It's very old (added in #12087). It's strange, and it's not clear what
its use cases are. It only works with the crate root file because it
runs before expansion. I suspect it won't be missed.
stop replacing bivariant args with `'static` when computing closure requirements
It is unnecessary, these get constrained when checking that the opaque type is well-formed.
It also results in the opaque type no longer being well formed. If you've got `fn foo<'a>() -> impl Sized + 'a` the opaque is `type Opaque<'a, 'aDummy> where 'a: 'aDummy, 'aDummy: 'a` where `'aDummy` is bivariant. If we call `foo::<'b>()` inside of a closure and its return type ends up in a type test, we start out with the WF `Opaque<'b, 'b>`, and then replace the bivariant `'b` with `'static`. `Opaque<'b, 'static>` is no longer well-formed. Given how these type tests are used, I don't think this caused any practical issues.
r? types
Fix MutVisitor's default implementations to visit Stmt's and BinOp's spans
The `Stmt` case is a bug introduced almost certainly unintentionally by https://github.com/rust-lang/rust/pull/126993. The code _used_ to visit and mutate `span` correctly, but got changed as follows by that PR. Notice how `span` is **copied** into the output by `|kind| Stmt { id, kind, span }` which happens after the mutation in the correct code (red) and before the mutation in the incorrect code (green).
```diff
pub fn noop_flat_map_stmt<T: MutVisitor>(
Stmt { kind, mut span, mut id }: Stmt,
vis: &mut T,
) -> SmallVec<[Stmt; 1]> {
vis.visit_id(&mut id);
- vis.visit_span(&mut span);
let stmts: SmallVec<_> = noop_flat_map_stmt_kind(kind, vis)
.into_iter()
.map(|kind| Stmt { id, kind, span })
.collect();
if stmts.len() > 1 {
panic!(...);
}
+ vis.visit_span(&mut span);
stmts
}
```
[AIX] change AIX default codemodel=large
On AIX, for most libraries, we run out of Table of Contents (TOC) offsets very quickly due to the default 16-bit offset limit. We want the large code model should be used as the default to provide more TOC entries so the end user does not have to specify `-Ccode-model=large` for all their packages. This is even more of an issue with ThinLTO as the ThinLTO globals can very quickly use all available TOC entry.
In addition, on AIX, code with different code-model across different compilation units will not cause undefined behavior, so this is safe to do.
Remove `generic_associated_types_extended` feature gate
This PR retires nightly support for the `generic_associated_types_extended` feature. This feature hasn't received much attention in the last two years or so, and I believe the feature still remains both unsound and ICEy to use. I think that if we were to redesign and reimplement it, we'd want to first figure out how to implement it soundly, but in the mean time I'd prefer to clean this up.
r? ``@lcnr`` cc ``@jackh726`` who added this feature gate I think
improve TagEncoding::Niche docs, sanity check, and UB checks
Turns out the `niche_variants` range can actually contain the `untagged_variant`. We should report this as UB in Miri, so this PR implements that.
Also rename `partially_check_layout` to `layout_sanity_check` for better consistency with how similar functions are called in other parts of the compiler.
Turns out my adjustments to the transmutation logic also fix https://github.com/rust-lang/rust/issues/126267.
Use correct `hir_id` for array const arg infers
Fixes#133771
`self.next_id()` results in the `DefId` for the const argument, created from the hack introduced by #133468, having no `HirId` associated with it. This then results in an ICE in metadata encoding. Fixing this then results in *another* ICE where `encode_defs` was not skipping encoding `type_of` and other queries for `DefId`s when they correspond to a `ConstArgKind::Infer` node.
This only reproduces with a library crate as metadata is not encoded for binaries, and apparently we had 0 tests for `generic_arg_infer` for array lengths in a library crate so this was not caught :<
cc #133589 `@voidc`
r? `@compiler-errors` `@lcnr`
Reduce false positives on some common cases from if-let-rescope lint
r? `@jieyouxu`
We would like to identify a very common case in the ecosystem in which we do not need to apply the lint suggestion for the new Edition 2024 `if let` semantics.
In this patch we excluded linting from `if let`s in statements and block tail expressions. In these simple cases, new Edition 2024 drop orders are identical to those of Edition 2021 and prior.
However, conservatively we should still lint for the other cases, because [this example](https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=2113df5ce78f161d32a1190faf5c7469) shows that the drop order changes are very pronounced, some of which are even sensitive to runtime data.
Gate async fn trait bound modifier on `async_trait_bounds`
This PR moves `async Fn()` trait bounds into a new feature gate: `feature(async_trait_bounds)`. The general vibe is that we will most likely stabilize the `feature(async_closure)` *without* the `async Fn()` trait bound modifier, so we need to gate that separately.
We're trying to work on the general vision of `async` trait bound modifier general in: https://github.com/rust-lang/rfcs/pull/3710, however that RFC still needs more time for consensus to converge, and we've decided that the value that users get from calling the bound `async Fn()` is *not really* worth blocking landing async closures in general.
switch `jemalloc-sys` back to `tikv-jemalloc-sys`, and update to 0.6.0
Some context:
- we used to use jemalloc bindings from https://github.com/gnzlbg/jemallocator, since #55238
- that crate was abandoned, picked up as a fork in https://github.com/tikv/jemallocator, so we switched to that in #83152.
- then they were able to publish to the original `jemalloc-sys` bindings crate, and `jemalloc-sys` and `tikv-jemalloc-sys` became the same thing -- so I switched back to the OG crate in #96790
- they're now having publishing problems again: I've been waiting for https://github.com/tikv/jemallocator/pull/96 for the `jemalloc-sys` 0.6.0 update for a few months, but `tikv-jemalloc-sys` is already updated to 0.6.0.
A perf run showed some improvements, so this PR switches back to `tikv-jemalloc-sys` to update to 0.6.0.
It is unnecessary, these get constrained when checking that the
opaque type is well-formed.
It also results in the opaque type no longer being well formed.
If you've got `fn foo<'a>() -> impl Sized + 'a` the opaque is
`type Opaque<'a, 'aDummy> where 'a: 'aDummy, 'aDummy: 'a` where
`'aDummy` is bivariant. If we call `foo::<'b>()` inside of a closure
and its return type ends up in a type test, we start out with the WF
`Opaque<'b, 'b>`, and then replace the bivariant `'b` with `'static`.
