From 61f2f2ad9e0635807bf80e8fb108ec2281277379 Mon Sep 17 00:00:00 2001
From: Jonathan Knowles <jonathan.knowles@iohk.io>
Date: Wed, 23 Feb 2022 05:11:15 +0000
Subject: [PATCH 1/4] Rename type parameter `u` to `s` in type `UTxOSelection`.

We eventually intend to use `u` as a type parameter that represents
unique UTxO identifiers.

So using `s` as a type parameter to represent a type of selection makes
sense here.
---
 .../Wallet/Primitive/Types/UTxOSelection.hs   | 66 +++++++++----------
 1 file changed, 33 insertions(+), 33 deletions(-)

diff --git a/lib/core/src/Cardano/Wallet/Primitive/Types/UTxOSelection.hs b/lib/core/src/Cardano/Wallet/Primitive/Types/UTxOSelection.hs
index 4ae7532b4c8..022470645ee 100644
--- a/lib/core/src/Cardano/Wallet/Primitive/Types/UTxOSelection.hs
+++ b/lib/core/src/Cardano/Wallet/Primitive/Types/UTxOSelection.hs
@@ -120,21 +120,21 @@ import qualified Data.Map.Strict as Map
 -- Classes
 --------------------------------------------------------------------------------
 
-class HasUTxOSelectionState u where
+class HasUTxOSelectionState s where
 
     -- | Retrieves the internal state from a selection.
-    state :: u -> State
+    state :: s -> State
 
     -- | Reconstructs a selection from an internal state.
-    fromState :: State -> u
+    fromState :: State -> s
 
-class HasUTxOSelectionState u => IsUTxOSelection u where
+class HasUTxOSelectionState s => IsUTxOSelection s where
 
     -- | The type of the list of selected UTxOs.
-    type SelectedList u
+    type SelectedList s
 
     -- | Retrieves a list of the selected UTxOs.
-    selectedList :: u -> SelectedList u
+    selectedList :: s -> SelectedList s
 
 --------------------------------------------------------------------------------
 -- Types
@@ -229,7 +229,7 @@ fromIndexPair (leftover, selected) =
 -- The 1st index in the pair represents the leftover set.
 -- The 2nd index in the pair represents the selected set.
 --
-toIndexPair :: IsUTxOSelection u => u -> (UTxOIndex InputId, UTxOIndex InputId)
+toIndexPair :: IsUTxOSelection s => s -> (UTxOIndex InputId, UTxOIndex InputId)
 toIndexPair s = (leftoverIndex s, selectedIndex s)
 
 --------------------------------------------------------------------------------
@@ -245,7 +245,7 @@ fromNonEmpty = UTxOSelection . state
 --
 -- Returns 'Nothing' if the the selected set is empty.
 --
-toNonEmpty :: IsUTxOSelection u => u -> Maybe UTxOSelectionNonEmpty
+toNonEmpty :: IsUTxOSelection s => s -> Maybe UTxOSelectionNonEmpty
 toNonEmpty s = bool Nothing (Just $ fromState $ state s) (isNonEmpty s)
 
 --------------------------------------------------------------------------------
@@ -254,12 +254,12 @@ toNonEmpty s = bool Nothing (Just $ fromState $ state s) (isNonEmpty s)
 
 -- | Returns 'True' if and only if the selected set is empty.
 --
-isEmpty :: IsUTxOSelection u => u -> Bool
+isEmpty :: IsUTxOSelection s => s -> Bool
 isEmpty = (== 0) . selectedSize
 
 -- | Returns 'True' if and only if the selected set is non-empty.
 --
-isNonEmpty :: IsUTxOSelection u => u -> Bool
+isNonEmpty :: IsUTxOSelection s => s -> Bool
 isNonEmpty = not . isEmpty
 
 -- | Returns 'True' if the given 'InputId' is a member of either set.
@@ -286,12 +286,12 @@ isSelected i = UTxOIndex.member i . selectedIndex
 -- of the 'select' function.
 --
 isSubSelectionOf
-    :: IsUTxOSelection u1 => IsUTxOSelection u2 => u1 -> u2 -> Bool
-isSubSelectionOf u1 u2 = state (selectMany toSelect u1) == state u2
+    :: IsUTxOSelection s1 => IsUTxOSelection s2 => s1 -> s2 -> Bool
+isSubSelectionOf s1 s2 = state (selectMany toSelect s1) == state s2
   where
     toSelect :: [InputId]
     toSelect = fst <$> Map.toList
-        (selectedUTxO u2 `Map.difference` selectedUTxO u1)
+        (selectedUTxO s2 `Map.difference` selectedUTxO s1)
 
 -- | Returns 'True' iff. the first selection is a proper sub-selection of the
 --   second.
@@ -301,8 +301,8 @@ isSubSelectionOf u1 u2 = state (selectMany toSelect u1) == state u2
 -- applications of the 'select' function.
 --
 isProperSubSelectionOf
-    :: IsUTxOSelection u1 => IsUTxOSelection u2 => u1 -> u2 -> Bool
-isProperSubSelectionOf u1 u2 = state u1 /= state u2 && u1 `isSubSelectionOf` u2
+    :: IsUTxOSelection s1 => IsUTxOSelection s2 => s1 -> s2 -> Bool
+isProperSubSelectionOf s1 s2 = state s1 /= state s2 && s1 `isSubSelectionOf` s2
 
 --------------------------------------------------------------------------------
 -- Accessor functions
@@ -318,10 +318,10 @@ isProperSubSelectionOf u1 u2 = state u1 /= state u2 && u1 `isSubSelectionOf` u2
 -- This result of this function remains constant over applications of 'select'
 -- and 'selectMany':
 --
--- >>> availableBalance u == availableBalance (selectMany is u)
+-- >>> availableBalance s == availableBalance (selectMany is s)
 --
-availableBalance :: IsUTxOSelection u => u -> TokenBundle
-availableBalance u = leftoverBalance u <> selectedBalance u
+availableBalance :: IsUTxOSelection s => s -> TokenBundle
+availableBalance s = leftoverBalance s <> selectedBalance s
 
 -- | Computes the available UTxO set.
 --
@@ -332,54 +332,54 @@ availableBalance u = leftoverBalance u <> selectedBalance u
 -- This result of this function remains constant over applications of 'select'
 -- and 'selectMany':
 --
--- >>> availableUTxO u == availableUTxO (selectMany is u)
+-- >>> availableUTxO s == availableUTxO (selectMany is s)
 --
-availableUTxO :: IsUTxOSelection u => u -> Map InputId TokenBundle
-availableUTxO u = leftoverUTxO u <> selectedUTxO u
+availableUTxO :: IsUTxOSelection s => s -> Map InputId TokenBundle
+availableUTxO s = leftoverUTxO s <> selectedUTxO s
 
 -- | Retrieves the balance of leftover UTxOs.
 --
-leftoverBalance :: IsUTxOSelection u => u -> TokenBundle
+leftoverBalance :: IsUTxOSelection s => s -> TokenBundle
 leftoverBalance = UTxOIndex.balance . leftoverIndex
 
 -- | Retrieves the size of the leftover UTxO set.
 --
-leftoverSize :: IsUTxOSelection u => u -> Int
+leftoverSize :: IsUTxOSelection s => s -> Int
 leftoverSize = UTxOIndex.size . leftoverIndex
 
 -- | Retrieves an index of the leftover UTxOs.
 --
-leftoverIndex :: IsUTxOSelection u => u -> UTxOIndex InputId
+leftoverIndex :: IsUTxOSelection s => s -> UTxOIndex InputId
 leftoverIndex = leftover . state
 
 -- | Retrieves the leftover UTxO set.
 --
-leftoverUTxO :: IsUTxOSelection u => u -> Map InputId TokenBundle
+leftoverUTxO :: IsUTxOSelection s => s -> Map InputId TokenBundle
 leftoverUTxO = UTxOIndex.toMap . leftoverIndex
 
 -- | Retrieves a list of the leftover UTxOs.
 --
-leftoverList :: IsUTxOSelection u => u -> [(InputId, TokenBundle)]
+leftoverList :: IsUTxOSelection s => s -> [(InputId, TokenBundle)]
 leftoverList = UTxOIndex.toList . leftoverIndex
 
 -- | Retrieves the balance of selected UTxOs.
 --
-selectedBalance :: IsUTxOSelection u => u -> TokenBundle
+selectedBalance :: IsUTxOSelection s => s -> TokenBundle
 selectedBalance = UTxOIndex.balance . selectedIndex
 
