main()1 fn main() {
2     1 + Some(1); //~ ERROR cannot add `Option<{integer}>` to `{integer}`
3     2 as usize - Some(1); //~ ERROR cannot subtract `Option<{integer}>` from `usize`
4     3 * (); //~ ERROR cannot multiply `{integer}` by `()`
5     4 / ""; //~ ERROR cannot divide `{integer}` by `&str`
6     5 < String::new(); //~ ERROR can't compare `{integer}` with `String`
7     6 == Ok(1); //~ ERROR can't compare `{integer}` with `Result<{integer}, _>`
8 }
9