Make it explicit that the analysis direction is constant.
This also makes the value immediately available for optimizations.
Previously those functions were neither inline nor generic and so their
definition was unavailable when using data flow framework from other
crates.
Previously, the linker script forcefully kept all `.lib.stub` sections,
unnecessarily bloating the binary. Now, the script is LTO and
`--gc-sections` friendly.
`--nmagic` was also added to the linker, because page alignment is not
required on the PSP. This further reduces binary size.
Accompanying changes for the PSP crate are found in:
https://github.com/overdrivenpotato/rust-psp/pull/118
Rollup of 5 pull requests
Successful merges:
- #97058 (Various refactors to the incr comp workproduct handling)
- #97301 (Allow unstable items to be re-exported unstably without requiring the feature be enabled)
- #97738 (Fix ICEs from zsts within unsized types with non-zero offsets)
- #97771 (Remove SIGIO reference on Haiku)
- #97808 (Add some unstable target features for the wasm target codegen)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Add some unstable target features for the wasm target codegen
I was experimenting with cross-language LTO for the wasm target recently
between Rust and C and found that C was injecting the `+mutable-globals`
flag on all functions. When specifying the corresponding
`-Ctarget-feature=+mutable-globals` feature to Rust it prints a warning
about an unknown feature. I've added the `mutable-globals` feature plus
another few I know of to the list of known features for wasm targets.
These features all continue to be unstable to source code as they were
before.
Fix ICEs from zsts within unsized types with non-zero offsets
- Fixes#97732
- Fixes ICEs while compiling `alloc` with `-Z randomize-layout`
r? ``@eddyb``
Allow unstable items to be re-exported unstably without requiring the feature be enabled
Closes#94972
The diagnostic may need some work still, and I haven't added a test yet
Various refactors to the incr comp workproduct handling
This is the result of me looking into adding support for having multiple object files for a single codegen unit to incr comp. This is necessary to support inline assembly in cg_clif without requiring partial linking which is not supported on Windows and seems to fail on macOS for some reason. Cg_clif uses an external assembler to handle inline asm and thus produces one object file with regular functions and one object file containing compiled inline asm for each codegen unit which uses inline asm. Current incr comp can't handle this. This PR doesn't yet add support for this, but it makes it easier to do so.
Add support for emitting functions with `coldcc` to LLVM
The eventual goal is to try using this for things like the internal panicking stuff, to see whether it helps.
Remove migrate borrowck mode
Closes#58781Closes#43234
# Stabilization proposal
This PR proposes the stabilization of `#![feature(nll)]` and the removal of `-Z borrowck`. Current borrow checking behavior of item bodies is currently done by first infering regions *lexically* and reporting any errors during HIR type checking. If there *are* any errors, then MIR borrowck (NLL) never occurs. If there *aren't* any errors, then MIR borrowck happens and any errors there would be reported. This PR removes the lexical region check of item bodies entirely and only uses MIR borrowck. Because MIR borrowck could never *not* be run for a compiled program, this should not break any programs. It does, however, change diagnostics significantly and allows a slightly larger set of programs to compile.
Tracking issue: #43234
RFC: https://github.com/rust-lang/rfcs/blob/master/text/2094-nll.md
Version: 1.63 (2022-06-30 => beta, 2022-08-11 => stable).
## Motivation
Over time, the Rust borrow checker has become "smarter" and thus allowed more programs to compile. There have been three different implementations: AST borrowck, MIR borrowck, and polonius (well, in progress). Additionally, there is the "lexical region resolver", which (roughly) solves the constraints generated through HIR typeck. It is not a full borrow checker, but does emit some errors.
The AST borrowck was the original implementation of the borrow checker and was part of the initially stabilized Rust 1.0. In mid 2017, work began to implement the current MIR borrow checker and that effort ompleted by the end of 2017, for the most part. During 2018, efforts were made to migrate away from the AST borrow checker to the MIR borrow checker - eventually culminating into "migrate" mode - where HIR typeck with lexical region resolving following by MIR borrow checking - being active by default in the 2018 edition.
In early 2019, migrate mode was turned on by default in the 2015 edition as well, but with MIR borrowck errors emitted as warnings. By late 2019, these warnings were upgraded to full errors. This was followed by the complete removal of the AST borrow checker.
In the period since, various errors emitted by the MIR borrow checker have been improved to the point that they are mostly the same or better than those emitted by the lexical region resolver.
