Make `Step` trait safe to implement
This PR makes a few modifications to the `Step` trait that I believe better position it for stabilization in the short term. In particular,
1. `unsafe trait TrustedStep` is introduced, indicating that the implementation of `Step` for a given type upholds all stated invariants (which have remained unchanged). This is gated behind a new `trusted_step` feature, as stabilization is realistically blocked on min_specialization.
2. The `Step` trait is internally specialized on the `TrustedStep` trait, which avoids a serious performance regression.
3. `TrustedLen` is implemented for `T: TrustedStep` as the latter's invariants subsume the former's.
4. The `Step` trait is no longer `unsafe`, as the invariants must not be relied upon by unsafe code (unless the type implements `TrustedStep`).
5. `TrustedStep` is implemented for all types that implement `Step` in the standard library and compiler.
6. The `step_trait_ext` feature is merged into the `step_trait` feature. I was unable to find any reasoning for the features being split; the `_unchecked` methods need not necessarily be stabilized at the same time, but I think it is useful to have them under the same feature flag.
All existing implementations of `Step` will be broken, as it is not possible to `unsafe impl` a safe trait. Given this trait only exists on nightly, I feel this breakage is acceptable. The blanket `impl<T: Step> TrustedLen for T` will likely cause some minor breakage, but this should be covered by the equivalent impl for `TrustedStep`.
Hopefully these changes are sufficient to place `Step` in decent position for stabilization, which would allow user-defined types to be used with `a..b` syntax.
const-eval: disallow unwinding across functions that `!fn_can_unwind()`
Following https://github.com/rust-lang/miri/pull/1776#discussion_r633074343, so r? `@RalfJung`
This PR turns `unwind` in `StackPopCleanup::Goto` into a new enum `StackPopUnwind`, with a `NotAllowed` variant to indicate that unwinding is not allowed. This variant is chosen based on `rustc_middle::ty::layout::fn_can_unwind()` in `eval_fn_call()` when pushing the frame. A check is added in `unwind_to_block()` to report UB if unwinding happens across a `StackPopUnwind::NotAllowed` frame.
Tested with Miri `HEAD` with [minor changes](https://github.com/rust-lang/miri/compare/HEAD..9cf3c7f0d86325a586fbcbf2acdc9232b861f1d8) and the rust-lang/miri#1776 branch with [these changes](d866c1c52f..626638fbfe).
Post-monomorphization errors traces MVP
This PR works towards better diagnostics for the errors encountered in #85155 and similar.
We can encounter post-monomorphization errors (PMEs) when collecting mono items. The current diagnostics are confusing for these cases when they happen in a dependency (but are acceptable when they happen in the local crate).
These kinds of errors will be more likely now that `stdarch` uses const generics for its intrinsics' immediate arguments, and validates these const arguments with a mechanism that triggers such PMEs.
(Not to mention that the errors happen during codegen, so only when building code that actually uses these code paths. Check builds don't trigger them, neither does unused code)
So in this PR, we detect these kinds of errors during the mono item graph walk: if any error happens while collecting a node or its neighbors, we print a diagnostic about the current collection step, so that the user has at least some context of which erroneous code and dependency triggered the error.
The diagnostics for issue #85155 now have this note showing the source of the erroneous const argument:
```
note: the above error was encountered while instantiating `fn std::arch::x86_64::_mm_blend_ps::<51_i32>`
--> issue-85155.rs:11:24
|
11 | let _blended = _mm_blend_ps(a, b, 0x33);
| ^^^^^^^^^^^^^^^^^^^^^^^^
error: aborting due to previous error
```
Note that #85155 is a reduced version of a case happening in the wild, to indirect users of the `rustfft` crate, as seen in https://github.com/ejmahler/RustFFT/issues/74. The crate had a few of these out-of-range immediates. Here's how the diagnostics in this PR would have looked on one of its examples before it was fixed:
<details>
```
error[E0080]: evaluation of constant value failed
--> ./stdarch/crates/core_arch/src/macros.rs:8:9
|
8 | assert!(IMM >= MIN && IMM <= MAX, "IMM value not in expected range");
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'IMM value not in expected range', ./stdarch/crates/core_arch/src/macros.rs:8:9
|
= note: this error originates in the macro `$crate::panic::panic_2015` (in Nightly builds, run with -Z macro-backtrace for more info)
note: the above error was encountered while instantiating `fn _mm_blend_ps::<51_i32>`
--> /tmp/RustFFT/src/avx/avx_vector.rs:1314:23
|
1314 | let blended = _mm_blend_ps(rows[0], rows[2], 0x33);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: the above error was encountered while instantiating `fn _mm_permute_pd::<5_i32>`
--> /tmp/RustFFT/src/avx/avx_vector.rs:1859:9
|
1859 | _mm_permute_pd(self, 0x05)
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
note: the above error was encountered while instantiating `fn _mm_permute_pd::<15_i32>`
--> /tmp/RustFFT/src/avx/avx_vector.rs:1863:32
|
1863 | (_mm_movedup_pd(self), _mm_permute_pd(self, 0x0F))
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
error: aborting due to previous error
For more information about this error, try `rustc --explain E0080`.
