diff --git a/alonzo/impl/src/Cardano/Ledger/Alonzo.hs b/alonzo/impl/src/Cardano/Ledger/Alonzo.hs
index cf753e9ca5f..08b08807943 100644
--- a/alonzo/impl/src/Cardano/Ledger/Alonzo.hs
+++ b/alonzo/impl/src/Cardano/Ledger/Alonzo.hs
@@ -23,6 +23,7 @@ where
 
 import Cardano.Ledger.Alonzo.Data (AuxiliaryData (..), getPlutusData)
 import Cardano.Ledger.Alonzo.PParams (PParams, PParams' (..), PParamsUpdate, updatePParams)
+import Cardano.Ledger.Alonzo.Rules.Ledger (AlonzoLEDGER)
 import qualified Cardano.Ledger.Alonzo.Rules.Utxo as Alonzo (AlonzoUTXO)
 import qualified Cardano.Ledger.Alonzo.Rules.Utxos as Alonzo (UTXOS)
 import qualified Cardano.Ledger.Alonzo.Rules.Utxow as Alonzo (AlonzoUTXOW)
@@ -51,6 +52,7 @@ import Data.Typeable (Typeable)
 import qualified Plutus.V1.Ledger.Api as Plutus (validateScript)
 import qualified Shelley.Spec.Ledger.API as API
 import qualified Shelley.Spec.Ledger.BaseTypes as Shelley
+import Shelley.Spec.Ledger.CompactAddr (CompactAddr)
 import Shelley.Spec.Ledger.Metadata (validMetadatum)
 import qualified Shelley.Spec.Ledger.STS.Bbody as STS
 import qualified Shelley.Spec.Ledger.STS.Bbody as Shelley
@@ -69,11 +71,16 @@ import Shelley.Spec.Ledger.TxBody (witKeyHash)
 -- | The Alonzo era
 data AlonzoEra c
 
-instance API.PraosCrypto c => API.ApplyTx (AlonzoEra c)
+{-
+instance
+  ( Show (CompactAddr c),
+    API.PraosCrypto c
+  ) => API.ApplyTx (AlonzoEra c)
+-}
 
-instance API.PraosCrypto c => API.ApplyBlock (AlonzoEra c)
+instance (Show (CompactAddr c), API.PraosCrypto c) => API.ApplyBlock (AlonzoEra c)
 
-instance API.PraosCrypto c => API.GetLedgerView (AlonzoEra c)
+instance (Show (CompactAddr c), API.PraosCrypto c) => API.GetLedgerView (AlonzoEra c)
 
 instance (CC.Crypto c) => Shelley.ValidateScript (AlonzoEra c) where
   isNativeScript x = not (isPlutusScript x)
@@ -97,8 +104,7 @@ instance
   -- initialState :: ShelleyGenesis era -> AdditionalGenesisConfig era -> NewEpochState era
   initialState _ _ = error "TODO: implement initialState"
 
-instance CC.Crypto c => UsesTxOut (AlonzoEra c) where
-  -- makeTxOut :: Proxy era -> Addr (Crypto era) -> Value era -> TxOut era
+instance (Show (CompactAddr c), CC.Crypto c) => UsesTxOut (AlonzoEra c) where
   makeTxOut _proxy addr val = TxOut addr val Shelley.SNothing
 
 instance
@@ -149,8 +155,13 @@ instance CC.Crypto c => EraModule.BlockDecoding (AlonzoEra c) where
   seqIsValidating tx = case isValidating' tx of IsValidating b -> b
   seqHasValidating = True -- Tx in AlonzoEra has an IsValidating field
 
-instance API.PraosCrypto c => API.ShelleyBasedEra (AlonzoEra c)
-
+{-
+instance
+  ( Show (CompactAddr c),
+    API.PraosCrypto c,
+    Core.Witnesses c ~ TxWitness c
+  ) => API.ShelleyBasedEra (AlonzoEra c)
+-}
 -------------------------------------------------------------------------------
 -- Era Mapping
 -------------------------------------------------------------------------------
@@ -163,6 +174,7 @@ type instance Core.EraRule "UTXO" (AlonzoEra c) = Alonzo.AlonzoUTXO (AlonzoEra c
 
 type instance Core.EraRule "UTXOW" (AlonzoEra c) = Alonzo.AlonzoUTXOW (AlonzoEra c)
 
