Rollup merge of #126754 - compiler-errors:use-rustfmt, r=calebcartwright

Implement `use<>` formatting in rustfmt

This PR implements formatting for precise-capturing `use<>` syntax as proposed in https://github.com/rust-lang/rust/pull/126753.

The syntax is implemented as-if the `use<>` bound were a trait bound but with the `use` keyword as its path segment identifier.

I opted to develop this in the rust-lang/rust tree since I'm not certain when the next rustfmt subtree sync is going to be, and I'd rather not block landing nightly support for `use<>` on something I have no control over. If ``@rust-lang/rustfmt`` would rather I move this PR over to that repository, then I would at least like to know when the next rustfmt->rust subtree sync is going to be, since stabilizing `precise_capturing` without formatting will be disruptive.

This implementation is otherwise rather straightforward.

Tracking:

- https://github.com/rust-lang/rust/issues/123432

1 files changed, 9 insertions, 0 deletions

diff --git a/src/tools/rustfmt/tests/source/precise-capturing.rs b/src/tools/rustfmt/tests/source/precise-capturing.rs
new file mode 100644
index 00000000000..b61cceeffe8
--- /dev/null
+++ b/src/tools/rustfmt/tests/source/precise-capturing.rs
@@ -0,0 +1,9 @@
+fn hello() -> impl
+use<'a> + Sized {}
+
+fn all_three() -> impl Sized + use<'a> + 'a;
+
+fn pathological() -> impl use<'a, 'a, 'a, 'a, 'a, 'a, 'a, 'a, 'a, 'a, 'a, 'a, 'a, 'a, 'a,
+'a, 'a, 'a, 'a, 'a, 'a, 'a, 'a, 'a,
+'a, 'a, 'a, 'a, 'a, 'a, 'a, 'a, 'a, 'a, 'a, 'a, 'a, 'a, 
+'a, 'a, 'a, 'a, 'a, 'a, 'a, 'a, 'a, 'a> + Sized {}