error: could not compile `rustfft`
To learn more, run the command again with --verbose.
```
</details>
I've developed and discussed this with them, so maybe r? `@oli-obk` -- but feel free to redirect to someone else of course.
(I'm not sure we can say that this PR definitely closes issue 85155, as it's still unclear exactly which diagnostics and information would be interesting to report in such cases -- and we've discussed printing backtraces before. I have prototypes of some complete and therefore noisy backtraces I showed Oli, but we decided to not include them in this PR for now)
Emit a diagnostic when the monomorphized item collector
encounters errors during a step of the recursive item collection.
These post-monomorphization errors otherwise only show the
erroneous expression without a trace, making them very obscure
and hard to pinpoint whenever they happen in dependencies.
Bump bootstrap compiler to beta 1.53.0
This PR bumps the bootstrap compiler to version 1.53.0 beta, as part of our usual release process (this was supposed to be Wednesday's step, but creating the beta release took longer than expected).
The PR also includes the "Bootstrap: skip rustdoc fingerprint for building docs" commit, see the reasoning [on Zulip](https://zulip-archive.rust-lang.org/241545trelease/88450153betabootstrap.html).
r? `@Mark-Simulacrum`
Make building THIR a stealable query
This PR creates a stealable `thir_body` query so that we can build the THIR only once for THIR unsafeck and MIR build.
Blocked on #83842.
r? `@nikomatsakis`
CTFE core engine allocation & memory API improvemenets
This is a first step towards https://github.com/rust-lang/miri/issues/841.
- make `Allocation` API offset-based (no more making up `Pointer`s just to access an `Allocation`)
- make `Memory` API higher-level (combine checking for access and getting access into one operation)
The Miri-side PR is at https://github.com/rust-lang/miri/pull/1804.
r? `@oli-obk`
- make Allocation API offset-based (no more Pointer)
- make Memory API higher-level (combine checking for access and getting access into one operation)
Rollup of 7 pull requests
Successful merges:
- #84587 (rustdoc: Make "rust code block is empty" and "could not parse code block" warnings a lint (`INVALID_RUST_CODEBLOCKS`))
- #85280 (Toggle-wrap items differently than top-doc.)
- #85338 (Implement more Iterator methods on core::iter::Repeat)
- #85339 (Report an error if a lang item has the wrong number of generic arguments)
- #85369 (Suggest borrowing if a trait implementation is found for &/&mut <type>)
- #85393 (Suppress spurious errors inside `async fn`)
- #85415 (Clean up remnants of BorrowOfPackedField)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Unify Regions with RegionVids in UnificationTable
A few test output changes; might be able to revert those but figured I would open this for perf and comments.
r? `@nikomatsakis`
Remove CrateNum parameter for queries that only work on local crate
The pervasive `CrateNum` parameter is a remnant of the multi-crate rustc idea.
Using `()` as query key in those cases avoids having to worry about the validity of the query key.
coverage bug fixes and some refactoring
This replaces the relevant commits (2 and 3) from PR #85082, and also corrects an error querying for coverageinfo.
1. `coverageinfo` query needs to use the same MIR as codegen
I ran into an error trying to fix dead block coverage and realized the
`coverageinfo` query is getting a different MIR compared to the
codegenned MIR, which can sometimes be a problem during mapgen.
