Trying to understand why this execution overflows

Question

I would like to know/learn in more detail mechanism why this throw a stack overflow error ? (.Net Fiddle link)

(Related to the fact that DisplayType is present in both the Interface and the abstract class, renaming the later make it work. I would like to understand what is the execution path that lead to this overflow).

using System;
using System.IO;
                
public class Program
{
    public static void Main()
    {
        Console.WriteLine("--------BEGIN--------");
    
        FIVan van = new FIVan();
        van.DisplayType();
    
        Console.WriteLine("---------END---------");
    }
}

public interface IVan
{
    public Type TheType {get;}
    public void DisplayType() => Console.WriteLine("Generic Type associated with this IVan<T> is : " + TheType.ToString());
}

public abstract class AVan<T> : IVan
    where T : class
{
    public Type TheType { get => typeof(T);}
    // NOTE : renaming DisplayType to something else (like Display()) doesn't Stack Overflow, it works.
    public void DisplayType() => ((IVan)this).DisplayType();
}

public class FIVan : AVan<FileInfo>
{
}

EDIT : Actually I didn't fully realize how default interface implementation work. I add this edit to point you to this article I found interesting about it.

Answer 1

AVan<T>.DisplayType() overrides the default interface implementation specified by IVan.DisplayType(). So it just calls itself recursively indefinitely.

If AVan<T>.DisplayType is renamed, it calls into the default interface implementation instead, so does not cause a stack overflow.