rustdoc: shrink GenericArgs/PathSegment with boxed slices
This PR also contains a few cleanup bits and pieces, but one of them is a broken intra-doc link, and the other is removing an unused Hash impl. The last commit is the one that matters.
Make write/print macros eagerly drop temporaries
This PR fixes the 2 regressions in #96434 (`println` and `eprintln`) and changes all the other similar macros (`write`, `writeln`, `print`, `eprint`) to match the old pre-#94868 behavior of `println` and `eprintln`.
argument position | before #94868 | after #94868 | after this PR
--- |:---:|:---:|:---:
`write!($tmp, "…", …)` | 😡 | 😡 | 😺
`write!(…, "…", $tmp)` | 😡 | 😡 | 😺
`writeln!($tmp, "…", …)` | 😡 | 😡 | 😺
`writeln!(…, "…", $tmp)` | 😡 | 😡 | 😺
`print!("…", $tmp)` | 😡 | 😡 | 😺
`println!("…", $tmp)` | 😺 | 😡 | 😺
`eprint!("…", $tmp)` | 😡 | 😡 | 😺
`eprintln!("…", $tmp)` | 😺 | 😡 | 😺
`panic!("…", $tmp)` | 😺 | 😺 | 😺
Example of code that is affected by this change:
```rust
use std::sync::Mutex;
fn main() {
let mutex = Mutex::new(0);
print!("{}", mutex.lock().unwrap()) /* no semicolon */
}
```
You can see several real-world examples like this in the Crater links at the top of #96434. This code failed to compile prior to this PR as follows, but works after this PR.
```console
error[E0597]: `mutex` does not live long enough
--> src/main.rs:5:18
|
5 | print!("{}", mutex.lock().unwrap()) /* no semicolon */
| ^^^^^^^^^^^^---------
| |
| borrowed value does not live long enough
| a temporary with access to the borrow is created here ...
6 | }
| -
| |
| `mutex` dropped here while still borrowed
| ... and the borrow might be used here, when that temporary is dropped and runs the `Drop` code for type `MutexGuard`
```
Avoid accidentally enabling unstable features in compilers (take 2)
This allows rustbuild to control whether crates can use nightly features or not.
It also prevents rustbuild from using nightly features itself.
This is #92261, but I fixed the CI error.
Do leak check after function pointer coercion
cc #73154
I still need to clean diagnostics just a tad, but figured I would put this up anyways.
This change is made in order to make match arm coercion order-independent.
Basically, any time we do function pointer coercion, we follow it by doing a leak check. This is necessary because the LUB code doesn't handler higher-ranked things correctly, leading us to "coerce", but use the wrong type. A proper fix is to actually fix that code (so the type returned by `unify_and` is a supertype of both `a` and `b` if `Ok`). However, that requires a more in-depth fix, likely heavily overlapping with the new subtyping changes.
Here, I've been conservative and error early if we generate unsatisfiable constraints. Note, this should *mostly* only affect NLL, since migrate mode falls back to the LUB implementation (followed by leak check), whereas NLL only does sub.
There could be other coercion code that has an order-dependence where a leak check in the coercion code might be useful. However, this is more of a spot-fix for #73154 than a "permanent" fix, since we likely want to go the other way long-term, and allow this pattern without error.
r? `@nikomatsakis`
Move the extended lifetime resolution into typeck context
Related to #15023
This PR is based on the [idea](https://github.com/rust-lang/rust/issues/15023#issuecomment-1070931433) of #15023 by `@nikomatsakis.`
This PR specifically proposes to
- Delay the resolution of scopes of rvalues to a later stage, so that enough type information is available to refine those scopes based on relationships of lifetimes.
- Highlight relevant parts that would help future reviews on the next installments of works to fully implement a solution to RFC 66.
Implement proper stability check for const impl Trait, fall back to unstable const when undeclared
Continuation of #93960
`@jhpratt` it looks to me like the test was simply not testing for the failure you were looking for? Your checks actually do the right thing for const traits?
Omit stdarch workspace from rust-src
The path `library/stdarch/crates/Cargo.toml` does not exist.
In Rust 1.61.0, `rust-src` still includes `src/rust/library/stdarch/Cargo.toml` (but not `stdarch-verify`), which includes
```toml
[workspace]
members = [
"crates/stdarch-verify"
```
This didn't show up when testing with `-Zbuild-std` in https://github.com/rust-lang/rust/pull/94907 since the [standard list of crates](f624095e1c/src/cargo/core/compiler/standard_lib.rs (L26-L30)) to include when building `std` does not include `stdarch`, but it will show up if a user explicitly requests `stdarch`. Or, perhaps more importantly, because of https://github.com/rust-lang/rust/issues/95736, many editors (like IntelliJ) won't treat the root of `rust-src` as a workspace, and will instead recurse into all the sub-crates directly, which then includes `stdarch`.
Also related to https://github.com/rust-lang/rust/issues/94906.
correctly deal with user type ascriptions in pat
supersedes #93856
`thir::PatKind::AscribeUserType` previously resulted in `CanonicalUserTypeAnnotations` where the inferred type already had a subtyping relation according to `variance` to the `user_ty`.
The bug can pretty much be summarized as follows:
- during mir building
- `user_ty -> inferred_ty`: considers variance
- `StatementKind::AscribeUserType`: `inferred_ty` is the type of the place, so no variance needed
- during mir borrowck
- `user_ty -> inferred_ty`: does not consider variance
- `StatementKind::AscribeUserType`: applies variance
This mostly worked fine. The lifetimes in `inferred_ty` were only bound by its relation to `user_ty` and to the `place` of `StatementKind::AscribeUserType`, so it doesn't matter where exactly the subtyping happens.
It does however matter when having higher ranked subtying. At this point the place where the subtyping happens is forced, causing this mismatch between building and borrowck to result in unintended errors.
cc #96514 which is pretty much the same issue
r? `@nikomatsakis`
