QDialog* dlg { new QDialog() };
QVBoxLayout* layout { new QVBoxLayout(dlg) };
QPushButton* btn { new QPushButton("Click me!") };
layout->addWidget(btn); // dlg is set as parent of btn here

But if the layout is created parentless, will it retroactively assign parentage once I add it to the Dialog?

QVBoxLayout* layout { new QVBoxLayout() }; // note: Not assigned to any widget yet
QPushButton* btn { new QPushButton("Click me!") };
layout->addWidget(btn); // btn cannot be assigned a parent
...
QDialog* dlg { new QDialog() };
dlg->setLayout(layout); // will btn be retroactively made a child of dlg here?

https://doc.qt.io/qt-6/layout.html mentions that

Widgets can only have other widgets as parent, not layouts.

If so, how would retroactive parenting even work?
Already searched the documentation as well as the forums and even google, but couldn't find any answer to this. So I'm asking it here since I'm worried it might create huge memory leaks when my dialog won't clean up the widgets in it once it goes out of scope.