Lint unnecessary safety comments
changelog: [`unnecessary_safety_comment`]: Add unnecessary safety comment lint
Addresses https://github.com/rust-lang/rust-clippy/issues/7954
This does not necessarily catch all occurences, as doing so would require checking all expressions in the entire source which seems rather expensive. Instead what the lint does is it checks items, statements and the tail expression of blocks for safety comments, then checks if those comments are necessary or not, then linting for the unnecessary ones.
I kept the tests in one file to check that the lints do not clash with each other.
Make rustc_target usable outside of rustc
I'm working on showing type size in rust-analyzer (https://github.com/rust-lang/rust-analyzer/pull/13490) and I currently copied rustc code inside rust-analyzer, which works, but is bad. With this change, I would become able to use `rustc_target` and `rustc_index` directly in r-a, reducing the amount of copy needed.
This PR contains some feature flag to put nightly features behind them to make crates buildable on the stable compiler + makes layout related types generic over index type + removes interning of nested layouts.
Avoid `GenFuture` shim when compiling async constructs
Previously, async constructs would be lowered to "normal" generators, with an additional `from_generator` / `GenFuture` shim in between to convert from `Generator` to `Future`.
The compiler will now special-case these generators internally so that async constructs will *directly* implement `Future` without the need to go through the `from_generator` / `GenFuture` shim.
The primary motivation for this change was hiding this implementation detail in stack traces and debuginfo, but it can in theory also help the optimizer as there is less abstractions to see through.
---
Given this demo code:
```rust
pub async fn a(arg: u32) -> Backtrace {
let bt = b().await;
let _arg = arg;
bt
}
pub async fn b() -> Backtrace {
Backtrace::force_capture()
}
```
I would get the following with the latest stable compiler (on Windows):
```
4: async_codegen:🅱️:async_fn$0
at .\src\lib.rs:10
5: core::future::from_generator::impl$1::poll<enum2$<async_codegen:🅱️:async_fn_env$0> >
at /rustc/897e37553bba8b42751c67658967889d11ecd120\library\core\src\future\mod.rs:91
6: async_codegen:🅰️:async_fn$0
at .\src\lib.rs:4
7: core::future::from_generator::impl$1::poll<enum2$<async_codegen:🅰️:async_fn_env$0> >
at /rustc/897e37553bba8b42751c67658967889d11ecd120\library\core\src\future\mod.rs:91
```
whereas now I get a much cleaner stack trace:
```
3: async_codegen:🅱️:async_fn$0
at .\src\lib.rs:10
4: async_codegen:🅰️:async_fn$0
at .\src\lib.rs:4
```
Previously, async constructs would be lowered to "normal" generators,
with an additional `from_generator` / `GenFuture` shim in between to
convert from `Generator` to `Future`.
The compiler will now special-case these generators internally so that
async constructs will *directly* implement `Future` without the need
to go through the `from_generator` / `GenFuture` shim.
The primary motivation for this change was hiding this implementation
detail in stack traces and debuginfo, but it can in theory also help
the optimizer as there is less abstractions to see through.
Add `clippy_utils::msrv::Msrv` to keep track of the current MSRV
changelog: Fix the scoping of the `#![clippy::msrv]` attribute
Fixes#6920
r? `@Jarcho`
Fix [`unnecessary_lazy_eval`] when type has significant drop
fix for https://github.com/rust-lang/rust-clippy/issues/9427#issuecomment-1295742590
However current implementation gives too many false positive, rending the lint almost useless.
I don't know what's the best way to check if a type has a "significant" drop (in the common meaning, not the internal rustc one, for example Option<(u8, u8)> should not be considered significant)
changelog: Fix [`unnecessary_lazy_eval`] when type has significant drop
Update Clippy
r? `@Manishearth`
Sorry for taking so long. There were so many blockers and so little time. This situation should be mitigated with #104007 in the future.
