Uplift the `let_underscore` lints from clippy into rustc.
This PR resolves#97241.
This PR adds three lints from clippy--`let_underscore_drop`, `let_underscore_lock`, and `let_underscore_must_use`, which are meant to capture likely-incorrect uses of `let _ = ...` bindings (in particular, doing this on a type with a non-trivial `Drop` causes the `Drop` to occur immediately, instead of at the end of the scope. For a type like `MutexGuard`, this effectively releases the lock immediately, which is almost certainly the wrong behavior)
In porting the lints from clippy I had to copy over a bunch of utility functions from `clippy_util` that these lints also relied upon. Is that the right approach?
Note that I've set the `must_use` and `drop` lints to Allow by default and set `lock` to Deny by default (this matches the same settings that clippy has). In talking with `@estebank` he informed me to do a Crater run (I am not sure what type of Crater run to request here--I think it's just "check only"?)
On the linked issue, there's some discussion about using `must_use` and `Drop` together as a heuristic for when to warn--I did not implement this yet.
r? `@estebank`
ci: Upgrade android containers from ubuntu:16.04 to 22.04
The main goal of updating to 22.04 is to get away from `llvm.allow-old-toolchain`.
These containers are not building LLVM for android, so only the host version matters.
A side benefit is that they can also use the system `cmake` instead of building one.
rustdoc: remove unneeded CSS `.content table td:first-child > a`
This rule was added in c1c6175e62 to benefit the module items table. However, the module items table stopped using table tags when 6020c79dde switched us over to grid layout.
Fix doc_auto_cfg for impl blocks in different modules with different `cfg`
Fixes#101129.
Just like reexports, impl blocks don't necessarily share the same "space" as the item they implement so we need to merge attributes from its parents as well.
r? `@notriddle`
Fix bad target name in Walkthrough
Walkthrough currently say:
```
rustup target add aarch_64-fuchsia
```
but should say
```
rustup target add aarch64-fuchsia
```
bootstrap: Add llvm-has-rust-patches target option
This is so you can check out an upstream commit in src/llvm-project and
have everything just work.
This simplifies the logic in `is_rust_llvm` a bit; it doesn't need to
check for download-ci-llvm because we would have already errored if both
that and llvm-config were specified on the host platform.
Add `special_module_name` lint
Declaring `lib` as a module is one of the most common beginner mistakes when trying to setup a binary and library target in the same crate. `special_module_name` lints against it, as well as `mod main;`
```
warning: found module declaration for main.rs
--> $DIR/special_module_name.rs:4:1
|
LL | mod main;
| ^^^^^^^^^
|
= note: a binary crate cannot be used as library
warning: found module declaration for lib.rs
--> $DIR/special_module_name.rs:1:1
|
LL | mod lib;
| ^^^^^^^^
|
= note: `#[warn(special_module_name)]` on by default
= note: lib.rs is the root of this crate's library target
= help: to refer to it from other targets, use the library's name as the path
```
Note that the help message is not the best in that it doesn't provide an example of an import path (`the_actual_crate_name::`), and doesn't check whether the current file is part of a library/binary target to provide more specific error messages. I'm not sure where this lint would have to be run to access that information.
Remove EntryKind from metadata.
This PR continues the refactor of metadata emission to be more systematic, iterating on definitions and filtering based on each definition's `DefKind`. This allows to remove the large `EntryKind` enum, replaced by linear tables in metadata.
This rule was added in c1c6175e62 to benefit
the module items table. However, the module items table stopped using table
tags when 6020c79dde switched us over to grid
layout.
ci: Upgrade non-dist Linux testers from ubuntu:16.04 to 22.04
The main goal of updating to 22.04 is to get away from `llvm.allow-old-toolchain`.
A side benefit is that they can also use the system `cmake` instead of building one.
compiler/rustc_codegen_ssa/src/mir/place.rs: Remove LLVM bug workaround
This memset was inserted as a workaround to Rust issue #34427, which was
an LLVM bug that apparently no longer manifests.
Replace `rustc_data_structures::thin_vec::ThinVec` with `thin_vec::ThinVec`
`rustc_data_structures::thin_vec::ThinVec` looks like this:
```
pub struct ThinVec<T>(Option<Box<Vec<T>>>);
```
It's just a zero word if the vector is empty, but requires two
allocations if it is non-empty. So it's only usable in cases where the
vector is empty most of the time.
This commit removes it in favour of `thin_vec::ThinVec`, which is also
word-sized, but stores the length and capacity in the same allocation as
the elements. It's good in a wider variety of situation, e.g. in enum
variants where the vector is usually/always non-empty.
The commit also:
- Sorts some `Cargo.toml` dependency lists, to make additions easier.
- Sorts some `use` item lists, to make additions easier.
- Changes `clean_trait_ref_with_bindings` to take a
`ThinVec<TypeBinding>` rather than a `&[TypeBinding]`, because this
avoid some unnecessary allocations.
r? `@spastorino`
Fix a bunch of typo
This PR will fix some typos detected by [typos].
I only picked the ones I was sure were spelling errors to fix, mostly in
the comments.
[typos]: https://github.com/crate-ci/typos
proc_macro/bridge: send diagnostics over the bridge as a struct
This removes some RPC when creating and emitting diagnostics, and
simplifies the bridge slightly.
After this change, there are no remaining methods which take advantage
of the support for `&mut` references to objects in the store as
arguments, meaning that support for them could technically be removed if
we wanted. The only remaining uses of immutable references into the
store are `TokenStream` and `SourceFile`.
r? `@eddyb`
lint: avoid linting diag functions with diag lints
Functions annotated with `#[rustc_lint_diagnostics]` are used by the diagnostic migration lints to know when to lint, but functions that are annotated with this attribute shouldn't themselves be linted.
cc #100717https://github.com/rust-lang/rust/pull/101041#discussion_r959303706
Link “? operator” to relevant chapter in The Book
Before, the text simply asked people to use a symbol which is hard to
search for. Now the text links back to the chapter on error
propagation in The Book. That should help people find the relevant
keywords for further searches.
Fix uintended diagnostic caused by `drain(..)`
Calling `drain(..)` makes later `suggestable_variants.is_empty()` always true, which makes the diagnostics unintended.
