GHCi accepts any operator as a value constructor when enclosed in parens
Eg:- 'data P = (+) Char Char' is accepted by GHCi However 'data P = (-) Char Char' is accepted by GHCi 7.8.2, but is reported to be rejected by GHC 7.6.3 GHCi 7.4 is reported to reject these inputs. GHC 7.8.2 also rejects these inputs. Operators defined this way are inaccessible and do not shadow existing operators. Legal operators(those prefixed by a colon) act normally when surrounded by parens