unsafe`):
1. Change the wording of the note to mention that the breaking change will be made in an edition _and_ in a future release
2. ~~Make these warnings be reported in deps (hopefully the lints are matured enough)~~
r? ``@compiler-errors``
cc ``@ehuss``
closes#132930
Delete the `cfg(not(parallel))` serial compiler
Since it's inception a long time ago, the parallel compiler and its cfgs have been a maintenance burden. This was a necessary evil the allow iteration while not degrading performance because of synchronization overhead.
But this time is over. Thanks to the amazing work by the parallel working group (and the dyn sync crimes), the parallel compiler has now been fast enough to be shipped by default in nightly for quite a while now.
Stable and beta have still been on the serial compiler, because they can't use `-Zthreads` anyways.
But this is quite suboptimal:
- the maintenance burden still sucks
- we're not testing the serial compiler in nightly
Because of these reasons, it's time to end it. The serial compiler has served us well in the years since it was split from the parallel one, but it's over now.
Let the knight slay one head of the two-headed dragon!
#113349
Note that the default is still 1 thread, as more than 1 thread is still fairly broken.
cc `@onur-ozkan` to see if i did the bootstrap field removal correctly, `@SparrowLii` on the sync parts
Since it's inception a long time ago, the parallel compiler and its cfgs
have been a maintenance burden. This was a necessary evil the allow
iteration while not degrading performance because of synchronization
overhead.
But this time is over. Thanks to the amazing work by the parallel
working group (and the dyn sync crimes), the parallel compiler has now
been fast enough to be shipped by default in nightly for quite a while
now.
Stable and beta have still been on the serial compiler, because they
can't use `-Zthreads` anyways.
But this is quite suboptimal:
- the maintenance burden still sucks
- we're not testing the serial compiler in nightly
Because of these reasons, it's time to end it. The serial compiler has
served us well in the years since it was split from the parallel one,
but it's over now.
Let the knight slay one head of the two-headed dragon!
move all mono-time checks into their own folder, and their own query
The mono item collector currently also drives two mono-time checks: the lint for "large moves", and the check whether function calls are done with all the required target features.
Instead of doing this "inside" the collector, this PR refactors things so that we have a new `rustc_monomorphize::mono_checks` module providing a per-instance query that does these checks. We already have a per-instance query for the ABI checks, so this should be "free" for incremental builds. Non-incremental builds might do a bit more work now since we now have two separate MIR visits (in the collector and the mono-time checks) -- but one of them is cached in case the MIR doesn't change, which is nice.
This slightly changes behavior of the large-move check since the "move_size_spans" deduplication logic now only works per-instance, not globally across the entire collector.
Cc `@saethlin` since you're also doing some work related to queries and caching and monomorphization, though I don't know if there's any interaction here.
Consolidate type system const evaluation under `traits::evaluate_const`
Part of #130704Fixes#128232Fixes#118545
Removes `ty::Const::{normalize_internal, eval_valtree}` and `InferCtxt::(try_)const_eval_resolve`, consolidating the associated logic into `evaluate_const` in `rustc_trait_selection`. This results in an API for `ty::Const` that is free of any normalization/evaluation functions that would be incorrect to use under `min_generic_const_args`/`associated_const_equality`/`generic_const_exprs` or, more generally, that would be incorrect to use in the presence of generic type system constants.
Moving this logic to `rustc_trait_selection` and out of `rustc_middle` is also a pre-requisite for ensuring that we do not evaluate constants whose where clauses do not hold.
From this point it should be relatively simple (hah) to implement more complex normalization of type system constants such as: checking wf'ness before invoking CTFE machinery, or being able to normalize const aliases that still refer to generic parameters.
r? `@compiler-errors`
cleanup: Remove outdated comment of `thir_body`
When typeck fails, `thir_body` returns `ErrorGuaranteed` rather than empty body.
