Implement Default for proc_macro::TokenStream
Hopefully this is uncontroversial. The only reason we've made it this far without is that proc-macro2 snuck this in for their TokenStream.
Updated documentation of Prefix::VerbatimDisk
PrefixComponent with Prefix::VerbatimDisk does not contain the trailing slash. The documentation here is also inconsistent with the documentation on other variants that reflect the `PrefixComponent::as_os_str()` return value.
Remove `lang_items\(\).*\.unwrap\(\)`
Follows up #72170 to remove the remaining uses of `lang_items\(\).*\.unwrap\(\)` (avoids a bunch of potential ICEs when working in `#![no_core]`).
Resolves#72195
Be less aggressive with `DroplessArena`/`TypedArena` growth.
`DroplessArena` and `TypedArena` use an aggressive growth strategy: the first chunk is 4 KiB, the second is 8 KiB, and it keeps on doubling indefinitely. DHAT profiles show that sometimes this results in large chunks (e.g. 16-128 MiB) that are barely filled.
This commit changes things so that the doubling stops at 2 MiB. This is large enough that chunk allocations are still rare (you might get 100s instead of 10s of them) but avoids lots of unused space in the worst case. It makes the same change to `TypedArena`, too.
Miri interning: replace ICEs by proper errors
Fixes https://github.com/rust-lang/rust/issues/71316
I also did some refactoring, as I kept being confused by all the parameters to `intern_shallow`, some of which have invalid combinations (such as a mutable const). So instead `InternMode` now contains all the information that is needed and invalid combinations are ruled out by the type system.
Also I removed interpreter errors from interning. We already ignored almost all errors, and the `ValidationFailure` errors that we handled separately actually cannot ever happen here. The only interpreter failure that was actually reachable was the UB on dangling pointers -- and arguably, a dangling raw pointer is not UB, so the error was not even correct. It's just that the rest of the compiler does not like "dangling" `AllocId`.
It should be possible to review the 3 commits separately.
r? @oli-obk
Cc @rust-lang/wg-const-eval
update stacker to 0.1.9 to unbreak build on OpenBSD
the version 0.1.8 of stacker (what is currently pinned in Cargo.lock) doesn't build on OpenBSD (see https://github.com/rust-lang/stacker/pull/34).
update the version to 0.1.9
[const-prop] Don't replace Rvalues that are already constants
This cleans up a few mir-opt tests which have slight changes to spans for `consts` as a result of replacing them with new Rvalues.
Cleanup stale 'FIXME(#64197)'
(My first PR in rust-lang, any feedback is welcome. Please don't hesitate to let me know if I'm trying to do something pointless!)
Trivial cleanup of a stale `FIXME`, `StringReader.pos` is no longer exposed. For testing added `pos()` method that returns cloned value of `pos`.
rustc_driver: factor out computing the exit code
In a recent Miri PR I [added a convenience wrapper](https://github.com/rust-lang/miri/pull/1405/files#diff-c3d602c5c8035a16699ce9c015bfeceaR125) around `catch_fatal_errors` and `run_compiler` that @oli-obk suggested I could upstream. However, after seeing what could be shared between `rustc_driver::main`, clippy and Miri, really the only thing I found is computing the exit code -- so that's what this PR does.
What prevents using the Miri convenience function in `rustc_driver::main` and clippy is that they do extra work inside `catch_fatal_errors`, and while I could abstract that away, clippy actually *computes the callbacks* inside there, and I fond no good way to abstract that and thus gave up. Maybe the clippy thing could be moved out, I am not sure if it ever can actually raise a `FatalErrorMarker` -- someone more knowledgeable in clippy would have to do that.
Doc alias improvements
After [this message](https://github.com/rust-lang/rust/issues/50146#issuecomment-496601755), I realized that the **doc alias**. So this PR does the followings:
* Align the alias discovery on items added into the search-index. It brings a few nice advantages:
* Instead of cloning the data between the two (in rustdoc source code), we now have the search-index one and aliases which reference to the first one. So we go from one big map containing a lot of duplicated data to just integers...
* In the front-end (main.js), I improved the code around aliases to allow them to go through the same transformation as other items when we show the search results.
* Improve the search tester in order to perform multiple requests into one file (I think it's better in this case than having a file for each case considering how many there are...)
* I also had to add the new function inside the tester (`handleAliases`)
Once this PR is merged, I intend to finally stabilize this feature.
r? @ollie27
cc @rust-lang/rustdoc
PrefixComponent with Prefix::VerbatimDisk does not contain the trailing slash. The documentation here is also inconsistent with the documentation on other variants that reflect the `PrefixComponent::as_os_str()` return value.
