There's not only a pedagogical task here, but the Rust community must learn how to write code safely. The major difficulty here is that in general, unsafe pieces of code cannot be safely composed, even if the unsafe pieces of code are individually safe. This allows you to bypass runtime safety checks without unsafe code just by composing "safe" modules that internally use unsafe code in their implementation.
This kind of problem comes up a lot. Composed atomic operations are not atomic. Composed correct threaded code is not always correct. Mixing Scheme control structures made with call/cc don't work as desired. Enabling different Haskell language extensions gets you off the deep end quickly, and some unsafe combinations are surprising (see GeneralizedNewtypeDeriving, which is considered unsafe even though it used to be safe).
This kind of problem comes up a lot. Composed atomic operations are not atomic. Composed correct threaded code is not always correct. Mixing Scheme control structures made with call/cc don't work as desired. Enabling different Haskell language extensions gets you off the deep end quickly, and some unsafe combinations are surprising (see GeneralizedNewtypeDeriving, which is considered unsafe even though it used to be safe).