"Extract into function" misses format string captures

rust-analyzer version: rust-analyzer version: 0.4.1237-standalone (61504c8d9 2022-10-08)

rustc version: rustc 1.64.0 (a55dd71d5 2022-09-19)

Start with:

pub fn tester() {
    let x = "hello";
    let y = "world";

    println!("{x} {}", y);
}

Run “Extract into function” on the println!. This produces:

pub fn tester() {
    let x = "hello";
    let y = "world";

    fun_name(y);
}

fn fun_name(y: &str) {
    println!("{x} {}", y);
}

Note that x does not become a parameter to the function, even though it must.

Reproduce the issue in rust-analyzer using the provided Rust snippet and the “Extract into function” action. Trace how format-string captures are identified during extraction, then verify that the generated function includes x as a parameter and that the resulting code compiles; add regression coverage if the project’s existing tests expose this action.