Rework the std::iter::Step trait
Previous attempts: #43127#62886#68807
Tracking issue: #42168
This PR reworks the `Step` trait to be phrased in terms of the *successor* and *predecessor* operations. With this, `Step` hopefully has a consistent identity that can have a path towards stabilization. The proposed trait:
```rust
/// Objects that have a notion of *successor* and *predecessor* operations.
///
/// The *successor* operation moves towards values that compare greater.
/// The *predecessor* operation moves towards values that compare lesser.
///
/// # Safety
///
/// This trait is `unsafe` because its implementation must be correct for
/// the safety of `unsafe trait TrustedLen` implementations, and the results
/// of using this trait can otherwise be trusted by `unsafe` code to be correct
/// and fulful the listed obligations.
pub unsafe trait Step: Clone + PartialOrd + Sized {
/// Returns the number of *successor* steps required to get from `start` to `end`.
///
/// Returns `None` if the number of steps would overflow `usize`
/// (or is infinite, or if `end` would never be reached).
///
/// # Invariants
///
/// For any `a`, `b`, and `n`:
///
/// * `steps_between(&a, &b) == Some(n)` if and only if `Step::forward(&a, n) == Some(b)`
/// * `steps_between(&a, &b) == Some(n)` if and only if `Step::backward(&a, n) == Some(a)`
/// * `steps_between(&a, &b) == Some(n)` only if `a <= b`
/// * Corollary: `steps_between(&a, &b) == Some(0)` if and only if `a == b`
/// * Note that `a <= b` does _not_ imply `steps_between(&a, &b) != None`;
/// this is the case wheen it would require more than `usize::MAX` steps to get to `b`
/// * `steps_between(&a, &b) == None` if `a > b`
fn steps_between(start: &Self, end: &Self) -> Option<usize>;
/// Returns the value that would be obtained by taking the *successor*
/// of `self` `count` times.
///
/// If this would overflow the range of values supported by `Self`, returns `None`.
///
/// # Invariants
///
/// For any `a`, `n`, and `m`:
///
/// * `Step::forward_checked(a, n).and_then(|x| Step::forward_checked(x, m)) == Step::forward_checked(a, m).and_then(|x| Step::forward_checked(x, n))`
///
/// For any `a`, `n`, and `m` where `n + m` does not overflow:
///
/// * `Step::forward_checked(a, n).and_then(|x| Step::forward_checked(x, m)) == Step::forward_checked(a, n + m)`
///
/// For any `a` and `n`:
///
/// * `Step::forward_checked(a, n) == (0..n).try_fold(a, |x, _| Step::forward_checked(&x, 1))`
/// * Corollary: `Step::forward_checked(&a, 0) == Some(a)`
fn forward_checked(start: Self, count: usize) -> Option<Self>;
/// Returns the value that would be obtained by taking the *successor*
/// of `self` `count` times.
///
/// If this would overflow the range of values supported by `Self`,
/// this function is allowed to panic, wrap, or saturate.
/// The suggested behavior is to panic when debug assertions are enabled,
/// and to wrap or saturate otherwise.
///
/// Unsafe code should not rely on the correctness of behavior after overflow.
///
/// # Invariants
///
/// For any `a`, `n`, and `m`, where no overflow occurs:
///
/// * `Step::forward(Step::forward(a, n), m) == Step::forward(a, n + m)`
///
/// For any `a` and `n`, where no overflow occurs:
///
/// * `Step::forward_checked(a, n) == Some(Step::forward(a, n))`
/// * `Step::forward(a, n) == (0..n).fold(a, |x, _| Step::forward(x, 1))`
/// * Corollary: `Step::forward(a, 0) == a`
/// * `Step::forward(a, n) >= a`
/// * `Step::backward(Step::forward(a, n), n) == a`
fn forward(start: Self, count: usize) -> Self {
Step::forward_checked(start, count).expect("overflow in `Step::forward`")
}
/// Returns the value that would be obtained by taking the *successor*
/// of `self` `count` times.
///
/// # Safety
///
/// It is undefined behavior for this operation to overflow the
/// range of values supported by `Self`. If you cannot guarantee that this
/// will not overflow, use `forward` or `forward_checked` instead.
///
/// # Invariants
///
/// For any `a`:
///
/// * if there exists `b` such that `b > a`, it is safe to call `Step::forward_unchecked(a, 1)`
/// * if there exists `b`, `n` such that `steps_between(&a, &b) == Some(n)`,
/// it is safe to call `Step::forward_unchecked(a, m)` for any `m <= n`.
