We'll try to use a weak `getrandom` symbol first, because that allows
things like `LD_PRELOAD` interposition. For example, perf measurements
might want to disable randomness to get reproducible results. If the
weak symbol is not found, we fall back to a raw `SYS_getrandom` call.
Update E0744 about control flow in `const` contexts to accurately describe when the error is triggered and why
This PR fixes#79083. `const fn` currently supports `if`, `match`, `loop`, and `while` in terms of control flow. The error relating to control flow in `const` contexts currently states that those control flow constructs are not allowed in `const` contexts. That is no longer true, as RFC 2342 and 2344 were [stabilized](https://github.com/rust-lang/rust/pull/72437). `for` loops, however, as well as `?` and `.await` are still not allowed, so I changed the error message to be more descriptive of the error as it is not just control flow that could trigger this error. I also added links to tracking issues that mark things that are blocking the usage of these expressions.
improve type const mismatch errors
Doesn't completely remove `check_generic_arg_count` as that would have required some more complex changes but
instead checks type and const params in only one step. Also moved the help added by `@JulianKnodt` in #75611 to `generic_arg_mismatch_err`.
r? `@varkor` cc `@petrochenkov`
Simplify output capturing
This is a sequence of incremental improvements to the unstable/internal `set_panic` and `set_print` mechanism used by the `test` crate:
1. Remove the `LocalOutput` trait and use `Arc<Mutex<dyn Write>>` instead of `Box<dyn LocalOutput>`. In practice, all implementations of `LocalOutput` were just `Arc<Mutex<..>>`. This simplifies some logic and removes all custom `Sink` implementations such as `library/test/src/helpers/sink.rs`. Also removes a layer of indirection, as the outermost `Box` is now gone. It also means that locking now happens per `write_fmt`, not per individual `write` within. (So `"{} {}\n"` now results in one `lock()`, not four or more.)
2. Since in all cases the `dyn Write`s were just `Vec<u8>`s, replace the type with `Arc<Mutex<Vec<u8>>>`. This simplifies things more, as error handling and flushing can be removed now. This also removes the hack needed in the default panic handler to make this work with `::realstd`, as (unlike `Write`) `Vec<u8>` is from `alloc`, not `std`.
3. Replace the `RefCell`s by regular `Cell`s. The `RefCell`s were mostly used as `mem::replace(&mut *cell.borrow_mut(), something)`, which is just `Cell::replace`. This removes an unecessary bookkeeping and makes the code a bit easier to read.
4. Merge `set_panic` and `set_print` into a single `set_output_capture`. Neither the test crate nor rustc (the only users of this feature) have a use for using these separately. Merging them simplifies things even more. This uses a new function name and feature name, to make it clearer this is internal and not supposed to be used by other crates.
Might be easier to review per commit.
Rename/Deprecate LayoutErr in favor of LayoutError
Implements rust-lang/wg-allocators#73.
This patch renames LayoutErr to LayoutError, and uses a type alias to support users using the old name.
The new name will be instantly stable in release 1.49 (current nightly), the type alias will become deprecated in release 1.51 (so that when the current nightly is 1.51, 1.49 will be stable).
This is the only error type in `std` that ends in `Err` rather than `Error`, if this PR lands all stdlib error types will end in `Error` 🥰
Test structural matching for all range types
As of #70166 all range types (`core::ops::Range` etc.) can be structurally matched upon, and by extension used in const generics. In reference to the fact that this is a publicly observable property of these types, and thus falls under the Rust stability guarantees of the standard library, a regression test was added in #70283.
This regression test was implemented by me by testing for the ability to use the range types within const generics, but that is not the actual property the std guarantees now (const generics is still unstable). This PR addresses that situation by adding extra tests for the range types that directly test whether they can be structurally matched upon.
Note: also adds the otherwise unrelated test `test_range_to_inclusive` for completeness with the other range unit tests
Implement `Index` and `IndexMut` for arrays
Adds implementations of `Index` and `IndexMut` for arrays that simply forward to the slice indexing implementation in order to fix the following problem:
If you implement `Index<MyIndexType>` for an array, you lose all the other indexing functionality that used to be available to the array via its implicit coercion to a slice. An example of what I'm talking about:
```rust
use std::ops::Index;
pub enum MyIndexType {
_0, _1, _2, _3, _4, _5, _6, _7,
}
impl<T> Index<MyIndexType> for [T; 8] {
type Output = T;
fn index(&self, index: MyIndexType) -> &T {
unsafe { self.get_unchecked(index as usize) }
}
}
fn main() {
let array = [11u8; 8];
println!("{:?}", array[MyIndexType::_0]); // OK
println!("{:?}", array[0usize]); // error[E0277]
// ^^^^^^^^^^^^^ `[u8; 8]` cannot be indexed by `usize`
}
```
This is a squash of these commits:
- Update E0744 about control flow in `const` contexts to reflect current status of `const fn`.
- E0744 isn't just about `for` loops or control flow
- Fix formatting on E0744 cause my editor decided to not copy it well
- Improve wording
- Fix a markdown formatting error
- Fix E0744's description as I interpreted some code wrong
- Fix a minor wording issue again
- Add a few more links to blocking issues
- Improve links to tracking issues
Now users will be able to do:
```
cargo build -Zbuild-std=core -Zbuild-std-features=compiler-builtins-asm
```
and correctly get the assembly implemenations for `memcpy` and friends.
BTreeMap: fix pointer provenance rules in underfullness
Continuing on #78480, and for readability, and possibly for performance: avoid aliasing when handling underfull nodes, and consolidate the code doing that. In particular:
- Avoid the rather explicit aliasing for internal nodes in `remove_kv_tracking`.
- Climb down to the root to handle underfull nodes using a reborrowed handle, rather than one copied with `ptr::read`, before resuming on the leaf level.
- Integrate the code tracking leaf edge position into the functions performing changes, rather than bolting it on.
r? `@Mark-Simulacrum`
Install CI llvm into the library directory
In other words, my concern in https://github.com/rust-lang/rust/issues/78932#issuecomment-725781767 was perfectly justified by something we were already doing. For now just special case CI LLVM, but in the future we may want a more general fix.
Fixes#79071.
r? `@alexcrichton`
Clippy uses `ExprUseVisitor` and atleast in some cases it runs
after writeback.
We currently don't writeback the min_capture results of closure
capture analysis since no place within the compiler itself uses it.
In the short term to fix clippy we add a fallback when walking captures
of a closure to check if closure_capture analysis has any entries in it.
Writeback for closure_min_captures will be implemented in
rust-lang/project-rfc-2229#18
Fix displaying errors when rustbook tests fail.
This ensures that output from mdbook is displayed when running the rustbook wrapper. I believe this was a regression as a result of #69115 where it was changed from running `rustdoc` directly to using rustbook.
It seems that by default the 32-bit headers are not actually installed
when installing development tooling. As we're using gcc headers,
we need to install them as an extra package.
See for reference:
- https://stackoverflow.com/a/54082790
- https://askubuntu.com/a/106092
Also removed the now unused arm tooling
Move likely/unlikely argument outside of invisible unsafe block
The previous `likely!`/`unlikely!` macros were unsound because it permits the caller's expr to contain arbitrary unsafe code.
```rust
pub fn huh() -> bool {
likely!(std::ptr::read(&() as *const () as *const bool))
}
```
**Before:** compiles cleanly.
**After:**
```console
error[E0133]: call to unsafe function is unsafe and requires unsafe function or block
|
70 | likely!(std::ptr::read(&() as *const () as *const bool))
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ call to unsafe function
|
= note: consult the function's documentation for information on how to avoid undefined behavior
```
