PlutusData typeclass implementation should be unconditionally printed during TyDef

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#148 opened on Nov 17, 2023 0 comments 0 reactions 0 assignees View on GitHub

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Assessment

Difficulty: 3/5
Estimated time: 1-2 days
Newbie friendliness: 42/100

Issue type: Bug
Clarity: Mostly clear
Activity status: Stale
Tech stack: haskell
Domain: compilers

Research direction

Start with the lbf-plutus-to-plutarch path that handles TyDef and inspect how the example sum type is rendered. Compare its generated declarations with the manual derive PlutusData NftMarketplaceRedeemer workaround, then compile the generated output. Done means the needed PlutusData-related declaration is emitted before GHC reports the missing PlutusType instance.

Written by the indexing model from the issue text.

Description

bug codegen plutarch

@t4ccer
Alright, I have first maybe bug. If I have

sum NftMarketplaceRedeemer = Buy | Cancel

and run it through lbf-plutus-to-plutarch and try to compile, I'll get a GHC error saying

    • No instance for (Plutarch.Prelude.PlutusType
                         NftMarketplaceRedeemer)
        arising from the 'deriving' clause of a data type declaration
      Possible fix:
        use a standalone 'deriving instance' declaration,
          so you can specify the instance context yourself
    • When deriving the instance for (Plutarch.Show.PShow
                                        NftMarketplaceRedeemer)
   |
40 |   deriving anyclass Plutarch.Show.PShow
   |                     ^^^^^^^^^^^^^^^^^^

Of course adding derive PlutusData NftMarketplaceRedeemer fixes the issue, but I have a feeling that it should be caught before going to ghc

Dominant language: Haskell
Stars: 32
Forks: 1
PR merge metrics: No merged PRs in 30d

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