When to make types non-moveable?

[lefticus]

The rule: if the type is not trivially destructible and is not default constructible, it should not be moveable.

Examples: handle types, mostly.

[LB--]

About handle types, I nearly always make them movable, difference being that I also make them default constructible and nullable. You can't do very much without that, since if you want to stick them in a container, you'd otherwise have to wrap them in a unique_ptr or something, which is wasteful when the handle is itself already a unique or shared pointer internally.

[bdeane-intel]

Nomenclature clash: to many people, a handle is a lightweight copyable thing used to access a more heavyweight thing. The point of such a handle is to pass it around. An example is say a std::stop_token being a handle to the state owned by the std::stop_source.

This does not seem to be the meaning of "handle" indicated here.