No other code follows this outdated description except `check_unsafety`, which is also cleaned up in this PR.
query/plumbing: adjust comment to reality
The limit for the query key size got changed recently in f51ec110a7 but the comment was not updated.
Though maybe it is time to intern `CanonicalTypeOpAscribeUserTypeGoal` rather than copying it everywhere?
r? `@lcnr`
coverage: Restrict empty-span expansion to only cover `{` and `}`
Coverage instrumentation has some tricky code for converting a coverage-relevant `Span` into a set of start/end line/byte-column coordinates that will be embedded in the CGU's coverage metadata.
A big part of this complexity is special code for handling empty spans, which are expanded into non-empty spans (if possible) because LLVM's coverage reporter does not handle empty spans well.
This PR simplifies that code by restricting it to only apply in two specific situations: when the character after the empty span is `{`, or the character before the empty span is `}`.
(As an added benefit, this means that the expanded spans no longer extend awkwardly beyond the end of a physical line, which was common under the previous implementation.)
Along the way, this PR also removes some unhelpful code for dealing with function source code spread across multiple files. Functions currently can't have coverage spans in multiple files, and if that ever changes (e.g. to properly support expansion regions) then this code will need to be completely overhauled anyway.
interpret: get_alloc_info: also return mutability
This will be needed for https://github.com/rust-lang/miri/pull/3971
This then tuned into a larger refactor where we introduce a new type for the `get_alloc_info` return data, and we move some code to methods on `GlobalAlloc` to avoid duplicating it between the validity check and `get_alloc_info`.
Emit warning when calling/declaring functions with unavailable vectors.
On some architectures, vector types may have a different ABI depending on whether the relevant target features are enabled. (The ABI when the feature is disabled is often not specified, but LLVM implements some de-facto ABI.)
As discussed in rust-lang/lang-team#235, this turns out to very easily lead to unsound code.
This commit makes it a post-monomorphization future-incompat warning to declare or call functions using those vector types in a context in which the corresponding target features are disabled, if using an ABI for which the difference is relevant. This ensures that these functions are always called with a consistent ABI.
See the [nomination comment](https://github.com/rust-lang/rust/pull/127731#issuecomment-2288558187) for more discussion.
Part of #116558
r? RalfJung
Make `Ty::primitive_symbol` recognize `str`
Make `Ty::primitive_symbol` recognize `str`, which makes `str` eligible for the "expected primitive, found local type" (and vice versa) [diagnostic](https://github.com/rust-lang/rust/blob/master/compiler/rustc_trait_selection/src/error_reporting/infer/mod.rs#L1430-L1437) that already exists for other primitives.
<details><summary> diagnostic difference</summary>
```rs
#[allow(non_camel_case_types)]
struct str;
fn foo() {
let _: &str = "hello";
let _: &core::primitive::str = &str;
}
```
`rustc --crate-type lib --edition 2021 a.rs`
Current nightly:
```rs
error[E0308]: mismatched types
--> a.rs:5:19
|
5 | let _: &str = "hello";
| ---- ^^^^^^^ expected `str`, found a different `str`
| |
| expected due to this
|
= note: expected reference `&str`
found reference `&'static str`
error[E0308]: mismatched types
--> a.rs:6:36
|
6 | let _: &core::primitive::str = &str;
| --------------------- ^^^^ expected `str`, found a different `str`
| |
| expected due to this
|
= note: expected reference `&str` (`str`)
found reference `&str` (`str`)
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0308`.
```
With this patch:
```rs
error[E0308]: mismatched types
--> a.rs:5:19
|
5 | let _: &str = "hello";
| ---- ^^^^^^^ expected `str`, found a different `str`
| |
| expected due to this
|
= note: str and `str` have similar names, but are actually distinct types
= note: str is a primitive defined by the language
note: `str` is defined in the current crate
--> a.rs:2:1
|
2 | struct str;
| ^^^^^^^^^^
error[E0308]: mismatched types
--> a.rs:6:36
|
6 | let _: &core::primitive::str = &str;
| --------------------- ^^^^ expected `str`, found a different `str`
| |
| expected due to this
|
= note: str and `str` have similar names, but are actually distinct types
= note: str is a primitive defined by the language
note: `str` is defined in the current crate
--> a.rs:2:1
|
2 | struct str;
| ^^^^^^^^^^
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0308`.