I changed that query to use the `InstandeDef` (which includes the
generic parameter substitutions, prosibly specific to const params)
instead of the `DefId` (without unknown/default const substitutions).
2. Simplified body_span and filtered span code
Some code cleanup extracted from future (but unfinished) commit to fix
coverage in attr macro functions.
3. Spanview needs the relevant body_span used for coverage
The coverage body_span doesn't always match the function body_span.
r? ```@tmandry```
Introduce the beginning of a THIR unsafety checker
This poses the foundations for the THIR unsafety checker, so that it can be implemented incrementally:
- implements a rudimentary `Visitor` for the THIR (which will definitely need some tweaking in the future)
- introduces a new `-Zthir-unsafeck` flag which tells the compiler to use THIR unsafeck instead of MIR unsafeck
- implements detection of unsafe functions
- adds revisions to the UI tests to test THIR unsafeck alongside MIR unsafeck
This uses a very simple query design, where bodies are unsafety-checked on a body per body basis. This however has some big flaws:
- the unsafety-checker builds the THIR itself, which means a lot of work is duplicated with MIR building constructing its own copy of the THIR
- unsafety-checking closures is currently completely wrong: closures should take into account the "safety context" in which they are created, here we are considering that closures are always a safe context
I had intended to fix these problems in follow-up PRs since they are always gated under the `-Zthir-unsafeck` flag (which is explicitely noted to be unsound).
r? `@nikomatsakis`
cc https://github.com/rust-lang/project-thir-unsafeck/issues/3https://github.com/rust-lang/project-thir-unsafeck/issues/7
I ran into an error trying to fix dead block coverage and realized the
`coverageinfo` query is getting a different MIR compared to the
codegenned MIR, which can sometimes be a problem during mapgen.
I changed that query to use the `InstandeDef` (which includes the
generic parameter substitutions, prosibly specific to const params)
instead of the `DefId` (without unknown/default const substitutions).
Fix `--remap-path-prefix` not correctly remapping `rust-src` component paths and unify handling of path mapping with virtualized paths
This PR fixes#73167 ("Binaries end up containing path to the rust-src component despite `--remap-path-prefix`") by preventing real local filesystem paths from reaching compilation output if the path is supposed to be remapped.
`RealFileName::Named` introduced in #72767 is now renamed as `LocalPath`, because this variant wraps a (most likely) valid local filesystem path.
`RealFileName::Devirtualized` is renamed as `Remapped` to be used for remapped path from a real path via `--remap-path-prefix` argument, as well as real path inferred from a virtualized (during compiler bootstrapping) `/rustc/...` path. The `local_path` field is now an `Option<PathBuf>`, as it will be set to `None` before serialisation, so it never reaches any build output. Attempting to serialise a non-`None` `local_path` will cause an assertion faliure.
When a path is remapped, a `RealFileName::Remapped` variant is created. The original path is preserved in `local_path` field and the remapped path is saved in `virtual_name` field. Previously, the `local_path` is directly modified which goes against its purpose of "suitable for reading from the file system on the local host".
`rustc_span::SourceFile`'s fields `unmapped_path` (introduced by #44940) and `name_was_remapped` (introduced by #41508 when `--remap-path-prefix` feature originally added) are removed, as these two pieces of information can be inferred from the `name` field: if it's anything other than a `FileName::Real(_)`, or if it is a `FileName::Real(RealFileName::LocalPath(_))`, then clearly `name_was_remapped` would've been false and `unmapped_path` would've been `None`. If it is a `FileName::Real(RealFileName::Remapped{local_path, virtual_name})`, then `name_was_remapped` would've been true and `unmapped_path` would've been `Some(local_path)`.
cc `@eddyb` who implemented `/rustc/...` path devirtualisation
This PR implements span quoting, allowing proc-macros to produce spans
pointing *into their own crate*. This is used by the unstable
`proc_macro::quote!` macro, allowing us to get error messages like this:
```
error[E0412]: cannot find type `MissingType` in this scope
--> $DIR/auxiliary/span-from-proc-macro.rs:37:20
|
LL | pub fn error_from_attribute(_args: TokenStream, _input: TokenStream) -> TokenStream {
| ----------------------------------------------------------------------------------- in this expansion of procedural macro `#[error_from_attribute]`
...
