diff --git a/hledger-lib/Hledger/Data/Dates.hs b/hledger-lib/Hledger/Data/Dates.hs
index f4af2e1ab..ec8220a82 100644
--- a/hledger-lib/Hledger/Data/Dates.hs
+++ b/hledger-lib/Hledger/Data/Dates.hs
@@ -360,7 +360,7 @@ latestSpanContaining datespans = go
 -- | Parse a period expression to an Interval and overall DateSpan using
 -- the provided reference date, or return a parse error.
 parsePeriodExpr
-  :: Day -> Text -> Either (ParseErrorBundle Text CustomErr) (Interval, DateSpan)
+  :: Day -> Text -> Either (ParseErrorBundle Text HledgerParseErrorData) (Interval, DateSpan)
 parsePeriodExpr refdate s = parsewith (periodexprp refdate <* eof) (T.toLower s)
 
 -- | Like parsePeriodExpr, but call error' on failure.
@@ -408,14 +408,14 @@ spanFromSmartDate refdate sdate = DateSpan (Just b) (Just e)
 fixSmartDateStr :: Day -> Text -> Text
 fixSmartDateStr d s =
   either (error' . printf "could not parse date %s %s" (show s) . show) id $  -- PARTIAL:
-  (fixSmartDateStrEither d s :: Either (ParseErrorBundle Text CustomErr) Text)
+  (fixSmartDateStrEither d s :: Either (ParseErrorBundle Text HledgerParseErrorData) Text)
 
 -- | A safe version of fixSmartDateStr.
-fixSmartDateStrEither :: Day -> Text -> Either (ParseErrorBundle Text CustomErr) Text
+fixSmartDateStrEither :: Day -> Text -> Either (ParseErrorBundle Text HledgerParseErrorData) Text
 fixSmartDateStrEither d = fmap showDate . fixSmartDateStrEither' d
 
 fixSmartDateStrEither'
-  :: Day -> Text -> Either (ParseErrorBundle Text CustomErr) Day
+  :: Day -> Text -> Either (ParseErrorBundle Text HledgerParseErrorData) Day
 fixSmartDateStrEither' d s = case parsewith smartdateonly (T.toLower s) of
                                Right sd -> Right $ fixSmartDate d sd
                                Left e -> Left e
diff --git a/hledger-lib/Hledger/Data/Journal.hs b/hledger-lib/Hledger/Data/Journal.hs
index 222dbea97..e4ab359f5 100644
--- a/hledger-lib/Hledger/Data/Journal.hs
+++ b/hledger-lib/Hledger/Data/Journal.hs
@@ -142,13 +142,13 @@ import Hledger.Query
 
 
 -- | A parser of text that runs in some monad, keeping a Journal as state.
-type JournalParser m a = StateT Journal (ParsecT CustomErr Text m) a
+type JournalParser m a = StateT Journal (ParsecT HledgerParseErrorData Text m) a
 
 -- | A parser of text that runs in some monad, keeping a Journal as
 -- state, that can throw an exception to end parsing, preventing
 -- further parser backtracking.
 type ErroringJournalParser m a =
-  StateT Journal (ParsecT CustomErr Text (ExceptT FinalParseError m)) a
+  StateT Journal (ParsecT HledgerParseErrorData Text (ExceptT FinalParseError m)) a
 
 -- deriving instance Show Journal
 instance Show Journal where
diff --git a/hledger-lib/Hledger/Read/Common.hs b/hledger-lib/Hledger/Read/Common.hs
index e3639dbb2..962a75fb8 100644
--- a/hledger-lib/Hledger/Read/Common.hs
+++ b/hledger-lib/Hledger/Read/Common.hs
@@ -271,7 +271,7 @@ initialiseAndParseJournal parser iopts f txt =
     y = first3 . toGregorian $ _ioDay iopts
     initJournal = nulljournal{jparsedefaultyear = Just y, jincludefilestack = [f]}
     -- Flatten parse errors and final parse errors, and output each as a pretty String.
-    prettyParseErrors :: ExceptT FinalParseError IO (Either (ParseErrorBundle Text CustomErr) a)
+    prettyParseErrors :: ExceptT FinalParseError IO (Either (ParseErrorBundle Text HledgerParseErrorData) a)
                       -> ExceptT String IO a
     prettyParseErrors = withExceptT customErrorBundlePretty . liftEither
                     <=< withExceptT (finalErrorBundlePretty . attachSource f txt)
@@ -855,7 +855,7 @@ amountwithoutpricep mult = do
           Right (q,p,d,g) -> pure (q, Precision p, d, g)
 
