plutus-core-1.30.0.0: Language library for Plutus Core
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LanguageHaskell2010

PlutusIR.Transform.RewriteRules.UnConstrConstrData

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unConstrConstrData ∷ (MonadQuote m, t ~ Term tyname Name DefaultUni DefaultFun a, Monoid a) ⇒ BuiltinsInfo DefaultUni DefaultFunVarsInfo tyname Name DefaultUni a → t → m t Source #

This rule rewrites terms of form `BUILTIN(unConstrData(constrData(x,y)))` , where builtin stands for FstPair or SndPair, to "x" or "y" respectively.

This rewrite-rule was originally meant to rewrite `unConstrData(constrData(x,y)) => (x,y)`, however we do not have a (polymorphic or monomorphic) builtin constructor to create a BuiltinPair "(x,y)". See Note [Representable built-in functions over polymorphic built-in types].

So we adapted the original rewrite rule to try to achieve a similar goal. Unfortunately, the adapted rule is less applicable and will most likely never fire (at least for PIR code generated by plutus-tx). The reason is that the TH code in plutus-tx does not create such "tight" code, but uses way more lets that get in the way preventing the rule from firing.

Possible solutions: Some more aggressive PIR inlining, rewriting the PlutusTx TH code, or introducing specialised pattern-matching builtins as last resort. Plutus Tx TH code responsible: https://github.com/IntersectMBO/plutus/blob/9364099b38e3aa27fb311af3299d2210e7e33e45/plutus-tx/src/PlutusTx/IsData/TH.hs#L174-L192