| //@ run-pass |
| //@ edition: 2024 |
| |
| #![feature(if_let_guard)] |
| |
| fn check_if_let(opt: Option<Option<Option<i32>>>, value: i32) -> bool { |
| if let Some(first) = opt |
| && let Some(second) = first |
| && let Some(third) = second |
| && third == value |
| { |
| true |
| } |
| else { |
| false |
| } |
| } |
| |
| fn check_let_guard(opt: Option<Option<Option<i32>>>, value: i32) -> bool { |
| match opt { |
| Some(first) if let Some(second) = first && let Some(third) = second && third == value => { |
| true |
| } |
| _ => { |
| false |
| } |
| } |
| } |
| |
| fn check_while_let(opt: Option<Option<Option<i32>>>, value: i32) -> bool { |
| while let Some(first) = opt |
| && let Some(second) = first |
| && let Some(third) = second |
| && third == value |
| { |
| return true; |
| } |
| false |
| } |
| |
| fn main() { |
| assert_eq!(check_if_let(Some(Some(Some(1))), 1), true); |
| assert_eq!(check_if_let(Some(Some(Some(1))), 9), false); |
| |
| assert_eq!(check_let_guard(Some(Some(Some(1))), 1), true); |
| assert_eq!(check_let_guard(Some(Some(Some(1))), 9), false); |
| |
| assert_eq!(check_while_let(Some(Some(Some(1))), 1), true); |
| assert_eq!(check_while_let(Some(Some(Some(1))), 9), false); |
| } |