While there do remain some degradations in errors (tracked under the [NLL-diagnostics tag](https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3ANLL-diagnostics), those are sufficiently small and rare enough that increased flexibility of MIR borrow check-only is now a worthwhile tradeoff.
## What is stabilized
As said previously, this does not fundamentally change the landscape of accepted programs. However, there are a [few](https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3ANLL-fixed-by-NLL) cases where programs can compile under `feature(nll)`, but not otherwise.
There are two notable patterns that are "fixed" by this stabilization. First, the `scoped_threads` feature, which is a continutation of a pre-1.0 API, can sometimes emit a [weird lifetime error](https://github.com/rust-lang/rust/issues/95527) without NLL. Second, actually seen in the standard library. In the `Extend` impl for `HashMap`, there is an implied bound of `K: 'a` that is available with NLL on but not without - this is utilized in the impl.
As mentioned before, there are a large number of diagnostic differences. Most of them are better, but some are worse. None are serious or happen often enough to need to block this PR. The biggest change is the loss of error code for a number of lifetime errors in favor of more general "lifetime may not live long enough" error. While this may *seem* bad, the former error codes were just attempts to somewhat-arbitrarily bin together lifetime errors of the same type; however, on paper, they end up being roughly the same with roughly the same kinds of solutions.
## What isn't stabilized
This PR does not completely remove the lexical region resolver. In the future, it may be possible to remove that (while still keeping HIR typeck) or to remove it together with HIR typeck.
## Tests
Many test outputs get updated by this PR. However, there are number of tests specifically geared towards NLL under `src/test/ui/nll`
## History
* On 2017-07-14, [tracking issue opened](https://github.com/rust-lang/rust/issues/43234)
* On 2017-07-20, [initial empty MIR pass added](https://github.com/rust-lang/rust/pull/43271)
* On 2017-08-29, [RFC opened](https://github.com/rust-lang/rfcs/pull/2094)
* On 2017-11-16, [Integrate MIR type-checker with NLL](https://github.com/rust-lang/rust/pull/45825)
* On 2017-12-20, [NLL feature complete](https://github.com/rust-lang/rust/pull/46862)
* On 2018-07-07, [Don't run AST borrowck on mir mode](https://github.com/rust-lang/rust/pull/52083)
* On 2018-07-27, [Add migrate mode](https://github.com/rust-lang/rust/pull/52681)
* On 2019-04-22, [Enable migrate mode on 2015 edition](https://github.com/rust-lang/rust/pull/59114)
* On 2019-08-26, [Don't downgrade errors on 2015 edition](https://github.com/rust-lang/rust/pull/64221)
* On 2019-08-27, [Remove AST borrowck](https://github.com/rust-lang/rust/pull/64790)
I was experimenting with cross-language LTO for the wasm target recently
between Rust and C and found that C was injecting the `+mutable-globals`
flag on all functions. When specifying the corresponding
`-Ctarget-feature=+mutable-globals` feature to Rust it prints a warning
about an unknown feature. I've added the `mutable-globals` feature plus
another few I know of to the list of known features for wasm targets.
These features all continue to be unstable to source code as they were
before.
Rollup of 5 pull requests
Successful merges:
- #97312 (Compute lifetimes in scope at diagnostic time)
- #97495 (Add E0788 for improper #[no_coverage] usage)
- #97579 (Avoid creating `SmallVec`s in `global_llvm_features`)
- #97767 (interpret: do not claim UB until we looked more into variadic functions)
- #97787 (E0432: rust 2018 -> rust 2018 or later in --explain message)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
interpret: better control over whether we read data with provenance
The resolution in https://github.com/rust-lang/unsafe-code-guidelines/issues/286 seems to be that when we load data at integer type, we implicitly strip provenance. So let's implement that in Miri at least for scalar loads. This makes use of the fact that `Scalar` layouts distinguish pointer-sized integers and pointers -- so I was expecting some wild bugs where layouts set this incorrectly, but so far that does not seem to happen.
This does not entirely implement the solution to https://github.com/rust-lang/unsafe-code-guidelines/issues/286; we still do the wrong thing for integers in larger types: we will `copy_op` them and then do validation, and validation will complain about the provenance. To fix that we need mutating validation; validation needs to strip the provenance rather than complaining about it. This is a larger undertaking (but will also help resolve https://github.com/rust-lang/miri/issues/845 since we can reset padding to `Uninit`).
