diff --git a/LICENSE b/LICENSE
--- a/LICENSE
+++ b/LICENSE
@@ -1,4 +1,4 @@
-Copyright 2010-2014 Edward Kmett
+Copyright 2010-2015 Edward Kmett
 Copyright 2008 Ross Patterson
 Copyright 2007 Paolo Martini
 Copyright 1999-2000 Daan Leijen
diff --git a/src/Text/Trifecta.hs b/src/Text/Trifecta.hs
--- a/src/Text/Trifecta.hs
+++ b/src/Text/Trifecta.hs
@@ -1,7 +1,6 @@
 -----------------------------------------------------------------------------
 -- |
--- Module      :  Text.Trifecta
--- Copyright   :  (C) 2011-2014 Edward Kmett,
+-- Copyright   :  (C) 2011-2015 Edward Kmett
 -- License     :  BSD-style (see the file LICENSE)
 --
 -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
diff --git a/src/Text/Trifecta/Combinators.hs b/src/Text/Trifecta/Combinators.hs
--- a/src/Text/Trifecta/Combinators.hs
+++ b/src/Text/Trifecta/Combinators.hs
@@ -6,7 +6,7 @@
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Text.Trifecta.Combinators
--- Copyright   :  (c) Edward Kmett 2011-2014
+-- Copyright   :  (c) Edward Kmett 2011-2015
 -- License     :  BSD3
 --
 -- Maintainer  :  ekmett@gmail.com
diff --git a/src/Text/Trifecta/Delta.hs b/src/Text/Trifecta/Delta.hs
--- a/src/Text/Trifecta/Delta.hs
+++ b/src/Text/Trifecta/Delta.hs
@@ -3,7 +3,6 @@
 {-# LANGUAGE DeriveGeneric #-}
 -----------------------------------------------------------------------------
 -- |
--- Module      :  Text.Trifecta.Delta
 -- Copyright   :  (C) 2011-2015 Edward Kmett
 -- License     :  BSD-style (see the file LICENSE)
 --
diff --git a/src/Text/Trifecta/Highlight.hs b/src/Text/Trifecta/Highlight.hs
--- a/src/Text/Trifecta/Highlight.hs
+++ b/src/Text/Trifecta/Highlight.hs
@@ -7,8 +7,7 @@
 #endif
 -----------------------------------------------------------------------------
 -- |
--- Module      :  Text.Trifecta.Highlight
--- Copyright   :  (C) 2011-2014 Edward Kmett
+-- Copyright   :  (C) 2011-2015 Edward Kmett
 -- License     :  BSD-style (see the file LICENSE)
 --
 -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
diff --git a/src/Text/Trifecta/Instances.hs b/src/Text/Trifecta/Instances.hs
--- a/src/Text/Trifecta/Instances.hs
+++ b/src/Text/Trifecta/Instances.hs
@@ -1,8 +1,7 @@
 {-# OPTIONS_GHC -fno-warn-orphans #-}
 -----------------------------------------------------------------------------
 -- |
--- Module      :  Text.Trifecta.Instances
--- Copyright   :  (c) Edward Kmett 2013-2014
+-- Copyright   :  (c) Edward Kmett 2013-2015
 -- License     :  BSD3
 --
 -- Maintainer  :  ekmett@gmail.com
diff --git a/src/Text/Trifecta/Parser.hs b/src/Text/Trifecta/Parser.hs
--- a/src/Text/Trifecta/Parser.hs
+++ b/src/Text/Trifecta/Parser.hs
@@ -10,8 +10,7 @@
 {-# LANGUAGE TemplateHaskell #-}
 -----------------------------------------------------------------------------
 -- |
--- Module      :  Text.Trifecta.Parser
--- Copyright   :  (c) Edward Kmett 2011-2014
+-- Copyright   :  (c) Edward Kmett 2011-2015
 -- License     :  BSD3
 --
 -- Maintainer  :  ekmett@gmail.com
@@ -66,7 +65,7 @@
     (a -> Err -> It Rope r) ->
     (Err -> It Rope r) ->
     (a -> Set String -> Delta -> ByteString -> It Rope r) -> -- committed success
-    (Doc -> It Rope r) ->                                -- committed err
+    (ErrInfo -> It Rope r) ->                                -- committed err
     Delta -> ByteString -> It Rope r
   }
 
