title: What does this strange line do?
body: <p>A <a href="https://github.com/rust-lang/rust/pull/51059/commits" rel="noreferrer">pull request</a> has been done with a new test for the Rust compiler. It verifies that a strange line can compile:</p>
  
  <pre><code>fn main() {
      let val = !((|(..):(_,_),__@_|__)((&amp;*"\\",'@')/**/,{})=={&amp;[..=..][..];})//
      ;
      assert!(!val);
  }
  </code></pre>
  
  <p>What does this line do exactly?</p>