```
</details>
pointee_info_at: fix logic for recursing into enums
Fixes https://github.com/rust-lang/rust/issues/131834
The logic in `pointee_info_at` was likely written at a time when the null pointer optimization was the *only* enum layout optimization -- and as `Variant::Multiple` kept getting expanded, nobody noticed that the logic is now unsound.
The job of this function is to figure out whether there is a dereferenceable-or-null and aligned pointer at a given offset inside a type. So when we recurse into a multi-variant enum, we better make sure that all the other enum variants must be null! This is the part that was forgotten, and this PR adds it.
The reason this didn't explode in many ways so far is that our references only have 1 niche value (null), so it's not possible on stable to have a multi-variant enum with a dereferenceable pointer and other enum variants that are not null. But with `rustc_layout_scalar_valid_range` attributes one can force such a layout, and if `@the8472's` work on alignment niches ever lands, that will make this possible on stable.
Get rid of `check_opaque_type_well_formed`
Instead, replicate it by improving the span of the opaque in `check_opaque_meets_bounds`.
This has two consequences:
1. We now prefer "concrete type differs" errors, since we'll hit those first before we check the opaque is WF.
2. Spans have gotten slightly worse.
Specifically, (2.) could be improved by adding a new obligation cause that explains that the definition's environment has stronger assumptions than the declaration.
r? lcnr
Functions currently can't have mappings in multiple files, and if that ever
changes (e.g. to properly support expansion regions), this code will need to be
completely overhauled anyway.
[StableMIR] API to retrieve definitions from crates
Add functions to retrieve function definitions and static items from all crates (local and external).
For external crates, we're still missing items from trait implementation and primitives.
r? ````@compiler-errors:```` Do you know what is the best way to retrieve the associated items for primitives and trait implementations for external crates? Thanks!
Add functions to retrieve function definitions and static items from
all crates (local and external).
For external crates, add a query to retrieve the number of defs in a
foreign crate.
mark some target features as 'forbidden' so they cannot be (un)set with -Ctarget-feature
The context for this is https://github.com/rust-lang/rust/issues/116344: some target features change the way floats are passed between functions. Changing those target features is unsound as code compiled for the same target may now use different ABIs.
So this introduces a new concept of "forbidden" target features (on top of the existing "stable " and "unstable" categories), and makes it a hard error to (un)set such a target feature. For now, the x86 and ARM feature `soft-float` is on that list. We'll have to make some effort to collect more relevant features, and similar features from other targets, but that can happen after the basic infrastructure for this landed. (These features are being collected in https://github.com/rust-lang/rust/issues/131799.)
I've made this a warning for now to give people some time to speak up if this would break something.
MCP: https://github.com/rust-lang/compiler-team/issues/780
Remove unnecessary pub enum glob-imports from `rustc_middle::ty`
We used to have an idiom in the compiler where we'd prefix or suffix all the variants of an enum, for example `BoundRegionKind`, with something like `Br`, and then *glob-import* that enum variant directly.
`@noratrieb` brought this up, and I think that it's easier to read when we just use the normal style `EnumName::Variant`.
This PR is a bit large, but it's just naming.