 -- | Try to parse an amount from a string
-amountp'' :: String -> Either (ParseErrorBundle Text CustomErr) Amount
+amountp'' :: String -> Either (ParseErrorBundle Text HledgerParseErrorData) Amount
 amountp'' s = runParser (evalStateT (amountp <* eof) nulljournal) "" (T.pack s)
 
 -- | Parse an amount from a string, or get an error.
diff --git a/hledger-lib/Hledger/Read/CsvReader.hs b/hledger-lib/Hledger/Read/CsvReader.hs
index 303167c99..80897ec55 100644
--- a/hledger-lib/Hledger/Read/CsvReader.hs
+++ b/hledger-lib/Hledger/Read/CsvReader.hs
@@ -216,7 +216,7 @@ parseAndValidateCsvRules rulesfile s =
       parseErrorPretty (FancyError 0 (S.singleton $ ErrorFail errorString) :: ParseError Text String)
 
 -- | Parse this text as CSV conversion rules. The file path is for error messages.
-parseCsvRules :: FilePath -> T.Text -> Either (ParseErrorBundle T.Text CustomErr) CsvRules
+parseCsvRules :: FilePath -> T.Text -> Either (ParseErrorBundle T.Text HledgerParseErrorData) CsvRules
 -- parseCsvRules rulesfile s = runParser csvrulesfile nullrules{baseAccount=takeBaseName rulesfile} rulesfile s
 parseCsvRules = runParser (evalStateT rulesp defrules)
 
@@ -1232,7 +1232,7 @@ renderTemplate rules record t = maybe t mconcat $ parseMaybe
         <|> replaceCsvFieldReference rules record <$> referencep)
     t
   where
-    referencep = liftA2 T.cons (char '%') (takeWhile1P (Just "reference") isFieldNameChar) :: Parsec CustomErr Text Text
+    referencep = liftA2 T.cons (char '%') (takeWhile1P (Just "reference") isFieldNameChar) :: Parsec HledgerParseErrorData Text Text
     isFieldNameChar c = isAlphaNum c || c == '_' || c == '-'
 
 -- | Replace something that looks like a reference to a csv field ("%date" or "%1)
diff --git a/hledger-lib/Hledger/Read/JournalReader.hs b/hledger-lib/Hledger/Read/JournalReader.hs
index 42902c37c..8d48442b8 100644
--- a/hledger-lib/Hledger/Read/JournalReader.hs
+++ b/hledger-lib/Hledger/Read/JournalReader.hs
@@ -113,7 +113,7 @@ import qualified Hledger.Read.CsvReader as CsvReader (reader)
 -- | Run a journal parser in some monad. See also: parseWithState.
 runJournalParser, rjp
   :: Monad m
-  => JournalParser m a -> Text -> m (Either (ParseErrorBundle Text CustomErr) a)
+  => JournalParser m a -> Text -> m (Either (ParseErrorBundle Text HledgerParseErrorData) a)
 runJournalParser p = runParserT (evalStateT p nulljournal) ""
 rjp = runJournalParser
 
@@ -122,7 +122,7 @@ runErroringJournalParser, rejp
   :: Monad m
   => ErroringJournalParser m a
   -> Text
-  -> m (Either FinalParseError (Either (ParseErrorBundle Text CustomErr) a))
+  -> m (Either FinalParseError (Either (ParseErrorBundle Text HledgerParseErrorData) a))
 runErroringJournalParser p t =
   runExceptT $ runParserT (evalStateT p nulljournal) "" t
 rejp = runErroringJournalParser
diff --git a/hledger-lib/Hledger/Utils/Parse.hs b/hledger-lib/Hledger/Utils/Parse.hs
index e242ed70d..6e1863d98 100644
--- a/hledger-lib/Hledger/Utils/Parse.hs
+++ b/hledger-lib/Hledger/Utils/Parse.hs
@@ -38,7 +38,7 @@ module Hledger.Utils.Parse (
   skipNonNewlineSpaces',
 