`Opaque<'b, 'static>` is no longer well-formed. Given how these type
tests are used, I don't think this caused any practical issues.
LLVM does not include an implementation of the va_arg instruction for
Xtensa. From what I understand, this is a conscious decision and
instead language frontends are encouraged to implement it themselves.
The rationale seems to be that loading values correctly requires
language and ABI-specific knowledge that LLVM lacks.
This is true of most architectures, and rustc already provides
implementation for a number of them. This commit extends the support to
include Xtensa.
See https://lists.llvm.org/pipermail/llvm-dev/2017-August/116337.html
for some discussion on the topic.
Unfortunately there does not seem to be a reference document for the
semantics of the va_list and va_arg on Xtensa. The most reliable source
is the GCC implementation, which this commit tries to follow. Clang also
provides its own compatible implementation.
This was tested for all the types that rustc allows in variadics.
Co-authored-by: Brian Tarricone <brian@tarricone.org>
Co-authored-by: Jonathan Bastien-Filiatrault <joe@x2a.org>
Co-authored-by: Paul Lietar <paul@lietar.net>
Approved in [ACP 491](https://github.com/rust-lang/libs-team/issues/491).
Remove the `unsafe` on `core::intrinsics::breakpoint()`, since it's a
safe intrinsic to call and has no prerequisites.
(Thanks to @zachs18 for figuring out the `bootstrap`/`not(bootstrap)`
logic.)
Deeply normalize when computing implied outlives bounds
r? lcnr
Unfortunately resolving regions is still slightly scuffed (though in an unrelated way). Specifically, we should be normalizing our param-env outlives when constructing the `OutlivesEnv`; otherwise, these assumptions (dd2837ec5d/compiler/rustc_infer/src/infer/outlives/env.rs (L78)) are not constructed correctly.
Let me know if you want us to track that somewhere.
Print name of env var in `--print=deployment-target`
The deployment target environment variable is OS-specific, and if you're in a place where you're asking `rustc` for the deployment target, you're likely to also wanna know the name of the environment variable. I myself wanted this for some code I'm working on in bootstrap, for example.
Behaviour before this PR:
```console
$ rustc --print=deployment-target --target=aarch64-apple-darwin
deployment_target=11.0
$ rustc --print=deployment-target --target=aarch64-apple-visionos
deployment_target=1.0
```
Behaviour after this PR:
```console
$ rustc --print=deployment-target --target=aarch64-apple-darwin
MACOSX_DEPLOYMENT_TARGET=11.0
$ rustc --print=deployment-target --target=aarch64-apple-visionos
XROS_DEPLOYMENT_TARGET=1.0
```
My _belief_ is that this option is extremely rarely used in general, and a GitHub search for "rustc print deployment-target" seems to confirm this, it revealed only the following actual pieces of code using this:
- b292ef6934/src/build_context.rs (L1199-L1220)
- daab9244b0/src/lib.rs (L3422-L3426)
`maturin` does `.split('=').last()`, so it will continue to work after this change, but `cc v1.0.84` did `.strip_prefix("deployment_target=")` since [this PR](https://github.com/rust-lang/cc-rs/pull/848), so it would break. That's _probably_ fine though, it was broken in a lot of scenarios anyway, and [got](https://github.com/rust-lang/cc-rs/pull/901) [reverted](https://github.com/rust-lang/cc-rs/pull/943) in `v1.0.85`.
So while this is _technically_ a breaking change, I really doubt that anyone is going to observe it, so it's probably fine.
``@BlackHoleFox`` wdyt?
``@rustbot`` label O-apple
r? compiler
Get rid of HIR const checker
As far as I can tell, the HIR const checker was implemented in https://github.com/rust-lang/rust/pull/66170 because we were not able to issue useful const error messages in the MIR const checker.
This seems to have changed in the last 5 years, probably due to work like #90532. I've tweaked the diagnostics slightly and think the error messages have gotten *better* in fact.
Thus I think the HIR const checker has reached the end of its usefulness, and we can retire it.
cc `@RalfJung`
Change `AttrArgs::Eq` to a struct variant
Cleanups for simplifying https://github.com/rust-lang/rust/pull/131808
Basically changes `AttrArgs::Eq` to a struct variant and then avoids several matches on `AttrArgsEq` in favor of methods on it. This will make future refactorings simpler, as they can either keep methods or switch to field accesses without having to restructure code
fix ICE when promoted has layout size overflow
Turns out there is no reason to distinguish `tainted_by_errors` and `can_be_spurious` here, we can just track whether we allow this even in "infallible" constants.
Fixes https://github.com/rust-lang/rust/issues/125476
Use c"lit" for CStrings without unwrap
I've reviewed uses of `CString::new("lit")`.
Some could be changed to `c"lit"`. Some could be changed to `c"lit".to_owned()`, avoiding an `unwrap()`.
Many `CString` documentation examples could be simplified. I deliberately haven't changed all the examples to use the exact same expression, so that they can demonstrate many ways of creating `CString`s.
I've left UI tests mostly unchanged, because `c""` requires edition 2021, but most UI tests use 2015, and I didn't want to accidentally change what the tests are testing.
Move `Const::{from_anon_const,try_from_lit}` to hir_ty_lowering
Fixes#128176.
This accomplishes one of the followup items from #131081.
These operations are much more about lowering the HIR than about
`Const`s themselves. They fit better in hir_ty_lowering with
`lower_const_arg` (formerly `Const::from_const_arg`) and the rest.
To accomplish this, `const_evaluatable_predicates_of` had to be changed
to not use `from_anon_const` anymore. Instead of visiting the HIR and
lowering anon consts on the fly, it now visits the `rustc_middle::ty`
data structures instead and directly looks for `UnevaluatedConst`s. This
approach was proposed in:
https://github.com/rust-lang/rust/pull/131081#discussion_r1821189257
r? `@BoxyUwU`
show forbidden_lint_groups in future-compat reports
Part of https://github.com/rust-lang/rust/issues/81670. This has been a future-compat lint for a while, time to dial it up to show up in reports.
