diff options
Diffstat (limited to 'tests')
| -rw-r--r-- | tests/ui/drop/or-pattern-drop-order.rs | 109 | ||||
| -rw-r--r-- | tests/ui/dropck/eager-by-ref-binding-for-guards.rs | 31 | ||||
| -rw-r--r-- | tests/ui/dropck/eager-by-ref-binding-for-guards.stderr | 28 | ||||
| -rw-r--r-- | tests/ui/dropck/let-else-more-permissive.rs | 30 | ||||
| -rw-r--r-- | tests/ui/dropck/let-else-more-permissive.stderr | 35 |
5 files changed, 233 insertions, 0 deletions
diff --git a/tests/ui/drop/or-pattern-drop-order.rs b/tests/ui/drop/or-pattern-drop-order.rs new file mode 100644 index 00000000000..fdc28225c35 --- /dev/null +++ b/tests/ui/drop/or-pattern-drop-order.rs @@ -0,0 +1,109 @@ +//@ run-pass +//! Test drop order for different ways of declaring pattern bindings involving or-patterns. +//! Currently, it's inconsistent between language constructs (#142163). + +use std::cell::RefCell; +use std::ops::Drop; + +// For more informative failures, we collect drops in a `Vec` before checking their order. +struct DropOrder(RefCell<Vec<u32>>); +struct LogDrop<'o>(&'o DropOrder, u32); + +impl<'o> Drop for LogDrop<'o> { + fn drop(&mut self) { + self.0.0.borrow_mut().push(self.1); + } +} + +#[track_caller] +fn assert_drop_order(expected_drops: impl IntoIterator<Item = u32>, f: impl Fn(&DropOrder)) { + let order = DropOrder(RefCell::new(Vec::new())); + f(&order); + let order = order.0.into_inner(); + let correct_order: Vec<u32> = expected_drops.into_iter().collect(); + assert_eq!(order, correct_order); +} + +#[expect(unused_variables, unused_assignments, irrefutable_let_patterns)] +fn main() { + // When bindings are declared with `let pat;`, they're visited in left-to-right order, using the + // order given by the first occurrence of each variable. They're later dropped in reverse. + assert_drop_order(1..=3, |o| { + // Drops are right-to-left: `z`, `y`, `x`. + let (x, Ok(y) | Err(y), z); + // Assignment order doesn't matter. + z = LogDrop(o, 1); + y = LogDrop(o, 2); + x = LogDrop(o, 3); + }); + assert_drop_order(1..=2, |o| { + // The first or-pattern alternative determines the bindings' drop order: `y`, `x`. + let ((true, x, y) | (false, y, x)); + x = LogDrop(o, 2); + y = LogDrop(o, 1); + }); + + // When bindings are declared with `let pat = expr;`, bindings within or-patterns are seen last, + // thus they're dropped first. + assert_drop_order(1..=3, |o| { + // Drops are right-to-left, treating `y` as rightmost: `y`, `z`, `x`. + let (x, Ok(y) | Err(y), z) = (LogDrop(o, 3), Ok(LogDrop(o, 1)), LogDrop(o, 2)); + }); + assert_drop_order(1..=2, |o| { + // The first or-pattern alternative determines the bindings' drop order: `y`, `x`. + let ((true, x, y) | (false, y, x)) = (true, LogDrop(o, 2), LogDrop(o, 1)); + }); + assert_drop_order(1..=2, |o| { + // That drop order is used regardless of which or-pattern alternative matches: `y`, `x`. + let ((true, x, y) | (false, y, x)) = (false, LogDrop(o, 1), LogDrop(o, 2)); + }); + + // `match` treats or-patterns as last like `let pat = expr;`, but also determines drop order + // using the order of the bindings in the *last* or-pattern alternative. + assert_drop_order(1..=3, |o| { + // Drops are right-to-left, treating `y` as rightmost: `y`, `z`, `x`. + match (LogDrop(o, 3), Ok(LogDrop(o, 1)), LogDrop(o, 2)) { (x, Ok(y) | Err(y), z) => {} } + }); + assert_drop_order(1..=2, |o| { + // The last or-pattern alternative determines the bindings' drop order: `x`, `y`. + match (true, LogDrop(o, 1), LogDrop(o, 2)) { (true, x, y) | (false, y, x) => {} } + }); + assert_drop_order(1..