nl_tokens: ES6 section 19 . 1 . 2 . 18 .
pl_tokens: function ObjectSetPrototypeOf ( obj , proto ) { CHECK_OBJECT_COERCIBLE ( obj , "Object.setPrototypeOf" ) ; if ( proto !== null && ! IS_RECEIVER ( proto ) ) { throw MakeTypeError ( kProtoObjectOrNull , proto ) ; } if ( IS_RECEIVER ( obj ) ) { % SetPrototype ( obj , proto ) ; } <mask> obj ; }