bumping nixpkgs version (#374)

Bumping nixpkgs version (pinned to a specific commit). This allows to bump HLS to  2.2.0.0 and Ormolu to a non problematic version.

cooked-validators.cabal

@@ -1,6 +1,6 @@
 cabal-version: 3.4
 
--- This file has been generated from package.yaml by hpack version 0.35.1.
+-- This file has been generated from package.yaml by hpack version 0.35.2.
 --
 -- see: https://github.com/sol/hpack
 

flake.nix

@@ -1,5 +1,8 @@
 {
-  inputs.nixpkgs.url = "github:NixOS/nixpkgs";
+  ## We need this specific version to target HLS 2.2.0.0
+  ## This is required because we are stuck with GHC 8.10.7 thanks to plutus-apps
+  inputs.nixpkgs.url =
+    "github:NixOS/nixpkgs/5836601367676bb1815f81181b78b5f9829aa302";
   inputs.flake-utils.url = "github:numtide/flake-utils";
   inputs.pre-commit-hooks.url = "github:cachix/pre-commit-hooks.nix";
   inputs.pre-commit-hooks.inputs.nixpkgs.follows = "nixpkgs";

src/Cooked/Attack/AddToken.hs

@@ -18,7 +18,7 @@ import qualified PlutusTx.Numeric as Pl
 -- This attack adds an 'AddTokenLbl' with the token name of the additional
 -- minted token(s). It returns additional value minted.
 addTokenAttack ::
-  MonadTweak m =>
+  (MonadTweak m) =>
   -- | For each policy that occurs in some 'Mints' constraint, return a list of
   -- token names together with how many tokens with that name should be
   -- minted.

src/Cooked/Attack/DoubleSat.hs

@@ -122,7 +122,7 @@ doubleSatAttack groupings optic change attacker = do
   addLabelTweak DoubleSatLbl
   where
     -- for each triple of additional inputs, outputs, and mints, calculate its balance
-    deltaBalance :: MonadTweak m => DoubleSatDelta -> m Pl.Value
+    deltaBalance :: (MonadTweak m) => DoubleSatDelta -> m Pl.Value
     deltaBalance (inputs, outputs, mints) = do
       inValue <- foldMap (outputValue . snd) . filter ((`elem` Map.keys inputs) . fst) <$> allUtxos
       return $ inValue <> Pl.negate outValue <> mintValue
@@ -131,7 +131,7 @@ doubleSatAttack groupings optic change attacker = do
         mintValue = txSkelMintsValue mints
 
     -- Helper tweak to add a 'DoubleSatDelta' to a transaction
-    addDoubleSatDeltaTweak :: MonadTweak m => DoubleSatDelta -> m ()
+    addDoubleSatDeltaTweak :: (MonadTweak m) => DoubleSatDelta -> m ()
     addDoubleSatDeltaTweak (ins, outs, mints) =
       mapM_ (uncurry addInputTweak) (Map.toList ins)
         >> mapM_ addOutputTweak outs

src/Cooked/Attack/DupToken.hs

@@ -18,7 +18,7 @@ import qualified PlutusTx.Numeric as Pl
 -- transaction using 'addLabel'. Returns the 'Value' by which the minted value
 -- was increased.
 dupTokenAttack ::
-  MonadTweak m =>
+  (MonadTweak m) =>
   -- | A function describing how the amount of tokens specified by a 'Mints'
   -- constraint should be changed, depending on the asset class and the amount
   -- specified by the constraint. The given function @f@ should probably satisfy
@@ -37,7 +37,7 @@ dupTokenAttack change attacker = do
   addLabelTweak DupTokenLbl
   return totalIncrement
   where
-    changeMintAmountsTweak :: MonadTweak m => m Pl.Value
+    changeMintAmountsTweak :: (MonadTweak m) => m Pl.Value
     changeMintAmountsTweak = do
       oldMintsList <- viewTweak $ txSkelMintsL % to txSkelMintsToList
       let newMintsList =

