Correct more doctests

9 files changed, 48 insertions, 20 deletions

diff --git a/libraries/base/Data/Bifoldable.hs b/libraries/base/Data/Bifoldable.hs
index e29c18e767..1d057ee919 100644
--- a/libraries/base/Data/Bifoldable.hs
+++ b/libraries/base/Data/Bifoldable.hs
@@ -55,6 +55,13 @@ import Data.Maybe (fromMaybe)
 import Data.Monoid
 import GHC.Generics (K1(..))
 
+-- $setup
+-- >>> import Prelude
+-- >>> import Data.Char
+-- >>> import Data.Monoid (Product (..), Sum (..))
+-- >>> data BiList a b = BiList [a] [b]
+-- >>> instance Bifoldable BiList where bifoldr f g z (BiList as bs) = foldr f (foldr g z bs) as
+
 -- | 'Bifoldable' identifies foldable structures with two different varieties
 -- of elements (as opposed to 'Foldable', which has one variety of element).
 -- Common examples are 'Either' and @(,)@:
diff --git a/libraries/base/Data/Bifunctor.hs b/libraries/base/Data/Bifunctor.hs
index 04de5ad7f2..e8cfe05979 100644
--- a/libraries/base/Data/Bifunctor.hs
+++ b/libraries/base/Data/Bifunctor.hs
@@ -20,6 +20,10 @@ module Data.Bifunctor
 import Control.Applicative  ( Const(..) )
 import GHC.Generics ( K1(..) )
 
+-- $setup
+-- >>> import Prelude
+-- >>> import Data.Char (toUpper)
+
 -- | A bifunctor is a type constructor that takes
 -- two type arguments and is a functor in /both/ arguments. That
 -- is, unlike with 'Functor', a type constructor such as 'Either'
diff --git a/libraries/base/Data/Foldable.hs b/libraries/base/Data/Foldable.hs
index c5cf09d20c..8e61c6a886 100644
--- a/libraries/base/Data/Foldable.hs
+++ b/libraries/base/Data/Foldable.hs
@@ -117,6 +117,10 @@ import GHC.Generics
 import GHC.Tuple (Solo (..))
 import GHC.Num  ( Num(..) )
 
+-- $setup
+-- >>> import Prelude
+-- >>> import Data.Monoid (Product (..), Sum (..))
+
 infix  4 `elem`, `notElem`
 
 -- XXX: Missing haddock feature.  Links to anchors in other modules
diff --git a/libraries/base/Data/Functor.hs b/libraries/base/Data/Functor.hs
index e48c19e080..9689a0e798 100644
--- a/libraries/base/Data/Functor.hs
+++ b/libraries/base/Data/Functor.hs
@@ -25,7 +25,7 @@
 --  Nothing                 --  (Int -> String) -> Maybe Int -> Maybe String
 --
 --  >>> fmap show [1,2,3]   --  (a   -> b)      -> f a       -> f b
---  ["1", "2", "3"]         --  (Int -> String) -> [Int]     -> [String]
+--  ["1","2","3"]           --  (Int -> String) -> [Int]     -> [String]
 --
 --  >>> fmap show []        --  (a   -> b)      -> f a       -> f b
 --  []                      --  (Int -> String) -> [Int]     -> [String]
diff --git a/libraries/base/Data/Traversable.hs b/libraries/base/Data/Traversable.hs
index 03283493e5..a17930dbc5 100644
--- a/libraries/base/Data/Traversable.hs
+++ b/libraries/base/Data/Traversable.hs
@@ -165,15 +165,9 @@ class (Functor t, Foldable t) => Traversable t where
     --
     -- ==== __Examples__
     --
-    -- 'mapM' is 'traverse' for 'Monad', and the following example shows
-    -- how 'mapM' can apply an 'IO' action to a 'List' to produce a
-    -- structured result.
-    --
-    -- Basic usage:
-    --
-    -- >>> import System.IO
-    -- >>> mapM (openTempFile ".") ["t1", "t2"]
-    -- [("./t169980-3",{handle: ./t169980-3}),("./t269980-4",{handle: ./t269980-4})]
+    -- 'mapM' is literally a 'traverse' with a type signature restricted
+    -- to 'Monad'. Its implementation may be more efficient due to additional
+    -- power of 'Monad'.
     --
     mapM :: Monad m => (a -> m b) -> t a -> m (t b)
     {-# INLINE mapM #-}  -- See Note [Inline default methods]
diff --git a/libraries/base/GHC/Base.hs b/libraries/base/GHC/Base.hs
index 4af6a2bd73..0378df032b 100644
--- a/libraries/base/GHC/Base.hs
+++ b/libraries/base/GHC/Base.hs
@@ -131,6 +131,9 @@ import {-# SOURCE #-} Data.Semigroup.Internal ( stimesDefault
                                               , stimesIdempotentMonoid
                                               )
 