These operations are much more about lowering the HIR than about
`Const`s themselves. They fit better in hir_ty_lowering with
`lower_const_arg` (formerly `Const::from_const_arg`) and the rest.
To accomplish this, `const_evaluatable_predicates_of` had to be changed
to not use `from_anon_const` anymore. Instead of visiting the HIR and
lowering anon consts on the fly, it now visits the `rustc_middle::ty`
data structures instead and directly looks for `UnevaluatedConst`s. This
approach was proposed in:
https://github.com/rust-lang/rust/pull/131081#discussion_r1821189257
`impl Default for EarlyDiagCtxt`
for small rustc_driver programs, most of their imports will currently be related to diagnostics. this change simplifies their code so it's more clear what in the driver is modified from the default.
this is especially important for external drivers which are out of tree and not updated in response to breaking changes. for these drivers, each import is a liability for future code, since it can be broken when refactors happen.
here is an example driver which is simplified by these changes:
```diff
diff --git a/src/main.rs b/src/main.rs
index f81aa3e..11e5f18 100644
--- a/src/main.rs
+++ b/src/main.rs
`@@` -1,16 +1,8 `@@`
#![feature(rustc_private)]
extern crate rustc_driver;
extern crate rustc_interface;
-extern crate rustc_errors;
-extern crate rustc_session;
use rustc_driver::Callbacks;
-use rustc_errors::{emitter::HumanReadableErrorType, ColorConfig};
use rustc_interface::interface;
-use rustc_session::config::ErrorOutputType;
-use rustc_session::EarlyDiagCtxt;
struct DisableSafetyChecks;
`@@` -26,11 +18,7 `@@` fn main() {
"https://github.com/jyn514/jyn514.github.io/issues/new",
|_| (),
);
- let handler = EarlyDiagCtxt::new(ErrorOutputType::HumanReadable(
- HumanReadableErrorType::Default,
- ColorConfig::Auto,
- ));
- rustc_driver::init_rustc_env_logger(&handler);
+ rustc_driver::init_rustc_env_logger(&Default::default());
std::process::exit(rustc_driver::catch_with_exit_code(move || {
let args: Vec<String> = std::env::args().collect();
rustc_driver::RunCompiler::new(&args, &mut DisableSafetyChecks).run()
```
remove `Ty::is_copy_modulo_regions`
Using these functions is likely incorrect if an `InferCtxt` is available, I moved this function to `TyCtxt` (and added it to `LateContext`) and added a note to the documentation that one should prefer `Infer::type_is_copy_modulo_regions` instead.
I didn't yet move `is_sized` and `is_freeze`, though I think we should move these as well.
r? `@compiler-errors` cc #132279
Eliminate magic numbers from expression precedence
Context: see https://github.com/rust-lang/rust/pull/133140.
This PR continues on backporting Syn's expression precedence design into rustc. Rustc's design used mysterious integer quantities represented variously as `i8` or `usize` (e.g. `PREC_CLOSURE = -40i8`), a special significance around `0` that is never named, and an extra `PREC_FORCE_PAREN` precedence level that does not correspond to any expression. Syn's design uses a C-like enum with variants that clearly correspond to specific sets of expression kinds.
This PR is a refactoring that has no intended behavior change on its own, but it unblocks other precedence work that rustc's precedence design was poorly suited to accommodate.
- Asymmetrical precedence, so that a pretty-printer can tell `(return 1) + 1` needs parens but `1 + return 1` does not.
- Squashing the `Closure` and `Jump` cases into a single precedence level.
- Numerous remaining false positives and false negatives in rustc pretty-printer's parenthesization of macro metavariables, for example in `$e < rhs` where $e is `lhs as Thing<T>`.
FYI `@fmease` — you don't need to review if rustbot picks someone else, but you mentioned being interested in the followup PRs.
check local cache even if global is usable
we store overflow errors locally, even if we can otherwise use the global cache for this goal. should fix#133616, didn't test it locally yet as diesel tends to hit an unrelated debug assertion in rustdoc.
r? types
for small rustc_driver programs, most of their imports will currently be related to diagnostics. this change simplifiers their code so it's more clear what in the driver is modified from the default.
this is especially important for external drivers which are out of tree and not updated in response to breaking changes. for these drivers, each import is a liability for future code, since it can be broken when refactors happen.
here is an example driver which is simplified by these changes:
```
diff --git a/src/main.rs b/src/main.rs
index f81aa3e..11e5f18 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,16 +1,8 @@
#![feature(rustc_private)]
extern crate rustc_driver;
extern crate rustc_interface;
-extern crate rustc_errors;
-extern crate rustc_session;
use rustc_driver::Callbacks;
-use rustc_errors::{emitter::HumanReadableErrorType, ColorConfig};
use rustc_interface::interface;
-use rustc_session::config::ErrorOutputType;
-use rustc_session::EarlyDiagCtxt;
struct DisableSafetyChecks;
@@ -26,11 +18,7 @@ fn main() {
"https://github.com/jyn514/jyn514.github.io/issues/new",
|_| (),
);
- let handler = EarlyDiagCtxt::new(ErrorOutputType::HumanReadable(
- HumanReadableErrorType::Default,
- ColorConfig::Auto,
- ));
- rustc_driver::init_rustc_env_logger(&handler);
+ rustc_driver::init_rustc_env_logger(&Default::default());
std::process::exit(rustc_driver::catch_with_exit_code(move || {
let args: Vec<String> = std::env::args().collect();
rustc_driver::RunCompiler::new(&args, &mut DisableSafetyChecks).run()
```
The `Borrowed` variant is no longer used. This commit removes it, along
with the `as_results_cursor` method that produces it, and renames
`as_results_cursor_mut` as `as_results_cursor`.
As of #133155 `Formatter:new` uses `as_results_cursor` to create a
non-mutable results reference, and then later that is accessed via
`deref_mut` which results in a runtime abort. Changing to
`as_results_cursor_mut` fixes it.
Fixes#133641.
Remove `hir::ArrayLen`
This refactoring removes `hir::ArrayLen`, replacing it with `hir::ConstArg`. To represent inferred array lengths (previously `hir::ArrayLen::Infer`), a new variant `ConstArgKind::Infer` is added.
r? `@BoxyUwU`
coverage: Use a query to identify which counter/expression IDs are used
Given that we already have a query to identify the highest-numbered counter ID in a MIR body, we can extend that query to also build bitsets of used counter/expression IDs. That lets us avoid some messy coverage bookkeeping during the main MIR traversal for codegen.