src/Cooked/Ltl.hs

@@ -86,7 +86,7 @@ data Ltl a
 -- <> b@ as the modification that first applies @b@ and then @a@. Attention:
 -- Since we use '<>' to define conjunction, if '<>' is not commutative,
 -- conjunction will also fail to be commutative!
-nowLater :: Monoid a => Ltl a -> [(a, Ltl a)]
+nowLater :: (Monoid a) => Ltl a -> [(a, Ltl a)]
 nowLater LtlTruth = [(mempty, LtlTruth)]
 nowLater LtlFalsity = []
 nowLater (LtlAtom g) = [(g, LtlTruth)]
@@ -120,7 +120,7 @@ finished (LtlRelease _ _) = True
 -- then the third and so on. We'd still like to compute a list of @(doNow,
 -- doLater)@ pairs as in 'nowLater', only that the @doLater@ should again be a
 -- list of formulas.
-nowLaterList :: Monoid a => [Ltl a] -> [(a, [Ltl a])]
+nowLaterList :: (Monoid a) => [Ltl a] -> [(a, [Ltl a])]
 nowLaterList = joinNowLaters . map nowLater
   where
     joinNowLaters [] = [(mempty, [])]
@@ -251,7 +251,7 @@ instance Monad (Staged op) where
 -- (But to write this, @modification@ has to be a 'Monoid' to make
 -- 'nowLaterList' work!) Look at the tests for this module and at
 -- "Cooked.MockChain.Monad.Staged" for examples of how to use this type class.
-class MonadPlus m => InterpLtl modification builtin m where
+class (MonadPlus m) => InterpLtl modification builtin m where
   interpBuiltin :: builtin a -> StateT [Ltl modification] m a
 
 -- | Interpret a 'Staged' computation into a suitable domain, using the function
@@ -297,7 +297,7 @@ interpLtlAndPruneUnfinished f = do
 -- LTL modifications beside the method above.
 
 -- | Monads that allow modificaitons with LTL formulas.
-class Monad m => MonadModal m where
+class (Monad m) => MonadModal m where
   type Modification m :: Type
   modifyLtl :: Ltl (Modification m) -> m a -> m a
 

src/Cooked/MockChain/Balancing.hs

@@ -42,7 +42,7 @@ import qualified Plutus.Script.Utils.Value as Pl
 import qualified Plutus.V2.Ledger.Api as PV2
 import qualified PlutusTx.Numeric as Pl
 
-balancedTxSkel :: MonadBlockChainBalancing m => TxSkel -> m (TxSkel, Fee, Set PV2.TxOutRef)
+balancedTxSkel :: (MonadBlockChainBalancing m) => TxSkel -> m (TxSkel, Fee, Set PV2.TxOutRef)
 balancedTxSkel skelUnbal = do
   let balancingWallet =
         case txOptBalanceWallet . txSkelOpts $ skelUnbal of
@@ -63,7 +63,7 @@ balancedTxSkel skelUnbal = do
 
 -- | Take the output of 'balancedTxSkel' and turn it into an actual Cardano
 -- transaction.
-balancedTx :: MonadBlockChainBalancing m => (TxSkel, Fee, Set PV2.TxOutRef) -> m (C.Tx C.BabbageEra)
+balancedTx :: (MonadBlockChainBalancing m) => (TxSkel, Fee, Set PV2.TxOutRef) -> m (C.Tx C.BabbageEra)
 balancedTx (skel, fee, collateralInputs) = do
   params <- applyEmulatorParamsModification (txOptEmulatorParamsModification . txSkelOpts $ skel) <$> getParams
   consumedData <- txSkelInputData skel
@@ -89,7 +89,7 @@ balancedTx (skel, fee, collateralInputs) = do
 -- | Ensure that the transaction outputs have the necessary minimum amount of
 -- Ada on them. This will only be applied if the 'txOptEnsureMinAda' is set to
 -- @True@.
-ensureTxSkelOutsMinAda :: MonadBlockChainBalancing m => TxSkel -> m TxSkel
+ensureTxSkelOutsMinAda :: (MonadBlockChainBalancing m) => TxSkel -> m TxSkel
 ensureTxSkelOutsMinAda skel = do
   theParams <- applyEmulatorParamsModification (txOptEmulatorParamsModification . txSkelOpts $ skel) <$> getParams
   case mapM (ensureTxSkelOutHasMinAda theParams) $ skel ^. txSkelOutsL of
@@ -116,16 +116,16 @@ ensureTxSkelOutsMinAda skel = do
         then ensureTxSkelOutHasMinAda theParams updatedTxSkelOut
         else return txSkelOut
 
