Add `AsyncFn` family of traits
I'm proposing to add a new family of `async`hronous `Fn`-like traits to the standard library for experimentation purposes.
## Why do we need new traits?
On the user side, it is useful to be able to express `AsyncFn` trait bounds natively via the parenthesized sugar syntax, i.e. `x: impl AsyncFn(&str) -> String` when experimenting with async-closure code.
This also does not preclude `AsyncFn` becoming something else like a trait alias if a more fundamental desugaring (which can take many[^1] different[^2] forms) comes around. I think we should be able to play around with `AsyncFn` well before that, though.
I'm also not proposing stabilization of these trait names any time soon (we may even want to instead express them via new syntax, like `async Fn() -> ..`), but I also don't think we need to introduce an obtuse bikeshedding name, since `AsyncFn` just makes sense.
## The lending problem: why not add a more fundamental primitive of `LendingFn`/`LendingFnMut`?
Firstly, for `async` closures to be as flexible as possible, they must be allowed to return futures which borrow from the async closure's captures. This can be done by introducing `LendingFn`/`LendingFnMut` traits, or (equivalently) by adding a new generic associated type to `FnMut` which allows the return type to capture lifetimes from the `&mut self` argument of the trait. This was proposed in one of [Niko's blog posts](https://smallcultfollowing.com/babysteps/blog/2023/05/09/giving-lending-and-async-closures/).
Upon further experimentation, for the purposes of closure type- and borrow-checking, I've come to the conclusion that it's significantly harder to teach the compiler how to handle *general* lending closures which may borrow from their captures. This is, because unlike `Fn`/`FnMut`, the `LendingFn`/`LendingFnMut` traits don't form a simple "inheritance" hierarchy whose top trait is `FnOnce`.
```mermaid
flowchart LR
Fn
FnMut
FnOnce
LendingFn
LendingFnMut
Fn -- isa --> FnMut
FnMut -- isa --> FnOnce
LendingFn -- isa --> LendingFnMut
Fn -- isa --> LendingFn
FnMut -- isa --> LendingFnMut
```
For example:
```
fn main() {
let s = String::from("hello, world");
let f = move || &s;
let x = f(); // This borrows `f` for some lifetime `'1` and returns `&'1 String`.
```
That trait hierarchy means that in general for "lending" closures, like `f` above, there's not really a meaningful return type for `<typeof(f) as FnOnce>::Output` -- it can't return `&'static str`, for example.
### Special-casing this problem:
By splitting out these traits manually, and making sure that each trait has its own associated future type, we side-step the issue of having to answer the questions of a general `LendingFn`/`LendingFnMut` implementation, since the compiler knows how to generate built-in implementations for first-class constructs like async closures, including the required future types for the (by-move) `AsyncFnOnce` and (by-ref) `AsyncFnMut`/`AsyncFn` trait implementations.
[^1]: For example, with trait transformers, we may eventually be able to write: `trait AsyncFn = async Fn;`
[^2]: For example, via the introduction of a more fundamental "`LendingFn`" trait, plus a [special desugaring with augmented trait aliases](https://rust-lang.zulipchat.com/#narrow/stream/213817-t-lang/topic/Lending.20closures.20and.20Fn*.28.29.20-.3E.20impl.20Trait/near/408471480).
Modify GenericArg and Term structs to use strict provenance rules
This is the first PR to solve issue #119217 . In this PR, I have modified the GenericArg struct to use the `NonNull` struct as the pointer instead of `NonZeroUsize`. The change were tested by running `./x test compiler/rustc_middle`.
Resolves https://github.com/rust-lang/rust/issues/119217
r? `@WaffleLapkin`
Replacement of #114390: Add new intrinsic `is_var_statically_known` and optimize pow for powers of two
This adds a new intrinsic `is_val_statically_known` that lowers to [``@llvm.is.constant.*`](https://llvm.org/docs/LangRef.html#llvm-is-constant-intrinsic).` It also applies the intrinsic in the int_pow methods to recognize and optimize the idiom `2isize.pow(x)`. See #114390 for more discussion.
