Revert "Fix #8745 - GND is now -XSafe compatible."

See #8827 - for now, we're making GND unsafe again.

This also fixes the tests since they were originally not using the new
unicode quote style we're using.

This reverts commit a8a01e742434df11b830ab99af12d9045dfcbc4b.

6 files changed, 78 insertions, 5 deletions

diff --git a/testsuite/tests/safeHaskell/safeLanguage/SafeLang02.hs b/testsuite/tests/safeHaskell/safeLanguage/SafeLang02.hs
index 8bc3f3cd00..9bf1c82a09 100644
--- a/testsuite/tests/safeHaskell/safeLanguage/SafeLang02.hs
+++ b/testsuite/tests/safeHaskell/safeLanguage/SafeLang02.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE Safe, TemplateHaskell #-}
+{-# LANGUAGE Safe, GeneralizedNewtypeDeriving #-}
 
 -- | Test SafeLanguage disables things
 module SafeLang02 where
diff --git a/testsuite/tests/safeHaskell/safeLanguage/SafeLang02.stderr b/testsuite/tests/safeHaskell/safeLanguage/SafeLang02.stderr
index e1643ed32b..069e5be4e9 100644
--- a/testsuite/tests/safeHaskell/safeLanguage/SafeLang02.stderr
+++ b/testsuite/tests/safeHaskell/safeLanguage/SafeLang02.stderr
@@ -1,3 +1,3 @@
 
 SafeLang02.hs:1:20:
-    Warning: -XTemplateHaskell is not allowed in Safe Haskell; ignoring -XTemplateHaskell
+    Warning: -XGeneralizedNewtypeDeriving is not allowed in Safe Haskell; ignoring -XGeneralizedNewtypeDeriving
diff --git a/testsuite/tests/safeHaskell/safeLanguage/SafeLang07.hs b/testsuite/tests/safeHaskell/safeLanguage/SafeLang07.hs
new file mode 100644
index 0000000000..006cd0ea08
--- /dev/null
+++ b/testsuite/tests/safeHaskell/safeLanguage/SafeLang07.hs
@@ -0,0 +1,41 @@
+{-# LANGUAGE Safe #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+
+-- Here we stop it succeeding (SAFE)
+
+-- | We use newtype to create an isomorphic type to Int
+-- with a reversed Ord dictionary. We now use the MinList
+-- API of Y1 to create a new MinList. Then we use newtype
+-- deriving to convert the newtype MinList to an Int
+-- MinList. This final result breaks the invariants of
+-- MinList which shouldn't be possible with the exposed
+-- API of Y1.
+module Main where
+
+import SafeLang07_A
+
+class IntIso t where
+    intIso :: c t -> c Int
+
+instance IntIso Int where
+    intIso = id
+
+newtype Down a = Down a deriving (Eq, Show, IntIso)
+
+instance Ord a => Ord (Down a) where
+    compare (Down a) (Down b) = compare b a
+
+forceInt :: MinList Int -> MinList Int
+forceInt = id
+
+a1, a2 :: MinList Int
+a1 = foldl insertMinList (newMinList $ head nums) (tail nums)
+a2 = forceInt $ intIso $ foldl (\x y -> insertMinList x $ Down y) (newMinList $ Down $ head nums) (tail nums)
+
+nums :: [Int]
+nums = [1,4,0,1,-5,2,3,5,-1,2,0,0,-4,-3,9]
+
+main = do
+    printIntMinList a1
+    printIntMinList a2
+
diff --git a/testsuite/tests/safeHaskell/safeLanguage/SafeLang07.stderr b/testsuite/tests/safeHaskell/safeLanguage/SafeLang07.stderr
new file mode 100644
index 0000000000..276c723203
--- /dev/null
+++ b/testsuite/tests/safeHaskell/safeLanguage/SafeLang07.stderr
@@ -0,0 +1,7 @@
+
+SafeLang07.hs:2:14: Warning:
+    -XGeneralizedNewtypeDeriving is not allowed in Safe Haskell; ignoring -XGeneralizedNewtypeDeriving
+
+SafeLang07.hs:15:1:
+    Failed to load interface for ‘SafeLang07_A’
+    Use -v to see a list of the files searched for.
diff --git a/testsuite/tests/safeHaskell/safeLanguage/SafeLang07_A.hs b/testsuite/tests/safeHaskell/safeLanguage/SafeLang07_A.hs
new file mode 100644
index 0000000000..6ef49d5946
--- /dev/null
+++ b/testsuite/tests/safeHaskell/safeLanguage/SafeLang07_A.hs
@@ -0,0 +1,24 @@
+{-# LANGUAGE Trustworthy #-}
+
+-- | Here we expose a MinList API that only allows elements
+-- to be inserted into a list if they are at least greater
+-- than an initial element the list is created with.
+module SafeLang07_A (
+        MinList,
+        newMinList,
+        insertMinList,
+        printIntMinList
+    ) where
+
+data MinList a = MinList a [a]
+
+newMinList :: Ord a => a -> MinList a
+newMinList n = MinList n []
+
+insertMinList :: Ord a => MinList a -> a -> MinList a
+insertMinList s@(MinList m xs) n | n > m     = MinList m (n:xs)
+                                 | otherwise = s
+
+printIntMinList :: MinList Int -> IO ()
+printIntMinList (MinList min xs) = putStrLn $ "MinList Int :: MinList " ++ show min ++ " " ++ show xs
+
diff --git a/testsuite/tests/safeHaskell/safeLanguage/all.T b/testsuite/tests/safeHaskell/safeLanguage/all.T
index dc968917fb..5932348594 100644
--- a/testsuite/tests/safeHaskell/safeLanguage/all.T
+++ b/testsuite/tests/safeHaskell/safeLanguage/all.T
@@ -15,10 +15,11 @@ test('SafeLang03', normal, compile, [''])
 test('SafeLang04', normal, compile_and_run, [''])
 test('SafeLang05', normal, compile_and_run, [''])
 
-# SafeLang06 and SafeLang07 wwere tests involving
-# GeneralizedNewtypeDeriving, but the code failed to compile with
-# roles; thus the tests were no longer valid and have been removed
+# SafeLang06 was a test involving GeneralizedNewtypeDeriving, but the code
+# fails to compile with roles; thus the test is no longer valid and has
+# been removed
 
+test('SafeLang07', normal, compile_fail, [''])
 test('SafeLang08', normal, compile_fail, [''])
 test('SafeLang09',
      [exit_code(1),