Rust only provides short reexports for a stable set of a few dozen items, rather than the "entire universe" of `using namespace std`. The only types that have a default reexport are `Option`, `Result`, `Box`, `String` and `Vec`.

To be even more specific, http://doc.rust-lang.org/std/prelude/

> we're comparing to Rust, whose namespace system seems very similar to a "using namespace std".

Not at all; only if you use globs ("use foo::*"). D's namespace system is like that, but not Rust's.