While I have extended the scope of the power of two optimization from #114390, I haven't added any new uses for the intrinsic. That can be done in later pull requests.
Note: When testing or using the library, be sure to use `--stage 1` or higher. Otherwise, the intrinsic will be a noop and the doctests will be skipped. If you are trying out edits, you may be interested in [`--keep-stage 0`](https://rustc-dev-guide.rust-lang.org/building/suggested.html#faster-builds-with---keep-stage).
Fixes#47234Resolves#114390
`@Centri3`
Remove all ConstPropNonsense
We track all locals and projections on them ourselves within the const propagator and only use the InterpCx to actually do some low level operations or read from constants (via `OpTy` we get for said constants).
This helps moving the const prop lint out from the normal pipeline and running it just based on borrowck information. This in turn allows us to make progress on https://github.com/rust-lang/rust/pull/108730#issuecomment-1875557745
there are various follow up cleanups that can be done after this PR (e.g. not matching on Rvalue twice and doing binop checks twice), but lets try landing this one first.
r? `@RalfJung`
They can't contain `\x` escapes, which means they can't contain high
bytes, which means we can used `unescape_unicode` instead of
`unescape_mixed` to unescape them. This avoids unnecessary used of
`MixedUnit`.
`unescape_literal` becomes `unescape_unicode`, and `unescape_c_string`
becomes `unescape_mixed`. Because rfc3349 will mean that C string
literals will no longer be the only mixed utf8 literals.
- Rename it as `MixedUnit`, because it will soon be used in more than
just C string literals.
- Change the `Byte` variant to `HighByte` and use it only for
`\x80`..`\xff` cases. This fixes the old inexactness where ASCII chars
could be encoded with either `Byte` or `Char`.
- Add useful comments.
- Remove `is_ascii`, in favour of `u8::is_ascii`.
The `T` type in these functions took me some time to understand, and I
find the explicit `T` in the use of `from` makes the code easier to
read, as does the `u8` annotation in `scan_escape`.
The parser already does a check-only unescaping which catches all
errors. So the checking done in `from_token_lit` never hits.
But literals causing warnings can still occur in `from_token_lit`. So
the commit changes `str-escape.rs` to use byte string literals and C
string literals as well, to give better coverage and ensure the new
assertions in `from_token_lit` are correct.
When encountering a type mismatch error involving `dyn Trait`, mention
the existence of boxed trait objects if the other type involved
implements `Trait`.
Partially addresses #102629.
privacy: Refactor top-level visiting in `TypePrivacyVisitor`
Full hierarchical visiting (`nested_filter::All`) is not necessary, visiting all item-likes in isolation is enough.
Tracking current item is not necessary, just keeping the current `mod` item is enough.
`visit_generic_arg` should behave like its default version, including checking types of const arguments.
Some comments, including FIXMEs, are also added.
Noticed while reading code to review https://github.com/rust-lang/rust/pull/113671.
r? ``@oli-obk``
coverage: Don't instrument `#[automatically_derived]` functions
This PR makes the coverage instrumentor detect and skip functions that have [`#[automatically_derived]`](https://doc.rust-lang.org/reference/attributes/derive.html#the-automatically_derived-attribute) on their enclosing impl block.
Most notably, this means that methods generated by built-in derives (e.g. `Clone`, `Debug`, `PartialEq`) are now ignored by coverage instrumentation, and won't appear as executed or not-executed in coverage reports.
This is a noticeable change in user-visible behaviour, but overall I think it's a net improvement. For example, we've had a few user requests for this sort of change (e.g. #105055, https://github.com/rust-lang/rust/issues/84605#issuecomment-1902069040), and I believe it's the behaviour that most users will expect/prefer by default.
It's possible to imagine situations where users would want to instrument these derived implementations, but I think it's OK to treat that as an opportunity to consider adding more fine-grained option flags to control the details of coverage instrumentation, while leaving this new behaviour as the default.