The only somewhat opinionated change that this PR does is rename `BorrowKind::Imm` to `BorrowKind::Immutable` and same for the other variants. I think these enums are used sparingly enough that the extra length is fine.
r? `@noratrieb` or reassign
Use backticks instead of single quotes for library feature names in diagnostics
This PR changes the text of library feature errors for using unstable or body-unstable items. Displaying library feature names in backticks is consistent with other diagnostics (e.g. those from `rustc_passes`) and with the `reason`s on unstable attributes in the library. Additionally, this simplifies diagnostics when supporting multiple unstable attributes on items (see #131824) since `DiagSymbolList` also displays symbols using backticks.
compiler: Directly use rustc_abi almost everywhere
Use rustc_abi instead of rustc_target where applicable. This is mostly described by the following substitutions:
```rust
match path_substring {
rustc_target::spec::abi::Abi => rustc_abi::ExternAbi,
rustc_target::abi::call => rustc_target::callconv,
rustc_target::abi => rustc_abi,
}
```
A number of spot-fixes make that not quite the whole story.
The main exception is in 33edc68 where I get a lot more persnickety about how things are imported, especially in `rustc_middle::ty::layout`, not just from where. This includes putting an end to a reexport of `rustc_middle::ty::ReprOptions`, for the same reason that the rest of this change is happening: reexports mostly confound things.
This notably omits rustc_passes and the ast crates, as I'm still examining a question I have about how they do stability checking of `extern "Abi"` strings and if I can simplify their logic. The rustc_abi and rustc_target crates also go untouched because they will be entangled in that cleanup.
r? compiler-errors
This is consistent with all other diagnostics I could find containing
features and enables the use of `DiagSymbolList` for generalizing
diagnostics for unstable library features to multiple features.
On some architectures, vector types may have a different ABI depending
on whether the relevant target features are enabled. (The ABI when the
feature is disabled is often not specified, but LLVM implements some
de-facto ABI.)
As discussed in rust-lang/lang-team#235, this turns out to very easily
lead to unsound code.
This commit makes it a post-monomorphization future-incompat warning to
declare or call functions using those vector types in a context in which
the corresponding target features are disabled, if using an ABI for
which the difference is relevant. This ensures that these functions are
always called with a consistent ABI.
See the [nomination comment](https://github.com/rust-lang/rust/pull/127731#issuecomment-2288558187)
for more discussion.
Part of #116558
continue `TypingMode` refactor
There are still quite a few places which (indirectly) rely on the `Reveal` of a `ParamEnv`, but we're slowly getting there
r? `@compiler-errors`
Remove region from adjustments
It's not necessary to store this region, because it's only used in THIR and MemCat/ExprUse, both of which already basically only deal with erased regions anyways.
Try to point out when edition 2024 lifetime capture rules cause borrowck issues
Lifetime capture rules in 2024 are modified to capture more lifetimes, which sometimes lead to some non-local borrowck errors. This PR attempts to link these back together with a useful note pointing out the capture rule changes.
This is not a blocking concern, but I'd appreciate feedback (though, again, I'd like to stress that I don't want to block this PR on this): I'm worried about this note drowning in the sea of other diagnostics that borrowck emits. I was tempted to change the level of the note to `.span_warn` just so it would show up in a different color. Thoughts?
Fixes#130545
Opening as a draft first since it's stacked on #131183.
r? `@ghost`
Rename `rustc_abi::Abi` to `BackendRepr`
Remove the confabulation of `rustc_abi::Abi` with what "ABI" actually means by renaming it to `BackendRepr`, and rename `Abi::Aggregate` to `BackendRepr::Memory`. The type never actually represented how things are passed, as that has to have `PassMode` considered, at minimum, but rather it just is how we represented some things to the backend. This conflation arose because LLVM, the primary backend at the time, would lower certain IR forms using certain ABIs. Even that only somewhat was true, as it broke down when one ventured significantly afield of what is described by the System V AMD64 ABI either by using different architectures, ABI-modifying IR annotations, the same architecture **with different ISA extensions enabled**, or other... unexpected delights.
Unfortunately both names are still somewhat of a misnomer right now, as people have written code for years based on this misunderstanding. Still, their original names are even moreso, and for better or worse, this backend code hasn't received as much maintenance as the rest of the compiler, lately. Actually arriving at a correct end-state will simply require us to disentangle a lot of code in order to fix, much of it pointlessly repeated in several places. Thus this is not an "actual fix", just a way to deflect further misunderstandings.