This does mean that we fail to treat some IDs as used in certain MIR-inlining scenarios, but I think that's fine, because it means that the results will be consistent across all instantiations of a function.
---
There's some more cleanup I want to do in the function coverage collector, since it isn't really collecting anything any more, but I'll leave that for future work.
Only error raw lifetime followed by `\'` in edition 2021+
Fixes#133479
cc #132341
I think this fixes a purely theoretical regression since it only affects edition 2015 (who is using that?) and only in the very rare case of a raw lifetime followed immediately by a lifetime like `'r#a'r`.
Make `adjust_fulfillment_errors` work with `HostEffectPredicate` and `const_conditions`
Greatly improves the spans for reporting unsatisfied `~const` bounds :)
r? project-const-traits or maybe ``@lcnr`` (if you want to deal with a diagnostics PR lmao)
Properly pass linker arguments that contain commas
When linking with the system C compiler, we sometimes want to forward certain arguments unchanged to the linker. This can be done with `-Wl,arg1,arg2` or `-Xlinker arg1 -Xlinker arg2`. `-Wl` is used when possible, since it is more compact, but it does not support commas in the argument itself - in those cases, we need to use `-Xlinker`, and that is what this PR implements.
This also fixes using sanitizers on macOS with `-Clinker-flavor=ld`, as those were previously manually using `-Wl`/`-Xlinker` (probably since the support wasn't present in the `link_args` function).
Note that there has been [a previous PR for this](https://github.com/rust-lang/rust/pull/38798), but it only implemented this in certain cases when passing `-rpath`.
r? compiler
Rollup of 8 pull requests
Successful merges:
- #128184 (std: refactor `pthread`-based synchronization)
- #132047 (Robustify and genericize return-type-notation resolution in `resolve_bound_vars`)
- #133515 (fix: hurd build, stat64.st_fsid was renamed to st_dev)
- #133602 (fix: fix codeblocks in `PathBuf` example)
- #133622 (update link to "C++ Exceptions under the hood" blog)
- #133660 (Do not create trait object type if missing associated types)
- #133686 (Add diagnostic item for `std::ops::ControlFlow`)
- #133689 (Fixed typos by changing `happend` to `happened`)
r? `@ghost`
`@rustbot` modify labels: rollup
Add diagnostic item for `std::ops::ControlFlow`
This will be used in Clippy to detect useless conversions done through `ControlFlow::map_break()` and `ControlFlow::map_continue()`.
Robustify and genericize return-type-notation resolution in `resolve_bound_vars`
#129629 implemented return-type-notation (RTN) in its path form, like `where T::method(..): Bound`. As part of lowering, we must record the late-bound vars for the where clause introduced by the method (namely, its early- and late-bound lifetime arguments, since `where T::method(..)` turns into a higher-ranked where clause over all of the lifetimes according to [RFC 3654](https://rust-lang.github.io/rfcs/3654-return-type-notation.html#converting-to-higher-ranked-trait-bounds)).
However, this logic was only looking at the where clauses of the parent item that the `T::method(..)` bound was written on, and not any parent items. This PR generalizes that logic to look at the parent item (i.e. the outer impl or trait) instead and fixes a (debug only) assertion as an effect.
This logic is also more general and likely easier to adapt to more interesting (though likely very far off) cases like non-lifetime binder `for<T: Trait> T::method(..): Send` bounds.
Tracking:
- https://github.com/rust-lang/rust/issues/109417
Respect verify-llvm-ir option in the backend
We are currently unconditionally verifying the LLVM IR in the backend (twice), ignoring the value of the verify-llvm-ir option. This has substantial compile-time impact for debug builds.
Make `compare_impl_item` into a query
Turns `compare_impl_item` into a query (generalizing the existing query for `compare_impl_const`), and uses that in `Instance::resolve` to fail resolution when an implementation is incompatible with the trait it comes from.
Fixes#119701Fixes#121127Fixes#121411Fixes#129075Fixes#129127Fixes#129214Fixes#131294
Eliminate print_expr_maybe_paren function from pretty printers
This PR is part of backporting Syn's expression precedence design into rustc. (See #133603 for other work on this.)
In Syn, our version of `print_expr_cond_paren` is called `print_subexpression` and it is called from 19 places. Of those calls, 12 of them need a "custom" behavior for the `needs_paren` argument, whereas only 7 use a "standard" behavior resembling `print_subexpression($e, $e.precedence() < Precedence::$Variant, ...)`. In other words the behavior that rustc_ast_pretty's `print_expr_maybe_paren` implements is actually not what you want most of the time. The current usage you see in rustc is overuse.
<details>
<summary>Aside: am I confident about the correctness of Syn's parenthesization? Yes. Click for details.</summary>
---
The behavior is constrained by the following pair of tests which both run over every Rust source file of rustc and the standard library and tools and test suites:
- To rule out **false positives**: for every expression in every source file, print the expression, parse it back, and verify that not a single new parenthesis got added. Since these are expressions parsed from source code, not macro-generated syntax trees, we know they must never need automatic parenthesis insertion. Rustc's pretty printer does not pass this.
Pseudocode: `assert(expr == parse(print(expr)))`
- To rule out **false negatives**: for every expression in every source file, replace every Expr::Paren node in the syntax tree with just its contents, i.e. stripping the parentheses but otherwise preserving the syntax tree structure. Then print the stripped expression performing parenthesis insertion wherever needed, and reparse it. Verify that the reparsed expression has identical structure to the original, despite there being no parentheses in the original prior to printing, i.e. all the right parentheses got re-inserted by the printer to preserve the expression's structure. Rustc's pretty printer does not pass this. See https://github.com/dtolnay/syn/pull/1788 which reveals multiple rustc_ast_pretty bugs.
