[Manishearth]

> Sometimes ref-counting (Rc<T> in Rust) is fine, although that's more expensive than GC.

This is a very interesting and hard comparison to make.

The marginal cost of GCing one more thing is much less than the marginal cost of RCing one more thing. But you need to pay the cost of the GC runtime to get there, and Rust doesn't, so it's a rather hard comparison to make.

However, the cost of RCing something itself is pretty small (and you don't RC very often in Rust anyway), so this rarely matters :)