Method overloads resolution and Jon Skeet's Brain Teasers

Question

Jon\'s Brain Teasers

Here Be Spoilers...

I\'m looking at the answer to #1, and I must admit I never knew this was the case in overload resol

Answer 1

The reason is because it is ambiguous. The compiler just has to decide for one. And somebody thought that the less indirect one would be better (performance might be a reason). If the developer just wrote:

((Base)d).Foo (i);

it's clear and giving you the expected result.