 -- | Retrieves the size of the selected UTxO set.
 --
-selectedSize :: IsUTxOSelection u => u -> Int
+selectedSize :: IsUTxOSelection s => s -> Int
 selectedSize = UTxOIndex.size . selectedIndex
 
 -- | Retrieves an index of the selected UTxOs.
 --
-selectedIndex :: IsUTxOSelection u => u -> UTxOIndex InputId
+selectedIndex :: IsUTxOSelection s => s -> UTxOIndex InputId
 selectedIndex = selected . state
 
 -- | Retrieves the selected UTxO set.
 --
-selectedUTxO :: IsUTxOSelection u => u -> Map InputId TokenBundle
+selectedUTxO :: IsUTxOSelection s => s -> Map InputId TokenBundle
 selectedUTxO = UTxOIndex.toMap . selectedIndex
 
 --------------------------------------------------------------------------------
@@ -390,12 +390,12 @@ selectedUTxO = UTxOIndex.toMap . selectedIndex
 --
 -- Returns 'Nothing' if the given entry is not a member of the leftover set.
 --
-select :: IsUTxOSelection u => InputId -> u -> Maybe UTxOSelectionNonEmpty
+select :: IsUTxOSelection s => InputId -> s -> Maybe UTxOSelectionNonEmpty
 select = (toNonEmpty <=<) . withState . selectState
 
 -- | Moves multiple entries from the leftover set to the selected set.
 --
-selectMany :: IsUTxOSelection u => Foldable f => f InputId -> u -> u
+selectMany :: IsUTxOSelection s => Foldable f => f InputId -> s -> s
 selectMany = ap fromMaybe . withState . flip (F.foldrM selectState)
 
 --------------------------------------------------------------------------------
@@ -414,5 +414,5 @@ selectState i s =
 
 -- | Applies the given function to the internal state.
 --
-withState :: Functor f => IsUTxOSelection u => (State -> f State) -> u -> f u
+withState :: Functor f => IsUTxOSelection s => (State -> f State) -> s -> f s
 withState f = fmap fromState . f . state

From e710b84956b9ef39195bc026d64ae007c38298c7 Mon Sep 17 00:00:00 2001
From: Jonathan Knowles <jonathan.knowles@iohk.io>
Date: Thu, 24 Feb 2022 01:09:02 +0000
Subject: [PATCH 2/4] Parameterize UTxO unique identifier type in
 `UTxOSelection`.

---
 lib/core/src/Cardano/Wallet.hs                |   2 +-
 lib/core/src/Cardano/Wallet/CoinSelection.hs  |   2 +-
 .../Cardano/Wallet/CoinSelection/Internal.hs  |   4 +-
 .../Wallet/CoinSelection/Internal/Balance.hs  |  61 ++++----
 .../Wallet/Primitive/Types/UTxOSelection.hs   | 132 ++++++++++--------
 .../Primitive/Types/UTxOSelection/Gen.hs      |  10 +-
 .../CoinSelection/Internal/BalanceSpec.hs     |  20 +--
 .../Wallet/CoinSelection/InternalSpec.hs      |   4 +-
 .../Primitive/Types/UTxOSelectionSpec.hs      |  56 ++++----
 9 files changed, 163 insertions(+), 128 deletions(-)

diff --git a/lib/core/src/Cardano/Wallet.hs b/lib/core/src/Cardano/Wallet.hs
index 82cfdca23ef..4997dfd1867 100644
--- a/lib/core/src/Cardano/Wallet.hs
+++ b/lib/core/src/Cardano/Wallet.hs
@@ -1913,7 +1913,7 @@ data SelectAssetsParams s result = SelectAssetsParams
     , randomSeed :: Maybe StdGenSeed
     , txContext :: TransactionCtx
     , utxoAvailableForCollateral :: Map InputId TokenBundle
-    , utxoAvailableForInputs :: UTxOSelection
+    , utxoAvailableForInputs :: UTxOSelection InputId
     , wallet :: Wallet s
     }
     deriving Generic
diff --git a/lib/core/src/Cardano/Wallet/CoinSelection.hs b/lib/core/src/Cardano/Wallet/CoinSelection.hs
index 29870b7ecb5..dd2644c7841 100644
--- a/lib/core/src/Cardano/Wallet/CoinSelection.hs
+++ b/lib/core/src/Cardano/Wallet/CoinSelection.hs
@@ -225,7 +225,7 @@ data SelectionParams = SelectionParams
         -- This set is allowed to intersect with 'utxoAvailableForInputs',
         -- since the ledger does not require that these sets are disjoint.
     , utxoAvailableForInputs
-        :: !UTxOSelection
+        :: !(UTxOSelection InputId)
         -- ^ Specifies a set of UTxOs that are available for selection as
         -- ordinary inputs and optionally, a subset that has already been
         -- selected.
diff --git a/lib/core/src/Cardano/Wallet/CoinSelection/Internal.hs b/lib/core/src/Cardano/Wallet/CoinSelection/Internal.hs
index 4534b4e2c6b..d71317140b8 100644
--- a/lib/core/src/Cardano/Wallet/CoinSelection/Internal.hs
+++ b/lib/core/src/Cardano/Wallet/CoinSelection/Internal.hs
@@ -215,7 +215,7 @@ data SelectionParams = SelectionParams
         -- This set is allowed to intersect with 'utxoAvailableForInputs',
         -- since the ledger does not require that these sets are disjoint.
     , utxoAvailableForInputs
-        :: !UTxOSelection
+        :: !(UTxOSelection InputId)
         -- ^ Specifies a set of UTxOs that are available for selection as
         -- ordinary inputs and optionally, a subset that has already been
         -- selected.
@@ -879,7 +879,7 @@ verifyBalanceInsufficientError cs ps e =
 --------------------------------------------------------------------------------
 
 newtype FailureToVerifyEmptyUTxOError = FailureToVerifyEmptyUTxOError
-    { utxoAvailableForInputs :: UTxOSelection }
+    { utxoAvailableForInputs :: UTxOSelection InputId }
     deriving (Eq, Show)
 
 verifyEmptyUTxOError :: VerifySelectionError ()
diff --git a/lib/core/src/Cardano/Wallet/CoinSelection/Internal/Balance.hs b/lib/core/src/Cardano/Wallet/CoinSelection/Internal/Balance.hs
index e89b7eb95e2..f7e46e068fc 100644
--- a/lib/core/src/Cardano/Wallet/CoinSelection/Internal/Balance.hs
+++ b/lib/core/src/Cardano/Wallet/CoinSelection/Internal/Balance.hs
@@ -247,7 +247,7 @@ data SelectionParamsOf outputs = SelectionParams
         :: !outputs
         -- ^ The complete set of outputs to be covered.
     , utxoAvailable
-        :: !UTxOSelection
+        :: !(UTxOSelection InputId)
         -- ^ Specifies a set of UTxOs that are available for selection as
         -- inputs and optionally, a subset that has already been selected.
         --
@@ -436,7 +436,11 @@ instance Ord a => Ord (SelectionLimitOf a) where
 
 -- | Indicates whether or not the given selection limit has been exceeded.
 --
-selectionLimitExceeded :: IsUTxOSelection s => s -> SelectionLimit -> Bool
+selectionLimitExceeded
+    :: IsUTxOSelection s InputId
+    => s InputId
+    -> SelectionLimit
+    -> Bool
 selectionLimitExceeded s = \case
     NoLimit -> False
     MaximumInputLimit n -> UTxOSelection.selectedSize s > n
@@ -946,7 +950,7 @@ performSelectionNonEmpty constraints params
     --     assets of the final resulting selection).
     --
     predictChange
-        :: UTxOSelectionNonEmpty
+        :: UTxOSelectionNonEmpty InputId
         -> [Set AssetId]
     predictChange s = either
         (const $ invariantResultWithNoCost $ UTxOSelection.selectedIndex s)
@@ -988,7 +992,7 @@ performSelectionNonEmpty constraints params
     -- function won't make associated outputs for them.
     --
     makeChangeRepeatedly
-        :: UTxOSelectionNonEmpty
+        :: UTxOSelectionNonEmpty InputId
         -> m
             ( Either
                 SelectionBalanceError
@@ -1092,7 +1096,7 @@ performSelectionNonEmpty constraints params
 data RunSelectionParams = RunSelectionParams
     { selectionLimit :: SelectionLimit
         -- ^ A limit to adhere to when performing a selection.
-    , utxoAvailable :: UTxOSelection
+    , utxoAvailable :: (UTxOSelection InputId)
         -- ^ UTxO entries available for selection.
     , minimumBalance :: TokenBundle
         -- ^ Minimum balance to cover.
@@ -1100,23 +1104,27 @@ data RunSelectionParams = RunSelectionParams
     deriving (Eq, Generic, Show)
 
