Emit only one nbsp error per file
Fixes#106101.
See https://github.com/rust-lang/rust/issues/106098 for an explanation of how someone would end up with a large number of these nbsp characters in their source code, which is why I think rustc needs to handle this specific case in a friendlier way.
Rework some `predicates_of`/`{Generic,Instantiated}Predicates` code
1. Make `instantiate_own` return an iterator, since it's a bit more efficient and easier to work with
2. Remove `bound_{explicit,}_predicates_of` -- these `bound_` methods in particular were a bit awkward to work with since `ty::GenericPredicates` *already* acts kinda like an `EarlyBinder` with its own `instantiate_*` methods, and had only a few call sites anyways.
3. Implement `IntoIterator` for `InstantiatedPredicates`, since it's *very* commonly being `zip`'d together.
Rollup of 5 pull requests
Successful merges:
- #106888 (Add tidy check to ensure that rustdoc GUI tests start with a small description)
- #106896 (suggest `is_empty` for collections when casting to `bool`)
- #106900 (Fix regression in `unused_braces` with macros)
- #106906 (remove redundant clones)
- #106909 (Only suggest adding type param if path being resolved was a type)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
suggest `is_empty` for collections when casting to `bool`
Fixes#106883
Matches on slices, `String` and `str`. It would be nice to do this with something like `Deref<Target=str>` as well, but AFAIK it's not possible in this part of the compiler.
Add tidy check to ensure that rustdoc GUI tests start with a small description
The first commit comes from https://github.com/rust-lang/rust/pull/106865 to prevent CI to fail.
This PR adds a tidy check to enforce having a small description at the top of the GUI test. Although the format is made to be as easy as possible to read, it's not always obvious what a test is actually checking. I think enforcing this will make it easier for us to come back on these tests if needed.
r? `@notriddle`
Simplify manual ptr arithmetic in slice::Iter with ptr_sub
The old code was introduced in #61885, which predates the ptr_sub method and underlying intrinsic. The codegen test still passes.
r? `@scottmcm`
Implement some FIXME methods in the new trait solver
Implement just enough of the solver's response logic to make it not ICE.
Also, fix a bug with `no_bound_vars` call failing due to canonical bound vars.
r? `@lcnr`
Consolidate two almost duplicated fn info extraction routines
Moves `extract_callable_info` up to trait selection, because it was being (almost) duplicated fully there for similar diagnostic purposes. This also generalizes the diagnostics we can give slightly (see UI test).
Leak amplification for peek_mut() to ensure BinaryHeap's invariant is always met
In the libs-api team's discussion around #104210, some of the team had hesitations around exposing malformed BinaryHeaps of an element type whose Ord and Drop impls are trusted, and which does not contain interior mutability.
For example in the context of this kind of code:
```rust
use std::collections::BinaryHeap;
use std::ops::Range;
use std::slice;
fn main() {
let slice = &mut ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9'];
let cut_points = BinaryHeap::from(vec![4, 2, 7]);
println!("{:?}", chop(slice, cut_points));
}
// This is a souped up slice::split_at_mut to split in arbitrary many places.
//
// usize's Ord impl is trusted, so 1 single bounds check guarantees all those
// output slices are non-overlapping and in-bounds
fn chop<T>(slice: &mut [T], mut cut_points: BinaryHeap<usize>) -> Vec<&mut [T]> {
let mut vec = Vec::with_capacity(cut_points.len() + 1);
let max = match cut_points.pop() {
Some(max) => max,
None => {
vec.push(slice);
return vec;
}
};
assert!(max <= slice.len());
let len = slice.len();
let ptr: *mut T = slice.as_mut_ptr();
let get_unchecked_mut = unsafe {
|range: Range<usize>| &mut *slice::from_raw_parts_mut(ptr.add(range.start), range.len())
};
vec.push(get_unchecked_mut(max..len));
let mut end = max;
while let Some(start) = cut_points.pop() {
vec.push(get_unchecked_mut(start..end));
end = start;
}
vec.push(get_unchecked_mut(0..end));
vec
}
```
```console
[['7', '8', '9'], ['4', '5', '6'], ['2', '3'], ['0', '1']]
```
In the current BinaryHeap API, `peek_mut()` is the only thing that makes the above function unsound.
```rust
let slice = &mut ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9'];
let mut cut_points = BinaryHeap::from(vec![4, 2, 7]);
{
let mut max = cut_points.peek_mut().unwrap();
*max = 0;
std::mem::forget(max);
}
println!("{:?}", chop(slice, cut_points));
```
```console
[['0', '1', '2', '3', '4', '5', '6', '7', '8', '9'], [], ['2', '3'], ['0', '1']]
```
Or worse:
```rust
let slice = &mut ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9'];
let mut cut_points = BinaryHeap::from(vec![100, 100]);
{
let mut max = cut_points.peek_mut().unwrap();
*max = 0;
std::mem::forget(max);
}
println!("{:?}", chop(slice, cut_points));
```
```console
[['0', '1', '2', '3', '4', '5', '6', '7', '8', '9'], [], ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '\u{1}', '\0', '?', '翾', '?', '翾', '\0', '\0', '?', '翾', '?', '翾', '?', '啿', '?', '啿', '?', '啿', '?', '啿', '?', '啿', '?', '翾', '\0', '\0', '', '啿', '\u{5}', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\u{8}', '\0', '`@',` '\0', '\u{1}', '\0', '?', '翾', '?', '翾', '?', '翾', '
thread 'main' panicked at 'index out of bounds: the len is 33 but the index is 33', library/core/src/unicode/unicode_data.rs:319:9
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
```
---
This PR makes `peek_mut()` use leak amplification (https://doc.rust-lang.org/1.66.0/nomicon/leaking.html#drain) to preserve the heap's invariant even in the situation that `PeekMut` gets leaked.
I'll also follow up in the tracking issue of unstable `drain_sorted()` (#59278) and `retain()` (#71503).
Rollup of 8 pull requests
Successful merges:
- #106072 (fix: misleading "add dyn keyword before derive macro" suggestion)
- #106859 (Suggestion for type mismatch when we need a u8 but the programmer wrote a char literal)
- #106863 (Remove various double spaces in compiler source comments.)
- #106865 (Add explanation comment for GUI test)
- #106867 (Fix the stability attributes for `std::os::fd`.)
- #106878 (Add regression test for #92157)
- #106879 (Add regression test for #42114)
- #106880 (doc: fix typo)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Fix the stability attributes for `std::os::fd`.
As `@bjorn3` pointed out [here], I used the wrong stability attribute in #98368 when making `std::os::fd` public. I set it to Rust 1.63, which was when io-safety was stabilized, but it should be Rust 1.66, which was when `std::os::fd` was stabilized.
[here]: https://github.com/rust-lang/rust/pull/98368#discussion_r1063721420
Suggestion for type mismatch when we need a u8 but the programmer wrote a char literal
Today Rust just points out that we have a char and we need a u8, but if I wrote 'A' then I could fix this by just writing b'A' instead. This code should detect the case where we're about to report a type mismatch of this kind, and the programmer wrote a char literal, and the char they wrote is ASCII, so therefore just prefixing b to make a byte literal will do what they meant.
I have definitely written this mistake more than once, it's not difficult to figure out what to do, but the compiler might as well tell us anyway.
I provided a test with two simple examples where the suggestion is appropriate, and one where it is not because the char literal is not ASCII, showing that the suggestion is only triggered in the former cases.
I have contributed only a small typo doc fix before, so this is my first substantive rustc change.
