Wasmtime GitHub notifications bot (Nov 29 2022 at 01:55): Wasmtime GitHub notifications bot (Nov 29 2022 at 01:55):jameysharp opened PR #5337 from isle-overlap-fixes to main:
Ulrich Weigand identified two bugs in this code due to it falsely claiming there were unreachable rules in the s390x backend. The fixes are:
- Add constraints for pure constructors.
I didn't notice that a constructor which is declared pure (which currently implies that it is fallible), when used on the left-hand side of a rule, can cause the rule to fail to match. Therefore, any constructors on the left-hand side must be noted as additional constraints on the rule, so that overlap checking can see them.
- Ignore subset-overlaps for rules with equality constraints
This eliminates false positives when checking for unreachable rules. It introduces false negatives instead but we prefer to fail to detect an error instead of claiming that valid input is wrong. We can implement a more accurate check later.
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Wasmtime GitHub notifications bot (Nov 29 2022 at 01:55):jameysharp requested fitzgen for a review on PR #5337.
Wasmtime GitHub notifications bot (Nov 29 2022 at 01:56):jameysharp edited PR #5337 from isle-overlap-fixes to main:
Ulrich Weigand identified two bugs in this code due to it falsely claiming there were unreachable rules in the s390x backend. The fixes are:
- Add constraints for pure constructors.
I didn't notice that a constructor which is declared pure (which currently implies that it is fallible), when used on the left-hand side of a rule, can cause the rule to fail to match. Therefore, any constructors on the left-hand side must be noted as additional constraints on the rule, so that overlap checking can see them.
- Ignore subset-overlaps for rules with equality constraints
This eliminates false positives when checking for unreachable rules. It introduces false negatives instead but we prefer to fail to detect an error instead of claiming that valid input is wrong. We can implement a more accurate check later.
Extracted from #5322.
Wasmtime GitHub notifications bot (Nov 29 2022 at 18:56):fitzgen submitted PR review.
Wasmtime GitHub notifications bot (Nov 29 2022 at 19:02):jameysharp merged PR #5337.
Last updated: Dec 23 2024 at 12:05 UTC