(Also note that while `-Cinstrument-coverage` is a stable feature, the exact details of coverage instrumentation are allowed to change. So we *can* make this change; the main question is whether we *should*.)
Fixes#105055.
Add a new `wasm32-wasi-preview2` target
This is the initial implementation of the MCP https://github.com/rust-lang/compiler-team/issues/694 creating a new tier 3 target `wasm32-wasi-preview2`. That MCP has been seconded and will most likely be approved in a little over a week from now. For more information on the need for this target, please read the [MCP](https://github.com/rust-lang/compiler-team/issues/694).
There is one aspect of this PR that will become insta-stable once these changes reach a stable compiler:
* A new `target_family` named `wasi` is introduced. This target family incorporates all wasi targets including `wasm32-wasi` and its derivative `wasm32-wasi-preview1-threads`. The difference between `target_family = wasi` and `target_os = wasi` will become much clearer when `wasm32-wasi` is renamed to `wasm32-wasi-preview1` and the `target_os` becomes `wasm32-wasi-preview1`. You can read about this target rename in [this MCP](https://github.com/rust-lang/compiler-team/issues/695) which has also been seconded and will hopefully be officially approved soon.
Additional technical details include:
* Both `std::sys::wasi_preview2` and `std::os::wasi_preview2` have been created and mostly use `#[path]` annotations on their submodules to reach into the existing `wasi` (soon to be `wasi_preview1`) modules. Over time the differences between `wasi_preview1` and `wasi_preview2` will grow and most like all `#[path]` based module aliases will fall away.
* Building `wasi-preview2` relies on a [`wasi-sdk`](https://github.com/WebAssembly/wasi-sdk) in the same way that `wasi-preview1` does (one must include a `wasi-root` path in the `Config.toml` pointing to sysroot included in the wasi-sdk). The target should build against [wasi-sdk v21](https://github.com/WebAssembly/wasi-sdk/releases/tag/wasi-sdk-21) without modifications. However, the wasi-sdk itself is growing [preview2 support](https://github.com/WebAssembly/wasi-sdk/pull/370) so this might shift rapidly. We will be following along quickly to make sure that building the target remains possible as the wasi-sdk changes.
* This requires a [patch to libc](https://github.com/rylev/rust-libc/tree/wasm32-wasi-preview2) that we'll need to land in conjunction with this change. Until that patch lands the target won't actually build.
coverage: Never emit improperly-ordered coverage regions
If we emit a coverage region that is improperly ordered (end < start), `llvm-cov` will fail with `coveragemap_error::malformed`, which is inconvenient for users and also very hard to debug.
Ideally we would fix the root causes of these situations, but they tend to occur in very obscure edge-case scenarios (often involving nested macros), and we don't always have a good MCVE to work from. So it makes sense to also have a catch-all check that will prevent improperly-ordered regions from ever being emitted.
---
This is mainly aimed at resolving #119453. We don't have a specific way to reproduce it, which is why I haven't been able to add a test case in this PR. But based on the information provided in that issue, this change seems likely to avoid the error in `llvm-cov`.
`````@rustbot````` label +A-code-coverage
Return a finite number of AllocIds per ConstAllocation in Miri
Before this, every evaluation of a const slice would produce a new AllocId. So in Miri, this program used to have unbounded memory use:
```rust
fn main() {
loop {
helper();
}
}
fn helper() {
"ouch";
}
```
Every trip around the loop creates a new AllocId which we need to keep track of a base address for. And the provenance GC can never clean up that AllocId -> u64 mapping, because the AllocId is for a const allocation which will never be deallocated.
So this PR moves the logic of producing an AllocId for a ConstAllocation to the Machine trait, and the implementation that Miri provides will only produce 16 AllocIds for each allocation. The cache is also keyed on the Instance that the const is evaluated in, so that equal consts evaluated in two functions will have disjoint base addresses.
r? RalfJung
Rollup of 9 pull requests
Successful merges:
- #112806 (Small code improvements in `collect_intra_doc_links.rs`)
- #119766 (Split tait and impl trait in assoc items logic)
- #120139 (Do not normalize closure signature when building `FnOnce` shim)
- #120160 (Manually implement derived `NonZero` traits.)
