diff options
Diffstat (limited to 'tests')
| -rw-r--r-- | tests/ui/drop/drop-order-comparisons.e2021.fixed | 575 | ||||
| -rw-r--r-- | tests/ui/drop/drop-order-comparisons.e2021.stderr | 477 | ||||
| -rw-r--r-- | tests/ui/drop/drop-order-comparisons.rs | 575 |
3 files changed, 1627 insertions, 0 deletions
diff --git a/tests/ui/drop/drop-order-comparisons.e2021.fixed b/tests/ui/drop/drop-order-comparisons.e2021.fixed new file mode 100644 index 00000000000..78cf421cfbf --- /dev/null +++ b/tests/ui/drop/drop-order-comparisons.e2021.fixed @@ -0,0 +1,575 @@ +// This tests various aspects of the drop order with a focus on: +// +// - The lifetime of temporaries with the `if let` construct (and with +// various similar constructs) and how these lifetimes were shortened +// for `if let` in Rust 2024. +// +// - The shortening of the lifetimes of temporaries in tail +// expressions in Rust 2024. +// +// - The behavior of `let` chains and how this behavior compares to +// nested `if let` expressions and chained `let .. else` statements. +// +// In the tests below, `Events` tracks a sequence of numbered events. +// Calling `e.mark(..)` logs a numbered event immediately. Calling +// `e.ok(..)` or `e.err(..)` returns an `Ok(_)` or `Err(_)` value, +// respectively, and logs the numbered event when that value is +// dropped. Calling `e.assert()` verifies that the correct number of +// events were logged and that they were logged in the correct order. + +//@ revisions: e2021 e2024 +//@ [e2021] edition: 2021 +//@ [e2021] run-rustfix +//@ [e2021] rustfix-only-machine-applicable +//@ [e2024] edition: 2024 +//@ run-pass + +#![feature(let_chains)] +#![cfg_attr(e2021, warn(rust_2024_compatibility))] + +fn t_bindings() { + let e = Events::new(); + _ = { + e.mark(1); + let _v = e.ok(8); + let _v = e.ok(2).is_ok(); + let _ = e.ok(3); + let Ok(_) = e.ok(4) else { unreachable!() }; + let Ok(_) = e.ok(5).as_ref() else { unreachable!() }; + let _v = e.ok(7); + e.mark(6); + }; + e.assert(8); +} + +fn t_tuples() { + let e = Events::new(); + _ = (e.ok(1), e.ok(4).is_ok(), e.ok(2), e.ok(3).is_ok()); + e.assert(4); +} + +fn t_arrays() { + let e = Events::new(); + trait Tr {} + impl<T> Tr for T {} + fn b<'a, T: 'a>(x: T) -> Box<dyn Tr + 'a> { + Box::new(x) + } + _ = [b(e.ok(1)), b(e.ok(4).is_ok()), b(e.ok(2)), b(e.ok(3).is_ok())]; + e.assert(4); +} + +fn t_fncalls() { + let e = Events::new(); + let f = |_, _, _, _| {}; + _ = f(e.ok(2), e.ok(4).is_ok(), e.ok(1), e.ok(3).is_ok()); + e.assert(4); +} + +#[cfg(e2021)] +#[rustfmt::skip] +fn t_tailexpr_bindings() { + let e = Events::new(); + _ = ({ + let _v = e.ok(2); + let _v = e.ok(1); + e.ok(5).is_ok() + //[e2021]~^ WARN relative drop order changing in Rust 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + }, e.mark(3), e.ok(4)); + e.assert(5); +} + +#[cfg(e2024)] +#[rustfmt::skip] +fn t_tailexpr_bindings() { + let e = Events::new(); + _ = ({ + let _v = e.ok(3); + let _v = e.ok(2); + e.ok(1).is_ok() + }, e.mark(4), e.ok(5)); + e.assert(5); +} + +#[cfg(e2021)] +#[rustfmt::skip] +fn t_tailexpr_tuples() { + let e = Events::new(); + _ = ({ + (e.ok(2), e.ok(6).is_ok(), e.ok(3), e.ok(5).is_ok()) + //[e2021]~^ WARN relative drop order changing in Rust 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + //[e2021]~| WARN relative drop order changing in Rust 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + }, e.mark(1), e.ok(4)); + e.assert(6); +} + +#[cfg(e2024)] +#[rustfmt::skip] +fn t_tailexpr_tuples() { + let e = Events::new(); + _ = ({ + (e.ok(4), e.ok(2).is_ok(), e.ok(5), e.ok(1).is_ok()) + }, e.mark(3), e.ok(6)); + e.assert(6); +} + +#[cfg(e2021)] +#[rustfmt::skip] +fn t_if_let_then() { + let e = Events::new(); + _ = (match e.ok(4).as_ref() { Ok(_) => { + //[e2021]~^ WARN if let` assigns a shorter lifetime since Edition 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + e.mark(1); + } _ => {}}, e.mark(2), e.ok(3)); + e.assert(4); +} + +#[cfg(e2024)] +#[rustfmt::skip] +fn t_if_let_then() { + let e = Events::new(); + _ = (if let Ok(_) = e.ok(2).as_ref() { + e.mark(1); + }, e.mark(3), e.ok(4)); + e.assert(4); +} + +#[cfg(e2021)] +#[rustfmt::skip] +fn t_if_let_else() { + let e = Events::new(); + _ = (match e.err(4).as_ref() { Ok(_) => {} _ => { + //[e2021]~^ WARN if let` assigns a shorter lifetime since Edition 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + e.mark(1); + }}, e.mark(2), e.ok(3)); + e.assert(4); +} + +#[cfg(e2024)] +#[rustfmt::skip] +fn t_if_let_else() { + let e = Events::new(); + _ = (if let Ok(_) = e.err(1).as_ref() {} else { + e.mark(2); + }, e.mark(3), e.ok(4)); + e.assert(4); +} + +#[rustfmt::skip] +fn t_match_then() { + let e = Events::new(); + _ = (match e.ok(4).as_ref() { + Ok(_) => e.mark(1), + _ => unreachable!(), + }, e.mark(2), e.ok(3)); + e.assert(4); +} + +#[rustfmt::skip] +fn t_match_else() { + let e = Events::new(); + _ = (match e.err(4).as_ref() { + Ok(_) => unreachable!(), + _ => e.mark(1), + }, e.mark(2), e.ok(3)); + e.assert(4); +} + +#[rustfmt::skip] +fn t_let_else_then() { + let e = Events::new(); + _ = ('top: { + 'chain: { + let Ok(_) = e.ok(1).as_ref() else { break 'chain }; + // The "then" branch: + e.mark(2); + break 'top; + } + // The "else" branch: + unreachable!() + }, e.mark(3), e.ok(4)); + e.assert(4); +} + +#[rustfmt::skip] +fn t_let_else_else() { + let e = Events::new(); + _ = ('top: { + 'chain: { + let Ok(_) = e.err(1).as_ref() else { break 'chain }; + // The "then" branch: + unreachable!