“Inline variable” assist doesn't adjust formatting macros

rust-analyzer version: 0.4.2014-standalone (b33a0cae3 2024-06-26)

rustc version: rustc 1.81.0-nightly (bcf94dec5 2024-06-23)

editor or extension: VSCode

code snippet to reproduce:

fn foo() {
    let numerator = 1;
    let denominator = 64;
    println!("{numerator}/{denominator}");
}

Apply the “Inline variable” assist to numerator. The result is

fn foo() {
    let denominator = 64;
    println!("{numerator}/{denominator}");
}

which leaves numerator undefined. The result should instead be

fn foo() {
    let denominator = 64;
    println!("{numerator}/{denominator}", numerator = 1);
}

@rustbot label +A-assists

Start with rust-analyzer's “Inline variable” assist and reproduce the provided Rust snippet in VSCode. The fix is done when inlining numerator leaves valid formatting-macro syntax, including an explicit numerator = 1 argument, and the undefined reference no longer occurs.