Name Suggestions from Parameter Names?

I thought R# used to do the following. With a method like:

public void DoSomething(string aString) {}

If I call it like:

DoSomething(some_long_expression);

I might select some_long_expression and then use Introduce Variable.

I could swear that at one time, R# would have included the name "aString" as
a suggestion. Was I imagining that, or is it a bug?

John Saunders