Remove global `next_disambiguator` state and handle it with a `DisambiguatorState` type
This removes `Definitions.next_disambiguator` as it doesn't guarantee deterministic def paths when `create_def` is called in parallel. Instead a new `DisambiguatorState` type is passed as a mutable reference to `create_def` to help create unique def paths. `create_def` calls with distinct `DisambiguatorState` instances must ensure that that the def paths are unique without its help.
Anon associated types did rely on this global state for uniqueness and are changed to use (method they're defined in + their position in the method return type) as the `DefPathData` to ensure uniqueness. This also means that the method they're defined in appears in error messages, which is nicer.
`DefPathData::NestedStatic` is added to use for nested data inside statics instead of reusing `DefPathData::AnonConst` to avoid conflicts with those.
cc `@oli-obk`
The edition gate is a bit stricter than the drop behaviour,
which is fine. The cases we want to avoid are the opposite:
not gated but 2021 drop behaviour.
Explicitly annotate edition for `unpretty=expanded` and `unpretty=hir` tests
These emit prelude imports which means they are always edition dependent and so running them with a different `--edition` will fail.
Stabilize `cfg_boolean_literals`
Closes#131204
`@rustbot` labels +T-lang +I-lang-nominated
This will end up conflicting with the test in #138293 so whichever doesn't land first will need updating
--
# Stabilization Report
## General design
### What is the RFC for this feature and what changes have occurred to the user-facing design since the RFC was finalized?
[RFC 3695](https://github.com/rust-lang/rfcs/pull/3695), none.
### What behavior are we committing to that has been controversial? Summarize the major arguments pro/con.
None
### Are there extensions to this feature that remain unstable? How do we know that we are not accidentally committing to those?
None
## Has a call-for-testing period been conducted? If so, what feedback was received?
Yes; only positive feedback was received.
## Implementation quality
### Summarize the major parts of the implementation and provide links into the code (or to PRs)
Implemented in [#131034](https://github.com/rust-lang/rust/pull/131034).
### Summarize existing test coverage of this feature
- [Basic usage, including `#[cfg()]`, `cfg!()` and `#[cfg_attr()]`](6d71251cf9/tests/ui/cfg/true-false.rs)
- [`--cfg=true/false` on the command line being accessible via `r#true/r#false`](6d71251cf9/tests/ui/cfg/raw-true-false.rs)
- [Interaction with the unstable `#[doc(cfg(..))]` feature](https://github.com/rust-lang/rust/tree/6d71251/tests/rustdoc-ui/cfg-boolean-literal.rs)
- [Denying `--check-cfg=cfg(true/false)`](https://github.com/rust-lang/rust/tree/6d71251/tests/ui/check-cfg/invalid-arguments.rs)
- Ensuring `--cfg false` on the command line doesn't change the meaning of `cfg(false)`: `tests/ui/cfg/cmdline-false.rs`
- Ensuring both `cfg(true)` and `cfg(false)` on the same item result in it being disabled: `tests/ui/cfg/both-true-false.rs`
### What outstanding bugs in the issue tracker involve this feature? Are they stabilization-blocking?
The above mentioned issue; it should not block as it interacts with another unstable feature.
### What FIXMEs are still in the code for that feature and why is it ok to leave them there?
None
### Summarize contributors to the feature by name for recognition and assuredness that people involved in the feature agree with stabilization
- `@clubby789` (RFC)
- `@Urgau` (Implementation in rustc)
### Which tools need to be adjusted to support this feature. Has this work been done?
`rustdoc`'s unstable`#[doc(cfg(..)]` has been updated to respect it. `cargo` has been updated with a forward compatibility lint to enable supporting it in cargo once stabilized.
## Type system and execution rules
### What updates are needed to the reference/specification? (link to PRs when they exist)
A few lines to be added to the reference for configuration predicates, specified in the RFC.
Notes about tests:
- tests/ui/rfcs/rfc-2294-if-let-guard/feature-gate.rs: some messages are
now duplicated due to repeated parsing.
- tests/ui/rfcs/rfc-2497-if-let-chains/disallowed-positions.rs: ditto.
- `tests/ui/proc-macro/macro-rules-derive-cfg.rs`: the diff looks large
but the only difference is the insertion of a single
invisible-delimited group around a metavar.
- `tests/ui/attributes/nonterminal-expansion.rs`: a slight span
degradation, somehow related to the recent massive attr parsing
rewrite (#135726). I couldn't work out exactly what is going wrong,
but I don't think it's worth holding things up for a single slightly
suboptimal error message.
raw-dylib is a link kind that allows rustc to link against a library
without having any library files present.
