Why this works in C# (generic class and self-reference)?

Why this works in C# (generic class and self-reference)?

I have
class X<T> : Base
{
//For exemple:
static T something();
}
And I can have
class A : X <A>
{
}
To logically have something like this:
class A : Base
{
static A something();
}
This works and works well.
But in my comprehension, it's kind of self-reference (A is the children of
X, while X doesn't exists before A...), which is breaks the foundation of
computer science, so I want to know what's wrong with my comprehension??