+{-
 type LEDGERSTUB c =
   STUB
     (API.LedgerEnv (AlonzoEra c))
@@ -173,8 +185,9 @@ type LEDGERSTUB c =
 
 instance Typeable c => STS.Embed (LEDGERSTUB c) (API.LEDGERS (AlonzoEra c)) where
   wrapFailed = error "TODO: implement LEDGER rule"
+-}
 
-type instance Core.EraRule "LEDGER" (AlonzoEra c) = LEDGERSTUB c
+type instance Core.EraRule "LEDGER" (AlonzoEra c) = AlonzoLEDGER c
 
 type instance
   Core.EraRule "BBODY" (AlonzoEra c) =
diff --git a/alonzo/impl/src/Cardano/Ledger/Alonzo/Data.hs b/alonzo/impl/src/Cardano/Ledger/Alonzo/Data.hs
index caf399f6601..e7c1febf8ad 100644
--- a/alonzo/impl/src/Cardano/Ledger/Alonzo/Data.hs
+++ b/alonzo/impl/src/Cardano/Ledger/Alonzo/Data.hs
@@ -122,18 +122,11 @@ newtype Data era = DataConstr (MemoBytes Plutus.Data)
   deriving (Eq, Ord, Generic, Show)
   deriving newtype (SafeToHash, ToCBOR)
 
-{-
 deriving via
   (Mem Plutus.Data)
   instance
     (Era era) =>
     FromCBOR (Annotator (Data era))
--}
-
-instance Typeable era => FromCBOR (Annotator (Data era)) where
-  fromCBOR = do
-    (Annotator getT, Annotator getBytes) <- withSlice fromCBOR
-    pure (Annotator (\fullbytes -> DataConstr (Memo (getT fullbytes) (toShort (toStrict (getBytes fullbytes))))))
 
 instance (Crypto era ~ c) => HashAnnotated (Data era) EraIndependentData c
 
diff --git a/alonzo/impl/src/Cardano/Ledger/Alonzo/PParams.hs b/alonzo/impl/src/Cardano/Ledger/Alonzo/PParams.hs
index 1d124ea879f..78c649618e3 100644
--- a/alonzo/impl/src/Cardano/Ledger/Alonzo/PParams.hs
+++ b/alonzo/impl/src/Cardano/Ledger/Alonzo/PParams.hs
@@ -340,14 +340,6 @@ instance NoThunks (PParamsUpdate era)
 -- writing only those fields where the field is (SJust x), that is the role of
 -- the local function (omitStrictMaybe key x)
 
-fromSJust :: StrictMaybe a -> a
-fromSJust (SJust x) = x
-fromSJust SNothing = error "SNothing in fromSJust"
-
-isSNothing :: StrictMaybe a -> Bool
-isSNothing SNothing = True
-isSNothing (SJust _) = False
-
 encodePParamsUpdate ::
   PParamsUpdate era ->
   Encode ('Closed 'Sparse) (PParamsUpdate era)
@@ -380,6 +372,14 @@ encodePParamsUpdate ppup =
       Word -> StrictMaybe a -> (a -> Encoding) -> Encode ('Closed 'Sparse) (StrictMaybe a)
     omitStrictMaybe key x enc = Omit isSNothing (Key key (E (enc . fromSJust) x))
 
+    fromSJust :: StrictMaybe a -> a
+    fromSJust (SJust x) = x
+    fromSJust SNothing = error "SNothing in fromSJust. This should never happen, it is guarded by isSNothing."
+
+    isSNothing :: StrictMaybe a -> Bool
+    isSNothing SNothing = True
+    isSNothing (SJust _) = False
+
 instance (Era era) => ToCBOR (PParamsUpdate era) where
   toCBOR ppup = encode (encodePParamsUpdate ppup)
 
