Result of calling IEquatable.Equals(T obj) when this == null and obj == null?

Question

What should IEquatable.Equals(T obj) do when this == null and obj == null?

1) This code is generated

Answer 1

The reason F# does this (I suspect) to optimize empty lists as null.

By adding this check, it allows one to call an instance method on a null instance without any problems.

See my blog post from a while back.

In C#, this is irrelevant.

To answer the question:

It should return true as both instances are null and deemed equal.