- copy (C++ containers), - reference (D containers), or - move (Rust) semantics
when an instance of `C` is assigned to a new variable. If not, could
`__traits(hasMember, C, "dup")` play a role in such an implementation? This could, for instance, be used as an - extra CT-check in C++ to D conversion tools, such as CPP2D and - aid when implementing `deepDup()`