(); + #[allow(unreachable_code)] + break 'top; + } + // The "else" branch: + e.mark(2); + }, e.mark(3), e.ok(4)); + e.assert(4); +} + +#[cfg(e2021)] +#[rustfmt::skip] +fn t_if_let_then_tailexpr() { + let e = Events::new(); + _ = ({ + if let Ok(_) = e.ok(4).as_ref() { + //[e2021]~^ WARN relative drop order changing in Rust 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + e.mark(1); + } + }, e.mark(2), e.ok(3)); + e.assert(4); +} + +#[cfg(e2024)] +#[rustfmt::skip] +fn t_if_let_then_tailexpr() { + let e = Events::new(); + _ = ({ + if let Ok(_) = e.ok(2).as_ref() { + e.mark(1); + } + }, e.mark(3), e.ok(4)); + e.assert(4); +} + +#[cfg(e2021)] +#[rustfmt::skip] +fn t_if_let_else_tailexpr() { + let e = Events::new(); + _ = ({ + match e.err(4).as_ref() { Ok(_) => {} _ => { + //[e2021]~^ WARN relative drop order changing in Rust 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + //[e2021]~| WARN if let` assigns a shorter lifetime since Edition 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + e.mark(1); + }} + }, e.mark(2), e.ok(3)); + e.assert(4); +} + +#[cfg(e2024)] +#[rustfmt::skip] +fn t_if_let_else_tailexpr() { + let e = Events::new(); + _ = ({ + if let Ok(_) = e.err(1).as_ref() {} else { + e.mark(2); + } + }, e.mark(3), e.ok(4)); + e.assert(4); +} + +#[rustfmt::skip] +fn t_if_let_nested_then() { + let e = Events::new(); + _ = { + // The unusual formatting, here and below, is to make the + // comparison with `let` chains more direct. + if e.ok(1).is_ok() { + if let true = e.ok(9).is_ok() { + if let Ok(_v) = e.ok(8) { + if let Ok(_) = e.ok(7) { + if let Ok(_) = e.ok(6).as_ref() { + if e.ok(2).is_ok() { + if let Ok(_v) = e.ok(5) { + if let Ok(_) = e.ok(4).as_ref() { + e.mark(3); + }}}}}}}} + }; + e.assert(9); +} + +#[rustfmt::skip] +fn t_let_else_chained_then() { + let e = Events::new(); + _ = 'top: { + 'chain: { + if e.ok(1).is_ok() {} else { break 'chain }; + let true = e.ok(2).is_ok() else { break 'chain }; + let Ok(_v) = e.ok(9) else { break 'chain }; + let Ok(_) = e.ok(3) else { break 'chain }; + let Ok(_) = e.ok(4).as_ref() else { break 'chain }; + if e.ok(5).is_ok() {} else { break 'chain }; + let Ok(_v) = e.ok(8) else { break 'chain }; + let Ok(_) = e.ok(6).as_ref() else { break 'chain }; + // The "then" branch: + e.mark(7); + break 'top; + } + // The "else" branch: + unreachable!() + }; + e.assert(9); +} + +#[cfg(e2021)] +#[rustfmt::skip] +fn t_if_let_chains_then() { + let e = Events::new(); + _ = if e.ok(1).is_ok() + && let true = e.ok(9).is_ok() + && let Ok(_v) = e.ok(5) + && let Ok(_) = e.ok(8) + && let Ok(_) = e.ok(7).as_ref() + && e.ok(2).is_ok() + && let Ok(_v) = e.ok(4) + && let Ok(_) = e.ok(6).as_ref() { + e.mark(3); + }; + e.assert(9); +} + +#[cfg(e2024)] +#[rustfmt::skip] +fn t_if_let_chains_then() { + let e = Events::new(); + _ = if e.ok(1).is_ok() + && let true = e.ok(9).is_ok() + && let Ok(_v) = e.ok(8) + && let Ok(_) = e.ok(7) + && let Ok(_) = e.ok(6).as_ref() + && e.ok(2).is_ok() + && let Ok(_v) = e.ok(5) + && let Ok(_) = e.ok(4).as_ref() { + e.mark(3); + }; + e.assert(9); +} + +#[cfg(e2021)] +#[rustfmt::skip] +fn t_if_let_nested_else() { + let e = Events::new(); + _ = if e.err(1).is_ok() {} else { + match e.err(9).is_ok() { true => {} _ => { + //[e2021]~^ WARN if let` assigns a shorter lifetime since Edition 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + match e.err(8) { Ok(_v) => {} _ => { + //[e2021]~^ WARN if let` assigns a shorter lifetime since Edition 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + match e.err(7) { Ok(_) => {} _ => { + //[e2021]~^ WARN if let` assigns a shorter lifetime since Edition 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + match e.err(6).as_ref() { Ok(_) => {} _ => { + //[e2021]~^ WARN if let` assigns a shorter lifetime since Edition 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + if e.err(2).is_ok() {} else { + match e.err(5) { Ok(_v) => {} _ => { + //[e2021]~^ WARN if let` assigns a shorter lifetime since Edition 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + match e.err(4) { Ok(_) => {} _ => { + //[e2021]~^ WARN if let` assigns a shorter lifetime since Edition 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + e.mark(3); + }}}}}}}}}}}}}}; + e.assert(9); +} + +#[cfg(e2024)] +#[rustfmt::skip] +fn t_if_let_nested_else() { + let e = Events::new(); + _ = if e.err(1).is_ok() {} else { + if let true = e.err(2).is_ok() {} else { + if let Ok(_v) = e.err(3) {} else { + if let Ok(_) = e.err(4) {} else { + if let Ok(_) = e.err(5).as_ref() {} else { + if e.err(6).is_ok() {} else { + if let Ok(_v) = e.err(7) {} else { + if let Ok(_) = e.err(8) {} else { + e.mark(9); + }}}}}}}}; + e.assert(9); +} + +#[cfg(e2021)] +#[rustfmt::skip] +fn t_if_let_nested_then_else() { + let e = Events::new(); + _ = if e.ok(1).is_ok() { + if let true = e.ok(9).is_ok() { + if let Ok(_v) = e.ok(8) { + if let Ok(_) = e.ok(7) { + if let Ok(_) = e.ok(6).as_ref() { + if e.ok(2).is_ok() { + if let Ok(_v) = e.ok(5) { + match e.err(4).as_ref() { Ok(_) => {} _ => { + //[e2021]~^ WARN if let` assigns a shorter lifetime since Edition 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + e.mark(3); + }}}}}}}}}; + e.assert(9); +} + +#[cfg(e2024)] +#[rustfmt::skip] +fn t_if_let_nested_then_else() { + let e = Events::new(); + _ = if e.ok(1).is_ok() { + if let true = e.ok(9).is_ok() { + if let Ok(_v) = e.ok(8) { + if let Ok(_) = e.ok(7) { + if let Ok(_) = e.ok(6).as_ref() { + if e.ok(2).is_ok() { + if let Ok(_v) = e.ok(5) { + if let Ok(_) = e.err(3).as_ref() {} else { + e.mark(4); + }}}}}}}}; + e.assert(9); +} + +#[rustfmt::skip] +fn t_let_else_chained_then_else() { + let e = Events::new(); + _ = 'top: { + 'chain: { + if e.ok(1).is_ok() {} else { break 'chain }; + let true = e.ok(2).is_ok() else { break 'chain }; + let Ok(_v) = e.ok(8) else { break 'chain }; + let Ok(_) = e.ok(3) else { break 'chain }; + let Ok(_) = e.ok(4).as_ref() else { break 'chain }; + if e.ok(5).is_ok() {} else { break 'chain }; + let Ok(_v) = e.ok(7) else { break 'chain }; + let Ok(_) = e.err(6).as_ref() else { break 'chain }; + // The "then" branch: + unreachable!