Remove flexible instances, remove primed singleton function

Author: jappeace

Data/HashMap/Internal.hs

@@ -4,7 +4,6 @@
 {-# LANGUAGE RoleAnnotations #-}
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE UnboxedTuples #-}
-{-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE LambdaCase #-}
 #if __GLASGOW_HASKELL__ >= 802
 {-# LANGUAGE TypeInType #-}
@@ -292,7 +291,7 @@ instance Foldable.Foldable (HashMapT salt k) where
 
 #if MIN_VERSION_base(4,10,0)
 -- | @since 0.2.11
-instance Bifoldable HashMap where
+instance Bifoldable (HashMapT salt) where
     bifoldMap f g = foldMapWithKey (\ k v -> f k `mappend` g v)
     {-# INLINE bifoldMap #-}
     bifoldr f g = foldrWithKey (\ k v acc -> k `f` (v `g` acc))
@@ -390,7 +389,7 @@ instance Traversable (HashMapT salt k) where
     {-# INLINABLE traverse #-}
 
 #if MIN_VERSION_base(4,9,0)
-instance Eq2 HashMap where
+instance Eq2 (HashMapT salt) where
     liftEq2 = equal2
 
 instance Eq k => Eq1 (HashMapT salt k) where
@@ -461,7 +460,7 @@ equal2 eqk eqv t1 t2 = go (toList' t1 []) (toList' t2 [])
     leafEq (L k v) (L k' v') = eqk k k' && eqv v v'
 
 #if MIN_VERSION_base(4,9,0)
-instance Ord2 HashMap where
+instance Ord2 (HashMapT salt) where
     liftCompare2 = cmp
 
 instance Ord k => Ord1 (HashMapT salt k) where
@@ -602,11 +601,8 @@ empty :: forall k v salt . HashMapT salt k v
 empty = Empty
 
 -- | /O(1)/ Construct a map with a single element.
-singleton :: (Hashable k, KnownNat salt) => k -> v -> HashMapT salt k v
-singleton = singleton'
-
-singleton' :: forall k v salt . (Hashable k, KnownNat salt) => k -> v -> HashMapT salt k v
-singleton' k v = Leaf (hash (Proxy :: Proxy salt) k) (L k v)
+singleton :: forall k v salt . (Hashable k, KnownNat salt) => k -> v -> HashMapT salt k v
+singleton k v = Leaf (hash (Proxy :: Proxy salt) k) (L k v)
 
 ------------------------------------------------------------------------
 -- * Basic interface