update `cfg_select!` documentation
tracking issue: https://github.com/rust-lang/rust/issues/115585
After rust-lang/rust#143461, and with an eye on a soon(ish) stabilization, I think the docs need some work.
The existing text read more like a motivation for the feature existing to me, so I've tried to now be a bit more descriptive. Still, suggestions are very welcome.
I also added a test for an empty `select! {}` because it's just the sort of thing that might break.
r? ``@traviscross``
Preserve constness in trait objects up to hir ty lowering
r? ``@compiler-errors``
While we don't support `dyn const Trait`, we can at least also inform the user that `const Trait` is only legal for `#[const_trait] trait Trait {}`
Rename `stable_mir` and `rustc_smir`
This PR only renames the two crate names.
There is no doubt that we want to rename `stable_mir` to `rustc_public`, while it hasn't been discussed yet that what the new name for `rustc_smir` should be.
This PR proposes a new name for `rustc_smir`, that is `rustc_public_shim`, since `rustc_smir` now is mostly a proxy to do calls to rustc queries and the public API of rustc that is invoked by the `rustc_public` crate.
However, I don't think that name is good enough. I hope there would be a way better name.
r? `@oli-obk`
Retire hir::*ItemRef.
This information was kept for various places that iterate on HIR to know about trait-items and impl-items.
This PR replaces them by uses of the `associated_items` query that contain pretty much the same information.
This shortens many spans to just `def_span`, which can be easier to read.
make `cfg_select` a builtin macro
tracking issue: https://github.com/rust-lang/rust/issues/115585
This parses mostly the same as the `macro cfg_select` version, except:
1. wrapping in double brackets is no longer supported (or needed): `cfg_select {{ /* ... */ }}` is now rejected.
2. in an expression context, the rhs is no longer wrapped in a block, so that this now works:
```rust
fn main() {
println!(cfg_select! {
unix => { "foo" }
_ => { "bar" }
});
}
```
3. a single wildcard rule is now supported: `cfg_select { _ => 1 }` now works
I've also added an error if none of the rules evaluate to true, and warnings for any arms that follow the `_` wildcard rule.
cc `@traviscross` if I'm missing any feature that should/should not be included
r? `@petrochenkov` for the macro logic details
Add --compile-time-deps argument for x check
Together with skipping building C++ code in rustc_llvm for check, this reduces the amount of time it takes to do the x check for rust-analyzer analysis from 12m16s to 3m06s when the bootstrap compiler is already downloaded.
Resolve: merge `source_bindings` and `target_bindings` into `bindings`
Attempts to merge the 2 fields `source_bindings` and `target_bindings` of `ImportKind::Single` into 1 field called `bindings`.
r? ````@petrochenkov````
interpret/allocation: expose init + write_wildcards on a range
Part of https://github.com/rust-lang/miri/pull/4456, so that we can mark down when a foreign access to our memory happened. Should this also move `prepare_for_native_access()` itself into Miri, given that everything there can be implemented on Miri's side?
