# Function std::intrinsics::unreachable

const: 1.57.0 · source ·

    pub const unsafe extern "rust-intrinsic" fn unreachable() -> !

🔬This is a nightly-only experimental API. (`core_intrinsics`)
Expand description

Informs the optimizer that this point in the code is not reachable, enabling further optimizations.

N.B., this is very different from the `unreachable!()` macro: Unlike the macro, which panics when it is executed, it is undefined behavior to reach code marked with this function.

The stabilized version of this intrinsic is `core::hint::unreachable_unchecked`.