feat: add preliminary support for `+ use<..>` `precise_capturing` syntax
## Summary
This PR adds basic support for the following syntax.
```rs
fn captures<'a: 'a, 'b: 'b, T>() -> impl Sized + use<'b, T> {}
// ~~~~~~~~~~~~~~~~~~~~~~~
// This opaque type does not capture `'a`.
fn outlives<'o, T: 'o>(_: T) {}
fn caller<'o, 'a, 'b: 'o, T: 'o>() {
// ~~
// ^ Note that we don't need `'a: 'o`.
outlives::<'o>(captures::<'a, 'b, T>());
}
```
Related to #17598
Avoid ref when using format! in compiler
Clean up a few minor refs in `format!` macro, as it has a performance cost. Apparently the compiler is unable to inline `format!("{}", &variable)`, and does a run-time double-reference instead (format macro already does one level referencing). Inlining format args prevents accidental `&` misuse.
See https://github.com/rust-lang/rust-clippy/issues/10851
Clean up a few minor refs in `format!` macro, as it has a performance cost. Apparently the compiler is unable to inline `format!("{}", &variable)`, and does a run-time double-reference instead (format macro already does one level referencing). Inlining format args prevents accidental `&` misuse.
handle {self} when removing unused imports
Fixes#17139
On master
```rs
mod inner {
pub struct X();
pub struct Y();
}
mod z {
use super::inner::{self, X}$0;
fn f() {
let y = inner::Y();
}
}
```
becomes
```rs
mod inner {
pub struct X();
pub struct Y();
}
mod z {
use super::inner:self;
fn f() {
let y = inner::Y();
}
}
```
with this fix it instead becomes
```
```rs
mod inner {
pub struct X();
pub struct Y();
}
mod z {
use super::inner;
fn f() {
let y = inner::Y();
}
}
```
Before this commit `UseTree::remove_unnecessary_braces` removed the braces
around `{self}` in `use x::y::{self};` but `use x::y::self;` is not valid
rust.
