- Constrained ListsConstrainedList<T, TConstraint>: immutable lists whose size, uniqueness or order is part of the type, checked once at construction, with Second() and Third() only where the constraint proves them.
- ValidationValidation<T, TError>: a valid value or a non-empty list of errors, with Combine, Sequence and Traverse to report every failure at once.
- Domain CollectionsThe [NonEmptyCollection] source generator: one attribute on a partial class gives you a named non-empty collection with factories, validation, JSON support and invariants enforced on every mutation.
Version: Next
Constraints and Validation
Cardinality and ordering in the type, error-accumulating validation, and generated domain collections.