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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:19:13 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:19:13 +0000 |
commit | 218caa410aa38c29984be31a5229b9fa717560ee (patch) | |
tree | c54bd55eeb6e4c508940a30e94c0032fbd45d677 /tests/ui/expr/compound-assignment/eval-order.rs | |
parent | Releasing progress-linux version 1.67.1+dfsg1-1~progress7.99u1. (diff) | |
download | rustc-218caa410aa38c29984be31a5229b9fa717560ee.tar.xz rustc-218caa410aa38c29984be31a5229b9fa717560ee.zip |
Merging upstream version 1.68.2+dfsg1.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tests/ui/expr/compound-assignment/eval-order.rs')
-rw-r--r-- | tests/ui/expr/compound-assignment/eval-order.rs | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/tests/ui/expr/compound-assignment/eval-order.rs b/tests/ui/expr/compound-assignment/eval-order.rs new file mode 100644 index 000000000..658adae19 --- /dev/null +++ b/tests/ui/expr/compound-assignment/eval-order.rs @@ -0,0 +1,76 @@ +// Test evaluation order of operands of the compound assignment operators + +// run-pass + +use std::ops::AddAssign; + +enum Side { + Lhs, + Rhs, +} + +// In the following tests, we place our value into a wrapper type so that we +// can do an element access as the outer place expression. If we just had the +// block expression, it'd be a value expression and not compile. +struct Wrapper<T>(T); + +// Evaluation order for `a op= b` where typeof(a) and typeof(b) are primitives +// is first `b` then `a`. +fn primitive_compound() { + let mut side_order = vec![]; + let mut int = Wrapper(0); + + { + side_order.push(Side::Lhs); + int + }.0 += { + side_order.push(Side::Rhs); + 0 + }; + + assert!(matches!(side_order[..], [Side::Rhs, Side::Lhs])); +} + +// Evaluation order for `a op=b` otherwise is first `a` then `b`. +fn generic_compound<T: AddAssign<T> + Default>() { + let mut side_order = vec![]; + let mut add_assignable: Wrapper<T> = Wrapper(Default::default()); + + { + side_order.push(Side::Lhs); + add_assignable + }.0 += { + side_order.push(Side::Rhs); + Default::default() + }; + + assert!(matches!(side_order[..], [Side::Lhs, Side::Rhs])); +} + +fn custom_compound() { + struct Custom; + + impl AddAssign<()> for Custom { + fn add_assign(&mut self, _: ()) { + // this block purposely left blank + } + } + + let mut side_order = vec![]; + let mut custom = Wrapper(Custom); + + { + side_order.push(Side::Lhs); + custom + }.0 += { + side_order.push(Side::Rhs); + }; + + assert!(matches!(side_order[..], [Side::Lhs, Side::Rhs])); +} + +fn main() { + primitive_compound(); + generic_compound::<i32>(); + custom_compound(); +} |