Module ownership

ownership helpers

SafeC has no implicit destructors, but it does check them: a value whose type has a 'void drop()' method (the builtin Drop trait), or an aggregate holding one, must be dropped — 'x.drop()', 'defer x.drop()', or a method declared 'consume' — or moved (returned, passed by value, stored into something that owns it, sent to another thread) exactly once on every path. The compiler rejects a leak, a use after drop or move, a double drop, and overwriting a live value. See the language reference's "Ownership & Drop" page.

Memory reached through a reference is borrowed: a Drop value can be dropped in place there, but not moved out. These move a value out of a place by putting another one in:

struct Waker w = std::replace(&self.w, Waker::noop());   // take self.w
std::swap(&a, &b);

forget(x) (a compiler built-in, only inside 'unsafe { }') gives up a value without dropping it.