Aborts the process with message.

Returns ! (the never type), so the compiler treats any code after a fatalError call as unreachable. Use sparingly — almost every "this should be impossible" branch is better expressed as a Result error or a precondition check, because fatalError produces no recovery opportunity for the caller.

Examples

let mode = readMode(); match mode { .Read => doRead(), .Write => doWrite(), _ => fatalError("unsupported mode") }