var in C# - Why can't it be used as a member variable?

Question

Why is it not possible to have implicitly-typed variables at a class level within C# for when these variables are immediately assigned?

ie:

public class TheClass
{
    private var aList = new List<string>();
}

Is it just something that hasn't been implemented or is there a conceptual/technical reason for why it hasn't been done?

Answer 1

Here's a blog post from Eric that explains the reasoning.