Rust has this. Data can be placed in atomic or non-atomic refcounted containers, and the type system disallows sharing non-thread-safe types across threads. Ad

Rust has this. Data can be placed in atomic or non-atomic refcounted containers, and the type system disallows sharing non-thread-safe types across threads. Additionally, data can be borrowed from inside the refcounted wrapper, and used freely within a scope without touching the reference count.