-txSkelInputUtxosPV2 :: MonadBlockChainBalancing m => TxSkel -> m (Map PV2.TxOutRef PV2.TxOut)
+txSkelInputUtxosPV2 :: (MonadBlockChainBalancing m) => TxSkel -> m (Map PV2.TxOutRef PV2.TxOut)
 txSkelInputUtxosPV2 = lookupUtxosPV2 . Map.keys . txSkelIns
 
-txSkelInputUtxos :: MonadBlockChainBalancing m => TxSkel -> m (Map PV2.TxOutRef Ledger.TxOut)
+txSkelInputUtxos :: (MonadBlockChainBalancing m) => TxSkel -> m (Map PV2.TxOutRef Ledger.TxOut)
 txSkelInputUtxos = lookupUtxos . Map.keys . txSkelIns
 
-txSkelReferenceInputUtxosPV2 :: MonadBlockChainBalancing m => TxSkel -> m (Map PV2.TxOutRef PV2.TxOut)
+txSkelReferenceInputUtxosPV2 :: (MonadBlockChainBalancing m) => TxSkel -> m (Map PV2.TxOutRef PV2.TxOut)
 txSkelReferenceInputUtxosPV2 skel = Map.map txOutV2FromLedger <$> txSkelReferenceInputUtxos skel
 
-txSkelReferenceInputUtxos :: MonadBlockChainBalancing m => TxSkel -> m (Map PV2.TxOutRef Ledger.TxOut)
+txSkelReferenceInputUtxos :: (MonadBlockChainBalancing m) => TxSkel -> m (Map PV2.TxOutRef Ledger.TxOut)
 txSkelReferenceInputUtxos skel =
   lookupUtxos $
     mapMaybe
@@ -137,7 +137,7 @@ txSkelReferenceInputUtxos skel =
       ++ (Set.toList . txSkelInsReference $ skel)
 
 -- | All validators which protect transaction inputs
-txSkelInputValidators :: MonadBlockChainBalancing m => TxSkel -> m (Map PV2.ValidatorHash (Pl.Versioned PV2.Validator))
+txSkelInputValidators :: (MonadBlockChainBalancing m) => TxSkel -> m (Map PV2.ValidatorHash (Pl.Versioned PV2.Validator))
 txSkelInputValidators skel = do
   utxos <- Map.toList <$> lookupUtxosPV2 (Map.keys . txSkelIns $ skel)
   mValidators <-
@@ -160,10 +160,10 @@ txSkelInputValidators skel = do
 -- Go through all of the 'PV2.TxOutRef's in the list and look them up in the
 -- state of the blockchain. If any 'PV2.TxOutRef' can't be resolved, throw an
 -- error.
-lookupUtxosPV2 :: MonadBlockChainBalancing m => [PV2.TxOutRef] -> m (Map PV2.TxOutRef PV2.TxOut)
+lookupUtxosPV2 :: (MonadBlockChainBalancing m) => [PV2.TxOutRef] -> m (Map PV2.TxOutRef PV2.TxOut)
 lookupUtxosPV2 outRefs = Map.map txOutV2FromLedger <$> lookupUtxos outRefs
 
-lookupUtxos :: MonadBlockChainBalancing m => [PV2.TxOutRef] -> m (Map PV2.TxOutRef Ledger.TxOut)
+lookupUtxos :: (MonadBlockChainBalancing m) => [PV2.TxOutRef] -> m (Map PV2.TxOutRef Ledger.TxOut)
 lookupUtxos outRefs = do
   Map.fromList
     <$> mapM
@@ -182,13 +182,13 @@ lookupUtxos outRefs = do
 
 -- | look up the UTxOs the transaction consumes, and sum the value contained in
 -- them.
-txSkelInputValue :: MonadBlockChainBalancing m => TxSkel -> m PV2.Value
+txSkelInputValue :: (MonadBlockChainBalancing m) => TxSkel -> m PV2.Value
 txSkelInputValue skel = do
   txSkelInputs <- txSkelInputUtxos skel
   return $ foldMap (PV2.txOutValue . txOutV2FromLedger) txSkelInputs
 
