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typestate

Using types to make illegal state changes fail to compile.

The typestate pattern encodes an object's state as a type parameter or separate type; transitions consume self and return the next state's type, so invalid calls don't exist.

Examples

  • Calling .deliver() on a Shipment<Packed> fails with E0599, because deliver exists only on Shipment<InTransit>.

See also

marker type PhantomData builder pattern
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