This currently only exists on Windows. rustc will take all the symbols
from raw-dylib link blocks and put them in an import library, where they
can then be resolved by the linker.
While import libraries don't exist on ELF, it would still be convenient
to have this same functionality. Not having the libraries present at
build-time can be convenient for several reasons, especially
cross-compilation. With raw-dylib, code linking against a library can be
cross-compiled without needing to have these libraries available on the
build machine. If the libc crate makes use of this, it would allow
cross-compilation without having any libc available on the build
machine. This is not yet possible with this implementation, at least
against libc's like glibc that use symbol versioning.
The raw-dylib kind could be extended with support for symbol versioning
in the future.
This implementation is very experimental and I have not tested it very
well. I have tested it for a toy example and the lz4-sys crate, where it
was able to successfully link a binary despite not having a
corresponding library at build-time.
Always perform discr read for never pattern in EUV
Always perform a read of `!` discriminants to ensure that it's captured by closures in expr use visitor
Fixes#136852
r? Nadrieril or reassign
Stabilize target_feature_11
# Stabilization report
This is an updated version of https://github.com/rust-lang/rust/pull/116114, which is itself a redo of https://github.com/rust-lang/rust/pull/99767. Most of this commit and report were copied from those PRs. Thanks ```@LeSeulArtichaut``` and ```@calebzulawski!```
## Summary
Allows for safe functions to be marked with `#[target_feature]` attributes.
Functions marked with `#[target_feature]` are generally considered as unsafe functions: they are unsafe to call, cannot *generally* be assigned to safe function pointers, and don't implement the `Fn*` traits.
However, calling them from other `#[target_feature]` functions with a superset of features is safe.
```rust
// Demonstration function
#[target_feature(enable = "avx2")]
fn avx2() {}
fn foo() {
// Calling `avx2` here is unsafe, as we must ensure
// that AVX is available first.
unsafe {
avx2();
}
}
#[target_feature(enable = "avx2")]
fn bar() {
// Calling `avx2` here is safe.
avx2();
}
```
Moreover, once https://github.com/rust-lang/rust/pull/135504 is merged, they can be converted to safe function pointers in a context in which calling them is safe:
```rust
// Demonstration function
#[target_feature(enable = "avx2")]
fn avx2() {}
fn foo() -> fn() {
// Converting `avx2` to fn() is a compilation error here.
avx2
}
#[target_feature(enable = "avx2")]
fn bar() -> fn() {
// `avx2` coerces to fn() here
avx2
}
```
See the section "Closures" below for justification of this behaviour.
## Test cases
Tests for this feature can be found in [`tests/ui/target_feature/`](f6cb952dc1/tests/ui/target-feature).
## Edge cases
### Closures
* [target-feature 1.1: should closures inherit target-feature annotations? #73631](https://github.com/rust-lang/rust/issues/73631)
Closures defined inside functions marked with #[target_feature] inherit the target features of their parent function. They can still be assigned to safe function pointers and implement the appropriate `Fn*` traits.
```rust
#[target_feature(enable = "avx2")]
fn qux() {
let my_closure = || avx2(); // this call to `avx2` is safe
let f: fn() = my_closure;
}
```
This means that in order to call a function with #[target_feature], you must guarantee that the target-feature is available while the function, any closures defined inside it, as well as any safe function pointers obtained from target-feature functions inside it, execute.
This is usually ensured because target features are assumed to never disappear, and:
- on any unsafe call to a `#[target_feature]` function, presence of the target feature is guaranteed by the programmer through the safety requirements of the unsafe call.
- on any safe call, this is guaranteed recursively by the caller.
If you work in an environment where target features can be disabled, it is your responsibility to ensure that no code inside a target feature function (including inside a closure) runs after this (until the feature is enabled again).
**Note:** this has an effect on existing code, as nowadays closures do not inherit features from the enclosing function, and thus this strengthens a safety requirement. It was originally proposed in #73631 to solve this by adding a new type of UB: “taking a target feature away from your process after having run code that uses that target feature is UB” .
This was motivated by userspace code already assuming in a few places that CPU features never disappear from a program during execution (see i.e. 2e29bdf908/crates/std_detect/src/detect/arch/x86.rs); however, concerns were raised in the context of the Linux kernel; thus, we propose to relax that requirement to "causing the set of usable features to be reduced is unsafe; when doing so, the programmer is required to ensure that no closures or safe fn pointers that use removed features are still in scope".
* [Fix #[inline(always)] on closures with target feature 1.1 #111836](https://github.com/rust-lang/rust/pull/111836)
Closures accept `#[inline(always)]`, even within functions marked with `#[target_feature]`. Since these attributes conflict, `#[inline(always)]` wins out to maintain compatibility.
