Insert Catchy Title Here

This is not a quiz, I would genuinely like some help here.

Can some explain to me why this compiles:

IEnumerable<int> ints = new int[0];

And this compiles:

IList<int[]> ints = new List<int[]>();

But this does not compile:

IList<IEnumerable<int>> ints = new List<int[]>();

And subsequently this does not compile:

public void Generic_List_Of_GenericType()
{
  List<int[]> ints = new List<int[]>(); 
  MyMethod( ints ); 
}

public void MyMethod(IEnumerable<IEnumerable<int>> test)
{
}

It is not clear to me why the compiler can figure out the first two cases but not the latter two.