What is the formal definition of ownership?

[parasyte]

@ZiCog

In the 'move' example nothing actually moved. The the thing we are interested in, the actual bits comprising the elements of the vector, did not move anywhere, they stay in the same position in memory. Which is an important consideration when there are a huge number of elements.

Ownership moved. This is perhaps a subtle detail, but it's really the "aha! moment" of move semantics in Rust. Ownership is purely conceptual, it is not something you can see in a disassembler.

@ZiCog

In the "copy" example the thing we are interested in, the actual bits of the string "Hello world", did not get copied anywhere.

The pointer is copied.

@ZiCog

Often a primary concern is what actually gets moved or copied, one does not want to waste time memcpying bytes around. But "move" and "copy" here don't really talk about actual data movement.

I was very careful with the terminology I used, can we try to stick with that? Moves do not necessarily copy anything. You are probably thinking about Copy vs Clone; Copy should never use memcpy since it's usually reserved for pointer-sized types (e.g. they fit in one or two registers), but Clone does memcpy (which may be optimized to a series of SIMD instructions).