 
   // Removes all traces of c from this variable.
   func removeConstraint(constraint: Constraint) {
-    constraints = constraints.filter({ $0 != constraint })
+    constraints = constraints.filter({ $0 !== constraint })
     if let c = determinedBy {
-      if (c == constraint) {
+      if (c === constraint) {
         determinedBy = nil
       }
     }

  change(dst, newValue: 1050)

  total = total + src.value
  print("Help swift: \(total)")
  if src.value != 5 {
    print("Projection 2 failed")
  }


      if let determining = v.determinedBy {
        for next in v.constraints {
          if next !== determining && next.isSatisfied {
            next.recalculate()
            todo.append(next.output)
          }
