When you compile a Solidity contract, the optimizer doesn't just remove unreachable paths — it buries them. But "unreachable" at compile time is not "unreachable at runtime" if the EVM state can change.
Don't bury code. Delete it.
Since "0xdeadcode" evokes low-level programming, EVM (Ethereum Virtual Machine) internals, security exploits, and perhaps a bit of rebellious cypherpunk energy, I'll write two versions: 0xdeadcode