(); + #[allow(unreachable_code)] + break 'top; + } + // The "else" branch: + e.mark(9); + }; + e.assert(9); +} + +#[cfg(e2021)] +#[rustfmt::skip] +fn t_if_let_chains_then_else() { + let e = Events::new(); + _ = if e.ok(1).is_ok() + && let true = e.ok(9).is_ok() + && let Ok(_v) = e.ok(4) + && let Ok(_) = e.ok(8) + && let Ok(_) = e.ok(7).as_ref() + && e.ok(2).is_ok() + && let Ok(_v) = e.ok(3) + && let Ok(_) = e.err(6) {} else { + e.mark(5); + }; + e.assert(9); +} + +#[cfg(e2024)] +#[rustfmt::skip] +fn t_if_let_chains_then_else() { + let e = Events::new(); + _ = if e.ok(1).is_ok() + && let true = e.ok(8).is_ok() + && let Ok(_v) = e.ok(7) + && let Ok(_) = e.ok(6) + && let Ok(_) = e.ok(5).as_ref() + && e.ok(2).is_ok() + && let Ok(_v) = e.ok(4) + && let Ok(_) = e.err(3) {} else { + e.mark(9); + }; + e.assert(9); +} + +fn main() { + t_bindings(); + t_tuples(); + t_arrays(); + t_fncalls(); + t_tailexpr_bindings(); + t_tailexpr_tuples(); + t_if_let_then(); + t_if_let_else(); + t_match_then(); + t_match_else(); + t_let_else_then(); + t_let_else_else(); + t_if_let_then_tailexpr(); + t_if_let_else_tailexpr(); + t_if_let_nested_then(); + t_let_else_chained_then(); + t_if_let_chains_then(); + t_if_let_nested_else(); + t_if_let_nested_then_else(); + t_let_else_chained_then_else(); + t_if_let_chains_then_else(); +} + +// # Test scaffolding + +use core::cell::RefCell; +use std::collections::HashSet; + +/// A buffer to track the order of events. +/// +/// First, numbered events are logged into this buffer. +/// +/// Then, `assert` is called to verify that the correct number of +/// events were logged, and that they were logged in the expected +/// order. +struct Events(RefCell<Option<Vec<u64>>>); + +impl Events { + const fn new() -> Self { + Self(RefCell::new(Some(Vec::new()))) + } + #[track_caller] + fn assert(&self, max: u64) { + let buf = &self.0; + let v1 = buf.borrow().as_ref().unwrap().clone(); + let mut v2 = buf.borrow().as_ref().unwrap().clone(); + *buf.borrow_mut() = None; + v2.sort(); + let uniq_len = v2.iter().collect::<HashSet<_>>().len(); + // Check that the sequence is sorted. + assert_eq!(v1, v2); + // Check that there are no duplicates. + assert_eq!(v2.len(), uniq_len); + // Check that the length is the expected one. + assert_eq!(max, uniq_len as u64); + // Check that the last marker is the expected one. + assert_eq!(v2.last().unwrap(), &max); + } + /// Return an `Ok` value that logs its drop. + fn ok(&self, m: u64) -> Result<LogDrop<'_>, LogDrop<'_>> { + Ok(LogDrop(self, m)) + } + /// Return an `Err` value that logs its drop. + fn err(&self, m: u64) -> Result<LogDrop, LogDrop> { + Err(LogDrop(self, m)) + } + /// Log an event. + fn mark(&self, m: u64) { + self.0.borrow_mut().as_mut().unwrap().push(m); + } +} + +impl Drop for Events { + fn drop(&mut self) { + if self.0.borrow().is_some() { + panic!("failed to call `Events::assert()`"); + } + } +} + +/// A type that logs its drop events. +struct LogDrop<'b>(&'b Events, u64); + +impl<'b> Drop for LogDrop<'b> { + fn drop(&mut self) { + self.0.mark(self.1); + } +} diff --git a/tests/ui/drop/drop-order-comparisons.e2021.stderr b/tests/ui/drop/drop-order-comparisons.e2021.stderr new file mode 100644 index 00000000000..158d18f6882 --- /dev/null +++ b/tests/ui/drop/drop-order-comparisons.e2021.stderr @@ -0,0 +1,477 @@ +warning: relative drop order changing in Rust 2024 + --> $DIR/drop-order-comparisons.rs:76:9 + | +LL | _ = ({ + | _________- +LL | | let _v = e.ok(2); + | | -- + | | | + | | `_v` calls a custom destructor + | | `_v` will be dropped later as of Edition 2024 +LL | | let _v = e.ok(1); + | | -- + | | | + | | this value will be stored in a temporary; let us call it `#2` + | | `#2` will be dropped later as of Edition 2024 +LL | | e.ok(5).is_ok() + | | ^^^^^^^ + | | | + | | this value will be stored in a temporary; let us call it `#3` + | | up until Edition 2021 `#3` is dropped last but will be dropped earlier in Edition 2024 +... | +LL | | }, e.mark(3), e.ok(4)); + | | - + | | | + | | now the temporary value is dropped here, before the local variables in the block or statement + | |__________________________this value will be stored in a temporary; let us call it `#1` + | `#1` will be dropped later as of Edition 2024 + | + = warning: this changes meaning in Rust 2024 + = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/temporary-tail-expr-scope.html> +note: `#3` invokes this custom destructor + --> $DIR/drop-order-comparisons.rs:571:1 + | +LL | / impl<'b> Drop for LogDrop<'b> { +LL | | fn drop(&mut self) { +LL | | self.0.mark(self.1); +LL | | } +LL | | } + | |_^ +note: `#1` invokes this custom destructor + --> $DIR/drop-order-comparisons.rs:571:1 + | +LL | / impl<'b> Drop for LogDrop<'b> { +LL | | fn drop(&mut self) { +LL | | self.0.mark(self.1); +LL | | } +LL | | } + | |_^ +note: `_v` invokes this custom destructor + --> $DIR/drop-order-comparisons.rs:571:1 + | +LL | / impl<'b> Drop for LogDrop<'b> { +LL | | fn drop(&mut self) { +LL | | self.0.mark(self.1); +LL | | } +LL | | } + | |_^ +note: `#2` invokes this custom destructor + --> $DIR/drop-order-comparisons.rs:571:1 + | +LL | / impl<'b> Drop for LogDrop<'b> { +LL | | fn drop(&mut self) { +LL | | self.0.mark(self.1); +LL | | } +LL | | } + | |_^ + = note: most of the time, changing drop order is harmless; inspect the `impl Drop`s for side effects