 runSelectionNonEmpty
-    :: MonadRandom m => RunSelectionParams -> m (Maybe UTxOSelectionNonEmpty)
+    :: MonadRandom m
+    => RunSelectionParams
+    -> m (Maybe (UTxOSelectionNonEmpty InputId))
 runSelectionNonEmpty = (=<<)
     <$> runSelectionNonEmptyWith . selectCoinQuantity . view #selectionLimit
     <*> runSelection
 
 runSelectionNonEmptyWith
     :: Monad m
-    => (UTxOSelection -> m (Maybe UTxOSelectionNonEmpty))
-    -> UTxOSelection
-    -> m (Maybe UTxOSelectionNonEmpty)
+    => (UTxOSelection InputId -> m (Maybe (UTxOSelectionNonEmpty InputId)))
+    -> UTxOSelection InputId
+    -> m (Maybe (UTxOSelectionNonEmpty InputId))
 runSelectionNonEmptyWith selectSingleEntry result =
     UTxOSelection.toNonEmpty result & maybe
         (result & selectSingleEntry)
         (pure . Just)
 
 runSelection
-    :: forall m. MonadRandom m => RunSelectionParams -> m UTxOSelection
+    :: forall m. MonadRandom m
+    => RunSelectionParams
+    -> m (UTxOSelection InputId)
 runSelection params =
     runRoundRobinM utxoAvailable UTxOSelection.fromNonEmpty selectors
   where
@@ -1130,7 +1138,8 @@ runSelection params =
     -- necessarily has a non-zero ada amount. By running the other selectors
     -- first, we increase the probability that the coin selector will be able
     -- to terminate without needing to select an additional coin.
-    selectors :: [UTxOSelection -> m (Maybe UTxOSelectionNonEmpty)]
+    selectors
+        :: [UTxOSelection InputId -> m (Maybe (UTxOSelectionNonEmpty InputId))]
     selectors =
         reverse (coinSelector : fmap assetSelector minimumAssetQuantities)
       where
@@ -1146,7 +1155,7 @@ assetSelectionLens
     :: MonadRandom m
     => SelectionLimit
     -> (AssetId, TokenQuantity)
-    -> SelectionLens m UTxOSelection UTxOSelectionNonEmpty
+    -> SelectionLens m (UTxOSelection InputId) (UTxOSelectionNonEmpty InputId)
 assetSelectionLens limit (asset, minimumAssetQuantity) = SelectionLens
     { currentQuantity = selectedAssetQuantity asset
     , updatedQuantity = selectedAssetQuantity asset
@@ -1159,7 +1168,7 @@ coinSelectionLens
     => SelectionLimit
     -> Coin
     -- ^ Minimum coin quantity.
-    -> SelectionLens m UTxOSelection UTxOSelectionNonEmpty
+    -> SelectionLens m (UTxOSelection InputId) (UTxOSelectionNonEmpty InputId)
 coinSelectionLens limit minimumCoinQuantity = SelectionLens
     { currentQuantity = selectedCoinQuantity
     , updatedQuantity = selectedCoinQuantity
@@ -1171,11 +1180,11 @@ coinSelectionLens limit minimumCoinQuantity = SelectionLens
 --
 selectAssetQuantity
     :: MonadRandom m
-    => IsUTxOSelection utxoSelection
+    => IsUTxOSelection utxoSelection InputId
     => AssetId
     -> SelectionLimit
-    -> utxoSelection
-    -> m (Maybe UTxOSelectionNonEmpty)
+    -> utxoSelection InputId
+    -> m (Maybe (UTxOSelectionNonEmpty InputId))
 selectAssetQuantity asset =
     selectMatchingQuantity (WithAssetOnly asset :| [WithAsset asset])
 
@@ -1183,10 +1192,10 @@ selectAssetQuantity asset =
 --
 selectCoinQuantity
     :: MonadRandom m
-    => IsUTxOSelection utxoSelection
+    => IsUTxOSelection utxoSelection InputId
     => SelectionLimit
-    -> utxoSelection
-    -> m (Maybe UTxOSelectionNonEmpty)
+    -> utxoSelection InputId
+    -> m (Maybe (UTxOSelectionNonEmpty InputId))
 selectCoinQuantity =
     selectMatchingQuantity (WithAdaOnly :| [Any])
 
@@ -1208,15 +1217,15 @@ selectCoinQuantity =
 --
 selectMatchingQuantity
     :: MonadRandom m
-    => IsUTxOSelection utxoSelection
+    => IsUTxOSelection utxoSelection InputId
     => NonEmpty SelectionFilter
         -- ^ A list of selection filters to be traversed from left-to-right,
         -- in descending order of priority.
     -> SelectionLimit
         -- ^ A limit to adhere to when selecting entries.
-    -> utxoSelection
+    -> utxoSelection InputId
         -- ^ The current selection state.
-    -> m (Maybe UTxOSelectionNonEmpty)
+    -> m (Maybe (UTxOSelectionNonEmpty InputId))
         -- ^ An updated selection state that includes a matching UTxO entry,
         -- or 'Nothing' if no such entry could be found.
 selectMatchingQuantity filters limit s
@@ -1232,7 +1241,7 @@ selectMatchingQuantity filters limit s
 
     updateState
         :: ((InputId, TokenBundle), UTxOIndex InputId)
-        -> Maybe UTxOSelectionNonEmpty
+        -> Maybe (UTxOSelectionNonEmpty InputId)
     updateState ((i, _b), _remaining) = UTxOSelection.select i s
 
 --------------------------------------------------------------------------------
@@ -2141,13 +2150,15 @@ runRoundRobinM state demote processors = go state processors []
 -- Accessor functions
 --------------------------------------------------------------------------------
 
-selectedAssetQuantity :: IsUTxOSelection s => AssetId -> s -> Natural
+selectedAssetQuantity
+    :: IsUTxOSelection s InputId => AssetId -> s InputId -> Natural
 selectedAssetQuantity asset
     = unTokenQuantity
     . flip TokenBundle.getQuantity asset
     . UTxOSelection.selectedBalance
 
-selectedCoinQuantity :: IsUTxOSelection s => s -> Natural
+selectedCoinQuantity
+    :: IsUTxOSelection s InputId => s InputId -> Natural
 selectedCoinQuantity
     = intCast
     . unCoin
diff --git a/lib/core/src/Cardano/Wallet/Primitive/Types/UTxOSelection.hs b/lib/core/src/Cardano/Wallet/Primitive/Types/UTxOSelection.hs
index 022470645ee..abb6f2ca258 100644
--- a/lib/core/src/Cardano/Wallet/Primitive/Types/UTxOSelection.hs
+++ b/lib/core/src/Cardano/Wallet/Primitive/Types/UTxOSelection.hs
@@ -1,6 +1,9 @@
 {-# LANGUAGE DeriveGeneric #-}
 {-# LANGUAGE DuplicateRecordFields #-}
 {-# LANGUAGE ExplicitForAll #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE NamedFieldPuns #-}
 {-# LANGUAGE OverloadedLabels #-}
 {-# LANGUAGE TypeFamilies #-}
@@ -82,12 +85,8 @@ module Cardano.Wallet.Primitive.Types.UTxOSelection
 
 import Prelude
 
-import Cardano.Wallet.Primitive.Types.Address
-    ( Address )
 import Cardano.Wallet.Primitive.Types.TokenBundle
     ( TokenBundle )
-import Cardano.Wallet.Primitive.Types.Tx
-    ( TxIn )
 import Cardano.Wallet.Primitive.Types.UTxOIndex
     ( UTxOIndex )
 import Control.Monad
@@ -120,66 +119,60 @@ import qualified Data.Map.Strict as Map
 -- Classes
 --------------------------------------------------------------------------------
 
-class HasUTxOSelectionState s where
+class HasUTxOSelectionState s u where
 
     -- | Retrieves the internal state from a selection.
-    state :: s -> State
+    state :: s u -> State u
 
     -- | Reconstructs a selection from an internal state.
-    fromState :: State -> s
+    fromState :: State u -> s u
 
-class HasUTxOSelectionState s => IsUTxOSelection s where
+class HasUTxOSelectionState s u => IsUTxOSelection s u where
 
     -- | The type of the list of selected UTxOs.
-    type SelectedList s
+    type SelectedList s u
 
