fix: type mismatches in cbv proof terms about ite/dite/Decide#12811
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wkrozowski wants to merge 3 commits intoleanprover:masterfrom
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fix: type mismatches in cbv proof terms about ite/dite/Decide#12811wkrozowski wants to merge 3 commits intoleanprover:masterfrom
cbv proof terms about ite/dite/Decide#12811wkrozowski wants to merge 3 commits intoleanprover:masterfrom
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This PR fixes `cbv`'s handling of `ite`/`dite`/`decide` when the condition is simplified via congruence. Previously, in the congruence case (where condition `c` simplifies to `c'`), the tactic would try to simplify the original decidable instance and fall back to a generic congruence result if it couldn't match `isTrue`/`isFalse`. Now it constructs a decidable instance for the simplified condition `c'` via `decidable_of_decidable_of_eq` and tries to match that, allowing full reduction. New `*_congr` lemmas in `Init.Sym.Lemmas` produce the correct proof terms for this case. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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…dite`/`decide`
When `simpAndMatch{Ite,DIte}Decidable` simplified the decidable instance,
the simplified instance was passed to `match{Ite,DIte}Decidable` which used
it in the proof term. This produced a proof about `@decide p simplified_inst`
instead of `@decide p original_inst`, causing a kernel type mismatch.
Now `match{Ite,DIte}Decidable` and `matchDecideInst` take an optional
`inst'` parameter for pattern matching while using the original `inst`
in proof construction.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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cbv decidable instance resolution in congruence casecbv handling of decide,ite and dite
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cbv handling of decide,ite and ditecbv proof terms
wkrozowski
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cbv proof termscbv proof terms about ite/dite/Decide
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Continuing work in #12816 |
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This PR fixes two issues in
cbv's proof term construction forite/dite/decide.First, when the condition/proposition is unchanged but the
Decidableinstance is simplified (e.g. via@[cbv_eval]rules), the proof terms were built using the simplified instance rather than the original, causing kernel type mismatches. NowmatchIteDecidable,matchDIteDecidable, andmatchDecideInstpattern-match on the simplified instance to determineisTrue/isFalsebut use the original instance in the proof term.Second, when the condition
csimplifies to a newc', the tactic previously could not reduce the resultingDecidableinstance. Now it derives aDecidable c'instance viadecidable_of_decidable_of_eq, simplifies it, and uses new*_congrlemmas (ite_true_congr,dite_true_congr,decide_isTrue_congr, etc.) to produce the correct proof terms.