[proto] Default constructor of proto::extends

Hi Eric, is there any reason why the default ctor of proto::extends uses the following form: extends() : proto_expr_() {} instead of simply extends() {} I use proto::extends over expressions that hold x86 SIMD registers (like proto::terminal<__m128i>), and the current version of

Re: [proto] Default constructor of proto::extends

Hi Eric, is there any reason why the default ctor of proto::extends uses the following form: extends() : proto_expr_() {} instead of simply extends() {} I use proto::extends over expressions that hold x86 SIMD registers (like proto::terminal<__m128i>), and the current version