The initial naming of "Abi" was an awful mistake, conveying wrong ideas
about how psABIs worked and even more about what the enum meant.
It was only meant to represent the way the value would be described to
a codegen backend as it was lowered to that intermediate representation.
It was never meant to mean anything about the actual psABI handling!
The conflation is because LLVM typically will associate a certain form
with a certain ABI, but even that does not hold when the special cases
that actually exist arise, plus the IR annotations that modify the ABI.
Reframe `rustc_abi::Abi` as the `BackendRepr` of the type, and rename
`BackendRepr::Aggregate` as `BackendRepr::Memory`. Unfortunately, due to
the persistent misunderstandings, this too is now incorrect:
- Scattered ABI-relevant code is entangled with BackendRepr
- We do not always pre-compute a correct BackendRepr that reflects how
we "actually" want this value to be handled, so we leave the backend
interface to also inject various special-cases here
- In some cases `BackendRepr::Memory` is a "real" aggregate, but in
others it is in fact using memory, and in some cases it is a scalar!
Our rustc-to-backend lowering code handles this sort of thing right now.
That will eventually be addressed by lifting duplicated lowering code
to either rustc_codegen_ssa or rustc_target as appropriate.
Add `LayoutS::is_uninhabited` and use it
Use accessors for the things that accessors are good at: reducing everyone's need to be nosy and peek at the internals of every data structure.
compiler: rename LayoutS to LayoutData
Bid `LayoutS` goodbye because it looks like a typo.
`LayoutS` is the last of the types that use the "`{TypeName}` is the interned type, `{TypeName}S` is the backing data that is interned" convention. This is pretty confusing to those not intimately familiar with the history of rustc's names for its types over time, and doubly so now that there are no other examples in the tree. Abolish this convention.
(Big performance change) Do not run lints that cannot emit
Before this change, adding a lint was a difficult matter because it always had some overhead involved. This was because all lints would run, no matter their default level, or if the user had `#![allow]`ed them. This PR changes that. This change would improve both the Rust lint infrastructure and Clippy, but Clippy will see the most benefit, as it has about 900 registered lints (and growing!)
So yeah, with this little patch we filter all lints pre-linting, and remove any lint that is either:
- Manually `#![allow]`ed in the whole crate,
- Allowed in the command line, or
- Not manually enabled with `#[warn]` or similar, and its default level is `Allow`
As some lints **need** to run, this PR also adds **loadbearing lints**. On a lint declaration, you can use the ``@eval_always` = true` marker to label it as loadbearing. A loadbearing lint will never be filtered (it will always run)
Fixes#106983
Effects cleanup
- removed extra bits from predicates queries that are no longer needed in the new system
- removed the need for `non_erasable_generics` to take in tcx and DefId, removed unused arguments in callers
r? compiler-errors
- removed extra bits from predicates queries that are no longer needed in the new system
- removed the need for `non_erasable_generics` to take in tcx and DefId, removed unused arguments in callers
Then we can rename the _raw functions to drop their suffix, and instead
explicitly use is_stable_const_fn for the few cases where that is really what
you want.
Fundamentally, we have *three* disjoint categories of functions:
1. const-stable functions
2. private/unstable functions that are meant to be callable from const-stable functions
3. functions that can make use of unstable const features
This PR implements the following system:
- `#[rustc_const_stable]` puts functions in the first category. It may only be applied to `#[stable]` functions.
- `#[rustc_const_unstable]` by default puts functions in the third category. The new attribute `#[rustc_const_stable_indirect]` can be added to such a function to move it into the second category.
- `const fn` without a const stability marker are in the second category if they are still unstable. They automatically inherit the feature gate for regular calls, it can now also be used for const-calls.
Also, several holes in recursive const stability checking are being closed.