like releasing locks or sending messages +note: the lint level is defined here + --> $DIR/drop-order-comparisons.rs:28:25 + | +LL | #![cfg_attr(e2021, warn(rust_2024_compatibility))] + | ^^^^^^^^^^^^^^^^^^^^^^^ + = note: `#[warn(tail_expr_drop_order)]` implied by `#[warn(rust_2024_compatibility)]` + +warning: relative drop order changing in Rust 2024 + --> $DIR/drop-order-comparisons.rs:100:45 + | +LL | _ = ({ + | _________- +LL | | (e.ok(2), e.ok(6).is_ok(), e.ok(3), e.ok(5).is_ok()) + | | ^^^^^^^ + | | | + | | this value will be stored in a temporary; let us call it `#2` + | | up until Edition 2021 `#2` is dropped last but will be dropped earlier in Edition 2024 +... | +LL | | }, e.mark(1), e.ok(4)); + | | - + | | | + | | now the temporary value is dropped here, before the local variables in the block or statement + | |__________________________this value will be stored in a temporary; let us call it `#1` + | `#1` will be dropped later as of Edition 2024 + | + = warning: this changes meaning in Rust 2024 + = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/temporary-tail-expr-scope.html> +note: `#2` invokes this custom destructor + --> $DIR/drop-order-comparisons.rs:571:1 + | +LL | / impl<'b> Drop for LogDrop<'b> { +LL | | fn drop(&mut self) { +LL | | self.0.mark(self.1); +LL | | } +LL | | } + | |_^ +note: `#1` invokes this custom destructor + --> $DIR/drop-order-comparisons.rs:571:1 + | +LL | / impl<'b> Drop for LogDrop<'b> { +LL | | fn drop(&mut self) { +LL | | self.0.mark(self.1); +LL | | } +LL | | } + | |_^ + = note: most of the time, changing drop order is harmless; inspect the `impl Drop`s for side effects like releasing locks or sending messages + +warning: relative drop order changing in Rust 2024 + --> $DIR/drop-order-comparisons.rs:100:19 + | +LL | _ = ({ + | _________- +LL | | (e.ok(2), e.ok(6).is_ok(), e.ok(3), e.ok(5).is_ok()) + | | ^^^^^^^ + | | | + | | this value will be stored in a temporary; let us call it `#2` + | | up until Edition 2021 `#2` is dropped last but will be dropped earlier in Edition 2024 +... | +LL | | }, e.mark(1), e.ok(4)); + | | - + | | | + | | now the temporary value is dropped here, before the local variables in the block or statement + | |__________________________this value will be stored in a temporary; let us call it `#1` + | `#1` will be dropped later as of Edition 2024 + | + = warning: this changes meaning in Rust 2024 + = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/temporary-tail-expr-scope.html> +note: `#2` invokes this custom destructor + --> $DIR/drop-order-comparisons.rs:571:1 + | +LL | / impl<'b> Drop for LogDrop<'b> { +LL | | fn drop(&mut self) { +LL | | self.0.mark(self.1); +LL | | } +LL | | } + | |_^ +note: `#1` invokes this custom destructor + --> $DIR/drop-order-comparisons.rs:571:1 + | +LL | / impl<'b> Drop for LogDrop<'b> { +LL | | fn drop(&mut self) { +LL | | self.0.mark(self.1); +LL | | } +LL | | } + | |_^ + = note: most of the time, changing drop order is harmless; inspect the `impl Drop`s for side effects like releasing locks or sending messages + +warning: relative drop order changing in Rust 2024 + --> $DIR/drop-order-comparisons.rs:221:24 + | +LL | _ = ({ + | _________- +LL | | if let Ok(_) = e.ok(4).as_ref() { + | | ^^^^^^^ + | | | + | | this value will be stored in a temporary; let us call it `#2` + | | up until Edition 2021 `#2` is dropped last but will be dropped earlier in Edition 2024 +... | +LL | | }, e.mark(2), e.ok(3)); + | | - + | | | + | | now the temporary value is dropped here, before the local variables in the block or statement + | |__________________________this value will be stored in a temporary; let us call it `#1` + | `#1` will be dropped later as of Edition 2024 + | + = warning: this changes meaning in Rust 2024 + = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/temporary-tail-expr-scope.html> +note: `#2` invokes this custom destructor + --> $DIR/drop-order-comparisons.rs:571:1 + | +LL | / impl<'b> Drop for LogDrop<'b> { +LL | | fn drop(&mut self) { +LL | | self.0.mark(self.1); +LL | | } +LL | | } + | |_^ +note: `#1` invokes this custom destructor + --> $DIR/drop-order-comparisons.rs:571:1 + | +LL | / impl<'b> Drop for LogDrop<'b> { +LL | | fn drop(&mut self) { +LL | | self.0.mark(self.1); +LL | | } +LL | | } + | |_^ + = note: most of the time, changing drop order is harmless; inspect the `impl Drop`s for side effects like releasing locks or sending messages + +warning: relative drop order changing in Rust 2024 + --> $DIR/drop-order-comparisons.rs:247:24 + | +LL | _ = ({ + | _________- +LL | | if let Ok(_) = e.err(4).as_ref() {} else { + | | ^^^^^^^^ + | | | + | | this value will be stored in a temporary; let us call it `#2` + | | up until Edition 2021 `#2` is dropped last but will be dropped earlier in Edition 2024 +... | +LL | | }, e.mark(2), e.ok(3)); + | | - + | | | + | | now the temporary value is dropped here, before the local variables in the block or statement + | |__________________________this value will be stored in a temporary; let us call it `#1` + | `#1` will be dropped later as of Edition 2024 + | + = warning: this changes meaning in Rust 2024 + = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/temporary-tail-expr-scope.html> +note: `#2` invokes this custom destructor + --> $DIR/drop-order-comparisons.rs:571:1 + | +LL | / impl<'b> Drop for LogDrop<'b> { +LL | | fn drop(&mut self) { +LL | | self.0.mark(self.1); +LL | | } +LL | | } + | |_^ +note: `#1` invokes this custom destructor + --> $DIR/drop-order-comparisons.rs:571:1 + | +LL | / impl<'b> Drop for LogDrop<'b> { +LL | | fn drop(&mut self) { +LL | | self.0.mark(self.1); +LL | | } +LL | | } + | |_^ + = note: most of the time, changing drop order is harmless; inspect the `impl Drop`s for side effects like releasing locks or sending messages + +warning: `if let` assigns a shorter lifetime since Edition 2024 + --> $DIR/drop-order-comparisons.rs:123:13 + | +LL | _ = (if let Ok(_) = e.ok(4).as_ref() { + | ^^^^^^^^^^^^-------^^^^^^^^^ + | | + | this value has a significant drop implementation which may observe a major change in drop order and requires your discretion + | + = warning: this changes meaning in Rust 2024 + = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/temporary-if-let-scope.html> +help: the value is now dropped here in Edition 2024 + --> $DIR/drop-order-comparisons.rs:127:5 + | +LL | }, e.mark(2), e.ok(3)); + | ^ + = note: `#[warn(if_let_rescope)]` implied by `#[warn(rust_2024_compatibility)]` +help: a `match` with a single arm can preserve the drop order up to Edition 2021 + | +LL ~ _ = (match e.ok(4).as_ref() { Ok(_) => { +LL | +LL | +LL | e.mark(1); +LL ~ } _ => {}}, e.mark(2), e.ok(3)); + | + +warning: `if let` assigns a shorter lifetime since Edition 2024 + --> $DIR/drop-order-comparisons.rs:145:13 + | +LL | _ = (if let Ok(_) = e.err(4).as_ref() {} else { + | ^^^^^^^^^^^^--------^^^^^^^^^ + | | + | this value has a significant drop implementation which may observe a major change in drop order and requires your discretion + | + = warning: this changes meaning in Rust 2024 + = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/temporary-if-let-scope.html> +help: the value is now dropped here in Edition 2024 + --> $DIR/drop-order-comparisons.rs:145:44 + | +LL | _ = (if let Ok(_) = e.err(4).as_ref() {} else { + | ^ +help: a `match` with a single arm can preserve the drop order up to Edition 2021 + | +LL ~ _ = (match e.err(4).as_ref() { Ok(_) => {} _ => { +LL | +LL | +LL | e.mark(1); +LL ~ }}, e.mark(2), e.ok(3)); + | + +warning: `if let` assigns a shorter lifetime since Edition 2024 + --> $DIR/drop-order-comparisons.rs:247:12 + | +LL | if let Ok(_) = e.err(4).as_ref() {} else { + | ^^^^^^^^^^^^--------^^^^^^^^^ + | | + | this value has a significant drop implementation which may observe a major change in drop order and requires your discretion + | + = warning: this changes meaning in Rust 2024 + = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/temporary-if-let-scope.html> +help: the value is now dropped here in Edition 2024 + --> $DIR/drop-order-comparisons.rs:247:43 + | +LL | if let Ok(_) = e.err(4).as_ref() {} else { + | ^ +help: a `match` with a single arm can preserve the drop order up to Edition 2021 + | +LL ~ match e.err(4).as_ref() { Ok(_) => {} _ => { +LL | +... +LL | e.mark(1); +LL ~ }} + | + +warning: `if let` assigns a shorter lifetime since Edition 2024 + --> $DIR/drop-order-comparisons.rs:352:12 + | +LL | if let true = e.err(9).is_ok() {} else { + | ^^^^^^^^^^^--------^^^^^^^^ + | | + | this value has a significant drop implementation which may observe a major change in drop order and requires your discretion + | + = warning: this changes meaning in Rust 2024 + = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/temporary-if-let-scope.html> +help: the value is now dropped here in Edition 2024 + --> $DIR/drop-order-comparisons.rs:352:41 + | +LL | if let true = e.err(9).is_ok() {} else { + | ^ +help: a `match` with a single arm can preserve the drop order up to Edition 2021 + | +LL ~ match e.err(9).is_ok() { true => {} _ => { +LL | +... +LL | e.mark(3); +LL ~ }}}}}}}}}; + | + +warning: `if let` assigns a shorter lifetime since Edition 2024 + --> $DIR/drop-order-comparisons.rs:355:12 + | +LL | if let Ok(_v) = e.err(8) {} else { + | ^^^^^^^^^^^^^-------- + | | + | this value has a significant drop implementation which may observe a major change in drop order and requires your discretion + | + = warning: this changes meaning in Rust 2024 + = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/temporary-if-let-scope.html> +help: the value is now dropped here in Edition 2024 + --> $DIR/drop-order-comparisons.rs:355:35 + | +LL | if let Ok(_v) = e.err(8) {} else { + | ^ +help: a `match` with a single arm can preserve the drop order up to Edition 2021 + | +LL ~ match e.err(8) { Ok(_v) => {} _ => { +LL | +... +LL | e.mark(3); +LL ~ }}}}}}}}}; + | + +warning: `if let` assigns a shorter lifetime since Edition 2024 + --> $DIR/drop-order-comparisons.rs:358:12 + | +LL | if let Ok(_) = e.err(7) {} else { + | ^^^^^^^^^^^^-------- + | | + | this value has a significant drop implementation which may observe a major change in drop order and requires your discretion + | + = warning: this changes meaning in Rust 2024 + = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/temporary-if-let-scope.html> +help: the value is now dropped here in Edition 2024 + --> $DIR/drop-order-comparisons.rs:358:34 + | +LL | if let Ok(_) = e.err(7) {} else { + | ^ +help: a `match` with a single arm can preserve the drop order up to Edition 2021 + | +LL ~ match e.err(7) { Ok(_) => {} _ => { +LL | +... +LL | e.mark(3); +LL ~ }}}}}}}}}; + | + +warning: `if let` assigns a shorter lifetime since Edition 2024 + --> $DIR/drop-order-comparisons.rs:361:12 + | +LL | if let Ok(_) = e.err(6).as_ref() {} else { + | ^^^^^^^^^^^^--------^^^^^^^^^ + | | + | this value has a significant drop implementation which may observe a major change in drop order and requires your discretion + | + = warning: this changes meaning in Rust 2024 + = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/temporary-if-let-scope.html> +help: the value is now dropped here in Edition 2024 + --> $DIR/drop-order-comparisons.rs:361:43 + | +LL | if let Ok(_) = e.err(6).as_ref() {} else { + | ^ +help: a `match` with a single arm can preserve the drop order up to Edition 2021 + | +LL ~ match e.err(6).as_ref() { Ok(_) => {} _ => { +LL | +... +LL | e.mark(3); +LL ~ }}}}}}}}}; + | + +warning: `if let` assigns a shorter lifetime since Edition 2024 + --> $DIR/drop-order-comparisons.rs:365:12 + | +LL | if let Ok(_v) = e.err(5) {} else { + | ^^^^^^^^^^^^^-------- + | | + | this value has a significant drop implementation which may observe a major change in drop order and requires your discretion + | + = warning: this changes meaning in Rust 2024 + = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/temporary-if-let-scope.html> +help: the value is now dropped here in Edition 2024 + --> $DIR/drop-order-comparisons.rs:365:35 + | +LL | if let Ok(_v) = e.err(5) {} else { + | ^ +help: a `match` with a single arm can preserve the drop order up to Edition 2021 + | +LL ~ match e.err(5) { Ok(_v) => {} _ => { +LL | +... +LL | e.mark(3); +LL ~ }}}}}}}}}; + | + +warning: `if let` assigns a shorter lifetime since Edition 2024 + --> $DIR/drop-order-comparisons.rs:368:12 + | +LL | if let Ok(_) = e.err(4) {} else { + | ^^^^^^^^^^^^-------- + | | + | this value has a significant drop implementation which may observe a major change in drop order and requires your discretion + | + = warning: this changes meaning in Rust 2024 + = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/temporary-if-let-scope.html> +help: the value is now dropped here in Edition 2024 + --> $DIR/drop-order-comparisons.rs:368:34 + | +LL | if let Ok(_) = e.err(4) {} else { + | ^ +help: a `match` with a single arm can preserve the drop order up to Edition 2021 + | +LL ~ match e.err(4) { Ok(_) => {} _ => { +LL | +LL | +LL | e.mark(3); +LL ~ }}}}}}}}}; + | + +warning: `if let` assigns a shorter lifetime since Edition 2024 + --> $DIR/drop-order-comparisons.rs:404:12 + | +LL | if let Ok(_) = e.err(4).as_ref() {} else { + | ^^^^^^^^^^^^--------^^^^^^^^^ + | | + | this value has a significant drop implementation which may observe a major change in drop order and requires your discretion + | + = warning: this changes meaning in Rust 2024 + = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2024/temporary-if-let-scope.html> +help: the value is now dropped here in Edition 2024 + --> $DIR/drop-order-comparisons.rs:404:43 + | +LL | if let Ok(_) = e.err(4).as_ref() {} else { + | ^ +help: a `match` with a single arm can preserve the drop order up to Edition 2021 + | +LL ~ match e.err(4).as_ref() { Ok(_) => {} _ => { +LL | +LL | +LL | e.mark(3); +LL ~ }}}}}}}}}; + | + +warning: 15 warnings emitted + diff --git a/tests/ui/drop/drop-order-comparisons.rs b/tests/ui/drop/drop-order-comparisons.rs new file mode 100644 index 00000000000..78c75a9449f --- /dev/null +++ b/tests/ui/drop/drop-order-comparisons.rs @@ -0,0 +1,575 @@ +// This tests various aspects of the drop order with a focus on: +// +// - The lifetime of temporaries with the `if let` construct (and with +// various similar constructs) and how these lifetimes were shortened +// for `if let` in Rust 2024. +// +// - The shortening of the lifetimes of temporaries in tail +// expressions in Rust 2024. +// +// - The behavior of `let` chains and how this behavior compares to +// nested `if let` expressions and chained `let .. else` statements. +// +// In the tests below, `Events` tracks a sequence of numbered events. +// Calling `e.mark(..)` logs a numbered event immediately. Calling +// `e.ok(..)` or `e.err(..)` returns an `Ok(_)` or `Err(_)` value, +// respectively, and logs the numbered event when that value is +// dropped. Calling `e.assert()` verifies that the correct number of +// events were logged and that they were logged in the correct order. + +//@ revisions: e2021 e2024 +//@ [e2021] edition: 2021 +//@ [e2021] run-rustfix +//@ [e2021] rustfix-only-machine-applicable +//@ [e2024] edition: 2024 +//@ run-pass + +#![feature(let_chains)] +#![cfg_attr(e2021, warn(rust_2024_compatibility))] + +fn t_bindings() { + let e = Events::new(); + _ = { + e.mark(1); + let _v = e.ok(8); + let _v = e.ok(2).is_ok(); + let _ = e.ok(3); + let Ok(_) = e.ok(4) else { unreachable!() }; + let Ok(_) = e.ok(5).as_ref() else { unreachable!() }; + let _v = e.ok(7); + e.mark(6); + }; + e.assert(8); +} + +fn t_tuples() { + let e = Events::new(); + _ = (e.ok(1), e.ok(4).is_ok(), e.ok(2), e.ok(3).is_ok()); + e.assert(4); +} + +fn t_arrays() { + let e = Events::new(); + trait Tr {} + impl<T> Tr for T {} + fn b<'a, T: 'a>(x: T) -> Box<dyn Tr + 'a> { + Box::new(x) + } + _ = [b(e.ok(1)), b(e.ok(4).is_ok()), b(e.ok(2)), b(e.ok(3).is_ok())]; + e.assert(4); +} + +fn t_fncalls() { + let e = Events::new(); + let f = |_, _, _, _| {}; + _ = f(e.ok(2), e.ok(4).is_ok(), e.ok(1), e.ok(3).is_ok()); + e.assert(4); +} + +#[cfg(e2021)] +#[rustfmt::skip] +fn t_tailexpr_bindings() { + let e = Events::new(); + _ = ({ + let _v = e.ok(2); + let _v = e.ok(1); + e.ok(5).is_ok() + //[e2021]~^ WARN relative drop order changing in Rust 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + }, e.mark(3), e.ok(4)); + e.assert(5); +} + +#[cfg(e2024)] +#[rustfmt::skip] +fn t_tailexpr_bindings() { + let e = Events::new(); + _ = ({ + let _v = e.ok(3); + let _v = e.ok(2); + e.ok(1).is_ok() + }, e.mark(4), e.ok(5)); + e.assert(5); +} + +#[cfg(e2021)] +#[rustfmt::skip] +fn t_tailexpr_tuples() { + let e = Events::new(); + _ = ({ + (e.ok(2), e.ok(6).is_ok(), e.ok(3), e.ok(5).is_ok()) + //[e2021]~^ WARN relative drop order changing in Rust 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + //[e2021]~| WARN relative drop order changing in