Fix the Monoid and Semigroup instances (Close issue #15)

CHANGELOG.markdown

@@ -1,3 +1,8 @@
+1.2.1
+-----
+* Bug fix for the `Monoid` instance in response to [issue #15](https://github.com/ekmett/trifecta/issues/14)
+* Made the `Semigroup` instance match the `Monoid` as well.
+
 1.2
 ---
 * Changed the `Monoid` instance for `Parser` in response to [issue #14](https://github.com/ekmett/trifecta/issues/14)

src/Text/Trifecta/Parser.hs

@@ -92,11 +92,11 @@ instance Alternative Parser where
   {-# INLINE many #-}
   some p = (:) <$> p <*> Alternative.many p
 
-instance Semigroup (Parser a) where
-  (<>) = (<|>)
+instance Semigroup a => Semigroup (Parser a) where
+  (<>) = liftA2 (<>)
   {-# INLINE (<>) #-}
 
-instance Monoid (Parser a) where
+instance Monoid a => Monoid (Parser a) where
   mappend = liftA2 mappend
   {-# INLINE mappend #-}
   mempty = pure mempty

trifecta.cabal

@@ -1,6 +1,6 @@
 name:          trifecta
 category:      Text, Parsing, Diagnostics, Pretty Printer, Logging
-version:       1.2
+version:       1.2.1
 license:       BSD3
 cabal-version: >= 1.10
 license-file:  LICENSE