Test #8851.

(cherry picked from commit 1ac91146)

Conflicts:
	testsuite/tests/deriving/should_compile/all.T

testsuite/tests/deriving/should_compile/T8851.hs

+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+
+module T8851 where
+
+import Control.Applicative
+
+class Parsing m where
+  notFollowedBy :: (Monad m, Show a) => m a -> m ()
+
+data Parser a
+instance Parsing Parser where
+  notFollowedBy = undefined
+
+instance Functor Parser where
+  fmap = undefined
+instance Applicative Parser where
+  pure = undefined
+  (<*>) = undefined
+instance Monad Parser where
+  return = undefined
+  (>>=) = undefined
+
+newtype MyParser a = MkMP (Parser a)
+  deriving Parsing
\ No newline at end of file

testsuite/tests/deriving/should_compile/all.T

@@ -45,3 +45,4 @@ test('T8138', reqlib('primitive'), compile, ['-O2'])
 test('T8631', normal, compile, [''])
 test('T8758', extra_clean(['T8758a.o', 'T8758a.hi']), multimod_compile, ['T8758a', '-v0'])
 test('T8865', normal, compile, [''])
+test('T8851', expect_broken(8851), compile, [''])