     -- | Retrieves a list of the selected UTxOs.
-    selectedList :: s -> SelectedList s
+    selectedList :: s u -> SelectedList s u
 
 --------------------------------------------------------------------------------
 -- Types
 --------------------------------------------------------------------------------
 
--- TODO: ADP-1448:
---
--- Replace this type synonym with a type parameter on types that use it.
---
-type InputId = (TxIn, Address)
-
 -- | The internal state of a selection.
 --
-data State = State
-    { leftover :: !(UTxOIndex InputId)
+data State u = State
+    { leftover :: !(UTxOIndex u)
       -- ^ UTxOs that have not yet been selected.
-    , selected :: !(UTxOIndex InputId)
+    , selected :: !(UTxOIndex u)
       -- ^ UTxOs that have already been selected.
     }
     deriving (Eq, Generic, Show)
 
 -- | A selection for which 'isNonEmpty' may be 'False'.
 --
-newtype UTxOSelection = UTxOSelection State
+newtype UTxOSelection u = UTxOSelection (State u)
     deriving (Eq, Generic, Show)
 
 -- | A selection for which 'isNonEmpty' must be 'True'.
 --
-newtype UTxOSelectionNonEmpty = UTxOSelectionNonEmpty State
+newtype UTxOSelectionNonEmpty u = UTxOSelectionNonEmpty (State u)
     deriving (Eq, Generic, Show)
 
-instance HasUTxOSelectionState UTxOSelection where
+instance HasUTxOSelectionState UTxOSelection u where
     state (UTxOSelection s) = s
     fromState s = UTxOSelection s
 
-instance HasUTxOSelectionState UTxOSelectionNonEmpty where
+instance HasUTxOSelectionState UTxOSelectionNonEmpty u where
     state (UTxOSelectionNonEmpty s) = s
     fromState s = UTxOSelectionNonEmpty s
 
-instance IsUTxOSelection UTxOSelection where
-    type SelectedList UTxOSelection = [(InputId, TokenBundle)]
+instance IsUTxOSelection UTxOSelection u where
+    type SelectedList UTxOSelection u = [(u, TokenBundle)]
     selectedList = UTxOIndex.toList . selectedIndex
 
-instance IsUTxOSelection UTxOSelectionNonEmpty where
-    type SelectedList UTxOSelectionNonEmpty = NonEmpty (InputId, TokenBundle)
+instance IsUTxOSelection UTxOSelectionNonEmpty u where
+    type SelectedList UTxOSelectionNonEmpty u = NonEmpty (u, TokenBundle)
     selectedList = NE.fromList . UTxOIndex.toList . selectedIndex
 
 --------------------------------------------------------------------------------
@@ -188,14 +181,14 @@ instance IsUTxOSelection UTxOSelectionNonEmpty where
 
 -- | A completely empty selection with no selected or leftover UTxOs.
 --
-empty :: UTxOSelection
+empty :: UTxOSelection u
 empty = fromIndex UTxOIndex.empty
 
 -- | Creates a selection where none of the UTxOs are selected.
 --
 -- All UTxOs in the index will be added to the leftover set.
 --
-fromIndex :: UTxOIndex InputId -> UTxOSelection
+fromIndex :: UTxOIndex u -> UTxOSelection u
 fromIndex i = UTxOSelection State
     { leftover = i
     , selected = UTxOIndex.empty
@@ -206,7 +199,7 @@ fromIndex i = UTxOSelection State
 -- All UTxOs that match the given filter will be added to the selected set,
 -- whereas all UTxOs that do not match will be added to the leftover set.
 --
-fromIndexFiltered :: (InputId -> Bool) -> UTxOIndex InputId -> UTxOSelection
+fromIndexFiltered :: Ord u => (u -> Bool) -> UTxOIndex u -> UTxOSelection u
 fromIndexFiltered f =
     UTxOSelection . uncurry State . swap . UTxOIndex.partition f
 
@@ -217,7 +210,7 @@ fromIndexFiltered f =
 --
 -- Any items that are in both sets are removed from the leftover set.
 --
-fromIndexPair :: (UTxOIndex InputId, UTxOIndex InputId) -> UTxOSelection
+fromIndexPair :: Ord u => (UTxOIndex u, UTxOIndex u) -> UTxOSelection u
 fromIndexPair (leftover, selected) =
     UTxOSelection State
         { leftover = leftover `UTxOIndex.difference` selected
@@ -229,7 +222,7 @@ fromIndexPair (leftover, selected) =
 -- The 1st index in the pair represents the leftover set.
 -- The 2nd index in the pair represents the selected set.
 --
-toIndexPair :: IsUTxOSelection s => s -> (UTxOIndex InputId, UTxOIndex InputId)
+toIndexPair :: IsUTxOSelection s u => s u -> (UTxOIndex u, UTxOIndex u)
 toIndexPair s = (leftoverIndex s, selectedIndex s)
 
 --------------------------------------------------------------------------------
@@ -238,14 +231,14 @@ toIndexPair s = (leftoverIndex s, selectedIndex s)
 
 -- | Demotes a non-empty selection to an ordinary selection.
 --
-fromNonEmpty :: UTxOSelectionNonEmpty -> UTxOSelection
+fromNonEmpty :: UTxOSelectionNonEmpty u -> UTxOSelection u
 fromNonEmpty = UTxOSelection . state
 
 -- | Promotes an ordinary selection to a non-empty selection.
 --
 -- Returns 'Nothing' if the the selected set is empty.
 --
-toNonEmpty :: IsUTxOSelection s => s -> Maybe UTxOSelectionNonEmpty
+toNonEmpty :: IsUTxOSelection s u => s u -> Maybe (UTxOSelectionNonEmpty u)
 toNonEmpty s = bool Nothing (Just $ fromState $ state s) (isNonEmpty s)
 
 --------------------------------------------------------------------------------
@@ -254,29 +247,29 @@ toNonEmpty s = bool Nothing (Just $ fromState $ state s) (isNonEmpty s)
 
 -- | Returns 'True' if and only if the selected set is empty.
 --
-isEmpty :: IsUTxOSelection s => s -> Bool
+isEmpty :: IsUTxOSelection s u => s u -> Bool
 isEmpty = (== 0) . selectedSize
 
 -- | Returns 'True' if and only if the selected set is non-empty.
 --
-isNonEmpty :: IsUTxOSelection s => s -> Bool
+isNonEmpty :: IsUTxOSelection s u => s u -> Bool
 isNonEmpty = not . isEmpty
 
 -- | Returns 'True' if the given 'InputId' is a member of either set.
 --
 -- Otherwise, returns 'False'.
 --
-isMember :: IsUTxOSelection s => InputId -> s -> Bool
+isMember :: IsUTxOSelection s u => Ord u => u -> s u -> Bool
 isMember i s = isLeftover i s || isSelected i s
 
 -- | Returns 'True' iff. the given 'InputId' is a member of the leftover set.
 --
-isLeftover :: IsUTxOSelection s => InputId -> s -> Bool
+isLeftover :: IsUTxOSelection s u => Ord u => u -> s u -> Bool
 isLeftover i = UTxOIndex.member i . leftoverIndex
 
 -- | Returns 'True' iff. the given 'InputId' is a member of the selected set.
 --
-isSelected :: IsUTxOSelection s => InputId -> s -> Bool
+isSelected :: IsUTxOSelection s u => Ord u => u -> s u -> Bool
 isSelected i = UTxOIndex.member i . selectedIndex
 
 -- | Returns 'True' iff. the first selection is a sub-selection of the second.
@@ -286,10 +279,14 @@ isSelected i = UTxOIndex.member i . selectedIndex
 -- of the 'select' function.
 --
 isSubSelectionOf
-    :: IsUTxOSelection s1 => IsUTxOSelection s2 => s1 -> s2 -> Bool
+    :: IsUTxOSelection s1 u
+    => IsUTxOSelection s2 u
+    => Ord u
+    => s1 u
+    -> s2 u
+    -> Bool
 isSubSelectionOf s1 s2 = state (selectMany toSelect s1) == state s2
   where
-    toSelect :: [InputId]
     toSelect = fst <$> Map.toList
         (selectedUTxO s2 `Map.difference` selectedUTxO s1)
 