The reason this is useful is that we can now implement `addr` as a `transmute` from a pointer to an integer, and actually get the desired behavior of stripping provenance without exposing it!
interpret: do not claim UB until we looked more into variadic functions
I am not actually sure if this is UB, and anyway for FFI shims, Miri currently does not attempt to distinguish between arguments passed via variadics vs directly. So let's be consistent.
(Programs that ran into this error will anyway immediately fall through to the "unsupported" message on the next line.)
Avoid creating `SmallVec`s in `global_llvm_features`
This PR made a simple optimization to avoid creating extra `SmallVec`s by adjusting the use of iterator statements.
Also, given the very small size of `tied_target_features`, there is no need to insert each feature into the FxHashMap.
Add E0788 for improper #[no_coverage] usage
Essentially, this adds proper checking for the attribute (tracking issue #84605) and throws errors when it's put in obviously-wrong places, like on struct or const definitions. Most of the code is taken directly from the checks for the `#[inline]` attribute, since it's very similar.
Right now, the code only checks at the function level, but it seems reasonable to allow adding `#[no_coverage]` to individual blocks or expressions, so, for now those just throw `unused_attributes` warnings. Similarly, since there was a lot of desire to eventually allow recursive definitions as well on modules and impl blocks, these also throw `unused_attributes` instead of an error.
I'm not sure if anything has to be done since this error is technically for an unstable feature, but since an error for using unstable features will show up anyway, I think it's okay.
This is the first big piece needed for stabilising this attribute, although I personally would like to explore renaming it to `#[coverage(never)]` on a separate PR, which I will offer soon. There's a lot of discussion still to be had about that, which is why it will be kept separate.
I don't think much is needed besides adding this simple check and a UI test, but let me know if there's something else that should be added to make this happen.
Compute lifetimes in scope at diagnostic time
The set of available lifetimes is currently computed during lifetime resolution on HIR. It is only used for one diagnostic.
In this PR, HIR lifetime resolution just reports whether elided lifetimes are well-defined at the place of use. The diagnostic code is responsible for building a list of lifetime names if elision is not allowed.
This will allow to remove lifetime resolution on HIR eventually.
The test relies on library/std/src/error.rs not corresponding to a local
path, but remapping might still find the related local file of a
remapped path. To fix the test, this adds a new -Z flag to disable
finding the corresponding local path of a remapped path.
Do `suggest_await_before_try` with infer variables in self, and clean up binders
Fixes#97704
Also cleans up binders in this fn, since everything is a `Poly*` and we really shouldn't have stray escaping late-bound regions everywhere. That's why the function changed so much. This isn't necessary, so I can revert if necessary.
Replace `&Vec<_>`s with `&[_]`s
It's generally preferable to use `&[_]` since it's one less indirection and it can be created from types other that `Vec`.
I've left `&Vec` in some locals where it doesn't really matter, in cases where `TypeFoldable` is expected (`TypeFoldable: Clone` so slice can't implement it) and in cases where it's `&TypeAliasThatIsActiallyVec`. Nothing important, really, I was just a little annoyed by `visit_generic_param_vec` :D
r? `@compiler-errors`
riscv32imac-unknown-xous-elf: add target
This PR starts the process of upstreaming support for our operating system, thanks to a suggestion from `@yaahc` [on Twitter](https://twitter.com/yaahc_/status/1530558574706839567?s=20&t=Mgkn1LEYvGU6FEi5SpZRsA). We have maintained a fork of Rust and have made changes to improve support for our platform since Rust 1.51. Now we would like to upstream these changes.
Xous is a microkernel operating system designed to run on small systems. The kernel contains a wide range of userspace processes that provide common services such as console output, networking, and time access.
The kernel and its services are completely written in Rust using a custom build of libstd. This adds support for this target to upstream Rust so that we can drop support for our out-of-tree `target.json` file.
This first patch adds a Tier 3 target for Xous running on RISC-V. Future patches will add libstd support, but those patches require changes to `dlmalloc` and `compiler_builtins`.
> Tier 3 policy:
>
> A tier 3 target must have a designated developer or developers (the "target maintainers") on record to be CCed when issues arise regarding the target. (The mechanism to track and CC such developers may evolve over time.)
I will be the target maintainer for this target on matters that pertain to the `xous` part of the triple. For matters pertaining to the `riscv32imac` part of the triple, there should be no difference from all other `riscv` targets. If there are issues, I will address issues regarding the target.
> Targets must use naming consistent with any existing targets; for instance, a target for the same CPU or OS as an existing Rust target should use the same name for that CPU or OS. Targets should normally use the same names and naming conventions as used elsewhere in the broader ecosystem beyond Rust (such as in other toolchains), unless they have a very good reason to diverge. Changing the name of a target can be highly disruptive, especially once the target reaches a higher tier, so getting the name right is important even for a tier 3 target.
