Why doesn't this C# code compile?

Question

double? test = true ? null : 1.0;

In my book, this is the same as

if (true) {
  test = null;
} else {
  test = 1.0;
}

Answer 1

The left hand side of the assignment is not used when deducing the type of an ?: expression.

In b ? A : B, the types of A and B must either be the same, or one must be implicitly convertible to the other.