Pseudocode: `assert(unparenthesize(expr) == unparenthesize(parse(print(unparenthesize(expr)))))`
---
</details>
If `print_expr_maybe_paren` is usually not correct, is there harm in keeping it for the minority of cases where it is correct? I think the answer is yes and Syn doesn't use any equivalent of this helper function. The problems with it are:
- Having both `print_expr_maybe_paren` and `print_expr_cond_paren` applies counterproductive inertia against moving from the first to the second. When looking at a call site like `print_expr_maybe_paren(e, Precedence::$Variant, ...)` with parentheses not being inserted where they should be, anyone's first inclination would be to solve the bug by tweaking $Variant because that is the only knob that visibly appears in the function call. For example to pass "prec + 1", like tweaking the code to conditionally pass `Precedence::Prefix` instead of `Precedence::Cast`.
Experience in Syn shows this is (almost?) never what you want the person to do. In a call `print_expr_cond_paren(e, e.precedence() < ExprPrecedence::$Variant, ...)` almost always the best fix involves one of:
- Changing `e.precedence()`, e.g. to `fixup.leading_precedence(e)` and `fixup.trailing_precedence(e)` in cases of asymmetrical precedence (`(return 1) + 1` vs `1 + return 1`).
- Changing `<` to `<=`, to handle associativity and other grammar restrictions like chained comparisons (which rustc gets wrong today).
- Adding `||` and/or `&&` clauses to the condition.
By using these 3 better knobs instead of $Variant, it upholds the property that any time we talk about precedence, it is always the precedence of some actual expression that our code is actively manipulating, instead of a value standing in for some imaginary precedence level that would exist between two consecutive [real levels](https://doc.rust-lang.org/1.83.0/reference/expressions.html#expression-precedence). For example consider that "`Cast` + 1" might be `Prefix` today, but only until some new Rust syntax ends up adding a level between those.
- The `print_expr_maybe_paren` call sites look shorter, but they are not clearer. For myself, a function argument that says "does this subexpression need parenthesization" is a concrete thing that is easy to think about, while a function argument that is "what is the effective precedence level associated with this subexpression's placement inside its parent expression" is abstract and tricky to even state a precise meaning for. I expect that for someone less familiar with the pretty printer working on adding a new expression kind (like postfix match, recently), having every subexpression consistently printed using `print_expr_cond_paren` will be more beneficial, for the same reason, than having `print_expr_maybe_paren` available.
r? ``@lcnr``
Mark visionOS as supporting `std`
Cargo's -Zbuild-std has recently started checking this field, which causes it to fail to compile even though we have full support for the standard library on these targets.
[Example of failed build](https://github.com/rust-random/getrandom/actions/runs/12069033154/job/33655430622).
Affected targets: `aarch64-apple-visionos` and `aarch64-apple-visionos-sim`.
r? Noratrieb (because you've worked with `rustc` target metadata IIRC)
``@rustbot`` label O-visionos
use stores of the correct size to set discriminants
Resolves an old HACK /FIXME.
Note that I haven't worked much with codegen so I'm not sure if I'm using the functions correctly and I was surprised seeing out-of-range values being fed into `const_uint_big` but apparently they're wrapped implicitly? By making it explicit we can pass in-range values instead.
Support input/output in vector registers of PowerPC inline assembly
This extends currently clobber-only vector registers (`vreg`) support to allow passing `#[repr(simd)]` types as input/output.
| Architecture | Register class | Target feature | Allowed types |
| ------------ | -------------- | -------------- | -------------- |
| PowerPC | `vreg` | `altivec` | `i8x16`, `i16x8`, `i32x4`, `f32x4` |
| PowerPC | `vreg` | `vsx` | `f32`, `f64`, `i64x2`, `f64x2` |
In addition to floats and `core::simd` types listed above, `core::arch` types and custom `#[repr(simd)]` types of the same size and type are also allowed. All allowed types and relevant target features are currently unstable.
r? `@Amanieu`
`@rustbot` label +O-PowerPC +A-inline-assembly
Improve span handling in `parse_expr_bottom`.
`parse_expr_bottom` stores `this.token.span` in `lo`, but then fails to use it in many places where it could. This commit fixes that, and likewise (to a smaller extent) in `parse_ty_common`.
r? ``@spastorino``
Simplify hir_typeck_pass_to_variadic_function
r? ``@compiler-errors``
This reworks a bit how the diagnostic is generated so that it does the same as #133538
The `help` is useless now so I removed it
Add `+forced-atomics` feature to esp32s2 no_std target
Similar to https://github.com/rust-lang/rust/pull/114499 but for the Xtensa backend. The ESP32-S2 doesn't have native atomic support, but can have atomic load/stores as part of the ISA with this LLVM codegen feature.
Note: The current rev of LLVM that rustc is using doesn't contain the `+forced-atomics` feature for Xtensa, but I'm pushing this now to remove the patch from our fork in `esp-rs/rust`.
r? ``@Amanieu`` because you reviewed the related RISC-V PR
Fix target_feature handling in freg of LoongArch inline assembly
In LoongArch inline assembly, freg currently always accepts f32/f64 as input/output.
9b4d7c6a40/compiler/rustc_target/src/asm/loongarch.rs (L41)
However, these types actually require f/d target features as in RISC-V.
Otherwise, an (ugly) compile error will occur: https://godbolt.org/z/K61Gq1E9E
f32/f64 without f:
```
error: couldn't allocate output register for constraint '{$f1}'
--> <source>:12:11
|
12 | asm!("", in("$f1") x, lateout("$f1") y);
| ^
```
f64 with f but without d:
```
error: scalar-to-vector conversion failed, possible invalid constraint for vector type
--> <source>:19:11
|
19 | asm!("", in("$f1") x, lateout("$f1") y);
| ^
```
cc ``@heiher``
r? ``@Amanieu``
``@rustbot`` label +O-LoongArch +A-inline-assembly
Do not call `extern_crate` on current trait on crate mismatch errors
When we encounter an error caused by traits/types of different versions of the same crate, filter out the current crate when collecting spans to add to the context so we don't call `extern_crate` on the `DefId` of the current crate, which is meaningless and ICEs.
