not exact “7.13 The null coalescing operator” in C# 4.0 spec

Question

in "7.13 The null coalescing operator" of C# 4.0 spec, it says

Otherwise, if b has a type B and an implicit conversion exists from a to B, the result type is B.

By my understand, it should be from A0 to B(A0 is the underlying type of A if A is a nullable type, or A otherwise).

int? a=null;
long b=5;

then type for a??b is long, because an implicit conversion exists from int(namely A0) to long.

please help confirm whether my view is correct.

Answer 1

in C#3.0 it says:

Otherwise, if an implicit conversion exists from A0 to B, the result type is B.

in my guess, it may be a typo in C#4.0.