improve `filesearch::get_or_default_sysroot`
`fn get_or_default_sysroot` is now improved and used in `miri` and `clippy`, and tests are still passing as they should. So we no longer need to implement custom workarounds/hacks to find sysroot in tools like miri/clippy.
Resolves https://github.com/rust-lang/rust/issues/98832
re-opened from #103581
Track where diagnostics were created.
This implements the `-Ztrack-diagnostics` flag, which uses `#[track_caller]` to track where diagnostics are created. It is meant as a debugging tool much like `-Ztreat-err-as-bug`.
For example, the following code...
```rust
struct A;
struct B;
fn main(){
let _: A = B;
}
```
...now emits the following error message:
```
error[E0308]: mismatched types
--> src\main.rs:5:16
|
5 | let _: A = B;
| - ^ expected struct `A`, found struct `B`
| |
| expected due to this
-Ztrack-diagnostics: created at compiler\rustc_infer\src\infer\error_reporting\mod.rs:2275:31
```
Causes cargo to re-run clippy when those paths are modified
Also tracks the path to `clippy-driver` in debug mode to remove the
workarounds in `cargo dev lint` and `lintcheck`
Add `unused_format_specs` lint
Currently catches two cases:
An empty precision specifier:
```rust
// the same as {}
println!("{:.}", x);
```
And using formatting specs on `format_args!()`:
```rust
// prints `x.`, not `x .`
println("{:5}.", format_args!("x"));
```
changelog: new lint: [`unused_format_specs`]
Add `manual_filter` lint for `Option`
Share much of its implementation with `manual_map` and should greatly benefit from its previous feedback.
I'm sure it's possible to even more refactor both and would gladly take input on that as well as any clippy idiomatic usage, since this is my first lint addition.
I've added the lint to the complexity section for now, I don't know if every new lint needs to go in nursery first.
The matching could be expanded to more than `Some(<value>)` to lint on arbitrary struct matching inside the `Some` but I've left it like it was for `manual_map` for now. `needless_match::pat_same_as_expr` provides a more generic match example.
close https://github.com/rust-lang/rust-clippy/issues/8822
changelog: Add lint [`manual_filter`] for `Option`
This lint detects calls to a `&self`-taking `as_ptr` method, where
the result is then immediately cast to a `*mut T`. Code like this
is probably invalid, as that pointer will not have write permissions,
and `*mut T` is usually used to write through.
add `box-default` lint
This adds a `box-default` lint to suggest using `Box::default()` instead of `Box::new(Default::default())`, which offers less moving parts and potentially better performance according to [the perf book](https://nnethercote.github.io/perf-book/standard-library-types.html#box).
---
changelog: add [`box_default`] lint
Implement https://github.com/rust-lang/rust-clippy/issues/8368 - a new
lint to inline format arguments such as `print!("{}", var)` into
`print!("{var}")`.
code | suggestion | comment
---|---|---
`print!("{}", var)` | `print!("{var}")` | simple variables
`print!("{0}", var)` | `print!("{var}")` | positional variables
`print!("{v}", v=var)` | `print!("{var}")` | named variables
`print!("{0} {0}", var)` | `print!("{var} {var}")` | aliased variables
`print!("{0:1$}", var, width)` | `print!("{var:width$}")` | width
support
`print!("{0:.1$}", var, prec)` | `print!("{var:.prec$}")` | precision
support
`print!("{:.*}", prec, var)` | `print!("{var:.prec$}")` | asterisk
support
code | suggestion | comment
---|---|---
`print!("{0}={1}", var, 1+2)` | `print!("{var}={0}", 1+2)` | Format
string uses an indexed argument that cannot be inlined. Supporting this
case requires re-indexing of the format string.
changelog: [`uninlined_format_args`]: A new lint to inline format
arguments, i.e. `print!("{}", var)` into `print!("{var}")`
Unlike past similar work done in #6228, expand the existing `or_fun_call`
lint to detect `or_insert` calls with a `T::new()` or `T::default()`
argument, much like currently done for `unwrap_or` calls. In that case,
suggest the use of `or_default`, which is more idiomatic.
Note that even with this change, `or_insert_with(T::default)` calls
aren't detected as candidates for `or_default()`, in the same manner
that currently `unwrap_or_else(T::default)` calls aren't detected as
candidates for `unwrap_or_default()`.
Also, as a nearby cleanup, change `KNOW_TYPES` from `static` to `const`,
since as far as I understand it's preferred (should Clippy have a lint
for that?).
Fixes#3812.