- #120171 (Fix assume and assert in jump threading)
- #120183 (Add `#[coverage(off)]` to closures introduced by `#[test]` and `#[bench]`)
- #120195 (add several resolution test cases)
- #120259 (Split Diagnostics for Uncommon Codepoints: Add List to Display Characters Involved)
- #120261 (Provide structured suggestion to use trait objects in some cases of `if` arm type divergence)
r? `@ghost`
`@rustbot` modify labels: rollup
Provide structured suggestion to use trait objects in some cases of `if` arm type divergence
```
error[E0308]: `if` and `else` have incompatible types
--> $DIR/suggest-box-on-divergent-if-else-arms.rs:15:9
|
LL | let _ = if true {
| _____________-
LL | | Struct
| | ------ expected because of this
LL | | } else {
LL | | foo()
| | ^^^^^ expected `Struct`, found `Box<dyn Trait>`
LL | | };
| |_____- `if` and `else` have incompatible types
|
= note: expected struct `Struct`
found struct `Box<dyn Trait>`
help: `Struct` implements `Trait` so you can box it to coerce to the trait object `Box<dyn Trait>`
|
LL | Box::new(Struct)
| +++++++++ +
error[E0308]: `if` and `else` have incompatible types
--> $DIR/suggest-box-on-divergent-if-else-arms.rs:20:9
|
LL | let _ = if true {
| _____________-
LL | | foo()
| | ----- expected because of this
LL | | } else {
LL | | Struct
| | ^^^^^^ expected `Box<dyn Trait>`, found `Struct`
LL | | };
| |_____- `if` and `else` have incompatible types
|
= note: expected struct `Box<dyn Trait>`
found struct `Struct`
= note: for more on the distinction between the stack and the heap, read https://doc.rust-lang.org/book/ch15-01-box.html, https://doc.rust-lang.org/rust-by-example/std/box.html, and https://doc.rust-lang.org/std/boxed/index.html
help: store this in the heap by calling `Box::new`
|
LL | Box::new(Struct)
| +++++++++ +
error[E0308]: `if` and `else` have incompatible types
--> $DIR/suggest-box-on-divergent-if-else-arms.rs:25:9
|
LL | fn bar() -> impl Trait {
| ---------- the found opaque type
...
LL | let _ = if true {
| _____________-
LL | | Struct
| | ------ expected because of this
LL | | } else {
LL | | bar()
| | ^^^^^ expected `Struct`, found opaque type
LL | | };
| |_____- `if` and `else` have incompatible types
|
= note: expected struct `Struct`
found opaque type `impl Trait`
help: `Struct` implements `Trait` so you can box both arms and coerce to the trait object `Box<dyn Trait>`
|
LL ~ Box::new(Struct) as Box<dyn Trait>
LL | } else {
LL ~ Box::new(bar())
|
error[E0308]: `if` and `else` have incompatible types
--> $DIR/suggest-box-on-divergent-if-else-arms.rs:30:9
|
LL | fn bar() -> impl Trait {
| ---------- the expected opaque type
...
LL | let _ = if true {
| _____________-
LL | | bar()
| | ----- expected because of this
LL | | } else {
LL | | Struct
| | ^^^^^^ expected opaque type, found `Struct`
LL | | };
| |_____- `if` and `else` have incompatible types
|
= note: expected opaque type `impl Trait`
found struct `Struct`
help: `Struct` implements `Trait` so you can box both arms and coerce to the trait object `Box<dyn Trait>`
|
LL ~ Box::new(bar()) as Box<dyn Trait>
LL | } else {
LL ~ Box::new(Struct)
|
```
Partially address #102629.
