Add test for eval order for a+=b #79293
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Yes, the order of evaluation *does* change depending on the types of the operands. Cursed, I know. I've elected to place this test into `expr/compound-assignment` creating both the `expr` directory and the `compound-assignment` directory. I plan in a future PR to also move the `if` directory and the loose `if` tests into `expr/if` and other similar cleanups of the `test/ui` directory. Future work: Test more than just `+=`, but all operators. I don't know if using a macro to generate these tests cases would be okay or not, but it'd be boilerplatey without it. I'm also confident you cannot change the evaluation order of one operator without changing all of them. Future work: Additionally, test more than just `i32 += i32` for the primitive version. I don't actually know the full set of primitive implementations, but I imagine there's enough to cause a combinatorial explosion with the previous future work item. Somewhere on the order of one to two hundred individual functions.
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It seems good to add a test for this -- I suspect there's probably at least one already out there, due to NLL/MIR work, but I wasn't able to quickly find it so this seems fine. @bors r+ rollup |
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Rollup of 10 pull requests Successful merges: - rust-lang#76941 (Add f{32,64}::is_subnormal) - rust-lang#77697 (Split each iterator adapter and source into individual modules) - rust-lang#78305 (Stabilize alloc::Layout const functions) - rust-lang#78608 (Stabilize refcell_take) - rust-lang#78793 (Clean up `StructuralEq` docs) - rust-lang#79267 (BTreeMap: address namespace conflicts) - rust-lang#79293 (Add test for eval order for a+=b) - rust-lang#79295 (BTreeMap: fix minor testing mistakes in rust-lang#78903) - rust-lang#79297 (BTreeMap: swap the names of NodeRef::new and Root::new_leaf) - rust-lang#79299 (Stabilise `then`) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup
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Yes, the order of evaluation does change depending on the types of
the operands. Cursed, I know.
I've elected to place this test into
expr/compound-assignmentcreatingboth the
exprdirectory and thecompound-assignmentdirectory. Iplan in a future PR to also move the
ifdirectory and the looseiftests into
expr/ifand other similar cleanups of thetest/uidirectory.
Future work: Test more than just
+=, but all operators. I don't knowif using a macro to generate these tests cases would be okay or not,
but it'd be boilerplatey without it. I'm also confident you cannot
change the evaluation order of one operator without changing all of
them.
Future work: Additionally, test more than just
i32 += i32for theprimitive version. I don't actually know the full set of primitive
implementations, but I imagine there's enough to cause a combinatorial
explosion with the previous future work item. Somewhere on the order of
one to two hundred individual functions.