   -- * re-exports
-  CustomErr
+  HledgerParseErrorData
 )
 where
 
@@ -54,13 +54,13 @@ import Text.Megaparsec.Custom
 import Text.Printf
 
 -- | A parser of string to some type.
-type SimpleStringParser a = Parsec CustomErr String a
+type SimpleStringParser a = Parsec HledgerParseErrorData String a
 
 -- | A parser of strict text to some type.
-type SimpleTextParser = Parsec CustomErr Text  -- XXX an "a" argument breaks the CsvRulesParser declaration somehow
+type SimpleTextParser = Parsec HledgerParseErrorData Text  -- XXX an "a" argument breaks the CsvRulesParser declaration somehow
 
 -- | A parser of text that runs in some monad.
-type TextParser m a = ParsecT CustomErr Text m a
+type TextParser m a = ParsecT HledgerParseErrorData Text m a
 
 -- | Render a pair of source positions in human-readable form, only displaying the range of lines.
 sourcePosPairPretty :: (SourcePos, SourcePos) -> String
@@ -76,7 +76,7 @@ choice' = choice . map try
 
 -- | Backtracking choice, use this when alternatives share a prefix.
 -- Consumes no input if all choices fail.
-choiceInState :: [StateT s (ParsecT CustomErr Text m) a] -> StateT s (ParsecT CustomErr Text m) a
+choiceInState :: [StateT s (ParsecT HledgerParseErrorData Text m) a] -> StateT s (ParsecT HledgerParseErrorData Text m) a
 choiceInState = choice . map try
 
 surroundedBy :: Applicative m => m openclose -> m a -> m a
@@ -87,7 +87,7 @@ parsewith p = runParser p ""
 
 -- | Run a text parser in the identity monad. See also: parseWithState.
 runTextParser, rtp
-  :: TextParser Identity a -> Text -> Either (ParseErrorBundle Text CustomErr) a
+  :: TextParser Identity a -> Text -> Either (ParseErrorBundle Text HledgerParseErrorData) a
 runTextParser = parsewith
 rtp = runTextParser
 
@@ -100,9 +100,9 @@ parsewithString p = runParser p ""
 parseWithState
   :: Monad m
   => st
-  -> StateT st (ParsecT CustomErr Text m) a
+  -> StateT st (ParsecT HledgerParseErrorData Text m) a
   -> Text
-  -> m (Either (ParseErrorBundle Text CustomErr) a)
+  -> m (Either (ParseErrorBundle Text HledgerParseErrorData) a)
 parseWithState ctx p = runParserT (evalStateT p ctx) ""
 
 parseWithState'
@@ -139,7 +139,7 @@ nonspace = satisfy (not . isSpace)
 isNonNewlineSpace :: Char -> Bool
 isNonNewlineSpace c = not (isNewline c) && isSpace c
 
-spacenonewline :: (Stream s, Char ~ Token s) => ParsecT CustomErr s m Char
+spacenonewline :: (Stream s, Char ~ Token s) => ParsecT HledgerParseErrorData s m Char
 spacenonewline = satisfy isNonNewlineSpace
 {-# INLINABLE spacenonewline #-}
 
@@ -147,17 +147,17 @@ restofline :: TextParser m String
 restofline = anySingle `manyTill` eolof
 
 -- Skip many non-newline spaces.
-skipNonNewlineSpaces :: (Stream s, Token s ~ Char) => ParsecT CustomErr s m ()
+skipNonNewlineSpaces :: (Stream s, Token s ~ Char) => ParsecT HledgerParseErrorData s m ()
 skipNonNewlineSpaces = () <$ takeWhileP Nothing isNonNewlineSpace
 {-# INLINABLE skipNonNewlineSpaces #-}
 
 -- Skip many non-newline spaces, failing if there are none.
-skipNonNewlineSpaces1 :: (Stream s, Token s ~ Char) => ParsecT CustomErr s m ()
+skipNonNewlineSpaces1 :: (Stream s, Token s ~ Char) => ParsecT HledgerParseErrorData s m ()
 skipNonNewlineSpaces1 = () <$ takeWhile1P Nothing isNonNewlineSpace
 {-# INLINABLE skipNonNewlineSpaces1 #-}
 
