only find segs chain for missing methods when no available candidates
Fixes#124946
This PR includes two changes:
- Extracting the lookup for the missing method in chains into a single function.
- Calling this function only when there are no candidates available.
Add x86_64-unknown-linux-none target
Adds a freestanding linux binary with no libc dependency. This is useful for writing programs written only in rust. It is also essential for writing low level stuff like libc or a dynamic linker.
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 designed maintainer for this 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.
The target triple is consistent with other targets
>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.
There is no confusion with other targets since it explicitly adds "none" at the end instead of omitting the environment
>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 does not introduce any unusual requirement
>The target must not introduce license incompatibilities.
There are no license incompatibilities
> Anything added to the Rust repository must be under the standard Rust license (MIT OR Apache-2.0).
Everything added is under that license
>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.
There are no new dependencies
>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.
There is no proprietary dependencies
>"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.
No such terms exist for this target
>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 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.
Understood
>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.
The target already implements core. It might be possible in the future to add support for alloc and std by leveraging crates such as [origin](https://github.com/sunfishcode/origin/) and [rustix](https://github.com/bytecodealliance/rustix)
> 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.
I believe the proper docs are added
>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.
> 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.
Understood
> 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.
> 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.
No other targets are effected
>Tier 3 targets must be able to produce assembly using at least one of rustc's supported backends from any host target.
The same backends used by other linux targets work without issues
Warn against changes in opaque lifetime captures in 2024
Adds a (mostly[^1]) machine-applicable lint `IMPL_TRAIT_OVERCAPTURES` which detects cases where we will capture more lifetimes in edition 2024 than in edition <= 2021, which may lead to erroneous borrowck errors.
This lint is gated behind the `precise_capturing` feature gate and marked `Allow` for now.
[^1]: Except when there are APITs -- I may work on that soon
r? oli-obk
Rollup of 4 pull requests
Successful merges:
- #116675 ([ptr] Document maximum allocation size)
- #124997 (Fix ICE while casting a type with error)
- #125072 (Add test for dynamic dispatch + Pin::new soundness)
- #125090 (Migrate fuchsia docs from `pm` to `ffx`)
r? `@ghost`
`@rustbot` modify labels: rollup
Remove `NtIdent` and `NtLifetime`
This is one part of the bigger "remove `Nonterminal` and `TokenKind::Interpolated`" change drafted in #114647. More details in the individual commit messages.
r? `@petrochenkov`
Split out `ty::AliasTerm` from `ty::AliasTy`
Splitting out `AliasTerm` (for use in project and normalizes goals) and `AliasTy` (for use in `ty::Alias`)
r? lcnr
The extra span is now recorded in the new `TokenKind::NtIdent` and
`TokenKind::NtLifetime`. These both consist of a single token, and so
there's no operator precedence problems with inserting them directly
into the token stream.
The other way to do this would be to wrap the ident/lifetime in invisible
delimiters, but there's a lot of code that assumes an interpolated
ident/lifetime fits in a single token, and changing all that code to work with
invisible delimiters would have been a pain. (Maybe it could be done in a
follow-up.)
This change might not seem like much of a win, but it's a first step toward the
much bigger and long-desired removal of `Nonterminal` and
`TokenKind::Interpolated`. That change is big and complex enough that it's
worth doing this piece separately. (Indeed, this commit is based on part of a
late commit in #114647, a prior attempt at that big and complex change.)
Subtree sync for rustc_codegen_cranelift
A variety of bug fixes, added support for naked functions, a couple more vendor intrinsics implemented.
r? `@ghost`
`@rustbot` label +A-codegen +A-cranelift +T-compiler
Unify `Rvalue::Aggregate` paths in cg_ssa
In #123840 and #123886 I added two different codepaths for `Rvalue::Aggregate` in `cg_ssa`.
This merges them into one, since raw pointers are also immediates that can be built from the immediates of their "fields".
Avoid clone in `Comments::next`
`Comments::next`, in `rustc_ast_pretty`, has this comment:
```
// FIXME: This shouldn't probably clone lmao
```
The obvious thing to try is to return `Option<&Comment>` instead of `Option<Comment>`. But that leads to multiple borrows all over the place, because `Comments` must be borrowed from `PrintState` and then processed by `&mut self` methods within `PrintState`.
This PR instead rearranges things so that comments are consumed as they are used, preserving the `Option<Comment>` return type without requiring any cloning.
r? `@compiler-errors`
This span records the declaration of the metavariable in the LHS of the macro.
It's used in a couple of error messages. Unfortunately, it gets in the way of
the long-term goal of removing `TokenKind::Interpolated`. So this commit
removes it, which degrades a couple of (obscure) error messages but makes
things simpler and enables the next commit.
Remove `#[macro_use] extern crate rustc middle` from numerous crates
Because explicit importing of macros via `use` items is nicer (more standard and readable) than implicit importing via `#[macro_use]`. This PR mops up some cases I didn't get to in #124511.
r? `@saethlin`
The current way of stepping through each comment in `Comments` is a bit
weird. There is a `Vec<Comments>` and a `current` index, which is fine.
The `Comments::next` method clones the current comment but doesn't
advance `current`; the advancing instead happens in `print_comment`,
which is where each cloned comment is actually finally used (or not, in
some cases, if the comment fails to satisfy a predicate).
This commit makes things more iterator-like:
- `Comments::next` now advances `current` instead of `print_comment`.
- `Comments::peek` is added so you can inspect a comment and check a
predicate without consuming it.
- This requires splitting `PrintState::comments` into immutable and
mutable versions. The commit also moves the ref inside the `Option` of
the return type, to save callers from having to use `as_ref`/`as_mut`.
- It also requires adding `PrintState::peek_comment` alongside the
existing `PrintState::next_comment`. (The lifetimes in the signature
of `peek_comment` ended up more complex than I expected.)
We now have a neat separation between consuming (`next`) and
non-consuming (`peek`) uses of each comment. As well as being clearer,
this will facilitate the next commit that avoids unnecessary cloning.
Pretty-print let-else with added parenthesization when needed
Rustc used to produce invalid syntax for the following code, which is problematic because it means we cannot apply rustfmt to the output of `-Zunpretty=expanded`.
```rust
macro_rules! expr {
($e:expr) => { $e };
}
fn main() {
let _ = expr!(loop {}) else { return; };
}
```
```console
$ rustc repro.rs -Zunpretty=expanded | rustfmt
error: `loop...else` loops are not supported
--> <stdin>:9:29
|
9 | fn main() { let _ = loop {} else { return; }; }
| ---- ^^^^^^^^^^^^^^^^
| |
| `else` is attached to this loop
|
= note: consider moving this `else` clause to a separate `if` statement and use a `bool` variable to control if it should run
```