There's still one potential hole that is hard to avoid, which is when MIR
building automatically inserts calls to a particular function in stable
functions -- which happens in the panic machinery. Those need to *not* be
`rustc_const_unstable` (or manually get a `rustc_const_stable_indirect`) to be
sure they follow recursive const stability. But that's a fairly rare and special
case so IMO it's fine.
The net effect of this is that a `#[unstable]` or unmarked function can be
constified simply by marking it as `const fn`, and it will then be
const-callable from stable `const fn` and subject to recursive const stability
requirements. If it is publicly reachable (which implies it cannot be unmarked),
it will be const-unstable under the same feature gate. Only if the function ever
becomes `#[stable]` does it need a `#[rustc_const_unstable]` or
`#[rustc_const_stable]` marker to decide if this should also imply
const-stability.
Adding `#[rustc_const_unstable]` is only needed for (a) functions that need to
use unstable const lang features (including intrinsics), or (b) `#[stable]`
functions that are not yet intended to be const-stable. Adding
`#[rustc_const_stable]` is only needed for functions that are actually meant to
be directly callable from stable const code. `#[rustc_const_stable_indirect]` is
used to mark intrinsics as const-callable and for `#[rustc_const_unstable]`
functions that are actually called from other, exposed-on-stable `const fn`. No
other attributes are required.
Minor tweaks to `compare_impl_item.rs`
1. Stop using the `InstantiatedPredicates` struct for `hybrid_preds` in `compare_impl_item.rs`, since we never actually push anything into the `spans` part of it.
2. Remove redundant impl args and don't do useless identity substitution, prefer calling `instantiate_identity`.
nightly feature tracking: get rid of the per-feature bool fields
The `struct Features` that tracks which features are enabled has a ton of public `bool`-typed fields that are basically caching the result of looking up the corresponding feature in `enabled_lang_features`. Having public fields with an invariant is not great, so at least they should be made private. However, it turns out caching these lookups is actually [not worth it](https://github.com/rust-lang/rust/pull/131321#issuecomment-2402068336), so this PR just entirely gets rid of these fields. (The alternative would be to make them private and have a method for each of them to expose them in a read-only way. Most of the diff of this PR would be the same in that case.)
r? `@nnethercote`
do not implement `Relate` for "boring" types
and update some macros while we're at it. This means we don't have to implement `TypeVisitable` for them.
r? `@compiler-errors`
Rollup of 8 pull requests
Successful merges:
- #125205 (Fixup Windows verbatim paths when used with the `include!` macro)
- #131049 (Validate args are correct for `UnevaluatedConst`, `ExistentialTraitRef`/`ExistentialProjection`)
- #131549 (Add a note for `?` on a `impl Future<Output = Result<..>>` in sync function)
- #131731 (add `TestFloatParse` to `tools.rs` for bootstrap)
- #131732 (Add doc(plugins), doc(passes), etc. to INVALID_DOC_ATTRIBUTES)
- #132006 (don't stage-off to previous compiler when CI rustc is available)
- #132022 (Move `cmp_in_dominator_order` out of graph dominator computation)
- #132033 (compiletest: Make `line_directive` return a `DirectiveLine`)
r? `@ghost`
`@rustbot` modify labels: rollup
Validate args are correct for `UnevaluatedConst`, `ExistentialTraitRef`/`ExistentialProjection`
For the `Existential*` ones, we have to do some adjustment to the args list to deal with the missing `Self` type, so we introduce a `debug_assert_existential_args_compatible` function to the interner as well.
terminology: #[feature] *enables* a feature (instead of "declaring" or "activating" it)
Mostly, we currently call a feature that has a corresponding `#[feature(name)]` attribute in the current crate a "declared" feature. I think that is confusing as it does not align with what "declaring" usually means. Furthermore, we *also* refer to `#[stable]`/`#[unstable]` as *declaring* a feature (e.g. in [these diagnostics](f25e5abea2/compiler/rustc_passes/messages.ftl (L297-L301))), which aligns better with what "declaring" usually means. To make things worse, the functions `tcx.features().active(...)` and `tcx.features().declared(...)` both exist and they are doing almost the same thing (testing whether a corresponding `#[feature(name)]` exists) except that `active` would ICE if the feature is not an unstable lang feature. On top of this, the callback when a feature is activated/declared is called `set_enabled`, and many comments also talk about "enabling" a feature.
