Stable way to prevent moving out of a type

[marcianx]

Relatedly, there's this recently-posted neat trick to make an object not movable:

Incomplete mini-guide to self-reference (non-movable objects)

(Based off of https://www.reddit.com/r/rust/comments/49wfej/detecting_when_a_value_is_moved/d0zkfwl?context=1 ) An object containing a self-reference cannot be moved. But it doesn't need to literally contain the self reference. Let's start with Rust Playground. We make a reference to a part of MyLittleImmovableType and store it in MyLittleImmovableType itself. Observe that since MyLittleImmovableType contains a reference, the lifetime of the reference is part of the type (MyLittleImmovableTyp…