Split Diagnostics for Uncommon Codepoints: Add List to Display Characters Involved
This Pull Request adds a list of the uncommon codepoints involved in the `uncommon_codepoints` lint, as outlined as a first step in #120228.
Example rendered diagnostic:
```
error: identifier contains an uncommon Unicode codepoint: 'µ'
--> $DIR/lint-uncommon-codepoints.rs:3:7
|
LL | const µ: f64 = 0.000001;
| ^
|
note: the lint level is defined here
--> $DIR/lint-uncommon-codepoints.rs:1:9
|
LL | #![deny(uncommon_codepoints)]
| ^^^^^^^^^^^^^^^^^^^
```
(Retrying #120258.)
Add `#[coverage(off)]` to closures introduced by `#[test]` and `#[bench]`
These closures are an internal implementation detail of the `#[test]` and `#[bench]` attribute macros, so from a user perspective there is no reason to instrument them for coverage.
Skipping them makes coverage reports slightly cleaner, and will also allow other changes to span processing during coverage instrumentation, without having to worry about how they affect the `#[test]` macro.
The `#[coverage(off)]` attribute has no effect when `-Cinstrument-coverage` is not used.
Fixes#120046.
---
Note that this PR has no effect on the user-written function that has the `#[test]` attribute attached to it. That function will still be instrumented as normal.
Do not normalize closure signature when building `FnOnce` shim
It is not necessary to normalize the closure signature when building an `FnOnce` shim for an `Fn`/`FnMut` closure. That closure shim is just calling `FnMut::call_mut(&mut self)` anyways.
It's also somewhat sketchy that we were ever doing this to begin with, since we're normalizing with a `ParamEnv::reveal_all()` param-env, which is definitely not right with possibly polymorphic substs.
This cuts out a tiny bit of unnecessary work in `Instance::resolve` and simplifies the signature because now we can unconditionally return an `Instance`.
A bunch of random modifications
r? oli-obk
Kitchen sink of changes that I didn't know where to put elsewhere. Documentation tweaks mostly, but also removing some unreachable code and simplifying the pretty printing for closures/coroutines.
These were added with good intentions, but a recent change in LLVM 18
emits a warning while examining .rmeta sections in .rlib files. Since
this flag is a nice-to-have and users can update their LLVM linker
independently of rustc's LLVM version, we can just omit the flag.
const-eval interning: get rid of type-driven traversal
This entirely replaces our const-eval interner, i.e. the code that takes the final result of a constant evaluation from the local memory of the const-eval machine to the global `tcx` memory. The main goal of this change is to ensure that we can detect mutable references that sneak into this final value -- this is something we want to reject for `static` and `const`, and while const-checking performs some static analysis to ensure this, I would be much more comfortable stabilizing const_mut_refs if we had a dynamic check that sanitizes the final value. (This is generally the approach we have been using on const-eval: do a static check to give nice errors upfront, and then do a dynamic check to be really sure that the properties we need for soundness, actually hold.)
We can do this now that https://github.com/rust-lang/rust/pull/118324 landed and each pointer comes with a bit (completely independent of its type) storing whether mutation is permitted through this pointer or not.
The new interner is a lot simpler than the old one: previously we did a complete type-driven traversal to determine the mutability of all memory we see, and then a second pass to intern any leftover raw pointers. The new interner simply recursively traverses the allocation holding the final result, and all allocations reachable from it (which can be determined from the raw bytes of the result, without knowing anything about types), and ensures they all get interned. The initial allocation is interned as immutable for `const` and pomoted and non-interior-mutable `static`; all other allocations are interned as immutable for `static`, `const`, and promoted. The main subtlety is justifying that those inner allocations may indeed be interned immutably, i.e., that mutating them later would anyway already be UB:
- for promoteds, we rely on the analysis that does promotion to ensure that this is sound.
- for `const` and `static`, we check that all pointers in the final result that point to things that are new (i.e., part of this const evaluation) are immutable, i.e., were created via `&<expr>` at a non-interior-mutable type. Mutation through immutable pointers is UB so we are free to intern that memory as immutable.