diff --git a/alonzo/impl/src/Cardano/Ledger/Alonzo/Rules/Utxo.hs b/alonzo/impl/src/Cardano/Ledger/Alonzo/Rules/Utxo.hs
index 86955896cb1..3bffc44c4f2 100644
--- a/alonzo/impl/src/Cardano/Ledger/Alonzo/Rules/Utxo.hs
+++ b/alonzo/impl/src/Cardano/Ledger/Alonzo/Rules/Utxo.hs
@@ -81,6 +81,7 @@ import Shelley.Spec.Ledger.BaseTypes
     StrictMaybe (..),
     networkId,
   )
+import Shelley.Spec.Ledger.CompactAddr (CompactAddr)
 import qualified Shelley.Spec.Ledger.LedgerState as Shelley
 import qualified Shelley.Spec.Ledger.STS.Utxo as Shelley
 import Shelley.Spec.Ledger.Tx (TxIn)
@@ -274,6 +275,7 @@ utxoTransition ::
   forall era.
   ( Era era,
     ValidateScript era,
+    Show (CompactAddr (Crypto era)),
     -- instructions for calling UTXOS from AlonzoUTXO
     Embed (Core.EraRule "UTXOS" era) (AlonzoUTXO era),
     Environment (Core.EraRule "UTXOS" era) ~ Shelley.UtxoEnv era,
@@ -392,6 +394,7 @@ utxoTransition = do
 instance
   forall era.
   ( ValidateScript era,
+    Show (CompactAddr (Crypto era)),
     -- Instructions needed to call the UTXOS transition from this one.
     Embed (Core.EraRule "UTXOS" era) (AlonzoUTXO era),
     Environment (Core.EraRule "UTXOS" era) ~ Shelley.UtxoEnv era,
diff --git a/alonzo/impl/src/Cardano/Ledger/Alonzo/Rules/Utxos.hs b/alonzo/impl/src/Cardano/Ledger/Alonzo/Rules/Utxos.hs
index ef9d114b803..3b38c7c5754 100644
--- a/alonzo/impl/src/Cardano/Ledger/Alonzo/Rules/Utxos.hs
+++ b/alonzo/impl/src/Cardano/Ledger/Alonzo/Rules/Utxos.hs
@@ -43,6 +43,7 @@ import GHC.Generics (Generic)
 import GHC.Records (HasField (..))
 import NoThunks.Class (NoThunks)
 import Shelley.Spec.Ledger.BaseTypes (ShelleyBase, StrictMaybe (..), strictMaybeToMaybe)
+import Shelley.Spec.Ledger.CompactAddr (CompactAddr)
 import Shelley.Spec.Ledger.LedgerState
 import qualified Shelley.Spec.Ledger.LedgerState as Shelley
 import Shelley.Spec.Ledger.PParams (Update)
@@ -63,6 +64,7 @@ instance
     Eq (Core.PParams era),
     Show (Core.PParams era),
     Show (PParamsDelta era),
+    Show (CompactAddr (Crypto era)),
     Eq (PParamsDelta era),
     Embed (Core.EraRule "PPUP" era) (UTXOS era),
     Environment (Core.EraRule "PPUP" era) ~ PPUPEnv era,
@@ -90,6 +92,7 @@ instance
 utxosTransition ::
   forall era.
   ( Era era,
+    Show (CompactAddr (Crypto era)),
     Core.Script era ~ Script era,
     Environment (Core.EraRule "PPUP" era) ~ PPUPEnv era,
     State (Core.EraRule "PPUP" era) ~ PPUPState era,
@@ -119,7 +122,8 @@ utxosTransition =
 
 scriptsValidateTransition ::
   forall era.
-  ( Show (Core.Value era), -- Arises because of the use of (∪) from SetAlgebra, needs Show to report errors.
+  ( Show (Core.Value era), -- Arises because of the use of (∪) from SetAlgebra, needs Show to report problems.
+    Show (CompactAddr (Crypto era)),
     Era era,
     Environment (Core.EraRule "PPUP" era) ~ PPUPEnv era,
     State (Core.EraRule "PPUP" era) ~ PPUPState era,
diff --git a/alonzo/impl/src/Cardano/Ledger/Alonzo/Rules/Utxow.hs b/alonzo/impl/src/Cardano/Ledger/Alonzo/Rules/Utxow.hs
index 23b9f5d0903..06e80118916 100644
--- a/alonzo/impl/src/Cardano/Ledger/Alonzo/Rules/Utxow.hs
+++ b/alonzo/impl/src/Cardano/Ledger/Alonzo/Rules/Utxow.hs
@@ -87,16 +87,19 @@ data AlonzoPredFail era
     WrongNetworkInTxBody
       !Network -- Actual Network ID
       !Network -- Network ID in transaction body
+  | ScriptsDidNotValidate [Core.Script era]
 
