question: f0 - > operator f1 - > reg f2 - > simpleexp concode_field_sep PlaceHolder placeHolder concode_field_sep placeholderType placeHolder
target: void function ( BinOp arg0 , A arg1 ) { arg0 . f0 . accept ( this , arg1 ) ; arg0 . f1 . accept ( this , arg1 ) ; arg0 . f2 . accept ( this , arg1 ) ; }