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Diffstat (limited to 'tests/ui/drop/if-let-super-let.rs')
| -rw-r--r-- | tests/ui/drop/if-let-super-let.rs | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/tests/ui/drop/if-let-super-let.rs b/tests/ui/drop/if-let-super-let.rs new file mode 100644 index 00000000000..c6543e6d3dc --- /dev/null +++ b/tests/ui/drop/if-let-super-let.rs @@ -0,0 +1,112 @@ +//! Test for #145328: ensure the lifetime of a `super let` binding within an `if let` scrutinee is +//! at most the scope of the `if` condition's temporaries. Additionally, test `pin!` since it's +//! implemented in terms of `super let` and exposes this behavior. +//@ run-pass +//@ revisions: e2021 e2024 +//@ [e2021] edition: 2021 +//@ [e2024] edition: 2024 + +#![feature(if_let_guard)] +#![feature(super_let)] +#![expect(irrefutable_let_patterns)] + +use std::cell::RefCell; +use std::pin::pin; + +fn main() { + // The `super let` bindings here should have the same scope as `if let` temporaries. + // In Rust 2021, this means it lives past the end of the `if` expression. + // In Rust 2024, this means it lives to the end of the `if`'s success block. + assert_drop_order(0..=2, |o| { + #[cfg(e2021)] + ( + if let _ = { super let _x = o.log(2); } { o.push(0) }, + o.push(1), + ); + #[cfg(e2024)] + ( + if let _ = { super let _x = o.log(1); } { o.push(0) }, + o.push(2), + ); + }); + assert_drop_order(0..=2, |o| { + #[cfg(e2021)] + ( + if let true = { super let _x = o.log(2); false } {} else { o.push(0) }, + o.push(1), + ); + #[cfg(e2024)] + ( + if let true = { super let _x = o.log(0); false } {} else { o.push(1) }, + o.push(2), + ); + }); + + // `pin!` should behave likewise. + assert_drop_order(0..=2, |o| { + #[cfg(e2021)] (if let _ = pin!(o.log(2)) { o.push(0) }, o.push(1)); + #[cfg(e2024)] (if let _ = pin!(o.log(1)) { o.push(0) }, o.push(2)); + }); + assert_drop_order(0..=2, |o| { + #[cfg(e2021)] + ( + if let None = Some(pin!(o.log(2))) {} else { o.push(0) }, + o.push(1), + ); + #[cfg(e2024)] + ( + if let None = Some(pin!(o.log(0))) {} else { o.push(1) }, + o.push(2), + ); + }); + + // `super let` bindings' scope should also be consistent with `if let` temporaries in guards. + // Here, that means the `super let` binding in the second guard condition operand should be + // dropped before the first operand's temporary. This is consistent across Editions. + assert_drop_order(0..=1, |o| { + match () { + _ if let _ = o.log(1) + && let _ = { super let _x = o.log(0); } => {} + _ => unreachable!(), + } + }); + assert_drop_order(0..=1, |o| { + match () { + _ if let _ = o.log(1) + && let _ = pin!(o.log(0)) => {} + _ => unreachable!(), + } + }); +} + +// # Test scaffolding... + +struct DropOrder(RefCell<Vec<u64>>); +struct LogDrop<'o>(&'o DropOrder, u64); + +impl DropOrder { + fn log(&self, n: u64) -> LogDrop<'_> { + LogDrop(self, n) + } + fn push(&self, n: u64) { + self.0.borrow_mut().push(n); + } +} + +impl<'o> Drop for LogDrop<'o> { + fn drop(&mut self) { + self.0.push(self.1); + } +} + +#[track_caller] +fn assert_drop_order( + ex: impl IntoIterator<Item = u64>, + f: impl Fn(&DropOrder), +) { + let order = DropOrder(RefCell::new(Vec::new())); + f(&order); + let order = order.0.into_inner(); + let expected: Vec<u64> = ex.into_iter().collect(); + assert_eq!(order, expected); +} |