@@ -109,7 +108,11 @@
     m (\a e -> unparser (k a) (\b e' -> eo b (e <> e')) (\e' -> ee (e <> e')) co ce d bs) ee
       (\a es d' bs' -> unparser (k a)
          (\b e' -> co b (es <> _expected e') d' bs')
-         (\e -> ce (explain (renderingCaret d' bs') e { _expected = _expected e <> es }))
+         (\e ->
+           let errDoc = explain (renderingCaret d' bs') e { _expected = _expected e <> es }
+               errDelta = _finalDeltas e
+           in  ce $ ErrInfo errDoc (d' : errDelta)
+         )
          co ce d' bs') ce d bs
   {-# INLINE (>>=) #-}
   (>>) = (*>)
@@ -126,7 +129,8 @@
 manyAccum :: (a -> [a] -> [a]) -> Parser a -> Parser [a]
 manyAccum f (Parser p) = Parser $ \eo _ co ce d bs ->
   let walk xs x es d' bs' = p (manyErr d' bs') (\e -> co (f x xs) (_expected e <> es) d' bs') (walk (f x xs)) ce d' bs'
-      manyErr d' bs' _ e  = ce $ explain (renderingCaret d' bs') (e <> failed "'many' applied to a parser that accepted an empty string")
+      manyErr d' bs' _ e  = ce (ErrInfo errDoc [d'])
+        where errDoc = explain (renderingCaret d' bs') (e <> failed "'many' applied to a parser that accepted an empty string")
   in p (manyErr d bs) (eo []) (walk []) ce d bs
 
 liftIt :: It Rope a -> Parser a
@@ -203,7 +207,7 @@
 
 data Step a
   = StepDone !Rope a
-  | StepFail !Rope Doc
+  | StepFail !Rope ErrInfo
   | StepCont !Rope (Result a) (Rope -> Step a)
 
 instance Show a => Show (Step a) where
@@ -246,21 +250,24 @@
   = EO a Err
   | EE Err
   | CO a (Set String) Delta ByteString
-  | CE Doc
+  | CE ErrInfo
 
 stepParser :: Parser a -> Delta -> ByteString -> Step a
 stepParser (Parser p) d0 bs0 = go mempty $ p eo ee co ce d0 bs0 where
   eo a e       = Pure (EO a e)
   ee e         = Pure (EE e)
   co a es d bs = Pure (CO a es d bs)
-  ce doc       = Pure (CE doc)
+  ce errInf    = Pure (CE errInf)
   go r (Pure (EO a _))     = StepDone r a
-  go r (Pure (EE e))       = StepFail r $ explain (renderingCaret d0 bs0) e
+  go r (Pure (EE e))       = StepFail r $
+                              let errDoc = explain (renderingCaret d0 bs0) e
+                              in  ErrInfo errDoc (_finalDeltas e)
   go r (Pure (CO a _ _ _)) = StepDone r a
   go r (Pure (CE d))       = StepFail r d
   go r (It ma k)           = StepCont r (case ma of
                                 EO a _     -> Success a
-                                EE e       -> Failure $ explain (renderingCaret d0 bs0) e
+                                EE e       -> Failure $
+                                  ErrInfo (explain (renderingCaret d0 bs0) e) (d0 : _finalDeltas e)
                                 CO a _ _ _ -> Success a
                                 CE d       -> Failure d
                               ) (go <*> k)
@@ -281,7 +288,7 @@
   case result of
    Success a  -> return (Just a)
    Failure xs -> do
-     liftIO $ displayIO stdout $ renderPretty 0.8 80 $ xs <> linebreak
+     liftIO $ displayIO stdout $ renderPretty 0.8 80 $ (_errDoc xs) <> linebreak
      return Nothing
 