Interning raises an error if it encounters a dangling pointer or a mutable pointer that violates the above rules.
I also extended our type-driven const validity checks to ensure that `&mut T` in the final value of a const points to mutable memory, at least if `T` is not zero-sized. This catches cases of people turning `&i32` into `&mut i32` (which would still be considered a read-only pointer). Similarly, when these checks encounter an `UnsafeCell`, they are checking that it lives in mutable memory. (Both of these only traverse the newly created values; if those point to other consts/promoteds, the check stops there. But that's okay, we don't have to catch all the UB.) I co-developed this with the stricter interner changes but I can split it out into a separate PR if you prefer.
This PR does have the immediate effect of allowing some new code on stable, for instance:
```rust
const CONST_RAW: *const Vec<i32> = &Vec::new() as *const _;
```
Previously that code got rejected since the type-based interner didn't know what to do with that pointer. It's a raw pointer, we cannot trust its type. The new interner does not care about types so it sees no issue with this code; there's an immutable pointer pointing to some read-only memory (storing a `Vec<i32>`), all is good. Accepting this code pretty much commits us to non-type-based interning, but I think that's the better strategy anyway.
This PR also leads to slightly worse error messages when the final value of a const contains a dangling reference. Previously we would complete interning and then the type-based validation would detect this dangling reference and show a nice error saying where in the value (i.e., in which field) the dangling reference is located. However, the new interner cannot distinguish dangling references from dangling raw pointers, so it must throw an error when it encounters either of them. It doesn't have an understanding of the value structure so all it can say is "somewhere in this constant there's a dangling pointer". (Later parts of the compiler don't like dangling pointers/references so we have to reject them either during interning or during validation.) This could potentially be improved by doing validation before interning, but that's a larger change that I have not attempted yet. (It's also subtle since we do want validation to use the final mutability bits of all involved allocations, and currently it is interning that marks a bunch of allocations as immutable -- that would have to still happen before validation.)
`@rust-lang/wg-const-eval` I hope you are okay with this plan. :)
`@rust-lang/lang` paging you in since this accepts new code on stable as explained above. Please let me know if you think FCP is necessary.
Only use dense bitsets in dataflow analyses
When a dataflow state has the size close to the number of locals, we should prefer a dense bitset, like we already store locals in a dense vector.
Other occurrences of `ChunkedBitSet` need to be justified by the size of the dataflow state.
riscv32im-risc0-zkvm-elf: add target
This pull request adds RISC Zero's Zero Knowledge Virtual Machine (zkVM) as a target for rust. The zkVM used to produce proofs of execution of RISC-V ELF binaries. In order to do this, the target will execute the ELF to generate a receipt containing the output of the computation along with a cryptographic seal. This receipt can be verified to ensure the integrity of the computation and its result. This target is implemented as software only; it has no hardware implementation.
## Tier 3 target policy:
Here is a copy of the tier 3 target policy:
> Tier 3 target policy:
>
> At this tier, the Rust project provides no official support for a target, so we
> place minimal requirements on the introduction of targets.
>
> A proposed new tier 3 target must be reviewed and approved by a member of the
> compiler team based on these requirements. The reviewer may choose to gauge
> broader compiler team consensus via a [[Major Change Proposal (MCP)](https://forge.rust-lang.org/compiler/mcp.html)](https://forge.rust-lang.org/compiler/mcp.html).
>
> A proposed target or target-specific patch that substantially changes code
> shared with other targets (not just target-specific code) must be reviewed and
> approved by the appropriate team for that shared code before acceptance.
>
> - 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.)
The maintainers are named in the target description file
> - 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.
> - 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.
> - If possible, use only letters, numbers, dashes and underscores for the name.
> Periods (`.`) are known to cause issues in Cargo.
>
We understand.
> - 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 target must not introduce license incompatibilities.
We understand and will not introduce incompatibilities. All of our code that we publish is licensed under Apache-2.0.
> - Anything added to the Rust repository must be under the standard Rust license (`MIT OR Apache-2.0`).
