testsuite: Add ClassOperator testcase

This is derived from Haddock's `Operators` `html-test`, which appears to
fail with GHC master yet compiles with 7.10.2

Reviewers: simonpj, austin

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D1667

GHC Trac Issues: #11264

testsuite/tests/typecheck/should_compile/ClassOperator.hs

+{-# LANGUAGE PatternSynonyms, TypeOperators, TypeFamilies, MultiParamTypeClasses, GADTs #-}
+
+module ClassOperator where
+
+-- | Class with fixity, including associated types
+class a ><> b where
+  type a <>< b :: *
+  data a ><< b
+  (>><), (<<>) :: a -> b -> ()
+
+  -- | Multiple fixities
+  (**>), (**<), (>**), (<**) :: a -> a -> ()
+
+infixr 1 ><>
+infixl 2 <><
+infixl 3 ><<
+infixr 4 >><
+infixl 5 <<>
+
+infixr 8 **>, >**
+infixl 8 **<, <**

testsuite/tests/typecheck/should_compile/all.T

@@ -481,3 +481,4 @@ test('T10935', normal, compile, [''])
 test('T10971a', normal, compile, [''])
 test('T11237', normal, compile, [''])
 test('T10592', normal, compile, [''])
+test('ClassOperator', expect_broken(11264), compile, [''])