This is a new OS, so I have taken the `riscv32imac-unknown-none-elf` target and changed the `os` section of the triple. This follows convention on targets such as `riscv32gc-unknown-linux-gnu` and `mipsel-unknown-linux-uclibc`. An argument could be made for omitting the `-elf` section of the triple, such as `riscv32imc-esp-espidf`, however I'm not certain what benefit that has.
> Target names should not introduce undue confusion or ambiguity unless absolutely necessary to maintain ecosystem compatibility. For example, if the name of the target makes people extremely likely to form incorrect beliefs about what it targets, the name should be changed or augmented to disambiguate it.
I feel that the target name does not introduce any ambiguity.
> Tier 3 targets may have unusual requirements to build or use, but must not create legal issues or impose onerous legal terms for the Rust project or for Rust developers or users.
The only unusual requirement for building the `compiler-builtins` crate is a standard RISC-V C compiler supported by `cc-rs`, and using this target does not require any additional software beyond what is shipped by `rustup`.
> The target must not introduce license incompatibilities.
All of the additional code will use Apache-2.0.
> Anything added to the Rust repository must be under the standard Rust license (MIT OR Apache-2.0).
Agreed, and there is no problem here.
> The target must not cause the Rust tools or libraries built for any other host (even when supporting cross-compilation to the target) to depend on any new dependency less permissive than the Rust licensing policy. This applies whether the dependency is a Rust crate that would require adding new license exceptions (as specified by the tidy tool in the rust-lang/rust repository), or whether the dependency is a native library or binary. In other words, the introduction of the target must not cause a user installing or running a version of Rust or the Rust tools to be subject to any new license requirements.
The only new dependency will be the `xous` crate, which is licensed `MIT OR Apache-2.0`
> Compiling, linking, and emitting functional binaries, libraries, or other code for the target (whether hosted on the target itself or cross-compiling from another target) must not depend on proprietary (non-FOSS) libraries. Host tools built for the target itself may depend on the ordinary runtime libraries supplied by the platform and commonly used by other applications built for the target, but those libraries must not be required for code generation for the target; cross-compilation to the target must not require such libraries at all. For instance, rustc built for the target may depend on a common proprietary C runtime library or console output library, but must not depend on a proprietary code generation library or code optimization library. Rust's license permits such combinations, but the Rust project has no interest in maintaining such combinations within the scope of Rust itself, even at tier 3.
Linking is performed by `rust-lld`
> "onerous" here is an intentionally subjective term. At a minimum, "onerous" legal/licensing terms include but are not limited to: non-disclosure requirements, non-compete requirements, contributor license agreements (CLAs) or equivalent, "non-commercial"/"research-only"/etc terms, requirements conditional on the employer or employment of any particular Rust developers, revocable terms, any requirements that create liability for the Rust project or its developers or users, or any requirements that adversely affect the livelihood or prospects of the Rust project or its developers or users.
There are no terms. Xous is completely open. It runs on open hardware. We even provide the source to the CPU.
> Neither this policy nor any decisions made regarding targets shall create any binding agreement or estoppel by any party. If any member of an approving Rust team serves as one of the maintainers of a target, or has any legal or employment requirement (explicit or implicit) that might affect their decisions regarding a target, they must recuse themselves from any approval decisions regarding the target's tier status, though they may otherwise participate in discussions.
This paragraph makes sense, but I don't think it's directed at me.
> This requirement does not prevent part or all of this policy from being cited in an explicit contract or work agreement (e.g. to implement or maintain support for a target). This requirement exists to ensure that a developer or team responsible for reviewing and approving a target does not face any legal threats or obligations that would prevent them from freely exercising their judgment in such approval, even if such judgment involves subjective matters or goes beyond the letter of these requirements.
This paragraph also does not appear to be directed at me.
> Tier 3 targets should attempt to implement as much of the standard libraries as possible and appropriate (core for most targets, alloc for targets that can support dynamic memory allocation, std for targets with an operating system or equivalent layer of system-provided functionality), but may leave some code unimplemented (either unavailable or stubbed out as appropriate), whether because the target makes it impossible to implement or challenging to implement. The authors of pull requests are not obligated to avoid calling any portions of the standard library on the basis of a tier 3 target not implementing those portions.
