| //@ edition: 2021 | |
| // https://github.com/rust-lang/rust/pull/111761#issuecomment-1557777314 | |
| macro_rules! m { | |
| () => { | |
| extern crate core as std; | |
| //~^ ERROR macro-expanded `extern crate` items cannot shadow names passed with `--extern` | |
| } | |
| } | |
| m!(); | |
| use std::mem; //~ ERROR `std` is ambiguous | |
| use ::std::mem as _; //~ ERROR `std` is ambiguous | |
| fn main() {} |