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
@@ -67,7 +67,7 @@
   restOfLine = Strict.drop . fromIntegral . columnByte <$> position <*> line
   {-# INLINE restOfLine #-}
 
-instance (MonadPlus m, DeltaParsing m, Show s) => DeltaParsing (Lazy.StateT s m) where
+instance (MonadPlus m, DeltaParsing m) => DeltaParsing (Lazy.StateT s m) where
   line = lift line
   {-# INLINE line #-}
   position = lift position
@@ -79,7 +79,7 @@
   restOfLine = lift restOfLine
   {-# INLINE restOfLine #-}
 
-instance (MonadPlus m, DeltaParsing m, Show s) => DeltaParsing (Strict.StateT s m) where
+instance (MonadPlus m, DeltaParsing m) => DeltaParsing (Strict.StateT s m) where
   line = lift line
   {-# INLINE line #-}
   position = lift position
@@ -103,7 +103,7 @@
   restOfLine = lift restOfLine
   {-# INLINE restOfLine #-}
 
-instance (MonadPlus m, DeltaParsing m, Monoid w, Show w) => DeltaParsing (Strict.WriterT w m) where
+instance (MonadPlus m, DeltaParsing m, Monoid w) => DeltaParsing (Strict.WriterT w m) where
   line = lift line
   {-# INLINE line #-}
   position = lift position
@@ -115,7 +115,7 @@
   restOfLine = lift restOfLine
   {-# INLINE restOfLine #-}
 
-instance (MonadPlus m, DeltaParsing m, Monoid w, Show w) => DeltaParsing (Lazy.WriterT w m) where
+instance (MonadPlus m, DeltaParsing m, Monoid w) => DeltaParsing (Lazy.WriterT w m) where
   line = lift line
   {-# INLINE line #-}
   position = lift position
@@ -127,7 +127,7 @@
   restOfLine = lift restOfLine
   {-# INLINE restOfLine #-}
 
-instance (MonadPlus m, DeltaParsing m, Monoid w, Show s, Show w) => DeltaParsing (Lazy.RWST r w s m) where
+instance (MonadPlus m, DeltaParsing m, Monoid w) => DeltaParsing (Lazy.RWST r w s m) where
   line = lift line
   {-# INLINE line #-}
   position = lift position
@@ -139,7 +139,7 @@
   restOfLine = lift restOfLine
   {-# INLINE restOfLine #-}
 
-instance (MonadPlus m, DeltaParsing m, Monoid w, Show s, Show w) => DeltaParsing (Strict.RWST r w s m) where
+instance (MonadPlus m, DeltaParsing m, Monoid w) => DeltaParsing (Strict.RWST r w s m) where
   line = lift line
   {-# INLINE line #-}
   position = lift position
@@ -201,13 +201,13 @@
   -- | Seek a previously marked location
   release :: d -> m ()
 
-instance (MonadPlus m, MarkParsing d m, Show s) => MarkParsing d (Lazy.StateT s m) where
+instance (MonadPlus m, MarkParsing d m) => MarkParsing d (Lazy.StateT s m) where
   mark = lift mark
   {-# INLINE mark #-}
   release = lift . release
   {-# INLINE release #-}
 
-instance (MonadPlus m, MarkParsing d m, Show s) => MarkParsing d (Strict.StateT s m) where
+instance (MonadPlus m, MarkParsing d m) => MarkParsing d (Strict.StateT s m) where
   mark = lift mark
   {-# INLINE mark #-}
   release = lift . release
@@ -219,25 +219,25 @@
   release = lift . release
   {-# INLINE release #-}
 
-instance (MonadPlus m, MarkParsing d m, Monoid w, Show w) => MarkParsing d (Strict.WriterT w m) where
+instance (MonadPlus m, MarkParsing d m, Monoid w) => MarkParsing d (Strict.WriterT w m) where
   mark = lift mark
   {-# INLINE mark #-}
   release = lift . release
   {-# INLINE release #-}
 
-instance (MonadPlus m, MarkParsing d m, Monoid w, Show w) => MarkParsing d (Lazy.WriterT w m) where
+instance (MonadPlus m, MarkParsing d m, Monoid w) => MarkParsing d (Lazy.WriterT w m) where
   mark = lift mark
   {-# INLINE mark #-}
   release = lift . release
   {-# INLINE release #-}
 
-instance (MonadPlus m, MarkParsing d m, Monoid w, Show s, Show w) => MarkParsing d (Lazy.RWST r w s m) where
+instance (MonadPlus m, MarkParsing d m, Monoid w) => MarkParsing d (Lazy.RWST r w s m) where
   mark = lift mark
   {-# INLINE mark #-}
   release = lift . release
   {-# INLINE release #-}
 
-instance (MonadPlus m, MarkParsing d m, Monoid w, Show s, Show w) => MarkParsing d (Strict.RWST r w s m) where
+instance (MonadPlus m, MarkParsing d m, Monoid w) => MarkParsing d (Strict.RWST r w s m) where
   mark = lift mark
   {-# INLINE mark #-}
   release = lift . release
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
+version:       1.5.1
 license:       BSD3
 cabal-version: >= 1.10
 license-file:  LICENSE
@@ -58,7 +58,7 @@
     hashable             >= 1.2.1   && < 1.3,
     lens                 >= 4.0     && < 5,
     mtl                  >= 2.0.1   && < 2.3,
-    parsers              >= 0.10    && < 1,
+    parsers              >= 0.12.1  && < 1,
     reducers             >= 3.10    && < 4,
     semigroups           >= 0.8.3.1 && < 1,
     transformers         >= 0.2     && < 0.5,