We understand. We are open to either license for the Rust repository.
> - 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.
We understand. The runtime libraries and the execution environment and software associated with this environment uses `Apache-2.0` so this should not be an issue.
> - 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.
We understand. We only depend on FOSS libraries. Dependencies such as runtime libraries for this target are licensed as `Apache-2.0`.
> - "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 such terms present
> - 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
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Revert stabilization of trait_upcasting feature
Reverts #118133
This reverts commit 6d2b84b3ed, reversing changes made to 73bc12199e.
The feature has a soundness bug:
* #120222
It is unclear to me whether we'll actually want to destabilize, but I thought it was still prudent to open the PR for easy destabilization once we get there.
Fix a `trimmed_def_paths` assertion failure.
`RegionHighlightMode::force_print_trimmed_def_path` can call `trimmed_def_paths` even when `tcx.sess.opts.trimmed_def_paths` is false. Based on the `force` in the method name, it seems this is deliberate, so I have removed the assertion.
Fixes#120035.
r? `@compiler-errors`
Track `verbose` and `verbose_internals`
`verbose_internals` has been UNTRACKED since it was introduced. When i added `verbose` in https://github.com/rust-lang/rust/pull/119129 i made it UNTRACKED as well.
``@bjorn3`` says: https://github.com/rust-lang/rust/pull/119286#discussion_r1436134354
> On errors we don't finalize the incr comp cache, but non-fatal diagnostics are cached afaik.
Otherwise we would have to replay the query in question, which we may not be able to do if the query key is not reconstructible from the dep node fingerprint.
So we must track these flags to avoid replaying incorrect diagnostics.
r? incremental
Consolidate logic around resolving built-in coroutine trait impls
Deduplicates a lot of code. Requires defining a new lang item for `Coroutine::resume` for consistency, but it seems not harmful at worst, and potentially later useful at best.
r? oli-obk
never_patterns: Count `!` bindings as diverging
A binding that is a never pattern is not reachable, hence counts as diverging code. This allows in particular `fn foo(!: Void) -> SomeType {}` to typecheck.
r? ``@compiler-errors``
When encountering
```rust
let _ = if true {
Struct
} else {
foo() // -> Box<dyn Trait>
};
```
if `Struct` implements `Trait`, suggest boxing the then arm tail expression.
Part of #102629.
Rollup of 10 pull requests
Successful merges:
- #117910 (Refactor uses of `objc_msgSend` to no longer have clashing definitions)
- #118639 (Undeprecate lint `unstable_features` and make use of it in the compiler)
- #119801 (Fix deallocation with wrong allocator in (A)Rc::from_box_in)
- #120058 (bootstrap: improvements for compiler builds)
- #120059 (Make generic const type mismatches not hide trait impls from the trait solver)
- #120097 (Report unreachable subpatterns consistently)
- #120137 (Validate AggregateKind types in MIR)
- #120164 (`maybe_lint_impl_trait`: separate `is_downgradable` from `is_object_safe`)
- #120181 (Allow any `const` expression blocks in `thread_local!`)
- #120218 (rustfmt: Check that a token can begin a nonterminal kind before parsing it as a macro arg)
r? `@ghost`
`@rustbot` modify labels: rollup
This also adds changes in the rust test suite in order to get a few of them to
pass.
Co-authored-by: Frank Laub <flaub@risc0.com>
Co-authored-by: Urgau <3616612+Urgau@users.noreply.github.com>
`maybe_lint_impl_trait`: separate `is_downgradable` from `is_object_safe`
https://github.com/rust-lang/rust/pull/119752 leveraged and overloaded `is_object_safe` to prevent an ICE, but accurate object safety information is needed for precise suggestions. This separates out `is_downgradable`, used for the ICE prevention, and `is_object_safe`, which returns to its original meaning.