=2, |o| { + // That drop order is used regardless of which or-pattern alternative matches: `x`, `y`. + match (false, LogDrop(o, 2), LogDrop(o, 1)) { (true, x, y) | (false, y, x) => {} } + }); + + // Function params are visited one-by-one, and the order of bindings within a param's pattern is + // the same as `let pat = expr`; + assert_drop_order(1..=3, |o| { + // Among separate params, the drop order is right-to-left: `z`, `y`, `x`. + (|x, (Ok(y) | Err(y)), z| {})(LogDrop(o, 3), Ok(LogDrop(o, 2)), LogDrop(o, 1)); + }); + assert_drop_order(1..=3, |o| { + // Within a param's pattern, or-patterns are treated as rightmost: `y`, `z`, `x`. + (|(x, Ok(y) | Err(y), z)| {})((LogDrop(o, 3), Ok(LogDrop(o, 1)), LogDrop(o, 2))); + }); + assert_drop_order(1..=2, |o| { + // The first or-pattern alternative determines the bindings' drop order: `y`, `x`. + (|((true, x, y) | (false, y, x))| {})((true, LogDrop(o, 2), LogDrop(o, 1))); + }); + + // `if let` and `let`-`else` see bindings in the same order as `let pat = expr;`. + // Vars in or-patterns are seen last (dropped first), and the first alternative's order is used. + assert_drop_order(1..=3, |o| { + if let (x, Ok(y) | Err(y), z) = (LogDrop(o, 3), Ok(LogDrop(o, 1)), LogDrop(o, 2)) {} + }); + assert_drop_order(1..=3, |o| { + let (x, Ok(y) | Err(y), z) = (LogDrop(o, 3), Ok(LogDrop(o, 1)), LogDrop(o, 2)) else { + unreachable!(); + }; + }); + assert_drop_order(1..=2, |o| { + if let (true, x, y) | (false, y, x) = (true, LogDrop(o, 2), LogDrop(o, 1)) {} + }); + assert_drop_order(1..=2, |o| { + let ((true, x, y) | (false, y, x)) = (true, LogDrop(o, 2), LogDrop(o, 1)) else { + unreachable!(); + }; + }); +} diff --git a/tests/ui/dropck/eager-by-ref-binding-for-guards.rs b/tests/ui/dropck/eager-by-ref-binding-for-guards.rs new file mode 100644 index 00000000000..3f475839171 --- /dev/null +++ b/tests/ui/dropck/eager-by-ref-binding-for-guards.rs @@ -0,0 +1,31 @@ +//! The drop check is currently more permissive when match arms have guards, due to eagerly creating +//! by-ref bindings for the guard (#142057). + +struct Struct<T>(T); +impl<T> Drop for Struct<T> { + fn drop(&mut self) {} +} + +fn main() { + // This is an error: `short1` is dead before `long1` is dropped. + match (Struct(&&0), 1) { + (mut long1, ref short1) => long1.0 = &short1, + //~^ ERROR `short1` does not live long enough + } + // This is OK: `short2`'s storage is live until after `long2`'s drop runs. + match (Struct(&&0), 1) { + (mut long2, ref short2) if true => long2.0 = &short2, + _ => unreachable!(), + } + // This depends on the binding modes of the final or-pattern alternatives (see #142163): + let res: &Result<u8, &u8> = &Ok(1); + match (Struct(&&0), res) { + (mut long3, Ok(short3) | &Err(short3)) if true => long3.0 = &short3, + //~^ ERROR `short3` does not live long enough + _ => unreachable!(), + } + match (Struct(&&0), res) { + (mut long4, &Err(short4) | Ok(short4)) if true => long4.0 = &short4, + _ => unreachable!