r? `````@RalfJung`````
Check assoc consts and tys later like assoc fns
This PR
1. checks assoc consts and tys later like assoc fns
2. marks assoc consts appear in poly-trait-ref live
For assoc consts, considering
```rust
#![deny(dead_code)]
trait Tr { // ERROR trait `Tr` is never used
const I: Self;
}
struct Foo; //~ ERROR struct `Foo` is never constructed
impl Tr for Foo {
const I: Self = Foo;
}
fn main() {}
```
Current this will produce unused `I` instead of unused `Tr` and `Foo` ([play](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2024&gist=e0490d4a2d522cb70437b26e514a3d9c)), because `const I: Self = Foo;` will be added into the worklist at first:
```
error: associated constant `I` is never used
--> src/main.rs:4:11
|
3 | trait Tr { // ERROR trait `Tr` is never used
| -- associated constant in this trait
4 | const I: Self;
| ^
|
note: the lint level is defined here
--> src/main.rs:1:9
|
1 | #![deny(dead_code)]
| ^^^^^^^^^
error: could not compile `playground` (bin "playground") due to 1 previous error
```
This also happens to assoc tys, see the [new test](https://github.com/rust-lang/rust/compare/master...mu001999-contrib:rust:dead-code/impl-items?expand=1#diff-bf45fa403934a31c9d610a073ed2603d885e7e81572e8edf38b7f4e08a1f3531)
Fixesrust-lang/rust#126729
r? `````@petrochenkov`````
Rollup of 12 pull requests
Successful merges:
- rust-lang/rust#143776 (std: move NuttX to use arc4random for random number generation)
- rust-lang/rust#143778 (Some const_trait_impl test cleanups)
- rust-lang/rust#143782 (Disambiguate between rustc vs std having debug assertions in `run-make-support` and `run-make` tests)
- rust-lang/rust#143791 (Update sysinfo version to `0.36.0`)
- rust-lang/rust#143796 (Fix ICE for parsed attributes with longer path not handled by CheckAttribute)
- rust-lang/rust#143798 (Remove format short command trait)
- rust-lang/rust#143803 (New tracking issues for const_ops and const_cmp)
- rust-lang/rust#143814 (htmldocck: better error messages for some negative directives)
- rust-lang/rust#143817 (Access `wasi_sdk_path` instead of reading environment variable in bootstrap)
- rust-lang/rust#143822 (./x test miri: fix cleaning the miri_ui directory)
- rust-lang/rust#143823 ([COMPILETEST-UNTANGLE 5/N] Test mode adjustments and other assorted cleanups)
- rust-lang/rust#143841 (Label clippy changes with `T-clippy`)
Failed merges:
- rust-lang/rust#143850 (Compiletest: Simplify {Html,Json}DocCk directive handling)
r? `@ghost`
`@rustbot` modify labels: rollup
de-duplicate condition scoping logic between AST→HIR lowering and `ScopeTree` construction
There was some overlap between `rustc_ast_lowering::LoweringContext::lower_cond` and `rustc_hir_analysis::check::region::resolve_expr`, so I've removed the former and migrated its logic to the latter, with some simplifications.
Consequences:
- For `while` and `if` expressions' `let`-chains, this changes the `HirId`s for the `&&`s to properly correspond to their AST nodes. This is how guards were handled already.
- This makes match guards share previously-duplicated logic with `if`/`while` expressions. This will also be used by guard pattern[^1] guards.
- Aside from legacy syntax extensions (e.g. some builtin macros) that directly feed AST to the compiler, it's currently impossible to put attributes directly on `&&` operators in `let` chains[^2]. Nonetheless, attributes on `&&` operators in `let` chains in `if`/`while` expression conditions are no longer silently ignored and will be lowered.
- This no longer wraps conditions in `DropTemps`, so the HIR and THIR will be slightly smaller.
- `DesugaringKind::CondTemporary` is now gone. It's no longer applied to any spans, and all uses of it were dead since they were made to account for `if` and `while` being desugared to `match` on a boolean scrutinee.
- Should be a marginal perf improvement beyond that due to leveraging [`ScopeTree` construction](5e749eb66f/compiler/rustc_hir_analysis/src/check/region.rs (L312-L355))'s clever handling of `&&` and `||`:
- This removes some unnecessary terminating scopes that were placed around top-level `&&` and `||` operators in conditions. When lowered to MIR, logical operator chains don't create intermediate boolean temporaries, so there's no temporary to drop. The linked snippet handles wrapping the operands in terminating scopes as necessary, in case they create temporaries.
- The linked snippet takes care of letting `let` temporaries live and terminating other operands, so we don't need separate traversals of `&&` chains for that.
[^1]: rust-lang/rust#129967
[^2]: Case-by-case, here's my justification: `#[attr] e1 && e2` applies the attribute to `e1`. In `#[attr] (e1 && e2)` , the attribute is on the parentheses in the AST, plus it'd fail to parse if `e1` or `e2` contains a `let`. In `#[attr] expands_to_let_chain!()`, the attribute would already be ignored (rust-lang/rust#63221) and it'd fail to parse anyway; even if the expansion site is a condition, the expansion wouldn't be parsed with `Restrictions::ALLOW_LET`. If it *was* allowed, the notion of a "reparse context" from https://github.com/rust-lang/rust/issues/61733#issuecomment-509626449 would be necessary in order to make `let`-chains left-associative; multiple places in the compiler assume they are.
