C# Error CS0529 – Inherited interface ‘interface1’ causes a cycle in the interface hierarchy of ‘interface2’

C# Compiler Error

CS0529 – Inherited interface ‘interface1’ causes a cycle in the interface hierarchy of ‘interface2’

Reason for the Error

You’ll get this error in your C# code when you have an inheritance list of an interface with self references either directly or indirectly.

The inheritance list for an interface includes a direct or indirect reference to itself. An interface cannot inherit from itself.

For example, let’s try to compile the below C# code snippet.

using System;

namespace DeveloperPublishConsole1
{
    public interface Interface1
    {
    }

    public interface Interface2 : Interface1, Interface3
    {
    }

    public interface Interface3 : Interface2   
    {
    }
    internal class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("No Error");
        }
    }
}

You’ll receive the error code CS0529 when run the above code snippet because you have included the interface Interface2 and Interface3 has a cyclic references in the inheritance list.

Error CS0529 Inherited interface ‘Interface3’ causes a cycle in the interface hierarchy of ‘Interface2’ DeveloperPublishConsole1 C:\Users\senth\source\repos\DeveloperPublishConsole1\DeveloperPublishConsole1\Program.cs 9 Active
Error CS0529 Inherited interface ‘Interface2’ causes a cycle in the interface hierarchy of ‘Interface3’ DeveloperPublishConsole1 C:\Users\senth\source\repos\DeveloperPublishConsole1\DeveloperPublishConsole1\Program.cs 13 Active

Solution

In C#, an interface cannot inherit from itself.

To fix this error in your C# code, you will need to remove the interface from the inheritance list that is causing the cyclic reference.