Incorrect attribute arguments are silently ignored

[wthrowe]

This test compiles with no warnings and passes.

#[test]
#[should_panic(exepcted = "foo")]
fn foo() {
    panic!("bar");
}

I would expect at least a warning that "exepcted" was unused.

[ExpHP]

This still occurs, and is going to make me exceptionally paranoid.

Note: Even #[should_panic = "text"] is silently accepted.