why is the return variable void in the setup considered an unexpected token?

btw: Disc is another class, I don't think it's the issue so I won't flood the forum with it's code  

 Disc disc1=new Disc(800,300,100);
 Disc disc2=new Disc(800,300,100);
 Disc disc3=new Disc(800,300,100);
 Disc disc4=new Disc(800,300,100);
 Disc disc5=new Disc(800,300,100);
 Disc disc6=new Disc(800,300,100);
 Disc disc7=new Disc(800,300,100);
 Disc disc8=new Disc(800,300,100);
 int level=1;
 Stack<Disc> fst;
 Stack<Disc> snd;
 Stack<Disc> trd;
 
 void setup() {
   size(1000,1000);
   Stack<Disc> fst=new Stack<Disc>();
   Stack<Disc> snd=new Stack<Disc>();
   Stack<Disc> trd=new Stack<Disc>();
 }
 
 void draw()
 {
   background(255);
   disc1.display();
   disc2.display();
   disc3.display();
   disc4.display();
 }
   boolean canMove(Stack a, Stack b)
   {
     int thisone=0;
     int thatone=0;
     if(!a.isEmpty())
     {
        thisone=a.peek().getSize();
        thatone=a.peek().getSize();
        if(thisone>thatone)
        {
          return false;
        }
        return true;
     }
   }