Fix termination and performance issues with DecEq#7840
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| ... | no a₁≠a₂ | _ = no λ { refl → a₁≠a₂ refl } | ||
| ... | _ | no b₁≠b₂ = no λ { refl → b₁≠b₂ refl } | ||
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| decEq-⊢⋆ [] [] = yes refl |
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The unicode character ⋆ seems to be used as a suffix for things that refer plutus types, like _⊢⋆_ and Ctx⋆ (probably referencing base kind). Perhaps we could have a different convention for a suffix for these map-like functions that appease the termination checker. I"ve used * in some of the translation relation machinery, but I think historically it was more often List, e.g. dischargeList.
basetunnel
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| decEq-⊢ : ∀{n} → DecidableEquality (n ⊢) | ||
| decEq-⊢ : {n : ℕ} → DecidableEquality (n ⊢) | ||
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| decEq-⊢⋆ : {n : ℕ} → DecidableEquality (List (n ⊢)) -- {n : ℕ} → (Ms : List (n ⊢)) → (Ns : List (n ⊢)) → Dec (Ms ≡ Ns) |
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Is this comment for documentation purposes or a left-over from writing out DecidableEquality?
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Jul 16, 2026
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Needs #7832
Needs #7843
Termination fix
Removes the need for the
TERMINATINGpragma in thedecEqdefinitions, Agda can now prove that they terminate.Performance fix
The matching on
reflinsidedecEqtriggered normalization of terms when typechecking, which affected performance significantly, to the point of using more than 128GB of memory for the example @basetunnel and I worked on.The example is an equality proof of the first AST to itself, from
agda-certificates/cardano_constitution_Cardano_Constitution_Validator_Data_Sorted-b48sy0.agda-cert. This was the certificate produced fordefaultConstitutionCodefromcardano-constitution/src/Cardano/Constitution/Validator/Data/Sorted.hs.For this particular example comparing
cons was the most expensive, so avoiding matching onreflin the recursive call todecEq-⟦ t ⟧tag x x₁insidedecEq-TmCondid the trick.