 deriving instance
   ( Era era,
-    Show (PredicateFailure (Core.EraRule "UTXO" era)) -- The Shelley UtxowPredicateFailure needs this to Show
+    Show (PredicateFailure (Core.EraRule "UTXO" era)), -- The Shelley UtxowPredicateFailure needs this to Show
+    Show (Core.Script era)
   ) =>
   Show (AlonzoPredFail era)
 
 deriving instance
   ( Era era,
-    Eq (PredicateFailure (Core.EraRule "UTXO" era)) -- The Shelley UtxowPredicateFailure needs this to Eq
+    Eq (PredicateFailure (Core.EraRule "UTXO" era)), -- The Shelley UtxowPredicateFailure needs this to Eq
+    Eq (Core.Script era)
   ) =>
   Eq (AlonzoPredFail era)
 
@@ -104,7 +107,8 @@ instance
   ( Era era,
     ToCBOR (PredicateFailure (Core.EraRule "UTXO" era)),
     Typeable (Core.AuxiliaryData era),
-    Typeable (Core.Script era)
+    Typeable (Core.Script era),
+    ToCBOR (Core.Script era)
   ) =>
   ToCBOR (AlonzoPredFail era)
   where
@@ -114,7 +118,8 @@ encodePredFail ::
   ( Era era,
     ToCBOR (PredicateFailure (Core.EraRule "UTXO" era)),
     Typeable (Core.Script era),
-    Typeable (Core.AuxiliaryData era)
+    Typeable (Core.AuxiliaryData era),
+    ToCBOR (Core.Script era)
   ) =>
   AlonzoPredFail era ->
   Encode 'Open (AlonzoPredFail era)
@@ -126,13 +131,15 @@ encodePredFail (PPViewHashesDontMatch x y) = Sum PPViewHashesDontMatch 4 !> To x
 encodePredFail (MissingRequiredSigners x) = Sum MissingRequiredSigners 5 !> To x
 encodePredFail (Phase1ScriptWitnessNotValidating x) = Sum Phase1ScriptWitnessNotValidating 6 !> To x
 encodePredFail (WrongNetworkInTxBody x y) = Sum WrongNetworkInTxBody 7 !> To x !> To y
+encodePredFail (ScriptsDidNotValidate x) = Sum ScriptsDidNotValidate 8 !> To x
 
 instance
   ( Era era,
     FromCBOR (PredicateFailure (Core.EraRule "UTXO" era)),
     FromCBOR (Script era),
     Typeable (Core.Script era),
-    Typeable (Core.AuxiliaryData era)
+    Typeable (Core.AuxiliaryData era),
+    FromCBOR (Core.Script era)
   ) =>
   FromCBOR (AlonzoPredFail era)
   where
@@ -143,7 +150,8 @@ decodePredFail ::
     FromCBOR (PredicateFailure (Core.EraRule "UTXO" era)), -- TODO, we should be able to get rid of this constraint
     FromCBOR (Script era),
     Typeable (Core.Script era),
-    Typeable (Core.AuxiliaryData era)
+    Typeable (Core.AuxiliaryData era),
+    FromCBOR (Core.Script era)
   ) =>
   Word ->
   Decode 'Open (AlonzoPredFail era)
@@ -155,6 +163,7 @@ decodePredFail 4 = SumD PPViewHashesDontMatch <! From <! From
 decodePredFail 5 = SumD MissingRequiredSigners <! From
 decodePredFail 6 = SumD Phase1ScriptWitnessNotValidating <! From
 decodePredFail 7 = SumD WrongNetworkInTxBody <! From <! From
+decodePredFail 8 = SumD ScriptsDidNotValidate <! From
 decodePredFail n = Invalid n
 
 -- =============================================
@@ -222,6 +231,13 @@ alonzoStyleWitness = do
           accum (PlutusScript _) bad = bad
   null failedScripts ?! (Phase1ScriptWitnessNotValidating $ Set.fromList failedScripts)
 