(), + } +} diff --git a/tests/ui/dropck/eager-by-ref-binding-for-guards.stderr b/tests/ui/dropck/eager-by-ref-binding-for-guards.stderr new file mode 100644 index 00000000000..cb1a04cd444 --- /dev/null +++ b/tests/ui/dropck/eager-by-ref-binding-for-guards.stderr @@ -0,0 +1,28 @@ +error[E0597]: `short1` does not live long enough + --> $DIR/eager-by-ref-binding-for-guards.rs:12:46 + | +LL | (mut long1, ref short1) => long1.0 = &short1, + | ---------- ^^^^^^- + | | | | + | | | `short1` dropped here while still borrowed + | | | borrow might be used here, when `long1` is dropped and runs the `Drop` code for type `Struct` + | | borrowed value does not live long enough + | binding `short1` declared here + | + = note: values in a scope are dropped in the opposite order they are defined + +error[E0597]: `short3` does not live long enough + --> $DIR/eager-by-ref-binding-for-guards.rs:23:69 + | +LL | (mut long3, Ok(short3) | &Err(short3)) if true => long3.0 = &short3, + | ------ ^^^^^^- + | | | | + | | | `short3` dropped here while still borrowed + | | | borrow might be used here, when `long3` is dropped and runs the `Drop` code for type `Struct` + | binding `short3` declared here borrowed value does not live long enough + | + = note: values in a scope are dropped in the opposite order they are defined + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0597`. diff --git a/tests/ui/dropck/let-else-more-permissive.rs b/tests/ui/dropck/let-else-more-permissive.rs new file mode 100644 index 00000000000..0020814aa81 --- /dev/null +++ b/tests/ui/dropck/let-else-more-permissive.rs @@ -0,0 +1,30 @@ +//! The drop check is currently more permissive when `let` statements have an `else` block, due to +//! scheduling drops for bindings' storage before pattern-matching (#142056). + +struct Struct<T>(T); +impl<T> Drop for Struct<T> { + fn drop(&mut self) {} +} + +fn main() { + { + // This is an error: `short1` is dead before `long1` is dropped. + let (mut long1, short1) = (Struct(&0), 1); + long1.0 = &short1; + //~^ ERROR `short1` does not live long enough + } + { + // This is OK: `short2`'s storage is live until after `long2`'s drop runs. + #[expect(irrefutable_let_patterns)] + let (mut long2, short2) = (Struct(&0), 1) else { unreachable!() }; + long2.0 = &short2; + } + { + // Sanity check: `short3`'s drop is significant; it's dropped before `long3`: + let tmp = Box::new(0); + #[expect(irrefutable_let_patterns)] + let (mut long3, short3) = (Struct(&tmp), Box::new(1)) else { unreachable!() }; + long3.0 = &short3; + //~^ ERROR `short3` does not live long enough + } +} diff --git a/tests/ui/dropck/let-else-more-permissive.stderr b/tests/ui/dropck/let-else-more-permissive.stderr new file mode 100644 index 00000000000..7c37e170afa --- /dev/null +++ b/tests/ui/dropck/let-else-more-permissive.stderr @@ -0,0 +1,35 @@ +error[E0597]: `short1` does not live long enough + --> $DIR/let-else-more-permissive.rs:13:19 + | +LL | let (mut long1, short1) = (Struct(&0), 1); + | ------ binding `short1` declared here +LL | long1.0 = &short1; + | ^^^^^^^ borrowed value does not live long enough +LL | +LL | } + | - + | | + | `short1` dropped here while still borrowed + | borrow might be used here, when `long1` is dropped and runs the `Drop` code for type `Struct` + | + = note: values in a scope are dropped in the opposite order they are defined + +error[E0597]: `short3` does not live long enough + --> $DIR/let-else-more-permissive.rs:27:19 + | +LL | let (mut long3, short3) = (Struct(&tmp), Box::new(1)) else { unreachable!() }; + | ------ binding `short3` declared here +LL | long3.0 = &short3; + | ^^^^^^^ borrowed value does not live long enough +LL | +LL | } + | - + | | + | `short3` dropped here while still borrowed + | borrow might be used here, when `long3` is dropped and runs the `Drop` code for type `Struct` + | + = note: values in a scope are dropped in the opposite order they are defined + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0597`. |