CPP.test

# Copyright (c) Facebook, Inc. and its affiliates.
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
#
--adhoc "forall f g xs. map f (map g xs) = map (f . g) xs"
-u CPP.otherthing
===
 {-# LANGUAGE CPP #-}
 module CPP where
 
 #define TRUE 1

 infixr 0 $

 main :: IO ()
 main = print $ foo (bar [1..10])
 
 foo :: Int -> Int
 foo x = x - 2
 
 #if TRUE
 bar :: [Int] -> Int
 bar ys = length (filter even zs)
   where
-    zs = map (+1) (map (*3) ys)
+    zs = map ((+1) . (*3)) ys
 #endif

 #if TRUE
 bar2 :: [Int] -> Int
 bar2 ys = length (filter even zs)
   where
-    zs = map (+2) (map (*3) ys)
+    zs = map ((+2) . (*3)) ys
 #else
 bar2 :: [Int] -> Int
 bar2 ys = length (filter even zs)
   where
-    zs = map (+2) (map (*4) ys)
+    zs = map ((+2) . (*4)) ys

 otherthing :: Maybe a -> Int
 otherthing mb = case mb of
   Just{} -> 1
   Nothing -> 0

 useit :: Int
-useit = otherthing (Just 54)
+useit = case Just 54 of
+  Just{} -> 1
+  Nothing -> 0

 #if TRUE
 useit2 :: Int
-useit2 = otherthing (Just 42)
+useit2 = case Just 42 of
+  Just{} -> 1
+  Nothing -> 0
 #endif
 #endif