// run-rustfix
#![warn(clippy::single_char_push_str)]

macro_rules! get_string {
    () => {
        String::from("Hello world!")
    };
}

fn main() {
    let mut string = String::new();
    string.insert(0, 'R');
    string.insert(1, '\'');

    string.insert(0, 'u');
    string.insert_str(2, "st");
    string.insert_str(0, "");
    string.insert(0, '\x52');
    string.insert(0, '\u{0052}');
    let x: usize = 2;
    string.insert(x, 'a');
    const Y: usize = 1;
    string.insert(Y, 'a');

    get_string!().insert(1, '?');
}