A generic type Never indicates the generic type variable is never of the generic type variable . It takes generic type variable constrained by a generic type variable which constraint causes its change to .
never.type.ts
type Never<Not, Type> = Type extends Not ? never : Type;
Generic type variables
Not
Type
A generic type variable Not constrain the generic type variable causing the change to .
A generic type variable Type constrained by generic type variable is never .