@@ -301,7 +298,12 @@ isSubSelectionOf s1 s2 = state (selectMany toSelect s1) == state s2
 -- applications of the 'select' function.
 --
 isProperSubSelectionOf
-    :: IsUTxOSelection s1 => IsUTxOSelection s2 => s1 -> s2 -> Bool
+    :: IsUTxOSelection s1 u
+    => IsUTxOSelection s2 u
+    => Ord u
+    => s1 u
+    -> s2 u
+    -> Bool
 isProperSubSelectionOf s1 s2 = state s1 /= state s2 && s1 `isSubSelectionOf` s2
 
 --------------------------------------------------------------------------------
@@ -320,7 +322,7 @@ isProperSubSelectionOf s1 s2 = state s1 /= state s2 && s1 `isSubSelectionOf` s2
 --
 -- >>> availableBalance s == availableBalance (selectMany is s)
 --
-availableBalance :: IsUTxOSelection s => s -> TokenBundle
+availableBalance :: IsUTxOSelection s u => s u -> TokenBundle
 availableBalance s = leftoverBalance s <> selectedBalance s
 
 -- | Computes the available UTxO set.
@@ -334,52 +336,52 @@ availableBalance s = leftoverBalance s <> selectedBalance s
 --
 -- >>> availableUTxO s == availableUTxO (selectMany is s)
 --
-availableUTxO :: IsUTxOSelection s => s -> Map InputId TokenBundle
+availableUTxO :: IsUTxOSelection s u => Ord u => s u -> Map u TokenBundle
 availableUTxO s = leftoverUTxO s <> selectedUTxO s
 
 -- | Retrieves the balance of leftover UTxOs.
 --
-leftoverBalance :: IsUTxOSelection s => s -> TokenBundle
+leftoverBalance :: IsUTxOSelection s u => s u -> TokenBundle
 leftoverBalance = UTxOIndex.balance . leftoverIndex
 
 -- | Retrieves the size of the leftover UTxO set.
 --
-leftoverSize :: IsUTxOSelection s => s -> Int
+leftoverSize :: IsUTxOSelection s u => s u -> Int
 leftoverSize = UTxOIndex.size . leftoverIndex
 
 -- | Retrieves an index of the leftover UTxOs.
 --
-leftoverIndex :: IsUTxOSelection s => s -> UTxOIndex InputId
+leftoverIndex :: IsUTxOSelection s u => s u -> UTxOIndex u
 leftoverIndex = leftover . state
 
 -- | Retrieves the leftover UTxO set.
 --
-leftoverUTxO :: IsUTxOSelection s => s -> Map InputId TokenBundle
+leftoverUTxO :: IsUTxOSelection s u => s u -> Map u TokenBundle
 leftoverUTxO = UTxOIndex.toMap . leftoverIndex
 
 -- | Retrieves a list of the leftover UTxOs.
 --
-leftoverList :: IsUTxOSelection s => s -> [(InputId, TokenBundle)]
+leftoverList :: IsUTxOSelection s u => s u -> [(u, TokenBundle)]
 leftoverList = UTxOIndex.toList . leftoverIndex
 
 -- | Retrieves the balance of selected UTxOs.
 --
-selectedBalance :: IsUTxOSelection s => s -> TokenBundle
+selectedBalance :: IsUTxOSelection s u => s u -> TokenBundle
 selectedBalance = UTxOIndex.balance . selectedIndex
 
 -- | Retrieves the size of the selected UTxO set.
 --
-selectedSize :: IsUTxOSelection s => s -> Int
+selectedSize :: IsUTxOSelection s u => s u -> Int
 selectedSize = UTxOIndex.size . selectedIndex
 
 -- | Retrieves an index of the selected UTxOs.
 --
-selectedIndex :: IsUTxOSelection s => s -> UTxOIndex InputId
+selectedIndex :: IsUTxOSelection s u => s u -> UTxOIndex u
 selectedIndex = selected . state
 
 -- | Retrieves the selected UTxO set.
 --
-selectedUTxO :: IsUTxOSelection s => s -> Map InputId TokenBundle
+selectedUTxO :: IsUTxOSelection s u => s u -> Map u TokenBundle
 selectedUTxO = UTxOIndex.toMap . selectedIndex
 
 --------------------------------------------------------------------------------
@@ -390,12 +392,23 @@ selectedUTxO = UTxOIndex.toMap . selectedIndex
 --
 -- Returns 'Nothing' if the given entry is not a member of the leftover set.
 --
-select :: IsUTxOSelection s => InputId -> s -> Maybe UTxOSelectionNonEmpty
+select
+    :: IsUTxOSelection s u
+    => Ord u
+    => u
+    -> s u
+    -> Maybe (UTxOSelectionNonEmpty u)
 select = (toNonEmpty <=<) . withState . selectState
 
 -- | Moves multiple entries from the leftover set to the selected set.
 --
-selectMany :: IsUTxOSelection s => Foldable f => f InputId -> s -> s
+selectMany
+    :: IsUTxOSelection s u
+    => Ord u
+    => Foldable f
+    => f u
+    -> s u
+    -> s u
 selectMany = ap fromMaybe . withState . flip (F.foldrM selectState)
 
 --------------------------------------------------------------------------------
@@ -404,7 +417,7 @@ selectMany = ap fromMaybe . withState . flip (F.foldrM selectState)
 
 -- | Moves a single entry from the leftover set to the selected set.
 --
-selectState :: InputId -> State -> Maybe State
+selectState :: Ord u => u -> State u -> Maybe (State u)
 selectState i s =
     updateFields <$> UTxOIndex.lookup i (leftover s)
   where
@@ -414,5 +427,10 @@ selectState i s =
 
 -- | Applies the given function to the internal state.
 --
-withState :: Functor f => IsUTxOSelection s => (State -> f State) -> s -> f s
+withState
+    :: Functor f
+    => IsUTxOSelection s u
+    => (State u -> f (State u))
+    -> s u
+    -> f (s u)
 withState f = fmap fromState . f . state
diff --git a/lib/core/src/Cardano/Wallet/Primitive/Types/UTxOSelection/Gen.hs b/lib/core/src/Cardano/Wallet/Primitive/Types/UTxOSelection/Gen.hs
index edbd74198c6..4754dde2570 100644
--- a/lib/core/src/Cardano/Wallet/Primitive/Types/UTxOSelection/Gen.hs
+++ b/lib/core/src/Cardano/Wallet/Primitive/Types/UTxOSelection/Gen.hs
@@ -51,7 +51,7 @@ coarbitraryInputId = coarbitrary . show
 genInputIdFunction :: Gen a -> Gen (InputId -> a)
 genInputIdFunction = genFunction coarbitraryInputId
 
-genUTxOSelection :: Gen UTxOSelection
+genUTxOSelection :: Gen (UTxOSelection InputId)
 genUTxOSelection = UTxOSelection.fromIndexFiltered
     <$> genFilter
     <*> genUTxOIndex
@@ -59,7 +59,7 @@ genUTxOSelection = UTxOSelection.fromIndexFiltered
     genFilter :: Gen (InputId -> Bool)
     genFilter = genInputIdFunction (arbitrary @Bool)
 
-shrinkUTxOSelection :: UTxOSelection -> [UTxOSelection]
+shrinkUTxOSelection :: UTxOSelection InputId -> [UTxOSelection InputId]
 shrinkUTxOSelection =
     shrinkMapBy UTxOSelection.fromIndexPair UTxOSelection.toIndexPair $
         liftShrink2
@@ -70,11 +70,13 @@ shrinkUTxOSelection =
 -- Selections that are non-empty
 --------------------------------------------------------------------------------
 
-genUTxOSelectionNonEmpty :: Gen UTxOSelectionNonEmpty
+genUTxOSelectionNonEmpty :: Gen (UTxOSelectionNonEmpty InputId)
 genUTxOSelectionNonEmpty =
     genUTxOSelection `suchThatMap` UTxOSelection.toNonEmpty
 
-shrinkUTxOSelectionNonEmpty :: UTxOSelectionNonEmpty -> [UTxOSelectionNonEmpty]
+shrinkUTxOSelectionNonEmpty
+    :: UTxOSelectionNonEmpty InputId
+    -> [UTxOSelectionNonEmpty InputId]
 shrinkUTxOSelectionNonEmpty
     = mapMaybe UTxOSelection.toNonEmpty
     . shrinkUTxOSelection
diff --git a/lib/core/test/unit/Cardano/Wallet/CoinSelection/Internal/BalanceSpec.hs b/lib/core/test/unit/Cardano/Wallet/CoinSelection/Internal/BalanceSpec.hs
index 850ea8ecc27..7472249572b 100644
--- a/lib/core/test/unit/Cardano/Wallet/CoinSelection/Internal/BalanceSpec.hs
+++ b/lib/core/test/unit/Cardano/Wallet/CoinSelection/Internal/BalanceSpec.hs
@@ -1267,7 +1267,7 @@ prop_runSelection_UTxO_empty balanceRequested = monadicIO $ do
   where
     utxoAvailable = UTxOSelection.fromIndex UTxOIndex.empty
 