Produced output with this filter:
```
error[E0277]: the trait bound `foo::Struct: Trait` is not satisfied
--> y.rs:13:19
|
13 | check_trait::<foo::Struct>();
| ^^^^^^^^^^^ the trait `Trait` is not implemented for `foo::Struct`
|
note: there are multiple different versions of crate `foo` in the dependency graph
--> y.rs:7:1
|
4 | extern crate foo;
| ----------------- one version of crate `foo` is used here, as a direct dependency of the current crate
5 |
6 | pub struct Struct;
| ----------------- this type implements the required trait
7 | pub trait Trait {}
| ^^^^^^^^^^^^^^^ this is the required trait
|
::: x.rs:4:1
|
4 | pub struct Struct;
| ----------------- this type doesn't implement the required trait
5 | pub trait Trait {}
| --------------- this is the found trait
= note: two types coming from two different versions of the same crate are different types even if they look the same
= help: you can use `cargo tree` to explore your dependency tree
note: required by a bound in `check_trait`
--> y.rs:10:19
|
10 | fn check_trait<T: Trait>() {}
| ^^^^^ required by this bound in `check_trait`
```
Fix#133563.
[AIX] handle libunwind native_libs
AIX should follow a similar path here to other libunwind platforms, with regards to system vs in-tree libunwind and the native lib search directories.
Having the right native lib search directories here is also required to get the correct default library search paths, due to some quirks of the AIX linker.
Stabilize `extended_varargs_abi_support`
I think that is everything? If there is any documentation regarding `extern` and/or varargs to correct, let me know, some quick greps suggest that there might be none.
Tracking issue: https://github.com/rust-lang/rust/issues/100189
Bump boostrap compiler to new beta
Currently failing due to something about the const stability checks and `panic!`. I'm not sure why though since I wasn't able to see any PRs merged in the past few days that would result in a `cfg(bootstrap)` that shouldn't be removed. cc `@RalfJung` #131349
Support `clobber_abi` in AVR inline assembly
This PR implements the `clobber_abi` part necessary to eventually stabilize the inline assembly for AVR. This is tracked in #93335.
This is heavily inspired by the sibling-PR #131310 for the MSP430. I've explained my reasoning in the first commit message in detail, which is reproduced below for easier reviewing:
This follows the [ABI documentation] of AVR-GCC:
> The [...] call-clobbered general purpose registers (GPRs) are registers that might be destroyed (clobbered) by a function call.
>
> - **R18–R27, R30, R31**
>
> These GPRs are call clobbered. An ordinary function may use them without restoring the contents. [...]
>
> - **R0, T-Flag**
>
> The temporary register and the T-flag in SREG are also call-clobbered, but this knowledge is not exposed explicitly to the compiler (R0 is a fixed register).
Therefore this commit lists the aforementioned registers `r18–r27`, `r30` and `r31` as clobbered registers. Since the `r0` register (listed above as well) is not available in inline assembly at all (potentially because the AVR-GCC considers it a fixed register causing the register to never be used in register allocation and LLVM adopting this), there is no need to list it in the clobber list (the `r0`-variant is not even available). A comment was added to ensure, that the `r0` gets added to the clobber-list once the register gets usable in inline ASM.
Since the SREG is normally considered clobbered anyways (unless the user supplies the `preserve_flags`-option), there is no need to explicitly list a bit in this register (which is not possible to list anyways).
Note, that this commit completely ignores the case of interrupts (that are described in the ABI-specification), since every register touched in an ISR need to be saved anyways.
[ABI documentation]: https://gcc.gnu.org/wiki/avr-gcc#Call-Used_Registers
r? ``@Amanieu``
``@rustbot`` label +O-AVR
This is currently handled automatically by the fact that codegen doesn't visit
coverage statements in unused functions, but that will no longer be the case
when unused IDs are identified by a separate query instead.
Rollup of 7 pull requests
Successful merges:
- #132782 (improvements on initial sysroot and libdir finding logics)
- #133466 (Fix typos in pin.rs)
- #133492 (bootstrap: allow skipping steps with start of path)
- #133501 (support revealing defined opaque post borrowck)
- #133530 (Use consistent wording in docs, use is zero instead of is 0)
- #133538 (Better diagnostic for fn items in variadic functions)
- #133590 (Rename `-Zparse-only`)
r? `@ghost`
`@rustbot` modify labels: rollup
support revealing defined opaque post borrowck
By adding a new `TypingMode::PostBorrowckAnalysis`. Currently only supported with the new solver and I didn't look into the way we replace `ReErased`. ``@compiler-errors`` mentioned that always using existentials may be unsound.
r? ``@compiler-errors``
Remove `HybridBitSet`
`HybridBitSet` was introduced under the name `HybridIdxSetBuf` way back in #53383 where it was a big win for NLL borrow checker performance. In #93984 the more flexible `ChunkedBitSet` was added. Uses of `HybridBitSet` have gradually disappeared (e.g. #116152) and there are now few enough that they can be replaced with `BitSet` or `ChunkedBitSet`, and `HybridBitSet` can be removed, cutting more than 700 lines of code.
r? `@Mark-Simulacrum`
As part of the larger goal of reducing `HybridBitSet` use in general.
This code is for debugging only and isn't performance sensitive, so
`ChunkedBitSet` should be fine.
The current implementation is slow because it does an operation for
every bit in the set, even zero bits. So if you have a large bitset with
many zero bits (which is common) it's very slow.
This commit improves the iterator to skip over `Zeros` chunks in a
single step, and uses the fast `BitIter` for `Mixed` chunks. It also
removes the existing `fold` implementation, which was only there because
the old iterator was slow.
- Fix a typo in a comment.
- Remove unnecessary `Chunk::` qualifiers.
- Rename `ChunkedBitIter::bitset` as `ChunkedBitIter::bit_set`, because
`bit_set` is the form used everywhere else.
- Avoid some unnecessary local variables.
`ChunkedBitSet::is_empty` currently does an unnecessary check. This
commit removes that check and adds clarifying comments and an assertion
that demonstrate why it's unnecessary.
Revert #133418 (Store coverage source regions as `Span`) due to regression #133606
This reverts commit adf9b5fcd1, reversing changes made to af1ca153d4.
Reverting #133418 due to regressions reported at #133606.
r? jieyouxu
this implements checks necessary to guarantee that we can actually
perform a tail call. while extremely restrictive, this is what is
documented in the RFC, and all these checks are needed for one reason or
another.
ensure JSON-defined targets are consistent
We have a `check_consistency` check that ensures some invariants which (presumably) the rest of the compiler relies on. However, JSON targets can easily be written in a way that violates those invariants. So this PR applies the same consistency check to JSON targets that we already enforce for built-in targets.
