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//@ run-pass
#![feature(if_let_guard, let_chains)]
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);
}
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