[Obsolete("In Metalama, use an aspect or a fabric, and register a reference validator using the 'IValidatorReceiver<TDeclaration>.ValidateReferences<TValidator>(Func<TDeclaration, TValidator>)' or 'IValidatorReceiver.ValidateReferences(ReferenceValidator)' method. For instance, from the 'IAspect<T>.BuildAspect(IAspectBuilder<T>)' method of an aspect, call <c>builder</c>.'!:IAspectReceiverSelector<TTarget>.With<TMember>(System.Func<TTarget,System.Collections.Generic.IEnumerable<TMember>>)'<c>(...)</c>.'IValidatorReceiver<TDeclaration>.ValidateReferences<TValidator>(Func<TDeclaration, TValidator>)'.", false)]
public abstract class Constraint : MulticastAttribute, IConstraint