So far we have:
* Thread
* Mutexex
* Condvar
* TcpStream
* TcpListener
* UdpSocket
* DateTime
* alloc
These will be merged as part of libstd in a future patch once I submit support for Xous in `dlmalloc` and `compiler-builtins`.
> The target must provide documentation for the Rust community explaining how to build for the target, using cross-compilation if possible. If the target supports running binaries, or running tests (even if they do not pass), the documentation must explain how to run such binaries or tests for the target, using emulation if possible or dedicated hardware if necessary.
Testing is currently done on real hardware or in a Renode emulator. I can add documentation on how to do this in a future patch, and I would need instructions on where to add said documentation.
> Tier 3 targets must not impose burden on the authors of pull requests, or other developers in the community, to maintain the target. In particular, do not post comments (automated or manual) on a PR that derail or suggest a block on the PR based on a tier 3 target. Do not send automated messages or notifications (via any medium, including via `@)` to a PR author or others involved with a PR regarding a tier 3 target, unless they have opted into such messages.
Alright.
> Backlinks such as those generated by the issue/PR tracker when linking to an issue or PR are not considered a violation of this policy, within reason. However, such messages (even on a separate repository) must not generate notifications to anyone involved with a PR who has not requested such notifications.
Sounds good.
> Patches adding or updating tier 3 targets must not break any existing tier 2 or tier 1 target, and must not knowingly break another tier 3 target without approval of either the compiler team or the maintainers of the other tier 3 target.
This shouldn't affect any other targets, so this is understood.
> In particular, this may come up when working on closely related targets, such as variations of the same architecture with different features. Avoid introducing unconditional uses of features that another variation of the target may not have; use conditional compilation or runtime detection, as appropriate, to let each target run code supported by that target.
This shouldn't come up right away. `xous` is a new operating system, and most features are keyed off of `target(os = "xous")` rather than a given architecture.
Handle more cases in cfg_accessible
This PR tries to handle more cases in the cfg_accessible implementation by only emitting a "not sure" error only if we have partially resolved a path.
This PR also adds many tests for the "not sure" cases and for private items.
r? `@petrochenkov`
Improve soundness of rustc_data_structures
Make it runnable in miri by adding some ignores and changing N in miri. Also fix a stacked borrows issue in sip128.
Iterate over `maybe_unused_trait_imports` when checking dead trait imports
Closes#96873
r? `@cjgillot`
Some questions, if you have time:
- Is there a way to shorten the `rustc_data_structures::fx::FxIndexSet` path in the query declaration? I wasn't sure where to put a `use`.
- Was returning by reference from the query the right choice here?
- How would I go about evaluating the importance of the `is_dummy()` call in `check_crate`? I don't see failing tests when I comment it out. Should I just try to determine whether dummy spans can ever be put into `maybe_unused_trait_imports`?
- Am I doing anything silly with the various ID types?
- Is that `let-else` with `unreachable!()` bad? (i.e is there a better idiom? Would `panic!("<explanation>")` be better?)
- If I want to evaluate the perf of using a `Vec` as mentioned in #96873, is the best way to use the CI or is it feasible locally?
Thanks :)
It creates the src pointer first, which is then invalidated by a
unique borrow of the destination pointer. Swap the borrows around
to fix this. Found with miri.
Some tests took too long and owning_ref is fundamentally flawed,
so don't run these tests or run them with a shorter N. This makes
miri with `-Zmiri-strict-provenance` usable to find UB.
Xous is a microkernel operating system designed to run on small systems.
The kernel contains a wide range of userspace processes that provide
common services such as console output, networking, and time access.
The kernel and its services are completely written in Rust using a
custom build of libstd. This adds support for this target to upstream
Rust so that we can drop support for our out-of-tree `target.json` file.
Add a Tier 3 target for Xous running on RISC-V.
Signed-off-by: Sean Cross <sean@xobs.io>
Fix reachability analysis for const methods
Use `method_might_be_inlined` directly for `ImplItemKind::Fn` instead of duplicating the logic in `def_id_represents_local_inlined_item`.
This is parallel to how we use `item_might_be_inlined` for `ItemKind::Fn` in that same body.
Fixes#97708
Remove all json handling from rustc_serialize
Json is now handled using serde_json. Where appropriate I have replaced json usage with binary serialization (rmeta files) or manual string formatting (emcc linker arg generation).
This allowed for removing and simplifying a lot of code, which hopefully results in faster serialization/deserialization and faster compiles of rustc itself.