 -- | @parseFromFileEx p filePath@ runs a parser @p@ on the
@@ -310,5 +317,5 @@
 
 parseTest :: (MonadIO m, Show a) => Parser a -> String -> m ()
 parseTest p s = case parseByteString p mempty (UTF8.fromString s) of
-  Failure xs -> liftIO $ displayIO stdout $ renderPretty 0.8 80 $ xs <> linebreak -- TODO: retrieve columns
+  Failure xs -> liftIO $ displayIO stdout $ renderPretty 0.8 80 $ (_errDoc xs) <> linebreak -- TODO: retrieve columns
   Success a  -> liftIO (print a)
diff --git a/src/Text/Trifecta/Rendering.hs b/src/Text/Trifecta/Rendering.hs
--- a/src/Text/Trifecta/Rendering.hs
+++ b/src/Text/Trifecta/Rendering.hs
@@ -6,8 +6,7 @@
 {-# LANGUAGE DeriveGeneric #-}
 -----------------------------------------------------------------------------
 -- |
--- Module      :  Text.Trifecta.Rendering
--- Copyright   :  (C) 2011-2014 Edward Kmett
+-- Copyright   :  (C) 2011-2015 Edward Kmett
 -- License     :  BSD-style (see the file LICENSE)
 --
 -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
diff --git a/src/Text/Trifecta/Result.hs b/src/Text/Trifecta/Result.hs
--- a/src/Text/Trifecta/Result.hs
+++ b/src/Text/Trifecta/Result.hs
@@ -11,8 +11,7 @@
 {-# LANGUAGE UndecidableInstances #-}
 -----------------------------------------------------------------------------
 -- |
--- Module      :  Text.Trifecta.Result
--- Copyright   :  (c) Edward Kmett 2011-2014
+-- Copyright   :  (c) Edward Kmett 2011-2015
 -- License     :  BSD3
 --
 -- Maintainer  :  ekmett@gmail.com
@@ -30,6 +29,7 @@
   , _Failure
   -- * Parsing Errors
   , Err(..), HasErr(..), Errable(..)
+  , ErrInfo(..)
   , explain
   , failed
   ) where
@@ -47,35 +47,41 @@
 import Text.Trifecta.Rendering
 import Text.Trifecta.Delta as Delta
 
+data ErrInfo = ErrInfo
+  { _errDoc    :: Doc
+  , _errDeltas :: [Delta]
+  } deriving(Show)
+
 -- | This is used to report an error. What went wrong, some supplemental docs and a set of things expected
 -- at the current location. This does not, however, include the actual location.
 data Err = Err
-  { _reason    :: Maybe Doc
-  , _footnotes :: [Doc]
-  , _expected  :: Set String
+  { _reason     :: Maybe Doc
+  , _footnotes  :: [Doc]
+  , _expected   :: Set String
+  , _finalDeltas :: [Delta]
   }
 
 makeClassy ''Err
 
 instance Semigroup Err where
-  Err md mds mes <> Err nd nds nes
-    = Err (nd <|> md) (if isJust nd then nds else if isJust md then mds else nds ++ mds) (mes <> nes)
+  Err md mds mes delta1 <> Err nd nds nes delta2
+    = Err (nd <|> md) (if isJust nd then nds else if isJust md then mds else nds ++ mds) (mes <> nes) (delta1 <> delta2)
   {-# INLINE (<>) #-}
 
 instance Monoid Err where
-  mempty = Err Nothing [] mempty
+  mempty = Err Nothing [] mempty mempty
   {-# INLINE mempty #-}
   mappend = (<>)
   {-# INLINE mappend #-}
 
 -- | Generate a simple 'Err' word-wrapping the supplied message.
 failed :: String -> Err
-failed m = Err (Just (fillSep (pretty <$> words m))) [] mempty
+failed m = Err (Just (fillSep (pretty <$> words m))) [] mempty mempty
 {-# INLINE failed #-}
 
 -- | Convert a location and an 'Err' into a 'Doc'
 explain :: Rendering -> Err -> Doc
-explain r (Err mm as es)
+explain r (Err mm as es _)
   | Set.null es = report (withEx mempty)
   | isJust mm   = report $ withEx $ Pretty.char ',' <+> expecting
   | otherwise   = report expecting
@@ -92,10 +98,14 @@
 class Errable m where
   raiseErr :: Err -> m a
 
