fn main() {
fn f() -> Option<i32> {
Some("fffffffsssssssssddddssssfffffddddff")
.map(|s| s)
.map(|s| s.to_string())
.map(|res| match Some(res) {
Some(ref s) if s == "" => 41,
Some(_) => 42,
_ => 43,
})
}
println!("{:?}", f())