Rust 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + }, e.mark(1), e.ok(4)); + e.assert(6); +} + +#[cfg(e2024)] +#[rustfmt::skip] +fn t_tailexpr_tuples() { + let e = Events::new(); + _ = ({ + (e.ok(4), e.ok(2).is_ok(), e.ok(5), e.ok(1).is_ok()) + }, e.mark(3), e.ok(6)); + e.assert(6); +} + +#[cfg(e2021)] +#[rustfmt::skip] +fn t_if_let_then() { + let e = Events::new(); + _ = (if let Ok(_) = e.ok(4).as_ref() { + //[e2021]~^ WARN if let` assigns a shorter lifetime since Edition 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + e.mark(1); + }, e.mark(2), e.ok(3)); + e.assert(4); +} + +#[cfg(e2024)] +#[rustfmt::skip] +fn t_if_let_then() { + let e = Events::new(); + _ = (if let Ok(_) = e.ok(2).as_ref() { + e.mark(1); + }, e.mark(3), e.ok(4)); + e.assert(4); +} + +#[cfg(e2021)] +#[rustfmt::skip] +fn t_if_let_else() { + let e = Events::new(); + _ = (if let Ok(_) = e.err(4).as_ref() {} else { + //[e2021]~^ WARN if let` assigns a shorter lifetime since Edition 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + e.mark(1); + }, e.mark(2), e.ok(3)); + e.assert(4); +} + +#[cfg(e2024)] +#[rustfmt::skip] +fn t_if_let_else() { + let e = Events::new(); + _ = (if let Ok(_) = e.err(1).as_ref() {} else { + e.mark(2); + }, e.mark(3), e.ok(4)); + e.assert(4); +} + +#[rustfmt::skip] +fn t_match_then() { + let e = Events::new(); + _ = (match e.ok(4).as_ref() { + Ok(_) => e.mark(1), + _ => unreachable!(), + }, e.mark(2), e.ok(3)); + e.assert(4); +} + +#[rustfmt::skip] +fn t_match_else() { + let e = Events::new(); + _ = (match e.err(4).as_ref() { + Ok(_) => unreachable!(), + _ => e.mark(1), + }, e.mark(2), e.ok(3)); + e.assert(4); +} + +#[rustfmt::skip] +fn t_let_else_then() { + let e = Events::new(); + _ = ('top: { + 'chain: { + let Ok(_) = e.ok(1).as_ref() else { break 'chain }; + // The "then" branch: + e.mark(2); + break 'top; + } + // The "else" branch: + unreachable!() + }, e.mark(3), e.ok(4)); + e.assert(4); +} + +#[rustfmt::skip] +fn t_let_else_else() { + let e = Events::new(); + _ = ('top: { + 'chain: { + let Ok(_) = e.err(1).as_ref() else { break 'chain }; + // The "then" branch: + unreachable!(); + #[allow(unreachable_code)] + break 'top; + } + // The "else" branch: + e.mark(2); + }, e.mark(3), e.ok(4)); + e.assert(4); +} + +#[cfg(e2021)] +#[rustfmt::skip] +fn t_if_let_then_tailexpr() { + let e = Events::new(); + _ = ({ + if let Ok(_) = e.ok(4).as_ref() { + //[e2021]~^ WARN relative drop order changing in Rust 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + e.mark(1); + } + }, e.mark(2), e.ok(3)); + e.assert(4); +} + +#[cfg(e2024)] +#[rustfmt::skip] +fn t_if_let_then_tailexpr() { + let e = Events::new(); + _ = ({ + if let Ok(_) = e.ok(2).as_ref() { + e.mark(1); + } + }, e.mark(3), e.ok(4)); + e.assert(4); +} + +#[cfg(e2021)] +#[rustfmt::skip] +fn t_if_let_else_tailexpr() { + let e = Events::new(); + _ = ({ + if let Ok(_) = e.err(4).as_ref() {} else { + //[e2021]~^ WARN relative drop order changing in Rust 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + //[e2021]~| WARN if let` assigns a shorter lifetime since Edition 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + e.mark(1); + } + }, e.mark(2), e.ok(3)); + e.assert(4); +} + +#[cfg(e2024)] +#[rustfmt::skip] +fn t_if_let_else_tailexpr() { + let e = Events::new(); + _ = ({ + if let Ok(_) = e.err(1).as_ref() {} else { + e.mark(2); + } + }, e.mark(3), e.ok(4)); + e.assert(4); +} + +#[rustfmt::skip] +fn t_if_let_nested_then() { + let e = Events::new(); + _ = { + // The unusual formatting, here and below, is to make the + // comparison with `let` chains more direct. + if e.ok(1).is_ok() { + if let true = e.ok(9).is_ok() { + if let Ok(_v) = e.ok(8) { + if let Ok(_) = e.ok(7) { + if let Ok(_) = e.ok(6).as_ref() { + if e.ok(2).is_ok() { + if let Ok(_v) = e.ok(5) { + if let Ok(_) = e.ok(4).as_ref() { + e.mark(3); + }}}}}}}} + }; + e.assert(9); +} + +#[rustfmt::skip] +fn t_let_else_chained_then() { + let e = Events::new(); + _ = 'top: { + 'chain: { + if e.ok(1).is_ok() {} else { break 'chain }; + let true = e.ok(2).is_ok() else { break 'chain }; + let Ok(_v) = e.ok(9) else { break 'chain }; + let Ok(_) = e.ok(3) else { break 'chain }; + let Ok(_) = e.ok(4).as_ref() else { break 'chain }; + if e.ok(5).is_ok() {} else { break 'chain }; + let Ok(_v) = e.ok(8) else { break 'chain }; + let Ok(_) = e.ok(6).as_ref() else { break 'chain }; + // The "then" branch: + e.mark(7); + break 'top; + } + // The "else" branch: + unreachable!() + }; + e.assert(9); +} + +#[cfg(e2021)] +#[rustfmt::skip] +fn t_if_let_chains_then() { + let e = Events::new(); + _ = if e.ok(1).is_ok() + && let true = e.ok(9).is_ok() + && let Ok(_v) = e.ok(5) + && let Ok(_) = e.ok(8) + && let Ok(_) = e.ok(7).as_ref() + && e.ok(2).is_ok() + && let Ok(_v) = e.ok(4) + && let Ok(_) = e.ok(6).as_ref() { + e.mark(3); + }; + e.assert(9); +} + +#[cfg(e2024)] +#[rustfmt::skip] +fn t_if_let_chains_then() { + let e = Events::new(); + _ = if e.ok(1).is_ok() + && let true = e.ok(9).is_ok() + && let Ok(_v) = e.ok(8) + && let Ok(_) = e.ok(7) + && let Ok(_) = e.ok(6).as_ref() + && e.ok(2).is_ok() + && let Ok(_v) = e.ok(5) + && let Ok(_) = e.ok(4).as_ref() { + e.mark(3); + }; + e.assert(9); +} + +#[cfg(e2021)] +#[rustfmt::skip] +fn t_if_let_nested_else() { + let e = Events::new(); + _ = if e.err(1).is_ok() {} else { + if let true = e.err(9).is_ok() {} else { + //[e2021]~^ WARN if let` assigns a shorter lifetime since Edition 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + if let Ok(_v) = e.err(8) {} else { + //[e2021]~^ WARN if let` assigns a shorter lifetime since Edition 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + