Why doesn't delegate contravariance work with value types?

Question

This snippet is not compiled in LINQPad.

void Main()
{
    (new[]{0,1,2,3}).Where(IsNull).Dump();
}

static bool IsNull(object arg) { return arg == null; }
<         


        

Answer 1

Because Int32 is value type and contra-variance doesn't work on value types.

You can try this one:

(new **object**[]{0,1,2,3}).Where(IsNull).Dump();