/// <summary>
/// The subsequent Bind* operations only apply when the Attribute's property is not null.
/// </summary>
/// <param name="propertyName"></param>
/// <returns></returns>
public FluentBindingRule <TAttribute> When <TValue>(string propertyName, TValue expectedEnumValue)
{
var prop = ResolveProperty(propertyName);
// C# doesn't allow generic enum constraints. Must enforce at runtime.
if (!typeof(TValue).IsEnum)
{
throw new InvalidOperationException($"Rule filter for '{propertyName}' can only be used with enums.");
}
AppendFilter(FilterNode.IsEqual(prop, expectedEnumValue));
return(this);
}