Safely moving structs in D

[bitwise via Digitalmars-d-learn]

I'm confused about what the rules would be here.

It would make sense to call the postblit if present, but 
std.Array currently does not:
https://github.com/dlang/phobos/blob/04cca5c85ddf2be25381fc63c3e941498b17541b/std/container/array.d#L884