Fixes#74053Fixes#55721
This PR adds a new lint `CONST_ITEM_MUTATION`.
Given an item `const FOO: SomeType = ..`, this lint fires on:
* Attempting to write directly to a field (`FOO.field = some_val`) or
array entry (`FOO.array_field[0] = val`)
* Taking a mutable reference to the `const` item (`&mut FOO`), including
through an autoderef `FOO.some_mut_self_method()`
The lint message explains that since each use of a constant creates a
new temporary, the original `const` item will not be modified.
Implement Seek::stream_position() for BufReader
Optimization over `BufReader::seek()` for getting the current position without flushing the internal buffer.
Related to #31100. Based on the code in #70577.
Remove unneeded `#[cfg(not(test))]` from libcore
This fixes rust-analyzer inside these modules (currently it does not analyze them, assuming they're configured out).
* Adds missing "tail" spans (spans that continue beyond the end of
overlapping spans)
* Adds a caret to highlight empty spans associated with MIR elements
that have a position, but otherwise would not be visible.
* Adds visual pointing brackets at the beginning and end of each span
This is generally a good idea, and will help with being able to build bootstrap
without Python over time as it means we can "just" build with cargo +beta build
rather than needing the user to set environment variables. This is a minor step,
but a necessary one on that road.
Rollup of 18 pull requests
Successful merges:
- #76273 (Move some Vec UI tests into alloc unit tests)
- #76274 (Allow try blocks as the argument to return expressions)
- #76287 (Remove an unnecessary allowed lint)
- #76293 (Implementation of incompatible features error)
- #76299 (Make `Ipv4Addr` and `Ipv6Addr` const tests unit tests under `library`)
- #76302 (Address review comments on `Peekable::next_if`)
- #76303 (Link to `#capacity-and-reallocation` when using with_capacity)
- #76305 (Move various ui const tests to `library`)
- #76309 (Indent a note to make folding work nicer)
- #76312 (time.rs: Make spelling of "Darwin" consistent)
- #76318 (Use ops::ControlFlow in rustc_data_structures::graph::iterate)
- #76324 (Move Vec slice UI tests in library)
- #76338 (add some intra-doc links to `Iterator`)
- #76340 (Remove unused duplicated `trivial_dropck_outlives`)
- #76344 (Improve docs for `std::env::args()`)
- #76346 (Docs: nlink example typo)
- #76358 (Minor grammar fix in doc comment for soft-deprecated methods)
- #76364 (Disable atomics on avr target.)
Failed merges:
- #76304 (Make delegation methods of `std::net::IpAddr` unstably const)
r? @ghost
Use ops::ControlFlow in rustc_data_structures::graph::iterate
Since I only know about this because you mentioned it,
r? @ecstatic-morse
If we're not supposed to use new `core` things in compiler for a while then feel free to close, but it felt reasonable to merge the two types since they're the same, and it might be convenient for people to use `?` in their traversal code.
(This doesn't do the type parameter swap; NoraCodes has signed up to do that one.)
time.rs: Make spelling of "Darwin" consistent
On line 89 of this file, the OS name is written as "Darwin", but on line 162 it is written in all-caps. Darwin is usually spelt as a standard proper noun, i.e. "Darwin", rather than in all-caps.
This change makes that form consistent in both places.
Indent a note to make folding work nicer
Sublime Text folds code based on indentation. It maybe an unnecessary change, but does it look nicer after that ?
Move various ui const tests to `library`
Move:
- `src\test\ui\consts\const-nonzero.rs` to `library\core`
- `src\test\ui\consts\ascii.rs` to `library\core`
- `src\test\ui\consts\cow-is-borrowed` to `library\alloc`
Part of #76268
r? @matklad
Make `Ipv4Addr` and `Ipv6Addr` const tests unit tests under `library`
These tests are about the standard library, not the compiler itself, thus should live in `library`, see #76268.
Implementation of incompatible features error
Proposal of a new error: Incompatible features
This error should happen if two features which are not compatible are used together.
For now the only incompatible features are `const_generics` and `min_const_generics`
fixes#76280
Allow try blocks as the argument to return expressions
Fixes#76271
I don't think this needs to be edition-aware (phew) since `return try` in 2015 is also the start of an expression, just with a struct literal instead of a block (`return try { x: 4, y: 5 }`).
Move some Vec UI tests into alloc unit tests
A bit of work towards #76268, makes a number of the Vec UI tests that are simply running code into unit tests. Ensured that they are being run when testing liballoc locally.
