Rustc may still need to do runtime bounds check if it can’t conclude that a dynamically computed index is in-bounds.
The length is known statically, but whether the index is in-bounds may not be.
The binary search GP talks about is exactly one such case, go on Godbolt, write up a simple binary search (with a static size so you get code), and you’ll see that the compiler checks against the literal array size on every iteration.
The length is known statically, but whether the index is in-bounds may not be.
The binary search GP talks about is exactly one such case, go on Godbolt, write up a simple binary search (with a static size so you get code), and you’ll see that the compiler checks against the literal array size on every iteration.