Fix#9771 (`unnecessary_to_owned` false positive)
Fixes#9771
In that issue's example(s), the lint tried to add a `&` to a value, which implicitly changed the type of a field to a reference. The fix is to add the reference to `receiver_ty` (the type of the receiver of the `to_owned`-like method), before passing `receiver_ty` to `can_change_type`. `can_change_type` properly rejects the modified `receiver_ty`.
cc: `@mikerite` just because I think he was the author of `can_change_type`.
changelog: fix `unnecessary_to_owned` false positive which implicitly tried to change the type of a field to a reference
Fix `redundant_closure_for_method_calls` suggestion
Fixes#7746. The issue turns out to be more general than raw pointers. The `redundant_closure_for_method_calls` lint produces incorrect suggestions when the method is associated with a type that must be enclosed in angle brackets or must be written with generic arguments substituted. For example:
```rust
fn main() {
// Clippy's suggestion: [T; N]::as_slice
// Correct suggestion: <[u8; 3]>::as_slice
let array_opt: Option<&[u8; 3]> = Some(&[4, 8, 7]);
array_opt.map(|a| a.as_slice());
// Clippy's suggestion: [T]::len
// Correct suggestion: <[u8]>::len
let slice_opt: Option<&[u8]> = Some(b"slice");
slice_opt.map(|s| s.len());
// Clippy's suggestion: *const T::is_null
// Correct suggestion: <*const usize>::is_null
let ptr_opt: Option<*const usize> = Some(&487);
ptr_opt.map(|p| p.is_null());
// Clippy's suggestion: dyn TestTrait::method_on_dyn
// Correct suggestion: <dyn TestTrait>::method_on_dyn
let test_struct = TestStruct {};
let dyn_opt: Option<&dyn TestTrait> = Some(&test_struct);
dyn_opt.map(|d| d.method_on_dyn());
}
// For the trait object example:
trait TestTrait {}
struct TestStruct {}
impl TestTrait for TestStruct {}
impl dyn TestTrait + '_ {
fn method_on_dyn(&self) -> bool {
false
}
}
```
The issue also affects references and tuples, though I had to patch the standard library with non-trait methods for those types to test that. Just in case, I also included handling for `!`, since it appeared to be possible to call methods on it with angle brackets. I just couldn't verify the resulting suggestion, since dead-code analysis eliminates the code first.
This is my first exposure to Rust compiler internals, so please let me know if I'm taking the wrong approach here!
changelog: [`redundant_closure_for_method_calls`]: add angle brackets and substitute generic arguments in suggestion when needed
Rollup of 11 pull requests
Successful merges:
- #103396 (Pin::new_unchecked: discuss pinning closure captures)
- #104416 (Fix using `include_bytes` in pattern position)
- #104557 (Add a test case for async dyn* traits)
- #104559 (Split `MacArgs` in two.)
- #104597 (Probe + better error messsage for `need_migrate_deref_output_trait_object`)
- #104656 (Move tests)
- #104657 (Do not check transmute if has non region infer)
- #104663 (rustdoc: factor out common button CSS)
- #104666 (Migrate alias search result to CSS variables)
- #104674 (Make negative_impl and negative_impl_exists take the right types)
- #104692 (Update test's cfg-if dependency to 1.0)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
`MacArgs` is an enum with three variants: `Empty`, `Delimited`, and `Eq`. It's
used in two ways:
- For representing attribute macro arguments (e.g. in `AttrItem`), where all
three variants are used.
- For representing function-like macros (e.g. in `MacCall` and `MacroDef`),
where only the `Delimited` variant is used.
In other words, `MacArgs` is used in two quite different places due to them
having partial overlap. I find this makes the code hard to read. It also leads
to various unreachable code paths, and allows invalid values (such as
accidentally using `MacArgs::Empty` in a `MacCall`).
This commit splits `MacArgs` in two:
- `DelimArgs` is a new struct just for the "delimited arguments" case. It is
now used in `MacCall` and `MacroDef`.
- `AttrArgs` is a renaming of the old `MacArgs` enum for the attribute macro
case. Its `Delimited` variant now contains a `DelimArgs`.
Various other related things are renamed as well.
These changes make the code clearer, avoids several unreachable paths, and
disallows the invalid values.
