nl_tokens: ES6 B . 2 . 2 . 1 . 2
pl_tokens: <mask> ObjectSetProto ( proto ) { CHECK_OBJECT_COERCIBLE ( this , "Object.prototype.__proto__" ) ; if ( ( IS_RECEIVER ( proto ) || IS_NULL ( proto ) ) && IS_RECEIVER ( this ) ) { % SetPrototype ( this , proto ) ; } }