 -- Skip many non-newline spaces, returning True if any have been skipped.
-skipNonNewlineSpaces' :: (Stream s, Token s ~ Char) => ParsecT CustomErr s m Bool
+skipNonNewlineSpaces' :: (Stream s, Token s ~ Char) => ParsecT HledgerParseErrorData s m Bool
 skipNonNewlineSpaces' = True <$ skipNonNewlineSpaces1 <|> pure False
 {-# INLINABLE skipNonNewlineSpaces' #-}
 
diff --git a/hledger-lib/Hledger/Utils/Test.hs b/hledger-lib/Hledger/Utils/Test.hs
index 6cdf1af5a..e3fc9bef8 100644
--- a/hledger-lib/Hledger/Utils/Test.hs
+++ b/hledger-lib/Hledger/Utils/Test.hs
@@ -31,7 +31,7 @@ import Test.Tasty.HUnit
 -- import Test.Tasty.SmallCheck as SC
 import Text.Megaparsec
 import Text.Megaparsec.Custom
-  ( CustomErr,
+  ( HledgerParseErrorData,
     FinalParseError,
     attachSource,
     customErrorBundlePretty,
@@ -56,7 +56,7 @@ assertRight (Left a)  = assertFailure $ "expected Right, got (Left " ++ show a +
 
 -- | Run a parser on the given text and display a helpful error.
 parseHelper :: (HasCallStack, Default st, Monad m) =>
-  StateT st (ParsecT CustomErr T.Text m) a -> T.Text -> ExceptT String m a
+  StateT st (ParsecT HledgerParseErrorData T.Text m) a -> T.Text -> ExceptT String m a
 parseHelper parser input =
   withExceptT (\e -> "\nparse error at " ++ customErrorBundlePretty e ++ "\n") . ExceptT
   $ runParserT (evalStateT (parser <* eof) def) "" input
@@ -65,7 +65,7 @@ parseHelper parser input =
 -- produce an 'Assertion'. Suitable for hledger's JournalParser parsers.
 assertParseHelper :: (HasCallStack, Default st) =>
   (String -> Assertion) -> (a -> Assertion)
-  -> StateT st (ParsecT CustomErr T.Text IO) a -> T.Text
+  -> StateT st (ParsecT HledgerParseErrorData T.Text IO) a -> T.Text
   -> Assertion
 assertParseHelper onFailure onSuccess parser input =
   either onFailure onSuccess =<< runExceptT (parseHelper parser input)
@@ -74,25 +74,25 @@ assertParseHelper onFailure onSuccess parser input =
 -- all of the given input text, showing the parse error if it fails.
 -- Suitable for hledger's JournalParser parsers.
 assertParse :: (HasCallStack, Default st) =>
-  StateT st (ParsecT CustomErr T.Text IO) a -> T.Text -> Assertion
+  StateT st (ParsecT HledgerParseErrorData T.Text IO) a -> T.Text -> Assertion
 assertParse = assertParseHelper assertFailure (const $ return ())
 
 -- | Assert a parser produces an expected value.
 assertParseEq :: (HasCallStack, Eq a, Show a, Default st) =>
-  StateT st (ParsecT CustomErr T.Text IO) a -> T.Text -> a -> Assertion
+  StateT st (ParsecT HledgerParseErrorData T.Text IO) a -> T.Text -> a -> Assertion
 assertParseEq parser input = assertParseEqOn parser input id
 
 -- | Like assertParseEq, but transform the parse result with the given function
 -- before comparing it.
 assertParseEqOn :: (HasCallStack, Eq b, Show b, Default st) =>
-  StateT st (ParsecT CustomErr T.Text IO) a -> T.Text -> (a -> b) -> b -> Assertion
+  StateT st (ParsecT HledgerParseErrorData T.Text IO) a -> T.Text -> (a -> b) -> b -> Assertion
 assertParseEqOn parser input f expected =
   assertParseHelper assertFailure (assertEqual "" expected . f) parser input
 
