warning: assigning the result of `ToOwned::to_owned()` may be inefficient
 --> src/main.rs:3:5
  |
3 |     s = format!("{} {}", "hello", "world").to_owned();
  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#assigning_clones
  = note: `#[warn(clippy::assigning_clones)]` on by default
help: use `clone_into()`
  |
3 ~     {
4 +         let res = $crate::fmt::format($crate::__export::format_args!($($arg)*));
5 +         res
6 ~     }.clone_into(&mut s);

rustc 1.78.0 (9b00956e5 2024-04-29)
binary: rustc
commit-hash: 9b00956e56009bab2aa15d7bff10916599e3d6d6
commit-date: 2024-04-29
host: aarch64-apple-darwin
release: 1.78.0
LLVM version: 18.1.2