warning: unreachable expression: unreachable!()

[crlf0710]

Hi, i'm not really sure if this is a bug, but the following code:

fn foo () -> usize {
    loop {
        return 1;
    }
    unreachable!()
}

emits

warning: unreachable expression
 --> src/main.rs:5:5
  |
5 |     unreachable!()
  |     ^^^^^^^^^^^^^^
  |
  = note: #[warn(unreachable_code)] on by default
  = note: this error originates in a macro outside of the current crate

I'm using a recent nightly and it works this way with 1.21 stable rustc too.

[bluss]

Hi, I don't think this is a bug — the compiler knows that code after the loop is unreachable. The compiler has warned the same way since (at least) Rust 1.0 for this. You can safely remove the unreachable!() macro.

If you find a warning that doesn't make sense, or where following the logical implication of the warning leads to code that doesn't compile, then please file a bug for that. Thanks!