Test not never

Currently fails to build:

    error[E0600]: cannot apply unary operator `!` to type `!`
       --> library/core/tests/ops.rs:239:8
        |
    239 |     if !return () {}
        |        ^^^^^^^^^^ cannot apply unary operator `!`

1 files changed, 6 insertions, 0 deletions

diff --git a/library/core/tests/ops.rs b/library/core/tests/ops.rs
index aa79dbac8f3..0c81cba35b3 100644
--- a/library/core/tests/ops.rs
+++ b/library/core/tests/ops.rs
@@ -232,3 +232,9 @@ fn deref_on_ref() {
     let y = deref(&mut x);
     assert_eq!(y, 4);
 }
+
+#[test]
+#[allow(unreachable_code)]
+fn test_not_never() {
+    if !return () {}
+}