LL | field: MissingType
| ^^^^^^^^^^^ not found in this scope
|
::: $DIR/span-from-proc-macro.rs:8:1
|
LL | #[error_from_attribute]
| ----------------------- in this macro invocation
```
Here, `MissingType` occurs inside the implementation of the proc-macro
`#[error_from_attribute]`. Previosuly, this would always result in a
span pointing at `#[error_from_attribute]`
This will make many proc-macro-related error message much more useful -
when a proc-macro generates code containing an error, users will get an
error message pointing directly at that code (within the macro
definition), instead of always getting a span pointing at the macro
invocation site.
This is implemented as follows:
* When a proc-macro crate is being *compiled*, it causes the `quote!`
macro to get run. This saves all of the sapns in the input to `quote!`
into the metadata of *the proc-macro-crate* (which we are currently
compiling). The `quote!` macro then expands to a call to
`proc_macro::Span::recover_proc_macro_span(id)`, where `id` is an
opaque identifier for the span in the crate metadata.
* When the same proc-macro crate is *run* (e.g. it is loaded from disk
and invoked by some consumer crate), the call to
`proc_macro::Span::recover_proc_macro_span` causes us to load the span
from the proc-macro crate's metadata. The proc-macro then produces a
`TokenStream` containing a `Span` pointing into the proc-macro crate
itself.
The recursive nature of 'quote!' can be difficult to understand at
first. The file `src/test/ui/proc-macro/quote-debug.stdout` shows
the output of the `quote!` macro, which should make this eaier to
understand.
This PR also supports custom quoting spans in custom quote macros (e.g.
the `quote` crate). All span quoting goes through the
`proc_macro::quote_span` method, which can be called by a custom quote
macro to perform span quoting. An example of this usage is provided in
`src/test/ui/proc-macro/auxiliary/custom-quote.rs`
Custom quoting currently has a few limitations:
In order to quote a span, we need to generate a call to
`proc_macro::Span::recover_proc_macro_span`. However, proc-macros
support renaming the `proc_macro` crate, so we can't simply hardcode
this path. Previously, the `quote_span` method used the path
`crate::Span` - however, this only works when it is called by the
builtin `quote!` macro in the same crate. To support being called from
arbitrary crates, we need access to the name of the `proc_macro` crate
to generate a path. This PR adds an additional argument to `quote_span`
to specify the name of the `proc_macro` crate. Howver, this feels kind
of hacky, and we may want to change this before stabilizing anything
quote-related.
Additionally, using `quote_span` currently requires enabling the
`proc_macro_internals` feature. The builtin `quote!` macro
has an `#[allow_internal_unstable]` attribute, but this won't work for
custom quote implementations. This will likely require some additional
tricks to apply `allow_internal_unstable` to the span of
`proc_macro::Span::recover_proc_macro_span`.
Use .name_str() to format primitive types in error messages
This pull request fixes#84976. The problem described there is caused by this code
506e75cbf8/compiler/rustc_middle/src/ty/error.rs (L161-L166)
using `Debug` formatting (`{:?}`), while the proper solution is to call `name_str()` of `ty::IntTy`, `ty::UintTy` and `ty::FloatTy`, respectively.
Add primary marker on codegen unit and generate main wrapper on primary codegen.
This is the codegen part of changes extracted from #84062.
This add a marker called `primary` on each codegen units, where exactly one codegen unit will be `primary = true` at a time. This specific codegen unit will take charge of generating `main` wrapper when `main` is imported from a foreign crate after the implementation of RFC 1260.
cc #28937
I'm not sure who should i ask for review for codegen changes, so feel free to reassign.
r? `@nagisa`
CTFE inbounds-error-messages tweak
* use CheckInAllocMsg::PointerArithmeticTest for ptr_offset error
* nicer errors for some null pointer cases
r? `@oli-obk`
This commit implements both the native linking modifiers infrastructure
as well as an initial attempt at the individual modifiers from the RFC.
