Compiler Error CS0529

Inherited interface 'interface1' causes a cycle in the interface hierarchy of 'interface2'

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

The following sample generates CS0529:

// CS0529.cs  
namespace x  
{  
   public interface a  
   {  
   }  
  
   public interface b : a, c  
   {  
   }  
  
   public interface c : b   // CS0529, b inherits from c  
   {  
   }  
}