 -- | Assert that this stateful parser runnable in IO fails to parse
 -- the given input text, with a parse error containing the given string.
 assertParseError :: (HasCallStack, Eq a, Show a, Default st) =>
-  StateT st (ParsecT CustomErr T.Text IO) a -> T.Text -> String -> Assertion
+  StateT st (ParsecT HledgerParseErrorData T.Text IO) a -> T.Text -> String -> Assertion
 assertParseError parser input errstr = assertParseHelper
   (\e -> unless (errstr `isInfixOf` e) $ assertFailure $ "\nparse error is not as expected:" ++ e)
   (\v -> assertFailure $ "\nparse succeeded unexpectedly, producing:\n" ++ pshow v ++ "\n")
@@ -102,7 +102,7 @@ assertParseError parser input errstr = assertParseHelper
 -- final state (the wrapped state, not megaparsec's internal state),
 -- transformed by the given function, matches the given expected value.
 assertParseStateOn :: (HasCallStack, Eq b, Show b, Default st) =>
-     StateT st (ParsecT CustomErr T.Text IO) a -> T.Text -> (st -> b) -> b -> Assertion
+     StateT st (ParsecT HledgerParseErrorData T.Text IO) a -> T.Text -> (st -> b) -> b -> Assertion
 assertParseStateOn parser input f expected = do
   es <- runParserT (execStateT (parser <* eof) def) "" input
   case es of
@@ -111,7 +111,7 @@ assertParseStateOn parser input f expected = do
 
 -- | These "E" variants of the above are suitable for hledger's ErroringJournalParser parsers.
 parseHelperE :: (HasCallStack, Default st, Monad m) =>
-  StateT st (ParsecT CustomErr T.Text (ExceptT FinalParseError m)) a -> T.Text -> ExceptT String m a
+  StateT st (ParsecT HledgerParseErrorData T.Text (ExceptT FinalParseError m)) a -> T.Text -> ExceptT String m a
 parseHelperE parser input = do
   withExceptT (\e -> "\nparse error at " ++ customErrorBundlePretty e ++ "\n") . liftEither
   =<< withExceptT (\e -> "parse error at " ++ finalErrorBundlePretty (attachSource "" input e))
@@ -119,30 +119,30 @@ parseHelperE parser input = do
 
 assertParseHelperE :: (HasCallStack, Default st) =>
   (String -> Assertion) -> (a -> Assertion)
-  -> StateT st (ParsecT CustomErr T.Text (ExceptT FinalParseError IO)) a -> T.Text
+  -> StateT st (ParsecT HledgerParseErrorData T.Text (ExceptT FinalParseError IO)) a -> T.Text
   -> Assertion
 assertParseHelperE onFailure onSuccess parser input =
   either onFailure onSuccess =<< runExceptT (parseHelperE parser input)
 
 assertParseE
   :: (HasCallStack, Eq a, Show a, Default st)
-  => StateT st (ParsecT CustomErr T.Text (ExceptT FinalParseError IO)) a -> T.Text -> Assertion
+  => StateT st (ParsecT HledgerParseErrorData T.Text (ExceptT FinalParseError IO)) a -> T.Text -> Assertion
 assertParseE = assertParseHelperE assertFailure (const $ return ())
 
 assertParseEqE
   :: (Default st, Eq a, Show a, HasCallStack)
-  => StateT st (ParsecT CustomErr T.Text (ExceptT FinalParseError IO)) a -> T.Text -> a -> Assertion
+  => StateT st (ParsecT HledgerParseErrorData T.Text (ExceptT FinalParseError IO)) a -> T.Text -> a -> Assertion
 assertParseEqE parser input = assertParseEqOnE parser input id
 
 assertParseEqOnE
   :: (HasCallStack, Eq b, Show b, Default st)
-  => StateT st (ParsecT CustomErr T.Text (ExceptT FinalParseError IO)) a -> T.Text -> (a -> b) -> b -> Assertion
+  => StateT st (ParsecT HledgerParseErrorData T.Text (ExceptT FinalParseError IO)) a -> T.Text -> (a -> b) -> b -> Assertion
 assertParseEqOnE parser input f expected =
   assertParseHelperE assertFailure (assertEqual "" expected . f) parser input
 