+-- $setup
+-- >>> import GHC.Num
+
 infixr 9  .
 infixr 5  ++
 infixl 4  <$
@@ -218,7 +221,7 @@ class Semigroup a where
         -- The default definition should be sufficient, but this can be
         -- overridden for efficiency.
         --
-        -- >>> import Data.List.NonEmpty
+        -- >>> import Data.List.NonEmpty (NonEmpty (..))
         -- >>> sconcat $ "Hello" :| [" ", "Haskell", "!"]
         -- "Hello Haskell!"
         sconcat :: NonEmpty a -> a
diff --git a/libraries/base/GHC/Float.hs b/libraries/base/GHC/Float.hs
index bd9c505de0..0828198251 100644
--- a/libraries/base/GHC/Float.hs
+++ b/libraries/base/GHC/Float.hs
@@ -70,6 +70,9 @@ import GHC.Num.BigNat
 
 infixr 8  **
 
+-- $setup
+-- >>> import Prelude
+
 ------------------------------------------------------------------------
 -- Standard numeric classes
 ------------------------------------------------------------------------
diff --git a/libraries/base/GHC/List.hs b/libraries/base/GHC/List.hs
index f3f2ad5909..34f338d67f 100644
--- a/libraries/base/GHC/List.hs
+++ b/libraries/base/GHC/List.hs
@@ -41,6 +41,17 @@ import GHC.Num.Integer (Integer)
 infixl 9  !!
 infix  4 `elem`, `notElem`
 
+-- $setup
+-- >>> import GHC.Base
+-- >>> import Prelude (Num (..), Ord (..), Int, Double, odd, not, undefined)
+-- >>> import Control.DeepSeq (force)
+--
+-- -- compiled versions are uninterruptible.
+-- https://gitlab.haskell.org/ghc/ghc/-/issues/367
+--
+-- >>> let or  = foldr (||) False
+-- >>> let and = foldr (&&) True
+
 --------------------------------------------------------------
 -- List-manipulation functions
 --------------------------------------------------------------
@@ -503,8 +514,8 @@ match on everything past the :, which is just the tail of scanl.
 -- False
 -- >>> foldr1 (||) [False, False, True, True]
 -- True
--- >>> foldr1 (+) [1..]
--- * Hangs forever *
+-- >>> force $ foldr1 (+) [1..]
+-- *** Exception: stack overflow
 foldr1                  :: (a -> a -> a) -> [a] -> a
 foldr1 f = go
   where go [x]            =  x
@@ -590,7 +601,7 @@ remove the cause for the chain of evaluations, and all is well.
 -- [False,False,True,True]
 -- >>> scanr1 (||) [True, True, False, False]
 -- [True,True,False,False]
--- >>> scanr1 (+) [1..]
+-- >>> force $ scanr1 (+) [1..]
 -- * Hangs forever *
 scanr1                  :: (a -> a -> a) -> [a] -> [a]
 scanr1 _ []             =  []
@@ -653,9 +664,9 @@ minimum xs              =  foldl1 min xs
 -- the consumer doesn't force each iterate. See 'iterate'' for a strict
 -- variant of this function.
 --
--- >>> iterate not True
+-- >>> take 10 $ iterate not True
 -- [True,False,True,False...
--- >>> iterate (+3) 42
+-- >>> take 10 $ iterate (+3) 42
 -- [42,45,48,51,54,57,60,63...
 {-# NOINLINE [1] iterate #-}
 iterate :: (a -> a) -> a -> [a]
@@ -698,7 +709,7 @@ iterate'FB c f x0 = go x0
 
 -- | 'repeat' @x@ is an infinite list, with @x@ the value of every element.
 --
--- >>> repeat 17
+-- >>> take 20 $ repeat 17
 --[17,17,17,17,17,17,17,17,17...
 repeat :: a -> [a]
 {-# INLINE [0] repeat #-}
@@ -735,10 +746,10 @@ replicate n x           =  take n (repeat x)
 -- on infinite lists.
 --
 -- >>> cycle []
--- Exception: Prelude.cycle: empty list
--- >>> cycle [42]
+-- *** Exception: Prelude.cycle: empty list
+-- >>> take 20 $ cycle [42]
 -- [42,42,42,42,42,42,42,42,42,42...
--- >>> cycle [2, 5, 7]
+-- >>> take 20 $ cycle [2, 5, 7]
 -- [2,5,7,2,5,7,2,5,7,2,5,7...
 cycle                   :: [a] -> [a]
 cycle []                = errorEmptyList "cycle"
diff --git a/libraries/base/Numeric.hs b/libraries/base/Numeric.hs
index 00e5f674de..afc83613f6 100644
--- a/libraries/base/Numeric.hs
+++ b/libraries/base/Numeric.hs
@@ -70,6 +70,8 @@ import GHC.Show
 import Text.ParserCombinators.ReadP( ReadP, readP_to_S, pfail )
 import qualified Text.Read.Lex as L
 
+-- $setup
+-- >>> import Prelude
 
 -- -----------------------------------------------------------------------------
 -- Reading