I have converted many of the assertions in that function to new macros that show a nice error instead of a panic; if people are okay with the general approach here, I can do that for the rest of the checks as well.
Enable -Zshare-generics for inline(never) functions
This avoids inlining cross-crate generic items when possible that are
already marked inline(never), implying that the author is not intending
for the function to be inlined by callers. As such, having a local copy
may make it easier for LLVM to optimize but mostly just adds to binary
bloat and codegen time. In practice our benchmarks indicate this is
indeed a win for larger compilations, where the extra cost in dynamic
linking to these symbols is diminished compared to the advantages in
fewer copies that need optimizing in each binary.
It might also make sense it expand this with other heuristics (e.g.,
`#[cold]`) in the future, but this seems like a good starting point.
FWIW, I expect that doing cleanup in where we make the decision
what should/shouldn't be shared is also a good idea. Way too
much code needed to be tweaked to check this. But I'm hoping
to leave that for a follow-up PR rather than blocking this on it.
this is funny though! apparently tidy parsed `.gitignore`, but did not
recognize unignore lines (`!...`), so tidy was ignoring `rustc_mir_build`
this whole time (at least for some lints?).
I was surprised to find that running with `-Zparse-only` only parses the
crate root file. Other files aren't parsed because that happens later
during expansion.
This commit renames the option and updates the help message to make this
clearer.
This reduces code sizes and better respects programmer intent when
marking inline(never). Previously such a marking was essentially ignored
for generic functions, as we'd still inline them in remote crates.
When we encounter an error caused by traits/types of different versions of the same crate, filter out the current crate when collecting spans to add to the context so we don't call `extern_crate` on the `DefId` of the current crate, which is meaningless and ICEs.
Produced output with this filter:
```
error[E0277]: the trait bound `foo::Struct: Trait` is not satisfied
--> y.rs:13:19
|
13 | check_trait::<foo::Struct>();
| ^^^^^^^^^^^ the trait `Trait` is not implemented for `foo::Struct`
|
note: there are multiple different versions of crate `foo` in the dependency graph
--> y.rs:7:1
|
4 | extern crate foo;
| ----------------- one version of crate `foo` is used here, as a direct dependency of the current crate
5 |
6 | pub struct Struct;
| ----------------- this type implements the required trait
7 | pub trait Trait {}
| ^^^^^^^^^^^^^^^ this is the required trait
|
::: x.rs:4:1
|
4 | pub struct Struct;
| ----------------- this type doesn't implement the required trait
5 | pub trait Trait {}
| --------------- this is the found trait
= note: two types coming from two different versions of the same crate are different types even if they look the same
= help: you can use `cargo tree` to explore your dependency tree
note: required by a bound in `check_trait`
--> y.rs:10:19
|
10 | fn check_trait<T: Trait>() {}
| ^^^^^ required by this bound in `check_trait`
```
Fix#133563.
always create `DefId`s for anon consts
but don't use them anywhere, we intentionally don't encode them in the crate metadata.
best reviewed by disabling whitespace.
This pretty much reimplements #133285 while adding the tests of #133455. Fixes#133064
r? `@BoxyUwU` `@compiler-errors`
This commit adds the relevant registers to the list of clobbered regis-
ters (part of #93335). This follows the [ABI documentation] of AVR-GCC:
> The [...] call-clobbered general purpose registers (GPRs) are
> registers that might be destroyed (clobbered) by a function call.
>
> - **R18–R27, R30, R31**
>
> These GPRs are call clobbered. An ordinary function may use them
> without restoring the contents. [...]
>
> - **R0, T-Flag**
>
> The temporary register and the T-flag in SREG are also call-
> clobbered, but this knowledge is not exposed explicitly to the
> compiler (R0 is a fixed register).
Therefore this commit lists the aforementioned registers `r18–r27`,
`r30` and `r31` as clobbered registers. Since the `r0` register (listed
above as well) is not available in inline assembly at all (potentially
because the AVR-GCC considers it a fixed register causing the register
to never be used in register allocation and LLVM adopting this), there
is no need to list it in the clobber list (the `r0`-variant is not even
available). A comment was added to ensure, that the `r0` gets added to
the clobber-list once the register gets usable in inline ASM.
Since the SREG is normally considered clobbered anyways (unless the user
supplies the `preserve_flags`-option), there is no need to explicitly
list a bit in this register (which is not possible to list anyways).
Note, that this commit completely ignores the case of interrupts (that
are described in the ABI-specification), since every register touched in
an ISR need to be saved anyways.
[ABI documentation]: https://gcc.gnu.org/wiki/avr-gcc#Call-Used_Registers
Cargo's -Zbuild-std has recently started checking this field, which
causes it to fail to compile even though we have full support for the
standard library on these targets.
Small doc fixes in `rustc_codegen_ssa`
I'm trying to make a toy codegen backend for `rustc`, and I got confused for a few minutes about what `codegen_backend` was referring to in the `CodegenBackend::join_codegen` docs.
Experimentally, it looks like the result of `CodegenBackend::codegen_crate` is passed to `CodegenBackend::join_codegen`, so this updates the docs to refer to that. This time using intra-doc links to hopefully cause people to notice if that gets out of date again.
Also, added another intra-doc link nearby, on `CodegenBackend::link`, for the same reason.
Fix clobber_abi in RV32E and RV64E inline assembly
Currently clobber_abi in RV32E and RV64E inline assembly is implemented using InlineAsmClobberAbi::RiscV, but broken since x16-x31 cannot be used in RV32E and RV64E.
