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fix(rvm): use arithmetic negation when folding constants - #935
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Anand Krishnamoorthi (anakrish) wants to merge 1 commit into
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Anand Krishnamoorthi (anakrish) wants to merge 1 commit into
Anand Krishnamoorthi (anakrish) wants to merge 1 commit into
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Number::neg implements bitwise complement. Fold unary numeric constants with subtraction from zero instead, and cover interpreter/RVM decision parity across collection forms, execution modes, strictness, and Program JSON round trips. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: 84271ec2-b466-4cfe-bf58-848f4dceb842
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🟡 Changes recommended
Constant folding bypasses unary-minus source-span validation for negative fractions, allowing p := [-(-1.5)] to compile even though the interpreter rejects it.
1 open issue
What changed in this PR
Corrects unary numeric constant folding in the RVM compiler by using arithmetic negation instead of bitwise complement. This keeps the change focused on constant folding, separate from #930’s definedness and matching work.
Changes:
- Fold unary numeric constants using subtraction from zero.
- Add six regression cases comparing interpreter results across both VM modes, strictness settings, and Program JSON round trips.
| File | Description |
|---|---|
tests/rvm/compiler.rs |
Adds unary-negation regression coverage for numbers and collections. |
src/languages/rego/compiler/expressions/collection_literals.rs |
Replaces bitwise complement with arithmetic subtraction during constant folding. |
Review effort: Max
| value: Value::Number(n), | ||
| .. | ||
| } => Some(Value::Number(n.neg()?)), | ||
| } => Some(Value::Number( |
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Summary
Use arithmetic subtraction from zero when folding unary numeric constants in the RVM compiler.
Number::neg()implements bitwise complement, not arithmetic negation.For example:
The interpreter returns
[-1], but the unfixed RVM compiler folds this to[-2].Validation
cargo xtask ci-debug, andcargo xtask pre-commitpass using CI-pinned Rust 1.95.0.