///
/// For any `a` and `n`, where no overflow occurs:
///
/// * `Step::forward_unchecked(a, n)` is equivalent to `Step::forward(a, n)`
#[unstable(feature = "unchecked_math", reason = "niche optimization path", issue = "none")]
unsafe fn forward_unchecked(start: Self, count: usize) -> Self {
Step::forward(start, count)
}
/// Returns the value that would be obtained by taking the *successor*
/// of `self` `count` times.
///
/// If this would overflow the range of values supported by `Self`, returns `None`.
///
/// # Invariants
///
/// For any `a`, `n`, and `m`:
///
/// * `Step::backward_checked(a, n).and_then(|x| Step::backward_checked(x, m)) == n.checked_add(m).and_then(|x| Step::backward_checked(a, x))`
/// * `Step::backward_checked(a, n).and_then(|x| Step::backward_checked(x, m)) == try { Step::backward_checked(a, n.checked_add(m)?) }`
///
/// For any `a` and `n`:
///
/// * `Step::backward_checked(a, n) == (0..n).try_fold(a, |x, _| Step::backward_checked(&x, 1))`
/// * Corollary: `Step::backward_checked(&a, 0) == Some(a)`
fn backward_checked(start: Self, count: usize) -> Option<Self>;
/// Returns the value that would be obtained by taking the *predecessor*
/// of `self` `count` times.
///
/// If this would overflow the range of values supported by `Self`,
/// this function is allowed to panic, wrap, or saturate.
/// The suggested behavior is to panic when debug assertions are enabled,
/// and to wrap or saturate otherwise.
///
/// Unsafe code should not rely on the correctness of behavior after overflow.
///
/// # Invariants
///
/// For any `a`, `n`, and `m`, where no overflow occurs:
///
/// * `Step::backward(Step::backward(a, n), m) == Step::backward(a, n + m)`
///
/// For any `a` and `n`, where no overflow occurs:
///
/// * `Step::backward_checked(a, n) == Some(Step::backward(a, n))`
/// * `Step::backward(a, n) == (0..n).fold(a, |x, _| Step::backward(x, 1))`
/// * Corollary: `Step::backward(a, 0) == a`
/// * `Step::backward(a, n) <= a`
/// * `Step::forward(Step::backward(a, n), n) == a`
fn backward(start: Self, count: usize) -> Self {
Step::backward_checked(start, count).expect("overflow in `Step::backward`")
}
/// Returns the value that would be obtained by taking the *predecessor*
/// of `self` `count` times.
///
/// # Safety
///
/// It is undefined behavior for this operation to overflow the
/// range of values supported by `Self`. If you cannot guarantee that this
/// will not overflow, use `backward` or `backward_checked` instead.
///
/// # Invariants
///
/// For any `a`:
///
/// * if there exists `b` such that `b < a`, it is safe to call `Step::backward_unchecked(a, 1)`
/// * if there exists `b`, `n` such that `steps_between(&b, &a) == Some(n)`,
/// it is safe to call `Step::backward_unchecked(a, m)` for any `m <= n`.
///
/// For any `a` and `n`, where no overflow occurs:
///
/// * `Step::backward_unchecked(a, n)` is equivalent to `Step::backward(a, n)`
#[unstable(feature = "unchecked_math", reason = "niche optimization path", issue = "none")]
unsafe fn backward_unchecked(start: Self, count: usize) -> Self {
Step::backward(start, count)
}
}
```
Note that all of these are associated functions and not callable via method syntax; the calling syntax is always `Step::forward(start, n)`. This version of the trait additionally changes the stepping functions to talk their arguments by value.
As opposed to previous attempts which provided a "step by one" method directly, this version of the trait only exposes "step by n". There are a few reasons for this:
- `Range*`, the primary consumer of `Step`, assumes that the "step by n" operation is cheap. If a single step function is provided, it will be a lot more enticing to implement "step by n" as n repeated calls to "step by one". While this is not strictly incorrect, this behavior would be surprising for anyone used to using `Range<{primitive integer}>`.
- With a trivial default impl, this can be easily added backwards-compatibly later.
- The debug-wrapping "step by n" needs to exist for `RangeFrom` to be consistent between "step by n" and "step by one" operation. (Note: the behavior is not changed by this PR, but making the behavior consistent is made tenable by this PR.)
Three "kinds" of step are provided: `_checked`, which returns an `Option` indicating attempted overflow; (unsuffixed), which provides "safe overflow" behavior (is allowed to panic, wrap, or saturate, depending on what is most convenient for a given type); and `_unchecked`, which is a version which assumes overflow does not happen.