It also introduces a feature flag for the general syntax along with
individual feature flags for each modifier.
Remove `rustc_middle::mir::interpret::CheckInAllocMsg::NullPointerTest`
Removing it per https://github.com/rust-lang/rust/pull/84842#discussion_r625589674: it's a dead enum variant.
Note that `PointerArithmeticTest` also seems dead:
```
$ rg -F PointerArithmeticTest -C5
compiler/rustc_middle/src/mir/interpret/error.rs
169-
170-/// Details of why a pointer had to be in-bounds.
171-#[derive(Debug, Copy, Clone, TyEncodable, TyDecodable, HashStable)]
172-pub enum CheckInAllocMsg {
173- MemoryAccessTest,
174: PointerArithmeticTest,
175- InboundsTest,
176-}
177-
178-impl fmt::Display for CheckInAllocMsg {
179- /// When this is printed as an error the context looks like this
--
182- write!(
183- f,
184- "{}",
185- match *self {
186- CheckInAllocMsg::MemoryAccessTest => "memory access",
187: CheckInAllocMsg::PointerArithmeticTest => "pointer arithmetic",
188- CheckInAllocMsg::InboundsTest => "inbounds test",
189- }
190- )
191- }
192-}
```
Not sure if that is also desirable to be removed, however.
Update BARE_TRAIT_OBJECT and ELLIPSIS_INCLUSIVE_RANGE_PATTERNS to errors in Rust 2021
This addresses https://github.com/rust-lang/rust/pull/81244 by updating two lints to errors in the Rust 2021 edition.
r? `@estebank`
This ensures that `ParamEnv::and` preserves the original `caller_bounds`
when we have a value containing fresh tys/consts. This ensures that when
we cache a `SelectionCandidate`, the cache key (a `ParamEnvAnd`)
contains all of the information that influenced the computation of our
result (e.g. we may end up choosing a `ParamCandidate`)
Move HIR parenting information out of hir_owner
Split out of #82681.
The parent of a HIR node and its content are currently bundled together, but are rarely used together.
This PR separates both information in two distinct queries for HIR owners.
This reduces incremental invalidation for HIR items that appear within a function body when this body (and the local ids) changes.
Move iter_results to dyn FnMut rather than a generic
This means that we're no longer generating the iteration/locking code for each invocation site of iter_results, rather just once per query (roughly), which seems much better: this is a 15% win in instruction counts when compiling the rustc_query_impl crate. The code where this is used also is pretty cold, I suspect; the old solution didn't fully monomorphize either.
Implement RFC 1260 with feature_name `imported_main`.
This is the second extraction part of #84062 plus additional adjustments.
This (mostly) implements RFC 1260.
However there's still one test case failure in the extern crate case. Maybe `LocalDefId` doesn't work here? I'm not sure.
cc https://github.com/rust-lang/rust/issues/28937
r? `@petrochenkov`
This means that we're no longer generating the iteration/locking code for each
invocation site of iter_results, rather just once per query.
This is a 15% win in instruction counts when compiling the rustc_query_impl crate.
Add TRACKED_NO_CRATE_HASH and use it for `--remap-path-prefix`
I verified locally that this fixes https://github.com/rust-lang/rust/issues/66955.
r? `@Aaron1011` (feel free to reassign)
Adds feature-gated `#[no_coverage]` function attribute, to fix derived Eq `0` coverage issue #83601
Derived Eq no longer shows uncovered
The Eq trait has a special hidden function. MIR `InstrumentCoverage`
would add this function to the coverage map, but it is never called, so
the `Eq` trait would always appear uncovered.
Fixes: #83601
The fix required creating a new function attribute `no_coverage` to mark
functions that should be ignored by `InstrumentCoverage` and the
coverage `mapgen` (during codegen).
Adding a `no_coverage` feature gate with tracking issue #84605.
r? `@tmandry`
cc: `@wesleywiser`
The Eq trait has a special hidden function. MIR `InstrumentCoverage`
would add this function to the coverage map, but it is never called, so
the `Eq` trait would always appear uncovered.
Fixes: #83601
The fix required creating a new function attribute `no_coverage` to mark
functions that should be ignored by `InstrumentCoverage` and the
coverage `mapgen` (during codegen).