 -- | Look up the data on UTxOs the transaction consumes.
-txSkelInputData :: MonadBlockChainBalancing m => TxSkel -> m (Map PV2.DatumHash PV2.Datum)
+txSkelInputData :: (MonadBlockChainBalancing m) => TxSkel -> m (Map PV2.DatumHash PV2.Datum)
 txSkelInputData skel = do
   txSkelInputs <- Map.elems <$> txSkelInputUtxosPV2 skel
   mDatums <-
@@ -205,7 +205,7 @@ txSkelInputData skel = do
       txSkelInputs
   return . Map.fromList . catMaybes $ mDatums
   where
-    datumFromHashWithError :: MonadBlockChainBalancing m => Pl.DatumHash -> m PV2.Datum
+    datumFromHashWithError :: (MonadBlockChainBalancing m) => Pl.DatumHash -> m PV2.Datum
     datumFromHashWithError dHash = do
       mDatum <- datumFromHash dHash
       case mDatum of
@@ -237,7 +237,7 @@ getEmulatorUTxO m =
 --
 --  This function also adjusts the transaction outputs to contain at least the
 --  minimum Ada amount, if the 'txOptEnsureMinAda option is @True@.
-setFeeAndBalance :: MonadBlockChainBalancing m => Wallet -> TxSkel -> m (TxSkel, Fee)
+setFeeAndBalance :: (MonadBlockChainBalancing m) => Wallet -> TxSkel -> m (TxSkel, Fee)
 setFeeAndBalance balanceWallet skel0 = do
   -- do the min Ada adjustment if it's requested
   skel <-
@@ -287,7 +287,7 @@ setFeeAndBalance balanceWallet skel0 = do
     -- Inspired by https://github.com/input-output-hk/plutus-apps/blob/d4255f05477fd8477ee9673e850ebb9ebb8c9657/plutus-contract/src/Wallet/Emulator/Wallet.hs#L329
 
     calcFee ::
-      MonadBlockChainBalancing m =>
+      (MonadBlockChainBalancing m) =>
       Int ->
       Fee ->
       Emulator.UTxO Emulator.EmulatorEra ->
@@ -346,7 +346,7 @@ estimateTxSkelFee params cUtxoIndex managedData managedTxOuts managedValidators
     C.Lovelace fee -> pure $ Fee fee
 
 -- | Calculates the collateral for a transaction
-calcCollateral :: MonadBlockChainBalancing m => Wallet -> m (Set PV2.TxOutRef)
+calcCollateral :: (MonadBlockChainBalancing m) => Wallet -> m (Set PV2.TxOutRef)
 calcCollateral w = do
   souts <-
     runUtxoSearch $
@@ -360,7 +360,7 @@ calcCollateral w = do
   -- investigated further for a better approach?
   return $ Set.fromList $ take 1 (fst <$> souts)
 
-balanceTxFromAux :: MonadBlockChainBalancing m => Wallet -> TxSkel -> Fee -> m TxSkel
+balanceTxFromAux :: (MonadBlockChainBalancing m) => Wallet -> TxSkel -> Fee -> m TxSkel
 balanceTxFromAux balanceWallet txskel fee = do
   bres@(BalanceTxRes {newInputs, returnValue, availableUtxos}) <- calcBalanceTx balanceWallet txskel fee
   case applyBalanceTx (walletPKHash balanceWallet) bres txskel of
@@ -397,7 +397,7 @@ data BalanceTxRes = BalanceTxRes
 -- | Calculate the changes needed to balance a transaction with money from a
 -- given wallet.  Every transaction that is sent to the chain must be balanced,
 -- that is: @inputs + mints == outputs + fee + burns@.
-calcBalanceTx :: MonadBlockChainBalancing m => Wallet -> TxSkel -> Fee -> m BalanceTxRes
+calcBalanceTx :: (MonadBlockChainBalancing m) => Wallet -> TxSkel -> Fee -> m BalanceTxRes
 calcBalanceTx balanceWallet skel fee = do
   inValue <- (<> positivePart (txSkelMintsValue $ txSkelMints skel)) <$> txSkelInputValue skel -- transaction inputs + minted value
   let outValue = txSkelOutputValue skel fee -- transaction outputs + fee + burned value

src/Cooked/MockChain/BlockChain.hs

@@ -122,7 +122,7 @@ class (MonadFail m, MonadError MockChainError m) => MonadBlockChainBalancing m w
   -- | Returns an output given a reference to it
   txOutByRefLedger :: PV2.TxOutRef -> m (Maybe Ledger.TxOut)
 