if let Ok(_) = e.err(7) {} else { + //[e2021]~^ WARN if let` assigns a shorter lifetime since Edition 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + if let Ok(_) = e.err(6).as_ref() {} else { + //[e2021]~^ WARN if let` assigns a shorter lifetime since Edition 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + if e.err(2).is_ok() {} else { + if let Ok(_v) = e.err(5) {} else { + //[e2021]~^ WARN if let` assigns a shorter lifetime since Edition 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + if let Ok(_) = e.err(4) {} else { + //[e2021]~^ WARN if let` assigns a shorter lifetime since Edition 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + e.mark(3); + }}}}}}}}; + e.assert(9); +} + +#[cfg(e2024)] +#[rustfmt::skip] +fn t_if_let_nested_else() { + let e = Events::new(); + _ = if e.err(1).is_ok() {} else { + if let true = e.err(2).is_ok() {} else { + if let Ok(_v) = e.err(3) {} else { + if let Ok(_) = e.err(4) {} else { + if let Ok(_) = e.err(5).as_ref() {} else { + if e.err(6).is_ok() {} else { + if let Ok(_v) = e.err(7) {} else { + if let Ok(_) = e.err(8) {} else { + e.mark(9); + }}}}}}}}; + e.assert(9); +} + +#[cfg(e2021)] +#[rustfmt::skip] +fn t_if_let_nested_then_else() { + let e = Events::new(); + _ = if e.ok(1).is_ok() { + if let true = e.ok(9).is_ok() { + if let Ok(_v) = e.ok(8) { + if let Ok(_) = e.ok(7) { + if let Ok(_) = e.ok(6).as_ref() { + if e.ok(2).is_ok() { + if let Ok(_v) = e.ok(5) { + if let Ok(_) = e.err(4).as_ref() {} else { + //[e2021]~^ WARN if let` assigns a shorter lifetime since Edition 2024 + //[e2021]~| WARN this changes meaning in Rust 2024 + e.mark(3); + }}}}}}}}; + e.assert(9); +} + +#[cfg(e2024)] +#[rustfmt::skip] +fn t_if_let_nested_then_else() { + let e = Events::new(); + _ = if e.ok(1).is_ok() { + if let true = e.ok(9).is_ok() { + if let Ok(_v) = e.ok(8) { + if let Ok(_) = e.ok(7) { + if let Ok(_) = e.ok(6).as_ref() { + if e.ok(2).is_ok() { + if let Ok(_v) = e.ok(5) { + if let Ok(_) = e.err(3).as_ref() {} else { + e.mark(4); + }}}}}}}}; + e.assert(9); +} + +#[rustfmt::skip] +fn t_let_else_chained_then_else() { + let e = Events::new(); + _ = 'top: { + 'chain: { + if e.ok(1).is_ok() {} else { break 'chain }; + let true = e.ok(2).is_ok() else { break 'chain }; + let Ok(_v) = e.ok(8) else { break 'chain }; + let Ok(_) = e.ok(3) else { break 'chain }; + let Ok(_) = e.ok(4).as_ref() else { break 'chain }; + if e.ok(5).is_ok() {} else { break 'chain }; + let Ok(_v) = e.ok(7) else { break 'chain }; + let Ok(_) = e.err(6).as_ref() else { break 'chain }; + // The "then" branch: + unreachable!(); + #[allow(unreachable_code)] + break 'top; + } + // The "else" branch: + e.mark(9); + }; + e.assert(9); +} + +#[cfg(e2021)] +#[rustfmt::skip] +fn t_if_let_chains_then_else() { + let e = Events::new(); + _ = if e.ok(1).is_ok() + && let true = e.ok(9).is_ok() + && let Ok(_v) = e.ok(4) + && let Ok(_) = e.ok(8) + && let Ok(_) = e.ok(7).as_ref() + && e.ok(2).is_ok() + && let Ok(_v) = e.ok(3) + && let Ok(_) = e.err(6) {} else { + e.mark(5); + }; + e.assert(9); +} + +#[cfg(e2024)] +#[rustfmt::skip] +fn t_if_let_chains_then_else() { + let e = Events::new(); + _ = if e.ok(1).is_ok() + && let true = e.ok(8).is_ok() + && let Ok(_v) = e.ok(7) + && let Ok(_) = e.ok(6) + && let Ok(_) = e.ok(5).as_ref() + && e.ok(2).is_ok() + && let Ok(_v) = e.ok(4) + && let Ok(_) = e.err(3) {} else { + e.mark(9); + }; + e.assert(9); +} + +fn main() { + t_bindings(); + t_tuples(); + t_arrays(); + t_fncalls(); + t_tailexpr_bindings(); + t_tailexpr_tuples(); + t_if_let_then(); + t_if_let_else(); + t_match_then(); + t_match_else(); + t_let_else_then(); + t_let_else_else(); + t_if_let_then_tailexpr(); + t_if_let_else_tailexpr(); + t_if_let_nested_then(); + t_let_else_chained_then(); + t_if_let_chains_then(); + t_if_let_nested_else(); + t_if_let_nested_then_else(); + t_let_else_chained_then_else(); + t_if_let_chains_then_else(); +} + +// # Test scaffolding + +use core::cell::RefCell; +use std::collections::HashSet; + +/// A buffer to track the order of events. +/// +/// First, numbered events are logged into this buffer. +/// +/// Then, `assert` is called to verify that the correct number of +/// events were logged, and that they were logged in the expected +/// order. +struct Events(RefCell<Option<Vec<u64>>>); + +impl Events { + const fn new() -> Self { + Self(RefCell::new(Some(Vec::new()))) + } + #[track_caller] + fn assert(&self, max: u64) { + let buf = &self.0; + let v1 = buf.borrow().as_ref().unwrap().clone(); + let mut v2 = buf.borrow().as_ref().unwrap().clone(); + *buf.borrow_mut() = None; + v2.sort(); + let uniq_len = v2.iter().collect::<HashSet<_>>().len(); + // Check that the sequence is sorted. + assert_eq!(v1, v2); + // Check that there are no duplicates. + assert_eq!(v2.len(), uniq_len); + // Check that the length is the expected one. + assert_eq!(max, uniq_len as u64); + // Check that the last marker is the expected one. + assert_eq!(v2.last().unwrap(), &max); + } + /// Return an `Ok` value that logs its drop. + fn ok(&self, m: u64) -> Result<LogDrop<'_>, LogDrop<'_>> { + Ok(LogDrop(self, m)) + } + /// Return an `Err` value that logs its drop. + fn err(&self, m: u64) -> Result<LogDrop, LogDrop> { + Err(LogDrop(self, m)) + } + /// Log an event. + fn mark(&self, m: u64) { + self.0.borrow_mut().as_mut().unwrap().push(m); + } +} + +impl Drop for Events { + fn drop(&mut self) { + if self.0.borrow().is_some() { + panic!("failed to call `Events::assert()`"); + } + } +} + +/// A type that logs its drop events. +struct LogDrop<'b>(&'b Events, u64); + +impl<'b> Drop for LogDrop<'b> { + fn drop(&mut self) { + self.0.mark(self.1); + } +} |