Restrict unnecessary_sort_by to non-reference, Copy types
`Vec::sort_by_key` closure parameter is `F: FnMut(&T) -> K`. The lint's suggestion destructures the `T` parameter; this was probably done to avoid different unnamed lifetimes when `K = Reverse<&T>`.
This change fixes two issues:
* Destructuring T when T is non-reference requires the type to be Copy, otherwise we would try to move from a shared reference. We make sure `T: Copy` holds.
* Make sure `T` is actually non-reference. I didn't go for destructuring multiple levels of references, as we would have to compensate in the closure body by removing derefs and maybe adding parens, which would add more complexity.
changelog: Restrict [`unnecessary_sort_by`] to non-reference, Copy types
Fixes#6001
Try to improve the documentation of `filter()` and `filter_map()`.
I believe the documentation is currently a little misleading.
For example, in the docs for `filter()`:
> If the closure returns `false`, it will try again, and call the closure on
> the next element, seeing if it passes the test.
This kind of implies that if the closure returns true then we *don't* "try
again" and no further elements are considered. In actuality that's not the
case, every element is tried regardless of what happened with the previous
element.
This change tries to clarify that by removing the uses of "try again"
altogether.
debuginfo: Ignore HashMap .natvis tests before cdb 10.0.18362.1
CDB <10.0.18362.1 chokes on casts within HashMap's natvis visualizers. This PR adds support for "min-cdb-version" (per existing "min-gdb-version" and "min-lldb-version" filters) and uses it. CI uses a more recent version of CDB for testing and thus should still run the tests.
Credit to @petrochenkov per https://github.com/rust-lang/rust/issues/76352 for helping catch this.
### SDK Testing
| Win 10 SDK | x64 CDB | rustc 1.47.0-nightly (bf4342114 2020-08-25) built-in .natvis | Note |
| --------------------------------------------------------------------- | ----------------- | ------------------------------------------------------------- | ---- |
| [10.0.19041.0](https://go.microsoft.com/fwlink/p/?linkid=2120843) | 10.0.19041.1 | ✔️ | CI
| [10.0.18362.1](https://go.microsoft.com/fwlink/?linkid=2083338) | 10.0.18362.1 | ✔️ | MaulingMonkey
| [10.0.17763.0](https://go.microsoft.com/fwlink/p/?LinkID=2033908) | 10.0.17763.132 | ❌ `Unable to find type 'tuple<u64,u64> *' for cast.`
| [10.0.17134.12](https://go.microsoft.com/fwlink/p/?linkid=870807) | 10.0.17134.12 | ❌ `Unable to find type 'tuple<u64,u64> *' for cast.`
| [10.0.16299.91](https://go.microsoft.com/fwlink/p/?linkid=864422) | 10.0.16299.91 | ❌ `Unable to find type 'tuple<u64,u64> *' for cast.`
| [10.0.15063.468](https://go.microsoft.com/fwlink/p/?LinkId=845298) | 10.0.15063.468 | ❌ `Unable to find type 'tuple<u64,u64> *' for cast.`
| [10.0.14393.795](https://go.microsoft.com/fwlink/p/?LinkId=838916) | 10.0.14321.1024 | ❌ `Unable to find type 'tuple<u64,u64> *' for cast.` | petrochenkov
| [10.0.10586.212](https://go.microsoft.com/fwlink/p/?LinkID=698771) | 10.0.10586.567 | ❌ `Expected ')' at '+ 1)].__1'`
| [10.0.10240](https://go.microsoft.com/fwlink/p/?LinkId=619296) | 10.0.10240? | ❔ Untested
### Rust Testing
```cmd
x.py test --stage 1 src/tools/tidy
x.py test --stage 1 --build x86_64-pc-windows-msvc src\test\debuginfo
```
Also verified test still fails when intentionally broken w/ CDB version >= min-cdb-version.
MIR peephole optimize {Ne, Eq}(_1, false) into _1
Add peephole optimization that simplifies Ne(_1, false) and Ne(false, _1) into _1. Similarly handles Eq(_1, true) and Eq(true, _1).
This was observed emitted from the MatchBranchSimplification pass.
Use Arc::clone and Rc::clone in documentation
This PR replaces uses of `x.clone()` by `Rc::clone(&x)` (or `Arc::clone(&x)`) to better match the documentation for those types.
@rustbot modify labels: T-doc
