The &* thing is due to Deref coercions. The deference operator is a trait (Deref), which has an associated type that it dereferences to. This lets you do nice things, like dereference a Box<T> to just a T, and let the Box implementation figure out how to get you there. (It's also used on method calls using .)

What you have is a reference to a type with a Deref-coercion to the type you want, but the compiler won't coerce under the reference for you, so you have to dereference and then reference it again, and then type inference can work out that you wanted to reference the coerced type.