using System;

using System.Collections.Generic;

​

public class Program

{

    public record ExplainedValue<TResult>(TResult? Value, IList<string> Messages);

​

    public class ExplainedValueBuilder<TResult> {

      private TResult? value;

      private IList<string> messages;

      public ExplainedValueBuilder()

      {

          this.value = default;

          this.messages = new List<string>();

      }

​

       public ExplainedValueBuilder(ExplainedValueBuilder<TResult> from)

       {

           this.value = from.value;

           this.messages = new List<string>(from.messages);

       }

      public ExplainedValueBuilder<TResult> WithValue(TResult newValue)

      {

        return new ExplainedValueBuilder<TResult>( this )

        {

            value = newValue

        };

      }

​

        public ExplainedValueBuilder<TResult> WithMessage(string message)

        {

            var newBuilder = new ExplainedValueBuilder<TResult>( this );

            newBuilder.messages.Add(message);

            return newBuilder;

        }

        public ExplainedValue<TResult> Build()

        {

            return new ExplainedValue<TResult>(this.value, this.messages);

        }

    }

​

    public static void Main()

    {

        var explainedValue = new ExplainedValueBuilder<bool>()

            .WithMessage("Message 1")

            .WithMessage("Message 2")

            .WithValue(false)

            .Build();

      foreach(var message in explainedValue.Messages)

      {

        Console.WriteLine($"Message = {message}");    

      }

    }

}