qmllint does warn about usages of destroy in Item and Rectangle (and also probably in other types deriving from QtObject):

Warning: /Users/sami/tmp/untitled68/HelloWorld.qml:6:9: Unqualified access [unqualified]
        destroy(400)
        ^^^^^^^
Info: Did you mean "destroyed"?
        destroyed(400)
        ^^^^^^^^^

In the attached project, changing the root Type of HelloWorld to QtObject does remove the warning, but it reappears when using Item or Rectangle (or probably any other type inheriting from QtObject).