mirror of https://github.com/rust-lang/rust
50 lines
1.2 KiB
Rust
50 lines
1.2 KiB
Rust
//@ run-pass
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#![feature(if_let_guard, let_chains)]
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fn check_if_let(opt: Option<Option<Option<i32>>>, value: i32) -> bool {
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if let Some(first) = opt
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&& let Some(second) = first
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&& let Some(third) = second
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&& third == value
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{
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true
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}
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else {
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false
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}
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}
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fn check_let_guard(opt: Option<Option<Option<i32>>>, value: i32) -> bool {
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match opt {
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Some(first) if let Some(second) = first && let Some(third) = second && third == value => {
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true
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}
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_ => {
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false
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}
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}
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}
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fn check_while_let(opt: Option<Option<Option<i32>>>, value: i32) -> bool {
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while let Some(first) = opt
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&& let Some(second) = first
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&& let Some(third) = second
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&& third == value
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{
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return true;
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}
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false
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}
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fn main() {
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assert_eq!(check_if_let(Some(Some(Some(1))), 1), true);
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assert_eq!(check_if_let(Some(Some(Some(1))), 9), false);
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assert_eq!(check_let_guard(Some(Some(Some(1))), 1), true);
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assert_eq!(check_let_guard(Some(Some(Some(1))), 9), false);
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assert_eq!(check_while_let(Some(Some(Some(1))), 1), true);
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assert_eq!(check_while_let(Some(Some(Some(1))), 9), false);
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}
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