 assertParseErrorE
   :: (Default st, Eq a, Show a, HasCallStack)
-  => StateT st (ParsecT CustomErr T.Text (ExceptT FinalParseError IO)) a -> T.Text -> String -> Assertion
+  => StateT st (ParsecT HledgerParseErrorData T.Text (ExceptT FinalParseError IO)) a -> T.Text -> String -> Assertion
 assertParseErrorE parser input errstr = assertParseHelperE
   (\e -> unless (errstr `isInfixOf` e) $ assertFailure $ "\nparse error is not as expected:" ++ e)
   (\v -> assertFailure $ "\nparse succeeded unexpectedly, producing:\n" ++ pshow v ++ "\n")
diff --git a/hledger-lib/Text/Megaparsec/Custom.hs b/hledger-lib/Text/Megaparsec/Custom.hs
index 436cba927..ab8352480 100644
--- a/hledger-lib/Text/Megaparsec/Custom.hs
+++ b/hledger-lib/Text/Megaparsec/Custom.hs
@@ -8,7 +8,7 @@
 
 module Text.Megaparsec.Custom (
   -- * Custom parse error type
-  CustomErr,
+  HledgerParseErrorData,
 
   -- * Failing with an arbitrary source position
   parseErrorAt,
@@ -60,7 +60,7 @@ import Text.Megaparsec
 -- | A custom error type for the parser. The type is specialized to
 -- parsers of 'Text' streams.
 
-data CustomErr
+data HledgerParseErrorData
   -- | Fail with a message at a specific source position interval. The
   -- interval must be contained within a single line.
   = ErrorFailAt Int -- Starting offset
@@ -69,7 +69,7 @@ data CustomErr
   -- | Re-throw parse errors obtained from the "re-parsing" of an excerpt
   -- of the source text.
   | ErrorReparsing
-      (NE.NonEmpty (ParseError Text CustomErr)) -- Source fragment parse errors
+      (NE.NonEmpty (ParseError Text HledgerParseErrorData)) -- Source fragment parse errors
   deriving (Show, Eq, Ord)
 
 -- We require an 'Ord' instance for 'CustomError' so that they may be
@@ -77,13 +77,13 @@ data CustomErr
 -- derive it, but the derived instance requires an (orphan) instance for
 -- 'ParseError'. Hopefully this does not cause any trouble.
 
-deriving instance Ord (ParseError Text CustomErr)
+deriving instance Ord (ParseError Text HledgerParseErrorData)
 
--- Note: the pretty-printing of our 'CustomErr' type is only partally
+-- Note: the pretty-printing of our 'HledgerParseErrorData' type is only partally
 -- defined in its 'ShowErrorComponent' instance; we perform additional
 -- adjustments in 'customErrorBundlePretty'.
 
-instance ShowErrorComponent CustomErr where
+instance ShowErrorComponent HledgerParseErrorData where
   showErrorComponent (ErrorFailAt _ _ errMsg) = errMsg
   showErrorComponent (ErrorReparsing _) = "" -- dummy value
 
@@ -98,7 +98,7 @@ instance ShowErrorComponent CustomErr where
 -- start of the input stream (the number of tokens processed at that
 -- point).
 
-parseErrorAt :: Int -> String -> CustomErr
+parseErrorAt :: Int -> String -> HledgerParseErrorData
 parseErrorAt offset = ErrorFailAt offset (offset+1)
 
 -- | Fail at a specific source interval, given by the raw offsets of its
@@ -112,7 +112,7 @@ parseErrorAtRegion
   :: Int    -- ^ Start offset
   -> Int    -- ^ End end offset
   -> String -- ^ Error message
-  -> CustomErr
+  -> HledgerParseErrorData
 parseErrorAtRegion startOffset endOffset msg =
   if startOffset < endOffset
     then ErrorFailAt startOffset endOffset msg
@@ -142,7 +142,7 @@ getExcerptText (SourceExcerpt _ txt) = txt
 -- This function could be extended to return the result of 'p', but we don't
 -- currently need this.
 
