Lint the compiler for extraneous LANGUAGE pragmas

3 files changed, 14 insertions, 9 deletions

diff --git a/compiler/GHC/Tc/Solver/Flatten.hs b/compiler/GHC/Tc/Solver/Flatten.hs
index 2a4c7be1bb..dd214ceb7c 100644
--- a/compiler/GHC/Tc/Solver/Flatten.hs
+++ b/compiler/GHC/Tc/Solver/Flatten.hs
@@ -1,4 +1,6 @@
-{-# LANGUAGE CPP, DeriveFunctor, ViewPatterns, BangPatterns #-}
+{-# LANGUAGE BangPatterns  #-}
+{-# LANGUAGE CPP           #-}
+{-# LANGUAGE DeriveFunctor #-}
 
 {-# OPTIONS_GHC -Wno-incomplete-record-updates #-}
 
diff --git a/compiler/GHC/Tc/Solver/Interact.hs b/compiler/GHC/Tc/Solver/Interact.hs
index 57bca5fcec..fe349866d2 100644
--- a/compiler/GHC/Tc/Solver/Interact.hs
+++ b/compiler/GHC/Tc/Solver/Interact.hs
@@ -939,7 +939,7 @@ can change the behavior of the user's code.
 The following four modules produce a program whose output would change depending
 on whether we apply this optimization when IncoherentInstances is in effect:
 
-#########
+=========
     {-# LANGUAGE MultiParamTypeClasses #-}
     module A where
 
@@ -949,8 +949,9 @@ on whether we apply this optimization when IncoherentInstances is in effect:
     class A a => C a b where
       m :: b -> a -> a
 
-#########
-    {-# LANGUAGE MultiParamTypeClasses, FlexibleInstances #-}
+=========
+    {-# LANGUAGE FlexibleInstances     #-}
+    {-# LANGUAGE MultiParamTypeClasses #-}
     module B where
 
     import A
@@ -961,9 +962,11 @@ on whether we apply this optimization when IncoherentInstances is in effect:
     instance C a [b] where
       m _ = id
 
-#########
-    {-# LANGUAGE FlexibleInstances, MultiParamTypeClasses, FlexibleContexts #-}
-    {-# LANGUAGE IncoherentInstances #-}
+=========
+    {-# LANGUAGE FlexibleContexts      #-}
+    {-# LANGUAGE FlexibleInstances     #-}
+    {-# LANGUAGE IncoherentInstances   #-}
+    {-# LANGUAGE MultiParamTypeClasses #-}
     module C where
 
     import A
@@ -977,7 +980,7 @@ on whether we apply this optimization when IncoherentInstances is in effect:
     intC :: C Int a => a -> Int -> Int
     intC _ x = int x
 
-#########
+=========
     module Main where
 
     import A
diff --git a/compiler/GHC/Tc/Solver/Monad.hs b/compiler/GHC/Tc/Solver/Monad.hs
index a524493b94..4c20eed977 100644
--- a/compiler/GHC/Tc/Solver/Monad.hs
+++ b/compiler/GHC/Tc/Solver/Monad.hs
@@ -1300,7 +1300,7 @@ This is triggered by test case typecheck/should_compile/SplitWD.
 
 Note [Examples of how Derived shadows helps completeness]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-#10009, a very nasty example:
+Ticket #10009, a very nasty example:
 
     f :: (UnF (F b) ~ b) => F b -> ()