Fix types being marked as dead when they are inferred generic arguments
Previously usages of a type in a pattern were ignored. This is incorrect, since if the type is in a pattern we're clearly producing it in the expression we're matching against.
I think this `in_pat` check was meant to be only for variants, which we should indeed ignore since we can just remove the match arm that matches the pattern. Please double check my logic here since this is my first time touching the dead-code pass and I'm not 100% sure this is what the `self.in_pat` check was for.
Fixes https://github.com/rust-lang/rust/issues/148144
Constify trait aliases
Allow `const trait Foo = Bar + [const] Baz;` trait alias declarations. Their rules are the same as with super traits of const traits. So `[const] Baz` or `const Baz` is only required for `[const] Foo` or `const Foo` bounds respectively.
tracking issue rust-lang/rust#41517 (part of the general trait alias feature gate, but I can split it out into a separate const trait alias feature gate. I just assumed that const traits would stabilize before trait aliases, and we'd want to stabilize trait aliases together with const trait aliases at the same time)
r? ``@compiler-errors`` ``@fee1-dead``
Move wasm `throw` intrinsic back to `unwind`
Fixesrust-lang/rust#148246, less invasive than the previously proposed rust-lang/rust#148269. Removes the publicly visible unstable intrinsic tracked in rust-lang/rust#122465 since it's not clear how to export it in a sound manner.
r? `@bjorn3`
---
rustc assumes that regular `extern "Rust"` functions unwind only if the `unwind` panic runtime is linked. `throw` was annotated as such, but unwound unconditionally. This could cause UB when a crate built with `-C panic=abort` called `throw` from `core` built with `-C panic=unwind`, since no terminator was added to handle the panic arising from calling an allegedly non-unwinding `extern "Rust"` function.
rustc was taught to recognize this condition since https://github.com/rust-lang/rust/pull/144225 and prevented such linkage, but this caused regressions in
https://github.com/rust-lang/rust/issues/148246, since this meant that Emscripten projects could not be built with `-C panic=abort` without recompiling std.
The most straightforward solution would be to move `throw` into the `panic_unwind` crate, so that it's only compiled if the panic runtime is guaranteed to be `unwind`, but this is messy due to our architecture. Instead, move it into `unwind::wasm`, which is only compiled for bare-metal targets that default to `panic = "abort"`, rendering the issue moot.
rustc assumes that regular `extern "Rust"` functions unwind only if the
`unwind` panic runtime is linked. `throw` was annotated as such, but
unwound unconditionally. This could cause UB when a crate built with `-C
panic=abort` called `throw` from `core` built with `-C panic=unwind`,
since no terminator was added to handle the panic arising from calling an
allegedly non-unwinding `extern "Rust"` function.
rustc was taught to recognize this condition since
https://github.com/rust-lang/rust/pull/144225 and prevented such
linkage, but this caused regressions in
https://github.com/rust-lang/rust/issues/148246, since this meant that
Emscripten projects could not be built with `-C panic=abort` without
recompiling std.
The most straightforward solution would be to move `throw` into the
`panic_unwind` crate, so that it's only compiled if the panic runtime is
guaranteed to be `unwind`, but this is messy due to our architecture.
Instead, move it into `unwind::wasm`, which is only compiled for
bare-metal targets that default to `panic = "abort"`, rendering the
issue moot.
[rustdoc] Include attribute and derive macros when filtering on "macros"
As discussed [here](https://github.com/rust-lang/rust/pull/147909), some filters should have been "grouped". This PR allows attribute and derive macros to match the `macro` filter.
I'll wait for https://github.com/rust-lang/rust/pull/148005 to add more tests as it would require a proc-macro library for now.
r? ```@notriddle```
rustdoc: Rename unstable option `--nocapture` to `--no-capture` in accordance with `libtest`
Context: https://github.com/rust-lang/rust/issues/133073, https://github.com/rust-lang/rust/pull/139224 (TL;DR: `libtest` has soft-deprecated `--nocapture` in favor a new & stable `--no-capture`; we should follow suit).
Since the rustdoc flag is unstable (tracking issue: https://github.com/rust-lang/rust/issues/148116), we're allowed to remove the old flag immediately. However since the flag has existed for 4 years we could hard-deprecate the flag first or at least be considerate and provide a diagnostic referring users to the new flag. This PR does neither. Let me know what you would think would be best.
Cargo doesn't use this flag, not yet at least (https://github.com/rust-lang/cargo/pull/9705), so we really are free to sunset this flag without bigger consequences.
Run regression test for #147964 on next solver too
Original regression: rust-lang/rust#147964
Longer-term tracking of issue: rust-lang/rust#148028
For now, this just makes sure that whatever tests we keep are working the same under both the current solver and the next solver, until we decide what to do with them.
Move rustdoc tests to appropriate subdirectories
## Summary
This PR reorganizes rustdoc tests into their correct subdirectories for better categorization and maintainability.
## Changes
- Moved 6 lint-related tests to `tests/rustdoc-ui/lints/`
- Moved 2 intra-doc link tests to `tests/rustdoc-ui/intra-doc/`
- Moved 3 deref-related tests to `tests/rustdoc-ui/deref/`
- Moved 1 doc-cfg test to `tests/rustdoc/doc-cfg/`
## Tests
All moved tests have been verified and pass in their new locations.
Skip parameter attribute deduction for MIR with `spread_arg`
When a MIR argument is spread at ABI level, deduced attributes are potentially misapplied, since a spread argument can correspond to zero or more arguments at ABI level.
Disable deduction for MIR using spread argument for the time being.
