Error: Reference to a name which is not a local, a builtin, or an external INLINABLE function

Question

I am writing a minting policy that takes half the bytes of one of the eUTXOs being used during mint and encoded them as a base89 readable string then checks that the Asset being minted has as a postfix said string, I am doing this in an attempt to create true NFTs without having different policy ids for each NFT.

To do this I slice the BuiltinByteString with the hash of the eUTXO in half, and then convert it to an int to pass it to the following function:

{-# INLINABLE encodeBase #-}
encodeBase :: BuiltinByteString -> Integer -> BuiltinByteString
encodeBase charset value = encoded where
  base     = lengthOfByteString charset
  encoded  = expand (value `divMod` base) emptyByteString
  lookup n = indexByteString charset n
  expand (dividend, remainder) xs
    | (dividend >  0) = expand (dividend `divMod` base) result
    | (dividend == 0 && remainder >  0) = result
    | (dividend == 0 && remainder == 0) = xs
    where result = consByteString (lookup remainder) xs 

charset is also a BuiltinByteString.

But when compiling I get the following error:

GHC Core to PLC plugin: E043:Error: Reference to a name which is not a local, a builtin, or an external INLINABLE function: Variable GHC.Integer.Type.orInteger

I don't understand, I have been using integers without issue so far in the contracts I have written, what causes this error in this case specifically?

This is the whole script:

{-|
Module      : Horrocubes.MintingScript.
Description : Mint policy for NFTs.
License     : Apache-2.0
Maintainer  : [email protected]
Stability   : experimental

This policy creates an NFT and uses an UTXO to make the NFT truly unique.

This minting policy was taken from https://github.com/input-output-hk/lobster-challenge
and sightly modified to the the token name as an outside parameter.

-}

-- LANGUAGE EXTENSIONS --------------------------------------------------------

{-# LANGUAGE DataKinds #-}
{-# LANGUAGE DeriveAnyClass #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE NamedFieldPuns #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE TypeApplications #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
 {-# LANGUAGE OverloadedStrings #-}

-- MODULE DEFINITION ----------------------------------------------------------

module Horrocubes.MintingScript
(
  mintScript,
  nftScriptShortBs
) where

-- IMPORTS --------------------------------------------------------------------

import           Cardano.Api.Shelley      (PlutusScript (..), PlutusScriptV1)
import           Codec.Serialise
import qualified Data.ByteString.Lazy     as LB
import qualified Data.ByteString.Short    as SBS
import           Ledger                   hiding (singleton)
import qualified Ledger.Typed.Scripts     as Scripts
import           Ledger.Value             as Value
import qualified PlutusTx
import           PlutusTx.Prelude         hiding (Semigroup (..), unless)
import qualified Data.ByteString.Char8    as C
import           PlutusTx.Builtins 
import Data.Bits (shift, (.|.))

-- DEFINITIONS ----------------------------------------------------------------

{- HLINT ignore "Avoid lambda" -}

{-# INLINABLE utxoHash #-}
utxoHash:: TxOutRef -> BuiltinByteString
utxoHash utxo = getTxId $ txOutRefId utxo

{-# INLINABLE readInt #-}
readInt :: BuiltinByteString -> Integer
readInt bs =     (byte 0  `shift` 120)
             .|. (byte 1  `shift` 112)
             .|. (byte 2  `shift` 104)
             .|. (byte 3  `shift` 96)
             .|. (byte 4  `shift` 88)
             .|. (byte 5  `shift` 80)
             .|. (byte 6  `shift` 72)
             .|. (byte 7  `shift` 64)
             .|. (byte 8  `shift` 56)
             .|. (byte 9  `shift` 48)
             .|. (byte 10 `shift` 40)
             .|. (byte 11 `shift` 32)
             .|. (byte 12 `shift` 24)
             .|. (byte 13 `shift` 16)
             .|. (byte 14 `shift` 8)
             .|.  byte 15
        where byte n = indexByteString bs n

{-# INLINABLE encodeBase #-}
encodeBase :: BuiltinByteString -> Integer -> BuiltinByteString
encodeBase charset value = encoded where
  base     = lengthOfByteString charset
  encoded  = expand (value `divMod` base) emptyByteString
  lookup n = indexByteString charset n
  expand (dividend, rem) xs
    | (dividend >  0) = expand (dividend `divMod` base) result
    | (dividend == 0 && rem >  0) = result
    | (dividend == 0 && rem == 0) = xs
    where result = consByteString (lookup rem) xs

-- | Creates the minting script for the NFT.
{-# INLINABLE mkNFTPolicy #-}
mkNFTPolicy :: BuiltinByteString -> PubKeyHash -> BuiltinData -> ScriptContext -> Bool
mkNFTPolicy charset _ _ ctx = traceIfFalse "Invalid Posfix" checkMintedAmount
  where
    info :: TxInfo
    info = scriptContextTxInfo ctx

    expectedPosfix :: BuiltinByteString
    expectedPosfix = encodeBase charset $ readInt $ sliceByteString 16 16 $ utxoHash getUTxO

    actuallPosfix :: TokenName -> BuiltinByteString
    actuallPosfix tn = sliceByteString 10 20 $ unTokenName tn

    getUTxO :: TxOutRef
    getUTxO = txInInfoOutRef $ ((txInfoInputs info) !! 0)

    checkMintedAmount :: Bool
    checkMintedAmount = case flattenValue (txInfoMint info) of
        [(_, tn', amt)] -> (equalsByteString (actuallPosfix tn') expectedPosfix) && amt == 1
        _               -> False

-- | Compiles the policy.
nftPolicy :: BuiltinByteString -> PubKeyHash -> Scripts.MintingPolicy
nftPolicy charset pkh = mkMintingPolicyScript $
    $$(PlutusTx.compile [|| \charset' pkh' -> Scripts.wrapMintingPolicy $ mkNFTPolicy charset' pkh' ||])
    `PlutusTx.applyCode`
     PlutusTx.liftCode charset
    `PlutusTx.applyCode`
     PlutusTx.liftCode pkh

-- | Generates the plutus script.
nftPlutusScript :: BuiltinByteString -> PubKeyHash -> Script
nftPlutusScript charset pkh = unMintingPolicyScript $ nftPolicy charset pkh

-- | Generates the NFT validator.
nftValidator :: BuiltinByteString -> PubKeyHash  -> Validator
nftValidator charset pkh = Validator $  nftPlutusScript charset pkh

-- | Serializes the contract in CBOR format.
nftScriptAsCbor :: BuiltinByteString -> PubKeyHash -> LB.ByteString
nftScriptAsCbor charset pkh = serialise $ nftValidator charset pkh

-- | Serializes the contract in CBOR format.
nftScriptShortBs :: BuiltinByteString -> PubKeyHash -> SBS.ShortByteString
nftScriptShortBs charset pkh = SBS.toShort . LB.toStrict $ nftScriptAsCbor charset pkh

-- | Gets a serizlize plutus script from the given UTXO and token name.
mintScript :: BuiltinByteString -> PubKeyHash -> PlutusScript PlutusScriptV1
mintScript charset pkh = PlutusScriptSerialised . SBS.toShort . LB.toStrict $ nftScriptAsCbor charset pkh

Answer 1

It's because one of the used functions in your INLINABLE functions doesn't belong to Plutus. For example, if you do something like this inside your validator, you'll get a similar error:

numberList :: [Integer]
numberList = [1..5]

It's because .. is not recognized by Plutus.

So, make sure all functions used in your INLINABLE functions are imported from Plutus library.

Answer 2

I would guess that the use of Data.Bits-functions in your on-chain code is the problem.