-prop_runSelection_UTxO_notEnough :: UTxOSelection -> Property
+prop_runSelection_UTxO_notEnough :: UTxOSelection InputId -> Property
 prop_runSelection_UTxO_notEnough utxoAvailable = monadicIO $ do
     result <- run $ runSelection
         RunSelectionParams
@@ -1290,7 +1290,7 @@ prop_runSelection_UTxO_notEnough utxoAvailable = monadicIO $ do
     balanceAvailable = UTxOSelection.availableBalance utxoAvailable
     balanceRequested = adjustAllTokenBundleQuantities (* 2) balanceAvailable
 
-prop_runSelection_UTxO_exactlyEnough :: UTxOSelection -> Property
+prop_runSelection_UTxO_exactlyEnough :: UTxOSelection InputId -> Property
 prop_runSelection_UTxO_exactlyEnough utxoAvailable = monadicIO $ do
     result <- run $ runSelection
         RunSelectionParams
@@ -1317,7 +1317,7 @@ prop_runSelection_UTxO_exactlyEnough utxoAvailable = monadicIO $ do
   where
     balanceRequested = UTxOSelection.availableBalance utxoAvailable
 
-prop_runSelection_UTxO_moreThanEnough :: UTxOSelection -> Property
+prop_runSelection_UTxO_moreThanEnough :: UTxOSelection InputId -> Property
 prop_runSelection_UTxO_moreThanEnough utxoAvailable = monadicIO $ do
     result <- run $ runSelection
         RunSelectionParams
@@ -1410,7 +1410,7 @@ prop_runSelection_UTxO_muchMoreThanEnough (Blind (Large index)) =
 -- Running a selection (non-empty)
 --------------------------------------------------------------------------------
 
-prop_runSelectionNonEmpty :: UTxOSelection -> Property
+prop_runSelectionNonEmpty :: UTxOSelection InputId -> Property
 prop_runSelectionNonEmpty result =
     case (haveLeftover, haveSelected) of
         (False, False) ->
@@ -1452,20 +1452,22 @@ prop_runSelectionNonEmpty result =
                     (UTxOSelection.leftoverIndex resultNonEmpty)
                 === UTxOSelection.leftoverIndex result
 
-    maybeResultNonEmpty :: Maybe UTxOSelectionNonEmpty
+    maybeResultNonEmpty :: Maybe (UTxOSelectionNonEmpty InputId)
     maybeResultNonEmpty = runIdentity $ runSelectionNonEmptyWith
         (Identity <$> mockSelectSingleEntry)
         (result)
 
-mockSelectSingleEntry :: UTxOSelection -> Maybe UTxOSelectionNonEmpty
+mockSelectSingleEntry
+    :: UTxOSelection InputId -> Maybe (UTxOSelectionNonEmpty InputId)
 mockSelectSingleEntry state =
     selectEntry =<< firstLeftoverEntry state
   where
-    firstLeftoverEntry :: UTxOSelection -> Maybe (InputId, TokenBundle)
+    firstLeftoverEntry :: UTxOSelection InputId -> Maybe (InputId, TokenBundle)
     firstLeftoverEntry =
         listToMaybe . UTxOIndex.toList . UTxOSelection.leftoverIndex
 
-    selectEntry :: (InputId, TokenBundle) -> Maybe UTxOSelectionNonEmpty
+    selectEntry
+        :: (InputId, TokenBundle) -> Maybe (UTxOSelectionNonEmpty InputId)
     selectEntry (i, _b) = UTxOSelection.select i state
 
 --------------------------------------------------------------------------------
@@ -4066,7 +4068,7 @@ instance Arbitrary TxOut where
     arbitrary = genTxOut
     shrink = shrinkTxOut
 
-instance Arbitrary UTxOSelection where
+instance Arbitrary (UTxOSelection InputId) where
     arbitrary = genUTxOSelection
     shrink = shrinkUTxOSelection
 
diff --git a/lib/core/test/unit/Cardano/Wallet/CoinSelection/InternalSpec.hs b/lib/core/test/unit/Cardano/Wallet/CoinSelection/InternalSpec.hs
index 86c7e432b24..afab8aa631e 100644
--- a/lib/core/test/unit/Cardano/Wallet/CoinSelection/InternalSpec.hs
+++ b/lib/core/test/unit/Cardano/Wallet/CoinSelection/InternalSpec.hs
@@ -788,7 +788,7 @@ genUTxOAvailableForCollateral = genMapWith genInputId genCoinPositive
     genInputId :: Gen InputId
     genInputId = genSized2 genTxIn genAddress
 
-genUTxOAvailableForInputs :: Gen UTxOSelection
+genUTxOAvailableForInputs :: Gen (UTxOSelection InputId)
 genUTxOAvailableForInputs = frequency
     [ (49, genUTxOSelection)
     , (01, pure UTxOSelection.empty)
@@ -804,7 +804,7 @@ shrinkUTxOAvailableForCollateral =
         <:> shrinkAddress
         <:> Nil
 
-shrinkUTxOAvailableForInputs :: UTxOSelection -> [UTxOSelection]
+shrinkUTxOAvailableForInputs :: UTxOSelection InputId -> [UTxOSelection InputId]
 shrinkUTxOAvailableForInputs = shrinkUTxOSelection
 
 --------------------------------------------------------------------------------
diff --git a/lib/core/test/unit/Cardano/Wallet/Primitive/Types/UTxOSelectionSpec.hs b/lib/core/test/unit/Cardano/Wallet/Primitive/Types/UTxOSelectionSpec.hs
index aba6b942b01..a0198566a24 100644
--- a/lib/core/test/unit/Cardano/Wallet/Primitive/Types/UTxOSelectionSpec.hs
+++ b/lib/core/test/unit/Cardano/Wallet/Primitive/Types/UTxOSelectionSpec.hs
@@ -1,4 +1,5 @@
 {-# LANGUAGE ExplicitForAll #-}
+{-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE FlexibleInstances #-}
 {-# OPTIONS_GHC -fno-warn-orphans #-}
 {- HLINT ignore "Use camelCase" -}
@@ -167,7 +168,7 @@ prop_shrinkUTxOSelectionNonEmpty =
     conjoin (isValidSelectionNonEmpty <$> shrinkUTxOSelectionNonEmpty s)
 
 checkCoverage_UTxOSelection
-    :: Testable p => IsUTxOSelection s => s -> (p -> Property)
+    :: Testable p => IsUTxOSelection s InputId => s InputId -> (p -> Property)
 checkCoverage_UTxOSelection s
     = checkCoverage_UTxOSelectionNonEmpty s
     . cover 2 (0 == ssize && ssize == lsize) "0 == lsize && lsize == ssize"
@@ -177,7 +178,7 @@ checkCoverage_UTxOSelection s
     ssize = UTxOSelection.selectedSize s
 
 checkCoverage_UTxOSelectionNonEmpty
-    :: Testable p => IsUTxOSelection s => s -> (p -> Property)
+    :: Testable p => IsUTxOSelection s InputId => s InputId -> (p -> Property)
 checkCoverage_UTxOSelectionNonEmpty s
     = checkCoverage
     . cover 2 (0 == lsize && lsize <  ssize) "0 == lsize && lsize <  ssize"
@@ -222,7 +223,7 @@ prop_fromIndexFiltered_toIndexPair f u =
     UTxOSelection.toIndexPair (UTxOSelection.fromIndexFiltered f u)
     === (UTxOIndex.filter (not . f) u, UTxOIndex.filter f u)
 
-prop_fromIndexPair_toIndexPair :: UTxOSelection -> Property
+prop_fromIndexPair_toIndexPair :: UTxOSelection InputId -> Property
 prop_fromIndexPair_toIndexPair s =
     checkCoverage_UTxOSelection s $
     UTxOSelection.fromIndexPair (UTxOSelection.toIndexPair s)
@@ -232,13 +233,13 @@ prop_fromIndexPair_toIndexPair s =
 -- Promotion and demotion
 --------------------------------------------------------------------------------
 
