If ATC normally approves a visual approach and asks the pilot to call the field in sight, can ATC still approve this approach if the pilot is flying into a temporary non-radar environment?
I flew into Canada's Toronto City Centre airport once under IFR and I recall that the controller could not give me a visual approach or even say that I could expect it, despite the conditions being about 5 miles in haze. He hinted that my only option was either to request a contact approach that far out or he would have to put me on the localizer. I requested the contact approach (remain clear of clouds in weather that was at least one mile visibility with the surface in sight).
In the US, ATC will often say, "expect the visual approach" even if the aircraft is currently in instrument conditions (assuming the field conditions allow a visual approach), but ATC cannot clear an aircraft for the visual until the pilot calls out either airport and/or preceding aircraft in sight, as Dave indicated.