# [−][src]Function std::intrinsics::coverage_unreachable

    pub unsafe extern "rust-intrinsic" fn coverage_unreachable(
        file_name: &'static str,
        start_line: u32,
        start_col: u32,
        end_line: u32,
        end_col: u32
    )

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

intrinsics are unlikely to ever be stabilized, instead they should be used through stabilized interfaces in the rest of the standard library

This marker identifies a code region to be added to the "coverage map" to indicate source code that can never be reached. (See `coverage_counter_add` for more information.)