Contract variable declarations
This change adds contract variables that can be declared in the `requires` clause and can be referenced both in `requires` and `ensures`, subject to usual borrow checking rules. This allows any setup common to both the `requires` and `ensures` clauses to only be done once.
In particular, one future use case would be for [Fulminate](https://dl.acm.org/doi/10.1145/3704879)-like ownership assertions in contracts, that are essentially side-effects, and executing them twice would alter the semantics of the contract.
As of this change, `requires` can now be an arbitrary sequence of statements, with the final expression being of type `bool`. They are executed in sequence as expected, before checking if the final `bool` expression holds.
This PR depends on rust-lang/rust#144438 (which has now been merged).
Contracts tracking issue: https://github.com/rust-lang/rust/issues/128044
**Other changes introduced**:
- Contract macros now wrap the content in braces to produce blocks, meaning there's no need to wrap the content in `{}` when using multiple statements. The change is backwards compatible, in that wrapping the content in `{}` still works as before. The macros also now treat `requires` and `ensures` uniformally, meaning the `requires` closure is built inside the parser, as opposed to in the macro.
**Known limiatations**:
- Contracts with variable declarations are subject to the regular borrow checking rules, and the way contracts are currently lowered limits the usefulness of contract variable declarations. Consider the below example:
```rust
#[requires(let init_x = *x; true)]
#[ensures(move |_| *x == 2 * init_x)]
fn double_in_place(x: &mut i32) {
*x *= 2;
}
```
We have used the new variable declarations feature to remember the initial value pointed to by `x`, however, moving `x` into the `ensures` does not pass the borrow checker, meaning the above function contract is illegal. Ideally, something like the above should be expressable in contracts.
Accept trivial consts based on trivial consts
This is an expansion of https://github.com/rust-lang/rust/pull/148040.
The previous implementation only accepted trivial consts that assign a literal. For example:
```rust
const A: usize = 0;
const B: usize = A;
```
Before this PR, only `A` was a trivial const. Now `B` is too.
When a MIR argument is spread at ABI level, deduced attributes are
potentially misapplied, since a spread argument can correspond to zero
or more arguments at ABI level.
Disable deduction for MIR using spread argument for the time being.
rustdoc: remove `--emit=unversioned-shared-resources`
This option hasn't done anything for a long time, and can be removed. I've kept a shim in place to avoid breaking docs.rs, but the option no longer does anything.
Using git-blame, I tracked this option down to
f77ebd4ffa, the commit that introduced EmitType in the first place. It was used with SharedResource::Unversioned, which no longer exists since f9e1f6ffdf removed them.
CC https://github.com/rust-lang/rust/pull/146220
Part of https://github.com/rust-lang/rust/issues/83784
Emit delayed bug during wfck for stranded opaque
Fixes https://github.com/rust-lang/trait-system-refactor-initiative/issues/235
## Problem
The fundamental issue here is ``OpaqueTypeCollector`` operates on ``rustc_middle::Ty``, but ``check_type_wf`` operates on HIR.
Since [check_type_wf](2f7620a5cc/compiler/rustc_hir_analysis/src/check/wfcheck.rs (L2262)) operates on HIR, it can see the stranded opaque and tries to infer it's hidden type. But ``OpaqueTypeCollector`` operates on ``rustc_middle::Ty``, so the ``OpaqueTypeCollector`` can no longer see a stranded opaque, hence its hidden type could not be inferred.
As a result, the tests ICE'ed at 34a8c7368c/compiler/rustc_hir_analysis/src/collect/type_of/opaque.rs (L253)
## Proposed solution
This PR detects stranded opaque types during wf check and emit a delayed bug for it.
## Alternative solution
`@BoxyUwU` and I had considered rewriting ``OpaqueTypeCollector`` to be a HIR visitor instead of a ``rustc_middle::Ty`` visitor, but we believe a HIR-based ``OpaqueTypeCollector`` will not work and might not worth the cost of rewriting.
## Acknowledgement
This PR is a joint effort with `@BoxyUwU` :3
CFI: Fix types that implement Fn, FnMut, or FnOnce
When looking for instances which could either be dynamically called through a vtable or through a concrete trait method, we missed `FnPtrShim`, instead only looking at `Item` and closure-likes. Fixesrust-lang/rust#144641.
cc ```@1c3t3a``` ```@Jakob-Koschel```
Do not lifetime-extend array/slice indices
When lowering non-overloaded indexing operations to MIR, this uses the temporary lifetime of the index expression for the index temporary, rather than applying the temporary lifetime of the indexing operation as a whole to the index.
For example, in
```rust
let x = &xs[i];
```
previously, the temporary containing the result of evaluating `i` would live until the end of the block due to the indexing operation being [lifetime-extended](https://doc.rust-lang.org/nightly/reference/destructors.html#temporary-lifetime-extension). Under this PR, the index temporary only lives to the end of the `let` statement because it uses the more precise temporary lifetime of the index expression.
I don't think this will affect semantics in an observable way, but the more precise `StorageDead` placement may slightly improve analysis/codegen performance.
r? mir
This option hasn't done anything for a long time, and can be
removed. I've kept a shim in place to avoid breaking docs.rs,
but the option no longer does anything.
Using git-blame, I tracked this option down to
f77ebd4ffa, the commit that
introduced EmitType in the first place. It was used with
SharedResource::Unversioned, which no longer exists since
f9e1f6ffdf removed them.
CC https://github.com/rust-lang/rust/pull/146220
Part of https://github.com/rust-lang/rust/issues/83784
When looking for instances which could either be dynamically called
through a vtable or through a concrete trait method, we missed
`FnPtrShim`, instead only looking at `Item` and closure-likes.