-class MonadBlockChainBalancing m => MonadBlockChainWithoutValidation m where
+class (MonadBlockChainBalancing m) => MonadBlockChainWithoutValidation m where
   -- | Returns a list of all currently known outputs.
   allUtxosLedger :: m [(PV2.TxOutRef, Ledger.TxOut)]
 
@@ -137,7 +137,7 @@ class MonadBlockChainBalancing m => MonadBlockChainWithoutValidation m where
   awaitSlot :: Ledger.Slot -> m Ledger.Slot
 
 -- | The main abstraction of the blockchain.
-class MonadBlockChainWithoutValidation m => MonadBlockChain m where
+class (MonadBlockChainWithoutValidation m) => MonadBlockChain m where
   -- | Generates, balances and validates a transaction from a skeleton.
   -- It returns the validated transaction and updates the state of the
   -- blockchain. In 'MockChainT', this means:
@@ -148,13 +148,13 @@ class MonadBlockChainWithoutValidation m => MonadBlockChain m where
   -- - adds the validators on outputs to the 'mcstValidators'.
   validateTxSkel :: TxSkel -> m Ledger.CardanoTx
 
-allUtxos :: MonadBlockChainWithoutValidation m => m [(PV2.TxOutRef, PV2.TxOut)]
+allUtxos :: (MonadBlockChainWithoutValidation m) => m [(PV2.TxOutRef, PV2.TxOut)]
 allUtxos = fmap (second txOutV2FromLedger) <$> allUtxosLedger
 
-utxosAt :: MonadBlockChainBalancing m => PV2.Address -> m [(PV2.TxOutRef, PV2.TxOut)]
+utxosAt :: (MonadBlockChainBalancing m) => PV2.Address -> m [(PV2.TxOutRef, PV2.TxOut)]
 utxosAt address = fmap (second txOutV2FromLedger) <$> utxosAtLedger address
 
-txOutByRef :: MonadBlockChainBalancing m => PV2.TxOutRef -> m (Maybe PV2.TxOut)
+txOutByRef :: (MonadBlockChainBalancing m) => PV2.TxOutRef -> m (Maybe PV2.TxOut)
 txOutByRef oref = fmap txOutV2FromLedger <$> txOutByRefLedger oref
 
 -- | Retrieve the ordered list of outputs of the given "CardanoTx".
@@ -279,14 +279,14 @@ resolveReferenceScript out =
               (out ^. outputDatumL)
               (Just val)
 
-outputDatumFromTxOutRef :: MonadBlockChainWithoutValidation m => PV2.TxOutRef -> m (Maybe PV2.OutputDatum)
+outputDatumFromTxOutRef :: (MonadBlockChainWithoutValidation m) => PV2.TxOutRef -> m (Maybe PV2.OutputDatum)
 outputDatumFromTxOutRef oref = do
   mOut <- txOutByRef oref
   case mOut of
     Nothing -> return Nothing
     Just out -> return . Just $ outputOutputDatum out
 
-datumFromTxOutRef :: MonadBlockChainWithoutValidation m => PV2.TxOutRef -> m (Maybe PV2.Datum)
+datumFromTxOutRef :: (MonadBlockChainWithoutValidation m) => PV2.TxOutRef -> m (Maybe PV2.Datum)
 datumFromTxOutRef oref = do
   mOutputDatum <- outputDatumFromTxOutRef oref
   case mOutputDatum of
@@ -306,7 +306,7 @@ typedDatumFromTxOutRef oref = do
     Nothing -> return Nothing
     Just (PV2.Datum datum) -> return $ PV2.fromBuiltinData datum
 
-valueFromTxOutRef :: MonadBlockChainWithoutValidation m => PV2.TxOutRef -> m (Maybe PV2.Value)
+valueFromTxOutRef :: (MonadBlockChainWithoutValidation m) => PV2.TxOutRef -> m (Maybe PV2.Value)
 valueFromTxOutRef oref = do
   mOut <- txOutByRef oref
   case mOut of
@@ -373,7 +373,7 @@ awaitEnclosingSlot :: (MonadBlockChainWithoutValidation m) => PV2.POSIXTime -> m
 awaitEnclosingSlot = awaitSlot <=< getEnclosingSlot
 
