Rust has plenty of constructs that do runtime checks in part to get around the fact that not everything can be expressed in a manner that the borrow checker can

Rust has plenty of constructs that do runtime checks in part to get around the fact that not everything can be expressed in a manner that the borrow checker can understand at compile time. IMO Rust should treat the array/index case in the same manner as these and provide a standard interface that prevents "use after free" and so on.