Never

Never is uninhabited: no runtime value can have it. The compiler uses it for an expression or control-flow path that cannot continue normally.

There is no Never literal. Trying to initialize it with an ordinary value is a type error:

local impossible: Never = 1 -- type error: Int is not Never

Most programs never write Never directly. Its important type-system role is that a non-returning path can fit where another branch expects a value without introducing nil, a dynamic value, or an implicit union.