 -- | The infinite range of slots ending before or at the given POSIX time
-slotRangeBefore :: MonadBlockChainWithoutValidation m => PV2.POSIXTime -> m Ledger.SlotRange
+slotRangeBefore :: (MonadBlockChainWithoutValidation m) => PV2.POSIXTime -> m Ledger.SlotRange
 slotRangeBefore t = do
   n <- getEnclosingSlot t
   (_, b) <- slotToTimeInterval n
@@ -386,7 +386,7 @@ slotRangeBefore t = do
     else return $ PV2.to (n - 1)
 
 -- | The infinite range of slots starting after or at the given POSIX time
-slotRangeAfter :: MonadBlockChainWithoutValidation m => PV2.POSIXTime -> m Ledger.SlotRange
+slotRangeAfter :: (MonadBlockChainWithoutValidation m) => PV2.POSIXTime -> m Ledger.SlotRange
 slotRangeAfter t = do
   n <- getEnclosingSlot t
   (a, _) <- slotToTimeInterval n
@@ -435,17 +435,17 @@ deriving via (AsTrans (WriterT w) m) instance (Monoid w, MonadBlockChainWithoutV
 
 deriving via (AsTrans (WriterT w) m) instance (Monoid w, MonadBlockChain m) => MonadBlockChain (WriterT w m)
 
-deriving via (AsTrans (ReaderT r) m) instance MonadBlockChainBalancing m => MonadBlockChainBalancing (ReaderT r m)
+deriving via (AsTrans (ReaderT r) m) instance (MonadBlockChainBalancing m) => MonadBlockChainBalancing (ReaderT r m)
 
-deriving via (AsTrans (ReaderT r) m) instance MonadBlockChainWithoutValidation m => MonadBlockChainWithoutValidation (ReaderT r m)
+deriving via (AsTrans (ReaderT r) m) instance (MonadBlockChainWithoutValidation m) => MonadBlockChainWithoutValidation (ReaderT r m)
 
-deriving via (AsTrans (ReaderT r) m) instance MonadBlockChain m => MonadBlockChain (ReaderT r m)
+deriving via (AsTrans (ReaderT r) m) instance (MonadBlockChain m) => MonadBlockChain (ReaderT r m)
 
-deriving via (AsTrans (StateT s) m) instance MonadBlockChainBalancing m => MonadBlockChainBalancing (StateT s m)
+deriving via (AsTrans (StateT s) m) instance (MonadBlockChainBalancing m) => MonadBlockChainBalancing (StateT s m)
 
-deriving via (AsTrans (StateT s) m) instance MonadBlockChainWithoutValidation m => MonadBlockChainWithoutValidation (StateT s m)
+deriving via (AsTrans (StateT s) m) instance (MonadBlockChainWithoutValidation m) => MonadBlockChainWithoutValidation (StateT s m)
 
-deriving via (AsTrans (StateT s) m) instance MonadBlockChain m => MonadBlockChain (StateT s m)
+deriving via (AsTrans (StateT s) m) instance (MonadBlockChain m) => MonadBlockChain (StateT s m)
 
 -- 'ListT' has no 'MonadTransControl' instance, so the @deriving via ...@
 -- machinery is unusable here. However, there is
@@ -456,17 +456,17 @@ deriving via (AsTrans (StateT s) m) instance MonadBlockChain m => MonadBlockChai
 -- 'MonadBlockChainWithoutValidation' and 'MonadBlockChain' instances for
 -- 'ListT', instead of more black magic...
 
-instance MonadBlockChainBalancing m => MonadBlockChainBalancing (ListT m) where
+instance (MonadBlockChainBalancing m) => MonadBlockChainBalancing (ListT m) where
   getParams = lift getParams
   validatorFromHash = lift . validatorFromHash
   utxosAtLedger = lift . utxosAtLedger
   txOutByRefLedger = lift . txOutByRefLedger
   datumFromHash = lift . datumFromHash
 
-instance MonadBlockChainWithoutValidation m => MonadBlockChainWithoutValidation (ListT m) where
+instance (MonadBlockChainWithoutValidation m) => MonadBlockChainWithoutValidation (ListT m) where
   allUtxosLedger = lift allUtxosLedger
   currentSlot = lift currentSlot
   awaitSlot = lift . awaitSlot
 
-instance MonadBlockChain m => MonadBlockChain (ListT m) where
+instance (MonadBlockChain m) => MonadBlockChain (ListT m) where
   validateTxSkel = lift . validateTxSkel