+  -- ONE OF THESE MAY BE REDUNDANT. validateScript NOW WORKS ON PLUTUS SCRIPTS TOO.
+  let failedScripts2 = Map.foldr accum2 [] scriptWitMap
+        where
+          accum2 script bad = if validateScript @era script tx then bad else script : bad
+  null failedScripts2 ?! ScriptsDidNotValidate failedScripts2
+
+
   let utxo = _utxo u'
       sphs :: [(ScriptPurpose (Crypto era), ScriptHash (Crypto era))]
       sphs = scriptsNeeded utxo tx
diff --git a/alonzo/impl/src/Cardano/Ledger/Alonzo/Tx.hs b/alonzo/impl/src/Cardano/Ledger/Alonzo/Tx.hs
index 90633140e3e..873d70ff754 100644
--- a/alonzo/impl/src/Cardano/Ledger/Alonzo/Tx.hs
+++ b/alonzo/impl/src/Cardano/Ledger/Alonzo/Tx.hs
@@ -475,24 +475,22 @@ instance (Typeable c, CC.Crypto c) => FromCBOR (ScriptPurpose c) where
 -- =======================================
 
 class Indexable elem container where
-  indexOf :: elem -> container -> Word64
-  atIndex :: Word64 -> container -> elem
+  indexOf :: elem -> container -> StrictMaybe Word64
 
 instance Ord k => Indexable k (Set k) where
-  indexOf n set = fromIntegral $ Set.findIndex n set
-  atIndex i set = Set.elemAt (fromIntegral i) set
+  indexOf n set = case Set.lookupIndex n set of
+    Just x -> SJust (fromIntegral x)
+    Nothing -> SNothing
 
 instance Eq k => Indexable k (StrictSeq k) where
   indexOf n seqx = case StrictSeq.findIndexL (== n) seqx of
-    Just m -> fromIntegral m
-    Nothing -> error "Not found in StrictSeq"
-  atIndex i seqx = case StrictSeq.lookup (fromIntegral i) seqx of
-    Just element -> element
-    Nothing -> error ("No elem at index " ++ show i)
+    Just m -> SJust (fromIntegral m)
+    Nothing -> SNothing
 
 instance Ord k => Indexable k (Map.Map k v) where
-  indexOf n mp = fromIntegral $ Map.findIndex n mp
-  atIndex i mp = fst (Map.elemAt (fromIntegral i) mp) -- If one needs the value, on can use Map.Lookup
+  indexOf n mp = case Map.lookupIndex n mp of
+    Just x -> SJust (fromIntegral x)
+    Nothing -> SNothing
 
 rdptr ::
   forall era.
@@ -503,11 +501,11 @@ rdptr ::
   ) =>
   Core.TxBody era ->
   ScriptPurpose (Crypto era) ->
-  RdmrPtr
-rdptr txb (Minting (PolicyID hash)) = RdmrPtr Mint (indexOf hash ((getField @"minted" txb) :: Set (ScriptHash (Crypto era))))
-rdptr txb (Spending txin) = RdmrPtr Spend (indexOf txin (getField @"inputs" txb))
-rdptr txb (Rewarding racnt) = RdmrPtr Rewrd (indexOf racnt (unWdrl (getField @"wdrls" txb)))
-rdptr txb (Certifying d) = RdmrPtr Cert (indexOf d (getField @"certs" txb))
+  StrictMaybe RdmrPtr
+rdptr txb (Minting (PolicyID hash)) = RdmrPtr Mint <$> (indexOf hash ((getField @"minted" txb) :: Set (ScriptHash (Crypto era))))
+rdptr txb (Spending txin) = RdmrPtr Spend <$> (indexOf txin (getField @"inputs" txb))
+rdptr txb (Rewarding racnt) = RdmrPtr Rewrd <$> (indexOf racnt (unWdrl (getField @"wdrls" txb)))
+rdptr txb (Certifying d) = RdmrPtr Cert <$> (indexOf d (getField @"certs" txb))
 
 getMapFromValue :: Value crypto -> Map.Map (PolicyID crypto) (Map.Map AssetName Integer)
 getMapFromValue (Value _ m) = m
@@ -523,10 +521,11 @@ indexedRdmrs ::
   Tx era ->
   ScriptPurpose (Crypto era) ->
   Maybe (Data era, ExUnits)
-indexedRdmrs tx sp = Map.lookup rdptr' rdmrs
-  where
-    rdmrs = unRedeemers $ txrdmrs' . getField @"wits" $ tx
-    rdptr' = rdptr @era (getField @"body" tx) sp
+indexedRdmrs tx sp = case rdptr @era (getField @"body" tx) sp of
+  SNothing -> Nothing
+  SJust policyid -> Map.lookup policyid rdmrs
+    where
+      rdmrs = unRedeemers $ txrdmrs' . getField @"wits" $ tx
 