+instance Monoid ErrInfo where
+  mempty = ErrInfo mempty mempty
+  mappend (ErrInfo xs d1) (ErrInfo ys d2) = ErrInfo (vsep [xs, ys]) (max d1 d2)
+
 -- | The result of parsing. Either we succeeded or something went wrong.
 data Result a
   = Success a
-  | Failure Doc
+  | Failure ErrInfo
   deriving (Show,Functor,Foldable,Traversable)
 
 -- | A 'Prism' that lets you embed or retrieve a 'Result' in a potentially larger type.
@@ -110,34 +120,36 @@
 _Success :: AsResult s t a b => Prism s t a b
 _Success = _Result . dimap seta (either id id) . right' . rmap (fmap Success) where
   seta (Success a) = Right a
-  seta (Failure d) = Left (pure (Failure d))
+  seta (Failure e) = Left (pure (Failure e))
 {-# INLINE _Success #-}
 
 -- | The 'Prism' for the 'Failure' constructor of 'Result'
-_Failure :: AsResult s s a a => Prism' s Doc
+_Failure :: AsResult s s a a => Prism' s ErrInfo
 _Failure = _Result . dimap seta (either id id) . right' . rmap (fmap Failure) where
-  seta (Failure d) = Right d
+  seta (Failure e) = Right e
   seta (Success a) = Left (pure (Success a))
 {-# INLINE _Failure #-}
 
 instance Show a => Pretty (Result a) where
-  pretty (Success a)  = pretty (show a)
-  pretty (Failure xs) = pretty xs
+  pretty (Success a)    = pretty (show a)
+  pretty (Failure xs) = pretty . _errDoc $ xs
 
 instance Applicative Result where
   pure = Success
   {-# INLINE pure #-}
-  Success f  <*> Success a  = Success (f a)
-  Success _  <*> Failure ys = Failure ys
-  Failure xs <*> Success _  = Failure xs
-  Failure xs <*> Failure ys = Failure $ vsep [xs, ys]
+  Success f <*> Success a = Success (f a)
+  Success _ <*> Failure y = Failure y
+  Failure x <*> Success _ = Failure x
+  Failure x <*> Failure y =
+    Failure $ ErrInfo (vsep [_errDoc x, _errDoc y]) (_errDeltas x <> _errDeltas y)
   {-# INLINE (<*>) #-}
 
