input:
{-# LANGUAGE TypeOperators #-}
import GHC.TypeLits (type (+))
Stylish complains:
Language.Haskell.Stylish.Parse.parseModule: could not parse A.hs: ParseFailed (SrcLoc "<unknown>.hs" 14 40) "ExplicitNamespaces language extension is not enabled. Please add {-# LANGUAGE ExplicitNamespaces #-} pragma at the top of your module."
But GHC allows this. TypeOperators seems to imply ExplicitNamespaces there.