-prop_fromNonEmpty_toNonEmpty :: UTxOSelectionNonEmpty -> Property
+prop_fromNonEmpty_toNonEmpty :: UTxOSelectionNonEmpty InputId -> Property
 prop_fromNonEmpty_toNonEmpty s =
     checkCoverage_UTxOSelectionNonEmpty s $
     UTxOSelection.toNonEmpty (UTxOSelection.fromNonEmpty s)
     === Just s
 
-prop_toNonEmpty_fromNonEmpty :: UTxOSelection -> Property
+prop_toNonEmpty_fromNonEmpty :: UTxOSelection InputId -> Property
 prop_toNonEmpty_fromNonEmpty s =
     checkCoverage_UTxOSelection s $
     (UTxOSelection.fromNonEmpty <$> UTxOSelection.toNonEmpty s)
@@ -248,31 +249,31 @@ prop_toNonEmpty_fromNonEmpty s =
 -- Indicator and accessor functions
 --------------------------------------------------------------------------------
 
-prop_availableBalance_availableUTxO :: UTxOSelection -> Property
+prop_availableBalance_availableUTxO :: UTxOSelection InputId -> Property
 prop_availableBalance_availableUTxO s =
     checkCoverage_UTxOSelection s $
     UTxOSelection.availableBalance s
     === F.fold (UTxOSelection.availableUTxO s)
 
-prop_isNonEmpty_selectedSize :: UTxOSelection -> Property
+prop_isNonEmpty_selectedSize :: UTxOSelection InputId -> Property
 prop_isNonEmpty_selectedSize s =
     checkCoverage_UTxOSelection s $
     UTxOSelection.isNonEmpty s
     === (UTxOSelection.selectedSize s > 0)
 
-prop_isNonEmpty_selectedIndex :: UTxOSelection -> Property
+prop_isNonEmpty_selectedIndex :: UTxOSelection InputId -> Property
 prop_isNonEmpty_selectedIndex s =
     checkCoverage_UTxOSelection s $
     UTxOSelection.isNonEmpty s
     === not (UTxOIndex.null (UTxOSelection.selectedIndex s))
 
-prop_isNonEmpty_selectedList :: UTxOSelection -> Property
+prop_isNonEmpty_selectedList :: UTxOSelection InputId -> Property
 prop_isNonEmpty_selectedList s =
     checkCoverage_UTxOSelection s $
     UTxOSelection.isNonEmpty s
     === not (null (UTxOSelection.selectedList s))
 
-prop_leftoverBalance_selectedBalance :: UTxOSelection -> Property
+prop_leftoverBalance_selectedBalance :: UTxOSelection InputId -> Property
 prop_leftoverBalance_selectedBalance s =
     checkCoverage_UTxOSelection s $
     (UTxOSelection.leftoverBalance s <> UTxOSelection.selectedBalance s)
@@ -281,7 +282,7 @@ prop_leftoverBalance_selectedBalance s =
         (UTxOIndex.balance (UTxOSelection.leftoverIndex s))
         (UTxOIndex.balance (UTxOSelection.selectedIndex s))
 
-prop_leftoverSize_selectedSize :: UTxOSelection -> Property
+prop_leftoverSize_selectedSize :: UTxOSelection InputId -> Property
 prop_leftoverSize_selectedSize s =
     checkCoverage_UTxOSelection s $
     (UTxOSelection.leftoverSize s + UTxOSelection.selectedSize s)
@@ -298,33 +299,34 @@ prop_select_empty :: InputId -> Property
 prop_select_empty i =
     UTxOSelection.select i UTxOSelection.empty === Nothing
 
-prop_select_isValid :: InputId -> UTxOSelection -> Property
+prop_select_isValid :: InputId -> UTxOSelection InputId -> Property
 prop_select_isValid i s = property $
     checkCoverage_select i s $
     maybe True isValidSelectionNonEmpty (UTxOSelection.select i s)
 
-prop_select_isLeftover :: InputId -> UTxOSelection -> Property
+prop_select_isLeftover :: InputId -> UTxOSelection InputId -> Property
 prop_select_isLeftover i s =
     checkCoverage_select i s $
     (UTxOSelection.isLeftover i <$> UTxOSelection.select i s)
     ===
     if UTxOSelection.isLeftover i s then Just False else Nothing
 
-prop_select_isSelected :: InputId -> UTxOSelection -> Property
+prop_select_isSelected :: InputId -> UTxOSelection InputId -> Property
 prop_select_isSelected i s =
     checkCoverage_select i s $
     (UTxOSelection.isSelected i <$> UTxOSelection.select i s)
     ===
     if UTxOSelection.isLeftover i s then Just True else Nothing
 
-prop_select_isProperSubSelectionOf :: InputId -> UTxOSelection -> Property
+prop_select_isProperSubSelectionOf
+    :: InputId -> UTxOSelection InputId -> Property
 prop_select_isProperSubSelectionOf i s =
     checkCoverage_select i s $
     (UTxOSelection.isProperSubSelectionOf s <$> UTxOSelection.select i s)
     ===
     if UTxOSelection.isLeftover i s then Just True else Nothing
 
-prop_select_availableBalance :: InputId -> UTxOSelection -> Property
+prop_select_availableBalance :: InputId -> UTxOSelection InputId -> Property
 prop_select_availableBalance i s =
     checkCoverage_select i s $
     (UTxOSelection.availableBalance <$> UTxOSelection.select i s)
@@ -333,7 +335,7 @@ prop_select_availableBalance i s =
     then Just (UTxOSelection.availableBalance s)
     else Nothing
 
-prop_select_availableUTxO :: InputId -> UTxOSelection -> Property
+prop_select_availableUTxO :: InputId -> UTxOSelection InputId -> Property
 prop_select_availableUTxO i s =
     checkCoverage_select i s $
     (UTxOSelection.availableUTxO <$> UTxOSelection.select i s)
@@ -342,7 +344,7 @@ prop_select_availableUTxO i s =
     then Just (UTxOSelection.availableUTxO s)
     else Nothing
 
-prop_select_leftoverSize :: InputId -> UTxOSelection -> Property
+prop_select_leftoverSize :: InputId -> UTxOSelection InputId -> Property
 prop_select_leftoverSize i s =
     checkCoverage_select i s $
     (UTxOSelection.leftoverSize <$> UTxOSelection.select i s)
@@ -351,7 +353,7 @@ prop_select_leftoverSize i s =
     then Just (UTxOSelection.leftoverSize s - 1)
     else Nothing
 
-prop_select_selectedSize :: InputId -> UTxOSelection -> Property
+prop_select_selectedSize :: InputId -> UTxOSelection InputId -> Property
 prop_select_selectedSize i s =
     checkCoverage_select i s $
     (UTxOSelection.selectedSize <$> UTxOSelection.select i s)
@@ -361,7 +363,7 @@ prop_select_selectedSize i s =
     else Nothing
 
 prop_selectMany_isSubSelectionOf
-    :: (InputId -> Bool) -> UTxOSelection -> Property
+    :: (InputId -> Bool) -> UTxOSelection InputId -> Property
 prop_selectMany_isSubSelectionOf f s =
     checkCoverage_UTxOSelection s $
     UTxOSelection.isSubSelectionOf s (UTxOSelection.selectMany toSelect s)
@@ -369,14 +371,14 @@ prop_selectMany_isSubSelectionOf f s =
   where
     toSelect = filter f $ fst <$> UTxOSelection.leftoverList s
 
-prop_selectMany_leftoverSize_all :: UTxOSelection -> Property
+prop_selectMany_leftoverSize_all :: UTxOSelection InputId -> Property
 prop_selectMany_leftoverSize_all s =
     checkCoverage_UTxOSelection s $
     UTxOSelection.leftoverSize
         (UTxOSelection.selectMany (fst <$> UTxOSelection.leftoverList s) s)
     === 0
 
-prop_selectMany_selectedSize_all :: UTxOSelection -> Property
+prop_selectMany_selectedSize_all :: UTxOSelection InputId -> Property
 prop_selectMany_selectedSize_all s =
     checkCoverage_UTxOSelection s $
     UTxOSelection.selectedSize
@@ -384,7 +386,7 @@ prop_selectMany_selectedSize_all s =
     === (UTxOSelection.leftoverSize s + UTxOSelection.selectedSize s)
 
 checkCoverage_select
-    :: Testable prop => InputId -> UTxOSelection -> (prop -> Property)
+    :: Testable prop => InputId -> UTxOSelection InputId -> (prop -> Property)
 checkCoverage_select i s
     = checkCoverage
     . cover 10 (UTxOSelection.isLeftover i s)
@@ -398,12 +400,12 @@ checkCoverage_select i s
 -- Validity
 --------------------------------------------------------------------------------
 
