You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: vec2b.rs
    path of file: ./repos/egui/crates/emath/src
    
    the code of the file until where you have to start completion: /// Two bools, one for each axis (X and Y).
#[derive(Copy, Clone, Debug, Defaul
    
    fn index_mut(&mut self, index: usize) -> &mut bool {
        match index {
            0 => &mut self.x,
            1 => &mut self.y,
            _ => panic!("Vec2b index out of bounds: {index}"),
        }
    }