-excerpt_ :: MonadParsec CustomErr Text m => m a -> m SourceExcerpt
+excerpt_ :: MonadParsec HledgerParseErrorData Text m => m a -> m SourceExcerpt
 excerpt_ p = do
   offset <- getOffset
   (!txt, _) <- match p
@@ -164,8 +164,8 @@ excerpt_ p = do
 reparseExcerpt
   :: Monad m
   => SourceExcerpt
-  -> ParsecT CustomErr Text m a
-  -> ParsecT CustomErr Text m a
+  -> ParsecT HledgerParseErrorData Text m a
+  -> ParsecT HledgerParseErrorData Text m a
 reparseExcerpt (SourceExcerpt offset txt) p = do
   (_, res) <- lift $ runParserT' p (offsetInitialState offset txt)
   case res of
@@ -210,7 +210,7 @@ reparseExcerpt (SourceExcerpt offset txt) p = do
 -- 0 (that is, the beginning of the source file), which is the
 -- case for 'ParseErrorBundle's returned from 'runParserT'.
 
-customErrorBundlePretty :: ParseErrorBundle Text CustomErr -> String
+customErrorBundlePretty :: ParseErrorBundle Text HledgerParseErrorData -> String
 customErrorBundlePretty errBundle =
   let errBundle' = errBundle { bundleErrors =
         NE.sortWith errorOffset $ -- megaparsec requires that the list of errors be sorted by their offsets
@@ -219,7 +219,7 @@ customErrorBundlePretty errBundle =
 
   where
     finalizeCustomError
-      :: ParseError Text CustomErr -> NE.NonEmpty (ParseError Text CustomErr)
+      :: ParseError Text HledgerParseErrorData -> NE.NonEmpty (ParseError Text HledgerParseErrorData)
     finalizeCustomError err = case findCustomError err of
       Nothing -> pure err
 
@@ -233,7 +233,7 @@ customErrorBundlePretty errBundle =
 
     -- If any custom errors are present, arbitrarily take the first one
     -- (since only one custom error should be used at a time).
-    findCustomError :: ParseError Text CustomErr -> Maybe CustomErr
+    findCustomError :: ParseError Text HledgerParseErrorData -> Maybe HledgerParseErrorData
     findCustomError err = case err of
       FancyError _ errSet ->
         finds (\case {ErrorCustom e -> Just e; _ -> Nothing}) errSet
@@ -280,7 +280,7 @@ data FinalParseError' e
   | FinalBundleWithStack (FinalParseErrorBundle' e)
   deriving (Show)
 
-type FinalParseError = FinalParseError' CustomErr
+type FinalParseError = FinalParseError' HledgerParseErrorData
 
 -- We need a 'Monoid' instance for 'FinalParseError' so that 'ExceptT
 -- FinalParseError m' is an instance of Alternative and MonadPlus, which
@@ -308,7 +308,7 @@ data FinalParseErrorBundle' e = FinalParseErrorBundle'
   , includeFileStack :: [FilePath]
   } deriving (Show)
 
-type FinalParseErrorBundle = FinalParseErrorBundle' CustomErr
+type FinalParseErrorBundle = FinalParseErrorBundle' HledgerParseErrorData
 
 
 --- * Constructing and throwing final parse errors
@@ -347,7 +347,7 @@ finalCustomFailure = finalFancyFailure . S.singleton . ErrorCustom
 -- 'attachSource' must be used on a "final" parse error before it can be
 -- pretty-printed.
 
-finalErrorBundlePretty :: FinalParseErrorBundle' CustomErr -> String
+finalErrorBundlePretty :: FinalParseErrorBundle' HledgerParseErrorData -> String
 finalErrorBundlePretty bundle =
      concatMap showIncludeFilepath (includeFileStack bundle)
   <> customErrorBundlePretty (finalErrorBundle bundle)
@@ -391,11 +391,11 @@ attachSource filePath sourceText finalParseError = case finalParseError of
 
 parseIncludeFile
   :: Monad m
-  => StateT st (ParsecT CustomErr Text (ExceptT FinalParseError m)) a
+  => StateT st (ParsecT HledgerParseErrorData Text (ExceptT FinalParseError m)) a
   -> st
   -> FilePath
   -> Text
-  -> StateT st (ParsecT CustomErr Text (ExceptT FinalParseError m)) a
+  -> StateT st (ParsecT HledgerParseErrorData Text (ExceptT FinalParseError m)) a
 parseIncludeFile parser initialState filepath text =
   catchError parser' handler
   where