nullable reference types support

Some thoughts:

• C# 8 introduces nullable reference types, and therefore non-nullable reference types
• FluentValidation API could then be enhanced and DRY’d up a bit to support even more fluent syntax
  • When builder syntax today is reflexive to the parent, not the property.

RuleFor(s => s.NullableReferenceProperty)
    .NotEmpty()
    // WhenNotNull wouldnt be possible if NON-NullableReferenceProperty
    .WhenNotNull(); // more succinct than: .When(s => s.NullableReferenceProperty.HasValue);

[JeremySkinner]

It’s trivial to implement a WhenNotNull method today which works against both reference types and nullable value types:

public static IRuleBuilderOptions<T,TProperty> WhenNotNull<T,TProperty>(this IRuleBuilderOptions<T,TProperty> rule) {
	return rule.Configure(cfg => {
		cfg.ApplyCondition(ctx => ctx.PropertyValue != null);
	});
}

I’m not following how c# 8’s nullable reference types would make any difference to this?

[JeremySkinner]

Yes I’ve read that before, I do understand nullable reference types and their impact. What I’m not understanding is what you expect FluentValidation to be doing differently. Do you have a specific example of how you’d expect the behaviour to change?

I did not make the mental connection that .When is a syntax for Configure.

Yes most methods in the public API are just wrappers around Configure, which provides access to the underlying model.