Where sensible we now use serde. Metadata and incr cache serialization keeps using a heavily modified (compared to crates.io) rustc-serialize version that in the future could probably be extended with zero-copy deserialization or other perf tricks that serde can't support due to supporting more than one serialization format.
Note that I had to remove `-Zast-json` and `-Zast-json-noexpand` as the relevant AST types don't implement `serde::Serialize`.
Fixes#40177
See also https://github.com/rust-lang/compiler-team/issues/418
Compute `is_late_bound_map` query separately from lifetime resolution
This query is actually very simple, and is only useful for functions and method. It can be computed directly by fetching the HIR, with no need to embed it within the lifetime resolution visitor.
Based on https://github.com/rust-lang/rust/pull/96296
rewrite error handling for unresolved inference vars
Pretty much completely rewrites `fn emit_inference_failure_err`.
This new setup should hopefully be easier to extend and is already a lot better when looking for generic arguments.
Because this is a rewrite there are still some parts which are lacking, these are tracked in #94483 and will be fixed in later PRs.
r? `@estebank` `@petrochenkov`
On E0204 suggest missing type param bounds
```
error[E0204]: the trait `Copy` may not be implemented for this type
--> f42.rs:9:17
|
9 | #[derive(Debug, Copy, Clone)]
| ^^^^
10 | pub struct AABB<K>{
11 | pub loc: Vector2<K>,
| ------------------- this field does not implement `Copy`
12 | pub size: Vector2<K>
| -------------------- this field does not implement `Copy`
|
note: the `Copy` impl for `Vector2<K>` requires that `K: Debug`
--> f42.rs:11:5
|
11 | pub loc: Vector2<K>,
| ^^^^^^^^^^^^^^^^^^^
note: the `Copy` impl for `Vector2<K>` requires that `K: Debug`
--> f42.rs:12:5
|
12 | pub size: Vector2<K>
| ^^^^^^^^^^^^^^^^^^^^
= note: this error originates in the derive macro `Copy` (in Nightly builds, run with -Z macro-backtrace for more info)
help: consider restricting type parameter `K`
|
10 | pub struct AABB<K: Debug>{
| +++++++
```
Fix#89137.
take back half-baked noaliasing check in Assignment
Doing an aliasing check in `copy_op` does not make a ton of sense. We have to eventually do something in the `Assignment` statement handling instead.
Remove label/lifetime shadowing warnings
This PR removes some pre-1.0 shadowing warnings for labels and lifetimes.
The current behaviour of the compiler is to warn
* labels that shadow unrelated labels in the same function --> removed
```rust
'a: loop {}
'a: loop {} // STOP WARNING
```
* labels that shadow enclosing labels --> kept, but only if shadowing is hygienic
```rust
'a: loop {
'a: loop {} // KEEP WARNING
}
```
* labels that shadow lifetime --> removed
```rust
fn foo<'a>() {
'a: loop {} // STOP WARNING
}
```
* lifetimes that shadow labels --> removed
```rust
'a: loop {
let b = Box::new(|x: &i8| *x) as Box<dyn for <'a> Fn(&'a i8) -> i8>; // STOP WARNING
}
```
* lifetimes that shadow lifetimes --> kept
```rust
fn foo<'a>() {
let b = Box::new(|x: &i8| *x) as Box<dyn for <'a> Fn(&'a i8) -> i8>; // KEEP WARNING
}
```
Closes https://github.com/rust-lang/rust/issues/31745.
-----
From `@petrochenkov` in https://github.com/rust-lang/rust/pull/95781#issuecomment-1105199014
> I think we should remove these silly checks entirely.
> They were introduced long time ago in case some new language features appear and require this space.
> Now we have another mechanism for such language changes - editions, and if "lifetimes in expressions" or something like that needs to be introduced it could be introduced as an edition change.
> However, there was no plans to introduce anything like for years, so it's unlikely that even the edition mechanism will be necessary.
r? rust-lang/lang
don't use a `span_note` for ignored impls
Searching for the `derive` isn't too difficult as it's right above the field definition.
By using a span these errors are a lot more verbose than they should be, which is especially annoying as one can end up with a lot of `dead_code` warnings.
