name: cfg_with_existing_use
description: 当已有顶层use时，cfg条件编译内部的代码可安全复用已有use进行路径简化，且不插入新的未保护use
input: |
use std::io;
pub struct Service;
impl Service {
#[cfg(feature = "extra")]
pub fn extra_call(&self) {
let _ = std::io::Error::new(std::io::ErrorKind::Other, "err");
}
}
expected: |
use std::io;
pub struct Service;
impl Service {
#[cfg(feature = "extra")]
pub fn extra_call(&self) {
let _ = io::Error::new(io::ErrorKind::Other, "err");
}
}