 -- =======================================================
 
diff --git a/alonzo/impl/src/Cardano/Ledger/Alonzo/TxBody.hs b/alonzo/impl/src/Cardano/Ledger/Alonzo/TxBody.hs
index 0d7db6ce4e3..4001922af12 100644
--- a/alonzo/impl/src/Cardano/Ledger/Alonzo/TxBody.hs
+++ b/alonzo/impl/src/Cardano/Ledger/Alonzo/TxBody.hs
@@ -136,12 +136,12 @@ deriving stock instance
   ) =>
   Eq (TxOut era)
 
-instance
-  ( Show (Core.Value era)
+deriving instance
+  ( Show (CompactAddr (Crypto era)),
+    Show (Core.Value era),
+    Show (CompactForm (Core.Value era))
   ) =>
   Show (TxOut era)
-  where
-  show = error "Not yet implemented"
 
 deriving via InspectHeapNamed "TxOut" (TxOut era) instance NoThunks (TxOut era)
 
@@ -205,7 +205,11 @@ instance
   NoThunks (TxBodyRaw era)
 
 deriving instance
-  (Era era, Show (Core.Value era), Show (PParamsDelta era)) =>
+  ( Era era,
+    Show (Core.Value era),
+    Show (PParamsDelta era),
+    Show (CompactAddr (Crypto era))
+  ) =>
   Show (TxBodyRaw era)
 
 newtype TxBody era = TxBodyConstr (MemoBytes (TxBodyRaw era))
@@ -231,7 +235,8 @@ deriving instance
   ( Era era,
     Compactible (Core.Value era),
     Show (Core.Value era),
-    Show (PParamsDelta era)
+    Show (PParamsDelta era),
+    Show (CompactAddr (Crypto era))
   ) =>
   Show (TxBody era)
 
@@ -475,7 +480,7 @@ encodeTxBodyRaw
 
       fromSJust :: StrictMaybe a -> a
       fromSJust (SJust x) = x
-      fromSJust SNothing = error "SNothing in fromSJust"
+      fromSJust SNothing = error "SNothing in fromSJust. This should never happen, it is guarded by isSNothing"
 
 instance
   forall era.
diff --git a/alonzo/impl/test/lib/Test/Cardano/Ledger/Alonzo/Serialisation/Generators.hs b/alonzo/impl/test/lib/Test/Cardano/Ledger/Alonzo/Serialisation/Generators.hs
index 52cf93f832e..5cfa76c4778 100644
--- a/alonzo/impl/test/lib/Test/Cardano/Ledger/Alonzo/Serialisation/Generators.hs
+++ b/alonzo/impl/test/lib/Test/Cardano/Ledger/Alonzo/Serialisation/Generators.hs
@@ -41,6 +41,7 @@ import Cardano.Ledger.Shelley.Constraints (UsesScript, UsesValue)
 import Data.Maybe (mapMaybe)
 import qualified Data.Set as Set
 import qualified Language.PlutusTx as Plutus
+import Shelley.Spec.Ledger.CompactAddr (CompactAddr)
 import Test.Cardano.Ledger.ShelleyMA.Serialisation.Generators (genMintValues)
 import Test.QuickCheck
 import Test.Shelley.Spec.Ledger.ConcreteCryptoTypes (Mock)
@@ -231,7 +232,7 @@ instance Mock c => Arbitrary (UtxosPredicateFailure (AlonzoEra c)) where
         UpdateFailure <$> arbitrary
       ]
 
-instance Mock c => Arbitrary (UtxoPredicateFailure (AlonzoEra c)) where
+instance (Show (CompactAddr c), Mock c) => Arbitrary (UtxoPredicateFailure (AlonzoEra c)) where
   arbitrary =
     oneof
       [ (BadInputsUTxO) <$> arbitrary,
@@ -253,7 +254,7 @@ instance Mock c => Arbitrary (UtxoPredicateFailure (AlonzoEra c)) where
         FeeContainsNonADA <$> arbitrary
       ]
 
