Make it compile with MicroHs

.gitignore

@@ -9,3 +9,4 @@ cabal.sandbox.config
 # cabal build outputs
 dist
 dist-newstyle
+dist-mcabal

Data/DList.hs

@@ -43,7 +43,7 @@ module Data.DList
   ( -- * Difference List Type
 
 -- CPP: GHC >= 8 for pattern synonyms allowed in the constructor
-#if __GLASGOW_HASKELL__ >= 800
+#if __GLASGOW_HASKELL__ >= 800 || __MHS__
     DList (Nil, Cons),
 #else
     DList,

Data/DList/DNonEmpty/Internal.hs

@@ -460,6 +460,7 @@ instance a ~ Char => IsString (DNonEmpty a) where
   {-# INLINE fromString #-}
   fromString = fromList
 
+#ifdef __GLASGOW_HASKELL__
 instance Exts.IsList (DNonEmpty a) where
   type Item (DNonEmpty a) = a
 
@@ -468,6 +469,7 @@ instance Exts.IsList (DNonEmpty a) where
 
   {-# INLINE toList #-}
   toList = toList
+#endif
 
 instance Semigroup.Semigroup (DNonEmpty a) where
   {-# INLINE (<>) #-}

Data/DList/Internal.hs

@@ -16,8 +16,8 @@ package depends on this module ('Data.DList.Internal'), we don't perform the
 same check everywhere else.
 
 -}
-#if !defined(__GLASGOW_HASKELL__)
-#error "Your compiler is not GHC. Let us know if dlist can be made to work on it."
+#if !defined(__GLASGOW_HASKELL__) && !defined(__MHS__)
+#error "Your compiler is not GHC or MicroHs. Let us know if dlist can be made to work on it."
 #endif
 
 -- For the IsList and IsString instances
@@ -64,9 +64,9 @@ import qualified Control.Applicative as Applicative
 import Control.DeepSeq (NFData (..))
 import qualified Control.Monad as Monad
 -- CPP: base >= 4.9 for MonadFail
--- CPP: base >= 4.13 for MonadFail exported from Control.Monad
+-- CPP: base >= 4.13 for MonadFail exported from Prelude
 #if MIN_VERSION_base(4,9,0) && !MIN_VERSION_base(4,13,0)
-import qualified Control.Monad.Fail as Monad
+import Control.Monad.Fail (MonadFail (..))
 #endif
 import qualified Data.Foldable as Foldable
 import Data.Function (on)
@@ -159,10 +159,10 @@ construction.
 toList :: DList a -> [a]
 toList = ($ []) . unsafeApplyDList
 
--- CPP: GHC >= 7.8 for pattern synonyms
-#if __GLASGOW_HASKELL__ >= 708
+-- CPP: GHC >= 7.8 or MicroHs for pattern synonyms
+#if __GLASGOW_HASKELL__ >= 708 || __MHS__
 
--- CPP: GHC >= 7.10 for pattern synonym signatures
+-- CPP: GHC >= 7.10 or MicroHs for pattern synonym signatures
 
 {- ORMOLU_DISABLE -}
 {-|
@@ -172,7 +172,7 @@ A unidirectional pattern synonym for 'empty'. This is implemented with 'toList'.
 -}
 {- ORMOLU_ENABLE -}
 
-#if __GLASGOW_HASKELL__ >= 710
+#if __GLASGOW_HASKELL__ >= 710 || __MHS__
 pattern Nil :: DList a
 #endif
 pattern Nil <- (toList -> [])
@@ -185,7 +185,7 @@ A unidirectional pattern synonym for 'cons'. This is implemented with 'toList'.
 -}
 {- ORMOLU_ENABLE -}
 
-#if __GLASGOW_HASKELL__ >= 710
+#if __GLASGOW_HASKELL__ >= 710 || __MHS__
 pattern Cons :: a -> [a] -> DList a
 #endif
 pattern Cons x xs <- (toList -> x : xs)
@@ -574,7 +574,7 @@ instance Monad DList where
 
 -- CPP: base >= 4.9 for MonadFail
 #if MIN_VERSION_base(4,9,0)
-instance Monad.MonadFail DList where
+instance MonadFail DList where
   {-# INLINE fail #-}
   fail _ = empty
 #endif
@@ -605,8 +605,8 @@ instance Foldable.Foldable DList where
   {-# INLINE foldl1 #-}
   foldl1 f = List.foldl1 f . toList
 
--- CPP: GHC >= 7.6 for foldl', foldr' in Foldable
-#if __GLASGOW_HASKELL__ >= 706
+-- CPP: base >= 4.6 for foldl', foldr' in Foldable
+#if MIN_VERSION_base(4,6,0)
   {-# INLINE foldl' #-}
   foldl' f x = List.foldl' f x . toList
 

dlist.cabal

@@ -13,7 +13,7 @@ maintainer:             Sean Leather <[email protected]>
 copyright:              2006-2009 Don Stewart, 2013-2020 Sean Leather, 2017-2020 Oleg Grenrus, contributors
 homepage:               https://github.com/spl/dlist
 bug-reports:            https://github.com/spl/dlist/issues
-extra-source-files:     readme.md,
+extra-source-files:     readme.md
                         changelog.md
                         tests/ImportUnsafe.hs
 build-type:             Simple
@@ -51,7 +51,7 @@ library
   exposed-modules:      Data.DList
                         Data.DList.Unsafe
   other-modules:        Data.DList.Internal
-  if impl(ghc >= 8.0)
+  if impl(ghc >= 8.0) || impl(mhs)
     exposed-modules:    Data.DList.DNonEmpty
     other-modules:      Data.DList.DNonEmpty.Internal
   default-language:     Haskell2010