Report unreachable subpatterns consistently
We weren't reporting unreachable subpatterns in function arguments and `let` expressions. This wasn't very important, but never patterns make it more relevant: a user might write `let (Ok(x) | Err(!)) = ...` in a case where `let Ok(x) = ...` is accepted, so we should report the `Err(!)` as redundant.
r? ```@compiler-errors```
Make generic const type mismatches not hide trait impls from the trait solver
pulled out of https://github.com/rust-lang/rust/pull/119895
It does improve diagnostics somewhat, but also causes some extraneous diagnostics in potentially misleading order.
The issue was that a const type mismatch, instead of reporting an error, would silently poison the constant, only for that information to be thrown away and the impl to be treated as "not matching". In #119895 this would cause ICEs as well as errors on impls stating that the impl needs to exist for itself to be valid.
Don't actually make bound ty/const for RTN
Avoid creating an unnecessary non-lifetime binder when we do RTN on a method that has ty/const params.
Fixes#120208
r? oli-obk
add help message for `exclusive_range_pattern` error
Fixes#120047
this error
```
error[E0658]: exclusive range pattern syntax is experimental
--> src/lib.rs:3:9
|
3 | 0..42 => {},
| ^^^^^
|
= note: see issue #37854 <https://github.com/rust-lang/rust/issues/37854> for more information
= help: use an inclusive range pattern, like N..=M
```
now includes a help message
Not sure of proper procedure here but this seemed like a good help message (used the one suggested in the original issue), if you have a idea for one that is better or something I missed please comment!
exclude unexported macro bindings from extern crate
Fixes#119301
Macros that aren't exported from an external crate should not be defined.
r? ``@petrochenkov``
Pack u128 in the compiler to mitigate new alignment
This is based on #116672, adding a new `#[repr(packed(8))]` wrapper on `u128` to avoid changing any of the compiler's size assertions. This is needed in two places:
* `SwitchTargets`, otherwise its `SmallVec<[u128; 1]>` gets padded up to 32 bytes.
* `LitKind::Int`, so that entire `enum` can stay 24 bytes.
* This change definitely has far-reaching effects though, since it's public.
Rollup of 9 pull requests
Successful merges:
- #118714 ( Explanation that fields are being used when deriving `(Partial)Ord` on enums)
- #119710 (Improve `let_underscore_lock`)
- #119726 (Tweak Library Integer Division Docs)
- #119746 (rustdoc: hide modals when resizing the sidebar)
- #119986 (Fix error counting)
- #120194 (Shorten `#[must_use]` Diagnostic Message for `Option::is_none`)
- #120200 (Correct the anchor of an URL in an error message)
- #120203 (Replace `#!/bin/bash` with `#!/usr/bin/env bash` in rust-installer tests)
- #120212 (Give nnethercote more reviews)
r? `@ghost`
`@rustbot` modify labels: rollup
`RegionHighlightMode::force_print_trimmed_def_path` can call
`trimmed_def_paths` even when `tcx.sess.opts.trimmed_def_paths` is
false. Based on the `force` in the method name, it seems this is
deliberate, so I have removed the assertion.
Fixes#120035.
We have several methods indicating the presence of errors, lint errors,
and delayed bugs. I find it frustrating that it's very unclear which one
you should use in any particular spot. This commit attempts to instill a
basic principle of "use the least general one possible", because that
reflects reality in practice -- `has_errors` is the least general one
and has by far the most uses (esp. via `abort_if_errors`).
Specifics:
- Add some comments giving some usage guidelines.
- Prefer `has_errors` to comparing `err_count` to zero.
- Remove `has_errors_or_span_delayed_bugs` because it's a weird one: in
the cases where we need to count delayed bugs, we should really be
counting lint errors as well.
- Rename `is_compilation_going_to_fail` as
`has_errors_or_lint_errors_or_span_delayed_bugs`, for consistency with
`has_errors` and `has_errors_or_lint_errors`.
- Change a few other `has_errors_or_lint_errors` calls to `has_errors`,
as per the "least general" principle.
This didn't turn out to be as neat as I hoped when I started, but I
think it's still an improvement.