```
error: cannot use register `x16`: register can't be used with the `e` target feature
--> <source>:42:14
|
42 | asm!("", clobber_abi("C"), options(nostack, nomem, preserves_flags));
| ^^^^^^^^^^^^^^^^
error: cannot use register `x17`: register can't be used with the `e` target feature
--> <source>:42:14
|
42 | asm!("", clobber_abi("C"), options(nostack, nomem, preserves_flags));
| ^^^^^^^^^^^^^^^^
error: cannot use register `x28`: register can't be used with the `e` target feature
--> <source>:42:14
|
42 | asm!("", clobber_abi("C"), options(nostack, nomem, preserves_flags));
| ^^^^^^^^^^^^^^^^
error: cannot use register `x29`: register can't be used with the `e` target feature
--> <source>:42:14
|
42 | asm!("", clobber_abi("C"), options(nostack, nomem, preserves_flags));
| ^^^^^^^^^^^^^^^^
error: cannot use register `x30`: register can't be used with the `e` target feature
--> <source>:42:14
|
42 | asm!("", clobber_abi("C"), options(nostack, nomem, preserves_flags));
| ^^^^^^^^^^^^^^^^
error: cannot use register `x31`: register can't be used with the `e` target feature
--> <source>:42:14
|
42 | asm!("", clobber_abi("C"), options(nostack, nomem, preserves_flags));
| ^^^^^^^^^^^^^^^^
```
r? `@Amanieu`
`@rustbot` label O-riscv +A-inline-assembly
Don't type error if we fail to coerce `Pin<T>` because it doesnt contain a ref
Fixes https://github.com/rust-lang/rust/issues/133222. Also moves some tests into a directory for better bookkeeping.
r? eholk or re-roll
`parse_expr_bottom` stores `this.token.span` in `lo`, but then fails to
use it in many places where it could. This commit fixes that, and
likewise (to a smaller extent) in `parse_ty_common`.
Rollup of 12 pull requests
Successful merges:
- #129409 (Expand std::os::unix::fs::chown() doc with a warning)
- #133320 (Add release notes for Rust 1.83.0)
- #133368 (Delay a bug when encountering an impl with unconstrained generics in `codegen_select`)
- #133428 (Actually use placeholder regions for trait method late bound regions in `collect_return_position_impl_trait_in_trait_tys`)
- #133512 (Add `as_array` and `as_mut_array` conversion methods to slices.)
- #133519 (Check `xform_ret_ty` for WF in the new solver to improve method winnowing)
- #133520 (Structurally resolve before applying projection in borrowck)
- #133534 (extend group-forbid-always-trumps-cli test)
- #133537 ([rustdoc] Fix new clippy lints)
- #133543 ([AIX] create shim for lgammaf_r)
- #133547 (rustc_span: Replace a `HashMap<_, ()>` with `HashSet`)
- #133550 (print generated doc paths)
r? `@ghost`
`@rustbot` modify labels: rollup
Structurally resolve before applying projection in borrowck
As far as I can tell, all other `.normalize` calls in borrowck are noops and can remain that way. This is the only one that actually requires structurally resolving the type.
r? lcnr
Check `xform_ret_ty` for WF in the new solver to improve method winnowing
This is a bit interesting. Method probing in the old solver is stronger than the new solver because eagerly normalizing types causes us to check their corresponding trait goals. This is important because we don't end up checking all of the where clauses of a method when method probing; just the where clauses of the impl. i.e., for:
```
impl Foo
where
WC1,
{
fn method()
where
WC2,
{}
}
```
We only check WC1 and not WC2. This is because at this point in probing the method is instantiated w/ infer vars, and checking the where clauses in WC2 will lead to cycles if we were to check them (at least that's my understanding; I could investigate changing that in general, incl. in the old solver, but I don't have much confidence that it won't lead to really bad overflows.)
This PR chooses to emulate the old solver by just checking that the return type is WF. This is theoretically stronger, but I'm not too worried about it. I think we alternatively have several approaches we can take here, though this one seems the simplest. Thoughts?
r? lcnr
Actually use placeholder regions for trait method late bound regions in `collect_return_position_impl_trait_in_trait_tys`
So in https://github.com/rust-lang/rust/pull/113182, I introduced a "diagnostics improvement" in the form of 473c88dfb6, which changes which signature we end up instantiating with placeholder regions and which signature we end up instantiating with fresh region vars so that we have placeholders corresponding to the names of the late-bound regions coming from the *impl*.
However, this is not sound, since now we're essentially no longer proving that *all* instantiations of the trait method are compatible with an instantiation of the impl method, but vice versa (which is weaker). Let's look at the example `tests/ui/impl-trait/in-trait/do-not-imply-from-trait-impl.rs`:
```rust
trait MkStatic {
fn mk_static(self) -> &'static str;
}
impl MkStatic for &'static str {
fn mk_static(self) -> &'static str { self }
}
trait Foo {
fn foo<'a: 'static, 'late>(&'late self) -> impl MkStatic;
}
impl Foo for str {
fn foo<'a: 'static>(&'a self) -> impl MkStatic + 'static {
self
}
}
fn call_foo<T: Foo + ?Sized>(t: &T) -> &'static str {
t.foo().mk_static()
}
fn main() {
let s = call_foo(String::from("hello, world").as_str());
println!("> {s}");
}
```
To collect RPITITs, we were previously instantiating the trait signature with infer vars (`fn(&'?0 str) -> ?1t` where `?1t` is the variable we use to infer the RPITIT) and the impl signature with placeholders (there are no late-bound regions in that signature, so we just have `fn(&'a str) -> Opaque`).
Equating the signatures works, since all we do is unify `?1t` with `Opaque` and `'?0` with `'a`. However, conceptually it *shouldn't* hold, since this definition is not valid for *all* instantiations of the trait method but just the one where `'0` (i.e. `'late`) is equal to `'a` :(
## So what
This PR effectively reverts 473c88dfb6 to fix the unsoundness.
Fixes#133427
Also fixes#133425, which is actually coincidentally another instance of this bug (but not one that is weaponized into UB, just one that causes an ICE in refinement checking).
Delay a bug when encountering an impl with unconstrained generics in `codegen_select`
Despite its name, `codegen_select` is what powers `Instance::try_resolve`, which is used in pre-codegen contexts to try to resolve a method where possible. One place that it's used is in the "recursion MIR lint" that detects recursive MIR bodies.
If we encounter an impl in `codegen_select` that contains unconstrained generic parameters, we expect that impl to caused an error to be reported; however, there's no temporal guarantee that this error is reported *before* we call `codegen_select`. This is what a delayed bug is *for*, and this PR makes us use a delayed bug rather than asserting something about errors already having been emitted.
Fixes #126646
