namespace XbrlPlus
{
    using System.Collections.Generic;
    using FluentAssertions.Common;
    using FluentAssertions.Equivalency;

    public class ReadOnlyListOrderingRule : IOrderingRule
    {
        public OrderStrictness Evaluate(IMemberInfo memberInfo) =>
            memberInfo.CompileTimeType.IsSameOrInherits(typeof(IReadOnlyList<>))
                ? OrderStrictness.Strict
                : OrderStrictness.Irrelevant;

        public override string ToString() => "Be strict about the order of items in read-only lists";
    }
}

AssertionOptions.AssertEquivalencyUsing(options => options.Using(new ReadOnlyListOrderingRule()));

object x = "";
x.Should().BeEquivalentTo("", options => options.Using(new ReadOnlyListOrderingRule()));