-isValidSelection :: IsUTxOSelection s => s -> Bool
+isValidSelection :: IsUTxOSelection s InputId => s InputId -> Bool
 isValidSelection s = UTxOIndex.disjoint
     (UTxOSelection.selectedIndex s)
     (UTxOSelection.leftoverIndex s)
 
-isValidSelectionNonEmpty :: UTxOSelectionNonEmpty -> Bool
+isValidSelectionNonEmpty :: UTxOSelectionNonEmpty InputId -> Bool
 isValidSelectionNonEmpty s =
     isValidSelection s
     && UTxOSelection.isNonEmpty s
@@ -431,11 +433,11 @@ instance Arbitrary (UTxOIndex InputId) where
     arbitrary = genUTxOIndex
     shrink = shrinkUTxOIndex
 
-instance Arbitrary UTxOSelection where
+instance Arbitrary (UTxOSelection InputId) where
     arbitrary = genUTxOSelection
     shrink = shrinkUTxOSelection
 
-instance Arbitrary UTxOSelectionNonEmpty where
+instance Arbitrary (UTxOSelectionNonEmpty InputId) where
     arbitrary = genUTxOSelectionNonEmpty
     shrink = shrinkUTxOSelectionNonEmpty
 

From 269e3dace2f2dc03c313527dc280ebaf0a05b634 Mon Sep 17 00:00:00 2001
From: Jonathan Knowles <jonathan.knowles@iohk.io>
Date: Thu, 24 Feb 2022 04:20:49 +0000
Subject: [PATCH 3/4] Rename `{leftover,selected}UTxO` to
 `{leftover,selected}Map`.

The `UTxOSelection` module already uses the term "UTxO" to refer to a
single UTxO (single unspent transaction output).

We no longer depend on the wallet's `UTxO` type here, and since these
functions both return values of type `Map`, we can avoid ambiguity by
using the term `Map` in the names of these functions.
---
 .../Wallet/Primitive/Types/UTxOSelection.hs   | 22 +++++++++----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/lib/core/src/Cardano/Wallet/Primitive/Types/UTxOSelection.hs b/lib/core/src/Cardano/Wallet/Primitive/Types/UTxOSelection.hs
index abb6f2ca258..63853d53604 100644
--- a/lib/core/src/Cardano/Wallet/Primitive/Types/UTxOSelection.hs
+++ b/lib/core/src/Cardano/Wallet/Primitive/Types/UTxOSelection.hs
@@ -70,12 +70,12 @@ module Cardano.Wallet.Primitive.Types.UTxOSelection
     , leftoverSize
     , leftoverIndex
     , leftoverList
-    , leftoverUTxO
+    , leftoverMap
     , selectedBalance
     , selectedSize
     , selectedIndex
     , selectedList
-    , selectedUTxO
+    , selectedMap
 
       -- * Modification
     , select
@@ -288,7 +288,7 @@ isSubSelectionOf
 isSubSelectionOf s1 s2 = state (selectMany toSelect s1) == state s2
   where
     toSelect = fst <$> Map.toList
-        (selectedUTxO s2 `Map.difference` selectedUTxO s1)
+        (selectedMap s2 `Map.difference` selectedMap s1)
 
 -- | Returns 'True' iff. the first selection is a proper sub-selection of the
 --   second.
@@ -329,7 +329,7 @@ availableBalance s = leftoverBalance s <> selectedBalance s
 --
 -- The available UTxO set is the union of the selected and leftover UTxO sets.
 --
--- It predicts what 'selectedUTxO' would be if every single UTxO were selected.
+-- It predicts what 'selectedMap' would be if every single UTxO were selected.
 --
 -- This result of this function remains constant over applications of 'select'
 -- and 'selectMany':
@@ -337,7 +337,7 @@ availableBalance s = leftoverBalance s <> selectedBalance s
 -- >>> availableUTxO s == availableUTxO (selectMany is s)
 --
 availableUTxO :: IsUTxOSelection s u => Ord u => s u -> Map u TokenBundle
-availableUTxO s = leftoverUTxO s <> selectedUTxO s
+availableUTxO s = leftoverMap s <> selectedMap s
 
 -- | Retrieves the balance of leftover UTxOs.
 --
@@ -354,10 +354,10 @@ leftoverSize = UTxOIndex.size . leftoverIndex
 leftoverIndex :: IsUTxOSelection s u => s u -> UTxOIndex u
 leftoverIndex = leftover . state
 
--- | Retrieves the leftover UTxO set.
+-- | Retrieves a map of the leftover UTxOs.
 --
-leftoverUTxO :: IsUTxOSelection s u => s u -> Map u TokenBundle
-leftoverUTxO = UTxOIndex.toMap . leftoverIndex
+leftoverMap :: IsUTxOSelection s u => s u -> Map u TokenBundle
+leftoverMap = UTxOIndex.toMap . leftoverIndex
 
 -- | Retrieves a list of the leftover UTxOs.
 --
@@ -379,10 +379,10 @@ selectedSize = UTxOIndex.size . selectedIndex
 selectedIndex :: IsUTxOSelection s u => s u -> UTxOIndex u
 selectedIndex = selected . state
 
--- | Retrieves the selected UTxO set.
+-- | Retrieves a map of the selected UTxOs.
 --
-selectedUTxO :: IsUTxOSelection s u => s u -> Map u TokenBundle
-selectedUTxO = UTxOIndex.toMap . selectedIndex
+selectedMap :: IsUTxOSelection s u => s u -> Map u TokenBundle
+selectedMap = UTxOIndex.toMap . selectedIndex
 
 --------------------------------------------------------------------------------
 -- Modification

From d75a860428c8ab5eb3f5a8a2879cbe7cceec9947 Mon Sep 17 00:00:00 2001
From: Jonathan Knowles <jonathan.knowles@iohk.io>
Date: Thu, 24 Feb 2022 08:02:45 +0000
Subject: [PATCH 4/4] Revise identifier names within module `UTxOSelection`.

We use the following convention for identifier names:

  - `s` represents a selection of type `UTxOSelection`.
  - `u` represents a unique identifier for an individual UTxO (unspent
        transaction output).
  - `b` represents a `TokenBundle` value.
  - `i` represents an index of type `UTxOIndex`.
---
 .../Wallet/Primitive/Types/UTxOSelection.hs      | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/lib/core/src/Cardano/Wallet/Primitive/Types/UTxOSelection.hs b/lib/core/src/Cardano/Wallet/Primitive/Types/UTxOSelection.hs
index 63853d53604..f011c862914 100644
--- a/lib/core/src/Cardano/Wallet/Primitive/Types/UTxOSelection.hs
+++ b/lib/core/src/Cardano/Wallet/Primitive/Types/UTxOSelection.hs
@@ -260,17 +260,17 @@ isNonEmpty = not . isEmpty
 -- Otherwise, returns 'False'.
 --
 isMember :: IsUTxOSelection s u => Ord u => u -> s u -> Bool
-isMember i s = isLeftover i s || isSelected i s
+isMember u s = isLeftover u s || isSelected u s
 
 -- | Returns 'True' iff. the given 'InputId' is a member of the leftover set.
 --
 isLeftover :: IsUTxOSelection s u => Ord u => u -> s u -> Bool
-isLeftover i = UTxOIndex.member i . leftoverIndex
+isLeftover u = UTxOIndex.member u . leftoverIndex
 
 -- | Returns 'True' iff. the given 'InputId' is a member of the selected set.
 --
 isSelected :: IsUTxOSelection s u => Ord u => u -> s u -> Bool
-isSelected i = UTxOIndex.member i . selectedIndex
+isSelected u = UTxOIndex.member u . selectedIndex
 
 -- | Returns 'True' iff. the first selection is a sub-selection of the second.
 --
@@ -418,12 +418,12 @@ selectMany = ap fromMaybe . withState . flip (F.foldrM selectState)
 -- | Moves a single entry from the leftover set to the selected set.
 --
 selectState :: Ord u => u -> State u -> Maybe (State u)
-selectState i s =
-    updateFields <$> UTxOIndex.lookup i (leftover s)
+selectState u s =
+    updateFields <$> UTxOIndex.lookup u (leftover s)
   where
-    updateFields o = s
-        & over #leftover (UTxOIndex.delete i)
-        & over #selected (UTxOIndex.insert i o)
+    updateFields b = s
+        & over #leftover (UTxOIndex.delete u)
+        & over #selected (UTxOIndex.insert u b)
 
 -- | Applies the given function to the internal state.
 --