### ABI concerns
* [The extern "C" ABI of SIMD vector types depends on target features #116558](https://github.com/rust-lang/rust/issues/116558)
The ABI of some types can change when compiling a function with different target features. This could have introduced unsoundness with target_feature_11, but recent fixes (#133102, #132173) either make those situations invalid or make the ABI no longer dependent on features. Thus, those issues should no longer occur.
### Special functions
The `#[target_feature]` attribute is forbidden from a variety of special functions, such as main, current and future lang items (e.g. `#[start]`, `#[panic_handler]`), safe default trait implementations and safe trait methods.
This was not disallowed at the time of the first stabilization PR for target_features_11, and resulted in the following issues/PRs:
* [`#[target_feature]` is allowed on `main` #108645](https://github.com/rust-lang/rust/issues/108645)
* [`#[target_feature]` is allowed on default implementations #108646](https://github.com/rust-lang/rust/issues/108646)
* [#[target_feature] is allowed on #[panic_handler] with target_feature 1.1 #109411](https://github.com/rust-lang/rust/issues/109411)
* [Prevent using `#[target_feature]` on lang item functions #115910](https://github.com/rust-lang/rust/pull/115910)
## Documentation
* Reference: [Document the `target_feature_11` feature reference#1181](https://github.com/rust-lang/reference/pull/1181)
---
cc tracking issue https://github.com/rust-lang/rust/issues/69098
cc ```@workingjubilee```
cc ```@RalfJung```
r? ```@rust-lang/lang```
```
error[E0610]: `{integer}` is a primitive type and therefore doesn't have fields
--> $DIR/attempted-access-non-fatal.rs:7:15
|
LL | let _ = 2.l;
| ^
|
help: if intended to be a floating point literal, consider adding a `0` after the period and a `f64` suffix
|
LL - let _ = 2.l;
LL + let _ = 2.0f64;
|
```
Clean up all dead files inside `tests/ui/`
While rebasing #135860 I noticed that there are several dead `*.stderr` files inside `tests/ui/`.
When I checked thoroughly, I found 69 dead `*.$revision.stderr` files, 3 other dead `*.stderr` files and one dead `*.rs` file.
Prior to #134808, compiletest's `--bless` didn't remove dead `*.stderr` files when the set of revisions changed in any way (renamings, removals, additions, …) which explains their existence.
Regarding the dead `*.rs` file, that one was located inside an `auxiliary/` directory (together with a `*.stderr` file) despite not being meant to be an auxiliary file (it's not referenced by any `//@ aux-*`, it has an accompanying `*.stderr` file and it's obvious from looking at #111056 which added it). Ideally compiletest or tidy would forbid `*.std{out,err}` files inside `auxiliary/` dirs, that would've caught it. I moved it, updated it and turned it into a proper UI test.
---
How to reproduce:
1. Run `rm tests/ui/**/*.stderr`
2. Run `./x test tests/ui --bless` (or similar)
3. Manually / semi-automatically go through all tests that were ignored (likely due to your OS etc. not matching) and restore any stderr files that were overzealously removed
---
r? compiler
Reword resolve errors caused by likely missing crate in dep tree
Reword label and add `help`:
```
error[E0432]: unresolved import `some_novel_crate`
--> f704.rs:1:5
|
1 | use some_novel_crate::Type;
| ^^^^^^^^^^^^^^^^ use of unresolved module or unlinked crate `some_novel_crate`
|
= help: if you wanted to use a crate named `some_novel_crate`, use `cargo add some_novel_crate` to add it to your `Cargo.toml`
```
Fix#133137.
```
error[E0432]: unresolved import `some_novel_crate`
--> file.rs:1:5
|
1 | use some_novel_crate::Type;
| ^^^^^^^^^^^^^^^^ use of unresolved module or unlinked crate `some_novel_crate`
```
On resolve errors where there might be a missing crate, mention `cargo add foo`:
```
error[E0433]: failed to resolve: use of unresolved module or unlinked crate `nope`
--> $DIR/conflicting-impl-with-err.rs:4:11
|
LL | impl From<nope::Thing> for Error {
| ^^^^ use of unresolved module or unlinked crate `nope`
|
= help: if you wanted to use a crate named `nope`, use `cargo add nope` to add it to your `Cargo.toml`
```
Fix ICE-133117: multiple never-pattern arm doesn't have false_edge_start_block
Fixes#133117 , and close fixes#133063 , fixes#130779
In order to fix ICE-133117, at first I needed to tackle to ICE-133063 (this fixed 130779 as well).