```
error[E0204]: the trait `Copy` may not be implemented for this type
--> f42.rs:9:17
|
9 | #[derive(Debug, Copy, Clone)]
| ^^^^
10 | pub struct AABB<K>{
11 | pub loc: Vector2<K>,
| ------------------- this field does not implement `Copy`
12 | pub size: Vector2<K>
| -------------------- this field does not implement `Copy`
|
note: the `Copy` impl for `Vector2<K>` requires that `K: Debug`
--> f42.rs:11:5
|
11 | pub loc: Vector2<K>,
| ^^^^^^^^^^^^^^^^^^^
note: the `Copy` impl for `Vector2<K>` requires that `K: Debug`
--> f42.rs:12:5
|
12 | pub size: Vector2<K>
| ^^^^^^^^^^^^^^^^^^^^
= note: this error originates in the derive macro `Copy` (in Nightly builds, run with -Z macro-backtrace for more info)
help: consider restricting type parameter `K`
|
10 | pub struct AABB<K: Debug>{
| +++++++
```
Fix#89137.
Lazify `SourceFile::lines`.
`SourceFile::lines` is a big part of metadata. It's stored in a compressed form
(a difference list) to save disk space. Decoding it is a big fraction of
compile time for very small crates/programs.
This commit introduces a new type `SourceFileLines` which has a `Lines`
form and a `Diffs` form. The latter is used when the metadata is first
read, and it is only decoded into the `Lines` form when line data is
actually needed. This avoids the decoding cost for many files,
especially in `std`. It's a performance win of up to 15% for tiny
crates/programs where metadata decoding is a high part of compilation
costs.
A `RefCell` is needed because the methods that access lines data (which can
trigger decoding) take `&self` rather than `&mut self`. To allow for this,
`SourceFile::lines` now takes a `FnMut` that operates on the lines slice rather
than returning the lines slice.
r? `@Mark-Simulacrum`
Revert #96682.
The change was "Show invisible delimiters (within comments) when pretty
printing". It's useful to show these delimiters, but is a breaking
change for some proc macros.
Fixes#97608.
r? ``@petrochenkov``
[RFC 2011] Basic compiler infrastructure
Splitting https://github.com/rust-lang/rust/pull/96496 into smaller pieces as was done in https://github.com/rust-lang/rust/pull/97233. Hope review will be easier.
This PR practically contains no logic and only serves as a building ground for the actual code that will be placed in a posterior step.
* Adds `context.rs` to place the new `assert!` logic. Has a lot of unused elements but all of them are used by the implementation.
* Creates an unstable flag because the feature is not yet complete and also to allow external feedback.
* Creates the necessary `sym` identifiers that are mostly based on the library elements -> https://github.com/rust-lang/rust/blob/master/library/core/src/asserting.rs
* Modifies `assert.rs` to branch to `context.rs` if the unstable flag is enabled.
* Adds a test to satisfy tidy but the test does nothing in reality.
Add #[rustc_box] and use it inside alloc
This commit adds an alternative content boxing syntax, and uses it inside alloc.
```Rust
#![feature(box_syntax)]
fn foo() {
let foo = box bar;
}
```
is equivalent to
```Rust
#![feature(rustc_attrs)]
fn foo() {
let foo = #[rustc_box] Box::new(bar);
}
```
The usage inside the very performance relevant code in
liballoc is the only remaining relevant usage of box syntax
in the compiler (outside of tests, which are comparatively easy to port).
box syntax was originally designed to be used by all Rust
developers. This introduces a replacement syntax more tailored
to only being used inside the Rust compiler, and with it,
lays the groundwork for eventually removing box syntax.
[Earlier work](https://github.com/rust-lang/rust/pull/87781#issuecomment-894714878) by `@nbdd0121` to lower `Box::new` to `box` during THIR -> MIR building ran into borrow checker problems, requiring the lowering to be adjusted in a way that led to [performance regressions](https://github.com/rust-lang/rust/pull/87781#issuecomment-894872367). The proposed change in this PR lowers `#[rustc_box] Box::new` -> `box` in the AST -> HIR lowering step, which is way earlier in the compiler, and thus should cause less issues both performance wise as well as regarding type inference/borrow checking/etc. Hopefully, future work can move the lowering further back in the compiler, as long as there are no performance regressions.
Diagnose anonymous lifetimes errors more uniformly between async and regular fns
Async fns and regular fns are desugared differently. For the former, we create a generic parameter at HIR level. For the latter, we just create an anonymous region for typeck.
I plan to migrate regular fns to the async fn desugaring.
Before that, this PR attempts to merge the diagnostics for both cases.
r? ```@estebank```
Apply track_caller to closure on `expect_non_local()`
r? `@petrochenkov`
Alternatively we could remove the closure by replicating the same logic of `map_id()`. I'm happy to switch to it if you'd like.
