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The absent value

The None type represents a type with no value.

It is often used to type code that fails to return control (e.g. an infinite loop) or to designate impossible values (e.g. the type ?None only contains null).

Type None

type None = Prim.Types.None

The empty type. A subtype of all types.

Value impossible

let impossible : <A>None -> A

Turns an absurd value into an arbitrary type.