### ICE-133063 and ICE-130779
This ICE is caused by those steps:
1. An arm has or-pattern, and all of the sub-candidates are never-pattern
2. In that case, all sub-candidates are removed in remove_never_subcandidates(). So the arm (candidate) has no sub-candidate.
3. In the current implementation, if there is no sub-candidate, the function assigns `pre_binding_block` into the candidate ([here](https://github.com/rust-lang/rust/blob/master/compiler/rustc_mir_build/src/builder/matches/mod.rs#L2002-L2004)). However, otherwise_block should be assigned to the candidate as well, because the otherwise_block is unwrapped in multiple place (like in lower_match_tree()). As a result, it causes the panic.
I simply added the same block as pre_binding_block into otherwise_block, but I'm wondering if there is a better block to assign to otherwise_block (is it ok to assign the same block into pre_binding and otherwise?)
### ICE-133117
This is caused by those steps:
1. There are two arms, both are or-pattern and each has one match-pair (in the test code, both are `(!|!)`), and the second arm has a guard.
2. In match_candidate() for the first arm, it expands the second arm’s sub-candidates as well ([here](https://github.com/rust-lang/rust/blob/master/compiler/rustc_mir_build/src/builder/matches/mod.rs#L1800-L1805)). As a result, the root candidate of the second arm is not evaluated/modified in match_candidate(). So a false_edge_start_block is not assigned to the candidate.
3. merge_trivial_subcandidates() is called against the candidate for the second arm. It just returns immediately because the candidate has a guard. So a flase_edge_start_block is not assigned to the candidate also in this function.
4. remove_never_subcandidates() is called against the candidate. Since all sub-candidates are never-pattern. they are removed.
5. In lower_match_tree(), since there is no sub-candidate for the candidate, the candidate itself is evaluated in visit_leave_rev ([here](https://github.com/rust-lang/rust/blob/master/compiler/rustc_mir_build/src/builder/matches/mod.rs#L1532)). Because the candidate has no false_edge_start_block, it causes the panic.
So I modified the order of if blocks in merge_trivial_subcandidates() to assign a false_edge_start_block if the candidate doesn't have.
remove support for the (unstable) #[start] attribute
As explained by `@Noratrieb:`
`#[start]` should be deleted. It's nothing but an accidentally leaked implementation detail that's a not very useful mix between "portable" entrypoint logic and bad abstraction.
I think the way the stable user-facing entrypoint should work (and works today on stable) is pretty simple:
- `std`-using cross-platform programs should use `fn main()`. the compiler, together with `std`, will then ensure that code ends up at `main` (by having a platform-specific entrypoint that gets directed through `lang_start` in `std` to `main` - but that's just an implementation detail)
- `no_std` platform-specific programs should use `#![no_main]` and define their own platform-specific entrypoint symbol with `#[no_mangle]`, like `main`, `_start`, `WinMain` or `my_embedded_platform_wants_to_start_here`. most of them only support a single platform anyways, and need cfg for the different platform's ways of passing arguments or other things *anyways*
`#[start]` is in a super weird position of being neither of those two. It tries to pretend that it's cross-platform, but its signature is a total lie. Those arguments are just stubbed out to zero on ~~Windows~~ wasm, for example. It also only handles the platform-specific entrypoints for a few platforms that are supported by `std`, like Windows or Unix-likes. `my_embedded_platform_wants_to_start_here` can't use it, and neither could a libc-less Linux program.
So we have an attribute that only works in some cases anyways, that has a signature that's a total lie (and a signature that, as I might want to add, has changed recently, and that I definitely would not be comfortable giving *any* stability guarantees on), and where there's a pretty easy way to get things working without it in the first place.
Note that this feature has **not** been RFCed in the first place.
*This comment was posted [in May](https://github.com/rust-lang/rust/issues/29633#issuecomment-2088596042) and so far nobody spoke up in that issue with a usecase that would require keeping the attribute.*
Closes https://github.com/rust-lang/rust/issues/29633
try-job: x86_64-gnu-nopt
try-job: x86_64-msvc-1
try-job: x86_64-msvc-2
try-job: test-various
Treat safe target_feature functions as unsafe by default [less invasive variant]
This unblocks
* #134090
As I stated in https://github.com/rust-lang/rust/pull/134090#issuecomment-2541332415 I think the previous impl was too easy to get wrong, as by default it treated safe target feature functions as safe and had to add additional checks for when they weren't. Now the logic is inverted. By default they are unsafe and you have to explicitly handle safe target feature functions.
This is the less (imo) invasive variant of #134317, as it doesn't require changing the Safety enum, so it only affects FnDefs and nothing else, as it should.
