Depends on what your definition of sparring is , in Wing Chun this can mean different things to different people.
In the school I taught and trained at in Australia there were various methods of sparring .
LIGHT HAND SPARRING - A bit of a misnomer , because it was usually anything but light. Wing Chun guard vs Wing Chun guard mainly attacks to body to work on reflex , hand speed , trapping and breaking through opponents guard , no leg attacks.
CHI SAU SPARRING - This is executing attacks and defences whilst in contact with the opponents arms at random during the rolling cycle of the arm sensitivity drill commonly known as Chi Sau.
Usually there is heavy contact to the body and controlled contact to the head unless wearing head gear. Chi Sau sparring can start in contact range but can also move in and out of contact range.
Students mainly are working on their trapping and counters to trapping and learning to hit with out being hit. Mainly using hands but sometimes leg attacks as well.
WING CHUN VS WING CHUN - Occasionally students will wear protective gear and spar each other using arms and legs from long range both using Wing Chun , this would be thought of as the conventional sparring distance seen in most martial styles.
In my opinion there is not much to be gained from this type of sparring because they both bridge the gap and end up in Chi Sau range any way.
RANDOM ARM SPARRING - This is where the student using Wing Chun will defend himself against any type of arm attack from random angles always attempting to use simultaneous counter attack. Head gear , mouth guards , smaller type gloves are often used .
This type of sparring hones the reflexes that are used before contact is made , and gets the student used to dealing with non Wing Chun types of attacks . Boxers punches , karate punches etc.
The emphasis is on moving in fast , using wrist latching to control the opponents hands and keeping him under pressure by continually advancing forward usually using a hook kick or stamp kick to the legs to finish.
RANDOM LEG SPARRING- The same principal as random arms , except the Wing Chun student defends against random kicking attacks , round house kicks , spinning kicks , low kicks etc.
The student mainly works on jamming the kicks before they start , using stop kicks down the centreline , leg deflections and then closing in with low kicks like low heel kicks , hook kick to thighs then finally hands , elbows and knees.
RANDOM ARMS AND LEGS - Student has to defend against any type of random attack , arms and legs.
RANDOM KNIFE ATTACKS- Student defends against any random knife attack , over head stabs , thrusts , slashes .
Emphasis on getting out of the path of weapon , immobilising the weapon holding arm and striking with speed and power using combinations of hand , elbow , knees , multiple low kicks , sweeps etc.
RANDOM STICK / CLUB ATTACKS - Student defends himself against impact weapon such as a club or stick . Again the emphasis is on getting out of the path of the weapon whilst deflecting , moving in close , controlling the weapon wielders hands while striking him.
MULTIPLE OPPONENT SPARRING - Pretty much the same as all of the above except the student must also be aware of his positioning in relation to all of the attackers , keeping them all lined up and in his front sector , being careful not to be out flanked.
A greater degree of reflex , speed and power must also be demonstrated so that the Wing Chun student spends as little time as possible dispatching each attacker.
These are mainly the methods that were used in our academy.