 instance Alternative Result where
-  Failure xs <|> Failure ys = Failure $ vsep [xs, ys]
-  Success a  <|> Success _  = Success a
-  Success a  <|> Failure _  = Success a
-  Failure _  <|> Success a  = Success a
+  Failure x <|> Failure y =
+    Failure $ ErrInfo (vsep [_errDoc x, _errDoc y]) (_errDeltas x <> _errDeltas y)
+  Success a <|> Success _ = Success a
+  Success a <|> Failure _ = Success a
+  Failure _ <|> Success a = Success a
   {-# INLINE (<|>) #-}
   empty = Failure mempty
   {-# INLINE empty #-}
diff --git a/src/Text/Trifecta/Rope.hs b/src/Text/Trifecta/Rope.hs
--- a/src/Text/Trifecta/Rope.hs
+++ b/src/Text/Trifecta/Rope.hs
@@ -1,8 +1,7 @@
-{-# LANGUAGE TypeFamilies, MultiParamTypeClasses, FlexibleInstances, BangPatterns, PatternGuards, DeriveDataTypeable, DeriveGeneric #-}
+{-# LANGUAGE TypeFamilies, MultiParamTypeClasses, FlexibleInstances, BangPatterns, DeriveDataTypeable, DeriveGeneric #-}
 -----------------------------------------------------------------------------
 -- |
--- Module      :  Text.Trifecta.Rope
--- Copyright   :  (C) 2011-2014 Edward Kmett
+-- Copyright   :  (C) 2011-2015 Edward Kmett
 -- License     :  BSD-style (see the file LICENSE)
 --
 -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
diff --git a/src/Text/Trifecta/Util/Array.hs b/src/Text/Trifecta/Util/Array.hs
--- a/src/Text/Trifecta/Util/Array.hs
+++ b/src/Text/Trifecta/Util/Array.hs
@@ -1,7 +1,6 @@
 {-# LANGUAGE BangPatterns, CPP, MagicHash, Rank2Types, UnboxedTuples #-}
 -----------------------------------------------------------------------------
 -- |
--- Module      :  Text.Trifecta.Util.Array
 -- Copyright   :  Edward Kmett 2011-2015
 --                Johan Tibell 2011
 -- License     :  BSD3
diff --git a/src/Text/Trifecta/Util/Combinators.hs b/src/Text/Trifecta/Util/Combinators.hs
--- a/src/Text/Trifecta/Util/Combinators.hs
+++ b/src/Text/Trifecta/Util/Combinators.hs
@@ -1,7 +1,6 @@
 -----------------------------------------------------------------------------
 -- |
--- Module      :  Text.Trifecta.Util.Combinators
--- Copyright   :  (C) 2011-2014 Edward Kmett
+-- Copyright   :  (C) 2011-2015 Edward Kmett
 -- License     :  BSD-style (see the file LICENSE)
 --
 -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
diff --git a/src/Text/Trifecta/Util/IntervalMap.hs b/src/Text/Trifecta/Util/IntervalMap.hs
--- a/src/Text/Trifecta/Util/IntervalMap.hs
+++ b/src/Text/Trifecta/Util/IntervalMap.hs
@@ -9,7 +9,7 @@
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Text.Trifecta.Util.IntervalMap
--- Copyright   :  (c) Edward Kmett 2011-2014
+-- Copyright   :  (c) Edward Kmett 2011-2015
 --                (c) Ross Paterson 2008
 -- License     :  BSD-style
 -- Maintainer  :  ekmett@gmail.com
diff --git a/src/Text/Trifecta/Util/It.hs b/src/Text/Trifecta/Util/It.hs
--- a/src/Text/Trifecta/Util/It.hs
+++ b/src/Text/Trifecta/Util/It.hs
@@ -7,7 +7,7 @@
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Text.Trifecta.Util.It
--- Copyright   :  (C) 2011-2014 Edward Kmett
+-- Copyright   :  (C) 2011-2015 Edward Kmett
 -- License     :  BSD-style (see the file LICENSE)
 --
 -- Maintainer  :  Edward Kmett <ekmett@gmail.com>
diff --git a/trifecta.cabal b/trifecta.cabal
--- a/trifecta.cabal
+++ b/trifecta.cabal
@@ -1,6 +1,6 @@
 name:          trifecta
 category:      Text, Parsing, Diagnostics, Pretty Printer, Logging
-version:       1.5.2
+version:       1.6
 license:       BSD3
 cabal-version: >= 1.10
 license-file:  LICENSE
@@ -9,7 +9,7 @@
 stability:     experimental
 homepage:      http://github.com/ekmett/trifecta/
 bug-reports:   http://github.com/ekmett/trifecta/issues
-copyright:     Copyright (C) 2010-2014 Edward A. Kmett
+copyright:     Copyright (C) 2010-2015 Edward A. Kmett
 synopsis:      A modern parser combinator library with convenient diagnostics
 description:
   A modern parser combinator library with slicing and Clang-style colored diagnostics
@@ -50,7 +50,7 @@
     blaze-markup         >= 0.5     && < 0.8,
     bytestring           >= 0.9.1   && < 0.11,
     charset              >= 0.3.5.1 && < 1,
-    comonad              >= 4       && < 5,
+    comonad              >= 4       && < 6,
     containers           >= 0.3     && < 0.6,
     deepseq              >= 1.2.0.1 && < 1.5,
     fingertree           >= 0.1     && < 0.2,
@@ -62,13 +62,13 @@
     profunctors          >= 4.0     && < 6,
     reducers             >= 3.10    && < 4,
     semigroups           >= 0.8.3.1 && < 1,
-    transformers         >= 0.2     && < 0.5,
+    transformers         >= 0.2     && < 0.6,
     unordered-containers >= 0.2.1   && < 0.3,
     utf8-string          >= 0.3.6   && < 1.1
 
   default-language: Haskell2010
   hs-source-dirs:   src
-  ghc-options:      -O2 -Wall
+  ghc-options:      -O2 -Wall -fobject-code
 
 
 test-suite doctests