Review is appreciated to check that:
- The invariants as described on the `Step` functions are enough to specify the "common sense" consistency for successor/predecessor.
- Implementation of `Step` functions is correct in the face of overflow and the edges of representable integers.
- Added tests of `Step` functions are asserting the correct behavior (and not just the implemented behavior).
Minor fixes to comments
* In 'src/librustc_ast_passes/node_count.rs'
* typo fix ('rought' -> 'rough')
* In 'src/librustc_middle/middle/region.rs',
* fixed broken link to 'rustc-dev-guide'
* typo fix ('aluded' -> 'alluded')
Thank you for reviewing this PR :)
Forbid stage arguments to check
Users generally expect that check builds are fast, and that's only true in stage
0 (stages beyond that need us to build a compiler, which is slow).
Closes#69337
r? @alexcrichton
Provide separate option for std debug asserts
On local one-off benchmarking of libcore metadata-only, debug asserts in std are a significant hit (15s to 20s). Provide an option for compiler developers to disable them. A build with a nightly compiler is around 10s, for reference.
Add built in PSP target
This adds a new target, `mipsel-sony-psp`, corresponding to the Sony PSP. The linker script is necessary to handle special sections, which are required by the target. This has been tested with my [rust-psp] crate and I can confirm it works as intended.
The linker script is taken from [here]. It has been slightly adapted to work with rust and LLD.
The `stdarch` submodule was also updated in order for `libcore` to build successfully.
[rust-psp]: https://github.com/overdrivenpotato/rust-psp
[here]: https://github.com/pspdev/pspsdk/blob/master/src/base/linkfile.prx.in
Use min_specialization in liballoc
- Remove a type parameter from `[A]RcFromIter`.
- Remove an implementation of `[A]RcFromIter` that didn't actually
specialize anything.
- Remove unused implementation of `IsZero` for `Option<&mut T>`.
- Change specializations of `[A]RcEqIdent` to use a marker trait version
of `Eq`.
- Remove `BTreeClone`. I couldn't find a way to make this work with
`min_specialization`.
- Add `rustc_unsafe_specialization_marker` to `Copy` and `TrustedLen`.
After this only libcore is the only standard library crate using `feature(specialization)`.
cc #31844
* In 'src/librustc_ast_passes/node_count.rs'
* typo fix ('rought' -> 'rough')
* In 'src/librustc_middle/middle/region.rs',
* fixed broken link to 'rustc-dev-guide'
* typo fix ('aluded' -> 'alluded')
Thank you for reviewing this PR :)
Don't ICE on missing `Unsize` impl
Previously code of the form
```rust
#![feature(unsize, dispatch_from_dyn)]
use std::marker::Unsize;
use std::ops::DispatchFromDyn;
pub struct Foo<'a, T: ?Sized> {
_inner: &'a &'a T,
}
impl<'a, T: ?Sized + Unsize<U>, U: ?Sized> DispatchFromDyn<Foo<'a, U>> for Foo<'a, T> {}
```
would generate an ICE due to the missing `Unsize` impl being run through the `suggest_change_mut` suggestion. This PR adds an early exit and a pointer to the appropriate docs regarding `Unsize` instead:
```
error[E0277]: the trait bound `&'a T: std::marker::Unsize<&'a U>` is not satisfied
--> src/test/ui/issues/issue-71036.rs:11:1
|
11 | impl<'a, T: ?Sized + Unsize<U>, U: ?Sized> DispatchFromDyn<Foo<'a, U>> for Foo<'a, T> {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::marker::Unsize<&'a U>` is not implemented for `&'a T`
|
= note: all implementations of `Unsize` are provided automatically by the compiler, see <https://doc.rust-lang.org/stable/std/marker/trait.Unsize.html> for more information
= note: required because of the requirements on the impl of `std::ops::DispatchFromDyn<&'a &'a U>` for `&'a &'a T`
error: aborting due to previous error
For more information about this error, try `rustc --explain E0277`.
```
r? @estebank
Resolves#71036
use `require_lang_item` over `unwrap`.
Does not yet replace all uses of `lang_items\(\)\.*\.unwrap\(\)`, as there are more
than I expected 😅Fixes#72099
r? @RalfJung
*edit: The goal of this this PR is to change ICE from missing lang items to a fatal error.*
Warn against thread::sleep in async fn
I've seen `thread::sleep` wrecking havoc in async servers. There's already an [issue for clippy](https://github.com/rust-lang/rust-clippy/issues/4377), but the std docs could warn against it too.
add long error explanation for E0228
Add long explanation for the E0228 error code
Part of #61137
Let me know if this is wrong at all (or can be written more clearly), I'm still learning Rust.