While testing, I also noticed two other issues:
* spanview debug file output ICEd on a function with no body. The
workaround for this is included in this PR.
* `assert_*!()` macro coverage can appear covered if followed by another
`assert_*!()` macro. Normally they appear uncovered. I submitted a new
Issue #84561, and added a coverage test to demonstrate this issue.
This is necessary for options that should invalidate the incremental
hash but *not* affect the crate hash (e.g. --remap-path-prefix).
This doesn't add `for_crate_hash` to the trait directly because it's not
relevant for *types*, only for *options*, which are fields on a larger
struct. Instead, it adds a new `SUBSTRUCT` directive for options, which
does take a `for_crate_hash` parameter.
- Use TRACKED_NO_CRATE_HASH for --remap-path-prefix
- Add test that `remap_path_prefix` is tracked
- Reduce duplication in the test suite to avoid future churn
Get rid of is_min_const_fn
This removes the last trace of the min_const_fn mechanism by making the unsafety checker agnostic about whether something is a min or "non-min" const fn. It seems this distinction was used to disallow some features inside `const fn`, but that is the responsibility of the const checker, not of the unsafety checker. No test seems to even notice this change in the unsafety checker so I guess we are good...
r? `@oli-obk`
Cc https://github.com/rust-lang/rust/issues/84510
various const parameter defaults improvements
Actually resolve names in const parameter defaults, fixing `struct Foo<const N: usize = { usize::MAX }>`.
---
Split generic parameter ban rib for types and consts, allowing
```rust
#![feature(const_generics_defaults)]
struct Q;
struct Foo<T = Q, const Q: usize = 3>(T);
```
---
Remove the type/const ordering restriction if `const_generics_defaults` is active, even if `const_generics` is not. allowing us to stabilize and test const param defaults separately.
---
Check well formedness of const parameter defaults, eagerly emitting an error for `struct Foo<const N: usize = { 0 - 1 }>`
---
Do not forbid const parameters in param defaults, allowing `struct Foo<const N: usize, T = [u8; N]>(T)` and `struct Foo<const N: usize, const M: usize = N>`. Note that this should not change anything which is stabilized, as on stable, type parameters must be in front of const parameters, which means that type parameter defaults are only allowed if no const parameters exist.
We still forbid generic parameters inside of const param types.
r? `@varkor` `@petrochenkov`
Cautiously add IntoIterator for arrays by value
Add the attribute described in #84133, `#[rustc_skip_array_during_method_dispatch]`, which effectively hides a trait from method dispatch when the receiver type is an array.
Then cherry-pick `IntoIterator for [T; N]` from #65819 and gate it with that attribute. Arrays can now be used as `IntoIterator` normally, but `array.into_iter()` has edition-dependent behavior, returning `slice::Iter` for 2015 and 2018 editions, or `array::IntoIter` for 2021 and later.
r? `@nikomatsakis`
cc `@LukasKalbertodt` `@rust-lang/libs`
further split up const_fn feature flag
This continues the work on splitting up `const_fn` into separate feature flags:
* `const_fn_trait_bound` for `const fn` with trait bounds
* `const_fn_unsize` for unsizing coercions in `const fn` (looks like only `dyn` unsizing is still guarded here)
I don't know if there are even any things left that `const_fn` guards... at least libcore and liballoc do not need it any more.
`@oli-obk` are you currently able to do reviews?
Implement a lint that highlights all moves larger than a configured limit
Tracking issue: #83518
[MCP 420](https://github.com/rust-lang/compiler-team/issues/420) still ~blazing~ in progress
r? ```@pnkfelix```
The main open issue I see with this minimal impl of the feature is that the lint is immediately "stable" (so it can be named on stable), even if it is never executed on stable. I don't think we have the concept of unstable lint names or hiding lint names without an active feature gate, so that would be a bigger change.
Introduce CompileMonoItem DepNode
This is likely required for allowing efficient hot code swap support in cg_clif's jit mode. My prototype currently requires re-compiling all functions, which is both slow and uses a lot of memory as there is not support for freeing the memory used by replaced functions yet.
cc https://github.com/bjorn3/rustc_codegen_cranelift/issues/1087