So really, our terminology is just a mess.
I would suggest we use "declaring a feature" for saying that something is/was guarded by a feature (e.g. `#[stable]`/`#[unstable]`), and "enabling a feature" for `#[feature(name)]`. This PR implements that.
rust_for_linux: -Zregparm=<N> commandline flag for X86 (#116972)
Command line flag `-Zregparm=<N>` for X86 (32-bit) for rust-for-linux: https://github.com/rust-lang/rust/issues/116972
Implemented in the similar way as fastcall/vectorcall support (args are marked InReg if fit).
stabilize Strict Provenance and Exposed Provenance APIs
Given that [RFC 3559](https://rust-lang.github.io/rfcs/3559-rust-has-provenance.html) has been accepted, t-lang has approved the concept of provenance to exist in the language. So I think it's time that we stabilize the strict provenance and exposed provenance APIs, and discuss provenance explicitly in the docs:
```rust
// core::ptr
pub const fn without_provenance<T>(addr: usize) -> *const T;
pub const fn dangling<T>() -> *const T;
pub const fn without_provenance_mut<T>(addr: usize) -> *mut T;
pub const fn dangling_mut<T>() -> *mut T;
pub fn with_exposed_provenance<T>(addr: usize) -> *const T;
pub fn with_exposed_provenance_mut<T>(addr: usize) -> *mut T;
impl<T: ?Sized> *const T {
pub fn addr(self) -> usize;
pub fn expose_provenance(self) -> usize;
pub fn with_addr(self, addr: usize) -> Self;
pub fn map_addr(self, f: impl FnOnce(usize) -> usize) -> Self;
}
impl<T: ?Sized> *mut T {
pub fn addr(self) -> usize;
pub fn expose_provenance(self) -> usize;
pub fn with_addr(self, addr: usize) -> Self;
pub fn map_addr(self, f: impl FnOnce(usize) -> usize) -> Self;
}
impl<T: ?Sized> NonNull<T> {
pub fn addr(self) -> NonZero<usize>;
pub fn with_addr(self, addr: NonZero<usize>) -> Self;
pub fn map_addr(self, f: impl FnOnce(NonZero<usize>) -> NonZero<usize>) -> Self;
}
```
I also did a pass over the docs to adjust them, because this is no longer an "experiment". The `ptr` docs now discuss the concept of provenance in general, and then they go into the two families of APIs for dealing with provenance: Strict Provenance and Exposed Provenance. I removed the discussion of how pointers also have an associated "address space" -- that is not actually tracked in the pointer value, it is tracked in the type, so IMO it just distracts from the core point of provenance. I also adjusted the docs for `with_exposed_provenance` to make it clear that we cannot guarantee much about this function, it's all best-effort.
There are two unstable lints associated with the strict_provenance feature gate; I moved them to a new [strict_provenance_lints](https://github.com/rust-lang/rust/issues/130351) feature since I didn't want this PR to have an even bigger FCP. ;)
`@rust-lang/opsem` Would be great to get some feedback on the docs here. :)
Nominating for `@rust-lang/libs-api.`
Part of https://github.com/rust-lang/rust/issues/95228.
[FCP comment](https://github.com/rust-lang/rust/pull/130350#issuecomment-2395114536)
Rollup of 4 pull requests
Successful merges:
- #126588 (Added more scenarios where comma to be removed in the function arg)
- #131728 (bootstrap: extract builder cargo to its own module)
- #131968 (Rip out old effects var handling code from traits)
- #131981 (Remove the `BoundConstness::NotConst` variant)
r? `@ghost`
`@rustbot` modify labels: rollup
