Indexing a fixed-length array (I.e. known at compile time) out of bounds is not prohibited at compile time. All array types trigger a task failure on out-of-bounds access (unless you explicitly opt-in to unchecked indexing).
Oh thanks for clearing that up! Is there any specific reason why the rust compilier currently doesn't check that a static int accessing into a known length slice doesn't result in a compile error? (I'm only referring to cases where the index you are trying to access is known at compile time as well as the length of the slice)