The Rust compiler/stdlib inserts bounds checks for accesses that cannot be proven to be safe, so in this example you'd get a panic on the out-of-bounds access i

The Rust compiler/stdlib inserts bounds checks for accesses that cannot be proven to be safe, so in this example you'd get a panic on the out-of-bounds access itself instead of hitting the assert afterwards. If you use get_unchecked() to intentionally bypass those bounds checks, the assert is indeed removed, but that requires an unsafe block. Speaking more generally, Rust gates UB behavior behind unsafe blocks, so it's much harder to unintentionally hit UB than in C.