-instance Mock c => Arbitrary (AlonzoPredFail (AlonzoEra c)) where
+instance (Show (CompactAddr c), Mock c) => Arbitrary (AlonzoPredFail (AlonzoEra c)) where
   arbitrary =
     oneof
       [ WrappedShelleyEraFailure <$> arbitrary,
diff --git a/alonzo/impl/test/test/Test/Cardano/Ledger/Alonzo/Serialisation/Tripping.hs b/alonzo/impl/test/test/Test/Cardano/Ledger/Alonzo/Serialisation/Tripping.hs
index 7656c39fad6..e7d6cf7db92 100644
--- a/alonzo/impl/test/test/Test/Cardano/Ledger/Alonzo/Serialisation/Tripping.hs
+++ b/alonzo/impl/test/test/Test/Cardano/Ledger/Alonzo/Serialisation/Tripping.hs
@@ -65,7 +65,7 @@ tripping :: (Eq src, Show src, ToCBOR src, FromCBOR src) => src -> Property
 tripping x = trippingF roundTrip x
 
 -- ==========================
--- Catch errors in toolong bytestrings
+-- Catch violations ofbytestrings that are toolong.
 
 toolong :: BS.ByteString
 toolong = "1234567890-=`~@#$%^&*()_+qwertyuiopQWERTYUIOPasdfghjklASDFGHJKLzxcvbnmZXCVBNM"
diff --git a/shelley/chain-and-ledger/executable-spec/src/Shelley/Spec/Ledger/API/Mempool.hs b/shelley/chain-and-ledger/executable-spec/src/Shelley/Spec/Ledger/API/Mempool.hs
index a69e697e91d..c2c5d3236e3 100644
--- a/shelley/chain-and-ledger/executable-spec/src/Shelley/Spec/Ledger/API/Mempool.hs
+++ b/shelley/chain-and-ledger/executable-spec/src/Shelley/Spec/Ledger/API/Mempool.hs
@@ -51,12 +51,11 @@ import Shelley.Spec.Ledger.PParams (PParams' (..))
 import Shelley.Spec.Ledger.STS.Ledgers (LedgersEnv, LedgersPredicateFailure)
 import qualified Shelley.Spec.Ledger.STS.Ledgers as Ledgers
 import Shelley.Spec.Ledger.Slot (SlotNo)
-import Shelley.Spec.Ledger.Tx (Tx)
 
 -- TODO #1304: add reapplyTxs
 class
-  ( ChainData (Tx era),
-    AnnotatedData (Tx era),
+  ( ChainData (Core.Tx era),
+    AnnotatedData (Core.Tx era),
     Eq (ApplyTxError era),
     Show (ApplyTxError era),
     Typeable (ApplyTxError era),
@@ -65,7 +64,7 @@ class
     BaseM (Core.EraRule "LEDGERS" era) ~ ShelleyBase,
     Environment (Core.EraRule "LEDGERS" era) ~ LedgersEnv era,
     State (Core.EraRule "LEDGERS" era) ~ MempoolState era,
-    Signal (Core.EraRule "LEDGERS" era) ~ Seq (Tx era),
+    Signal (Core.EraRule "LEDGERS" era) ~ Seq (Core.Tx era),
     PredicateFailure (Core.EraRule "LEDGERS" era) ~ LedgersPredicateFailure era
   ) =>
   ApplyTx era
@@ -74,14 +73,14 @@ class
     MonadError (ApplyTxError era) m =>
     Globals ->
     SlotNo ->
-    Seq (Tx era) ->
+    Seq (Core.Tx era) ->
     NewEpochState era ->
     m (NewEpochState era)
   default applyTxs ::
     (MonadError (ApplyTxError era) m) =>
     Globals ->
     SlotNo ->
-    Seq (Tx era) ->
+    Seq (Core.Tx era) ->
     NewEpochState era ->
     m (NewEpochState era)
   applyTxs globals slot txs state =
@@ -164,13 +163,13 @@ applyTxsTransition ::
     BaseM (Core.EraRule "LEDGERS" era) ~ ShelleyBase,
     Environment (Core.EraRule "LEDGERS" era) ~ LedgersEnv era,
     State (Core.EraRule "LEDGERS" era) ~ MempoolState era,
-    Signal (Core.EraRule "LEDGERS" era) ~ Seq (Tx era),
+    Signal (Core.EraRule "LEDGERS" era) ~ Seq (Core.Tx era),
     PredicateFailure (Core.EraRule "LEDGERS" era) ~ LedgersPredicateFailure era,
     MonadError (ApplyTxError era) m
   ) =>
   Globals ->
   MempoolEnv era ->
-  Seq (Tx era) ->
+  Seq (Core.Tx era) ->
   MempoolState era ->
   m (MempoolState era)
 applyTxsTransition globals env txs state =