小编MR *_*SIR的帖子

fn main() {
   let string = "Rust Programming".to_string();
   let mut slice = &string[5..12].to_string();       // Doesn't work...why?
   let mut slice = string[5..12].to_string();        // works
   let mut slice2 = String::from(&string[5..12]);    // Works

   slice.push('p');
   println!("slice: {}, slice2: {}, string: {}", slice,slice2,string);
}

这里发生了什么？请解释。