Add Windows application manifest to rustc-main
Windows allows setting some runtime options using a manifest file. The format of the XML file is documented here: https://docs.microsoft.com/en-us/windows/win32/sbscs/application-manifests
The manifest file in this PR does three things:
* Declares which Windows versions we support. This may help avoid unnecessary compatibility shims.
* Uses the UTF-8 code page. While Rust itself uses UTF-16 APIs, other code may rely on the code page.
* Makes the application long path aware (if also enabled by the user). This allows for the current directory to be longer than `PATH_MAX`.
These changes only affect the `rustc` process and not any other DLLs or compiled programs.
The change was "Show invisible delimiters (within comments) when pretty
printing". It's useful to show these delimiters, but is a breaking
change for some proc macros.
Fixes#97608.
rename PointerAddress → PointerExposeAddress
`PointerAddress` sounds a bit too much like `ptr.addr()`, but this corresponds to `ptr.expose_addr()`.
r? `@tmiasko`
Move conditions out of recover/report functions.
`Parser` has six recover/report functions that are passed a boolean, and
nothing is done if the boolean has a particular value.
This PR moves the tests outside the functions. This has the following effects.
- The number of lines of code goes down.
- Some `use` items become shorter.
- Avoids the strangeness whereby 11 out of 12 calls to
`maybe_recover_from_bad_qpath` pass `true` as the second argument.
- Makes it clear at the call site that only one of
`maybe_recover_from_bad_type_plus` and `maybe_report_ambiguous_plus` will be
run.
r? `@estebank`
* Confirm the path segment being modified is an `enum`
* Check whether type has type param before suggesting changing `Self`
* Wording changes
* Add clarifying comments
* Suggest removing args from `Self` if the type doesn't have type params
Rollup of 4 pull requests
Successful merges:
- #96271 (suggest `?` when method is missing on `Result<T, _>` but found on `T`)
- #97264 (Suggest `extern crate foo` when failing to resolve `use foo`)
- #97592 (rustdoc: also index impl trait and raw pointers)
- #97621 (update Miri)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Tweak insert docs
For `{Hash, BTree}Map::insert`, I always have to take a few extra seconds to think about the slight weirdness about the fact that if we "did not" insert (which "sounds" false), we return true, and if we "did" insert, (which "sounds" true), we return false.
This tweaks the doc comments for the `insert` methods of those types (as well as what looks like a rustc internal data structure that I found just by searching the codebase for "If the set did") to first use the "Returns whether _something_" pattern used in e.g. `remove`, where we say that `remove` "returns whether the value was present".
simplify code of finding arg index in `opt_const_param_of`
From the FIXME in the impl of `opt_const_param_of`. Part of the code is simplified by blending two iterator statements and using `let...else` statement.
Ensure we never consider the null pointer dereferencable
This replaces the checks that are being removed in https://github.com/rust-lang/rust/pull/97188. Those checks were too early and hence incorrect.
`SourceFile::lines` is a big part of metadata. It's stored in a compressed form
(a difference list) to save disk space. Decoding it is a big fraction of
compile time for very small crates/programs.
This commit introduces a new type `SourceFileLines` which has a `Lines`
form and a `Diffs` form. The latter is used when the metadata is first
read, and it is only decoded into the `Lines` form when line data is
actually needed. This avoids the decoding cost for many files,
especially in `std`. It's a performance win of up to 15% for tiny
crates/programs where metadata decoding is a high part of compilation
costs.
A `Lock` is needed because the methods that access lines data (which can
trigger decoding) take `&self` rather than `&mut self`. To allow for this,
`SourceFile::lines` now takes a `FnMut` that operates on the lines slice rather
than returning the lines slice.
This commit adds an alternative content boxing syntax,
and uses it inside alloc.
The usage inside the very performance relevant code in
liballoc is the only remaining relevant usage of box syntax
in the compiler (outside of tests, which are comparatively
easy to port).
box syntax was originally designed to be used by all Rust
developers. This introduces a replacement syntax more tailored
to only being used inside the Rust compiler, and with it,
lays the groundwork for eventually removing box syntax.
Rollup of 6 pull requests
Successful merges:
- #89685 (refactor: VecDeques Iter fields to private)
- #97172 (Optimize the diagnostic generation for `extern unsafe`)
- #97395 (Miri call ABI check: ensure type size+align stay the same)
- #97431 (don't do `Sized` and other return type checks on RPIT's real type)
- #97555 (Source code page: line number click adds `NaN`)
- #97558 (Fix typos in comment)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
