Fix #5682. Now, '(:) parses.

compiler/parser/Parser.y.pp

@@ -1155,6 +1155,8 @@ atype :: { LHsType RdrName }
         | SIMPLEQUOTE  '(' ')'                        { LL $ HsTyVar $ getRdrName unitDataCon }
         | SIMPLEQUOTE  '(' ctype ',' comma_types1 ')' { LL $ HsExplicitTupleTy [] ($3 : $5) }
         | SIMPLEQUOTE  '[' comma_types0 ']'           { LL $ HsExplicitListTy placeHolderKind $3 }
+        | SIMPLEQUOTE '(' qconop ')'                  { LL $ HsTyVar (unLoc $3) }
+        | SIMPLEQUOTE '(' varop  ')'                  { LL $ HsTyVar (unLoc $3) }
         | '[' ctype ',' comma_types1 ']'              { LL $ HsExplicitListTy placeHolderKind ($2 : $4) }
         | INTEGER            {% mkTyLit $ LL $ HsNumTy $ getINTEGER $1 }
         | STRING             {% mkTyLit $ LL $ HsStrTy $ getSTRING  $1 }

testsuite/tests/parser/should_compile/T5682.hs

+{-# LANGUAGE DataKinds, DeriveDataTypeable, StandaloneDeriving, TypeOperators #-}
+
+module T5682 where
+
+import Data.Typeable
+
+data a :+: b = Mk a b
+data Foo = Bool :+: Bool
+
+type X = True ':+: False
+
+deriving instance Typeable '(:+:)
\ No newline at end of file

testsuite/tests/parser/should_compile/all.T

@@ -96,3 +96,4 @@ test('T5243', extra_clean(['T5243A.hi', 'T5243A.o']),
      multimod_compile, ['T5243',''])
 test('T7118', normal, compile, [''])
 test('T7776', normal, compile, [''])
+test('T5682', normal, compile, [''])
\ No newline at end of file