Built In Types: Noreturn
After executing, almost all functions return to their caller. However, in certain very-specialized situations, a function might always
throw an exception or terminate the program abnormally (such as by calling the library function
exit). Such functions have the return
noreturn, and must not contain any
return statements. Strictly speaking,
noreturn is not a type; it is just used in one type
context, in place of a type.