title: Swift PrepareForSegue EXC_BREAKPOINT
body: <p>I have a runtime error: <em>Thread 1: EXC_BreakPoint(cod=EXC_I1386_BPT,subcode=0x0)</em></p>
  
  <p>I did not set any breakpoint inside Xcode. From the debugger,error is due to PrepareForSegue that stops a thread "swift_dynamicCastClassUnconditional"</p>
  
  <p><strong>BarTableViewController1 Class</strong></p>
  
  <pre><code>    @IBAction func solve_PressedBar(sender: AnyObject) {
  
          self.performSegueWithIdentifier("SolveBar", sender: sender)
  
      }
  
      override func prepareForSegue ( segue: UIStoryboardSegue, sender: AnyObject!) {
          if (segue.identifier == "SolveBar") {
              var svcBar = segue.destinationViewController as BarTableViewController2
  
              for items in textField1 {
                  length.append((items as NSString).floatValue)
              }
  
              for items in textField2 {
                  youngMod.append((items as NSString).floatValue)
              }
  
              for items in textField3 {
                  diameter.append((items as NSString).floatValue)
              }
  
              for items in textField4 {
                  forceBarWall.append((items as NSString).floatValue)
              }
  
              self.funcForceBarWall()
  
              println("variables are from TableViewController2")
              println(self.length)
              println(self.youngMod)
              println(self.forceBarWall)
              println(self.diameter)
  
              svcBar.length2 = self.length
              svcBar.youngMod2 = self.youngMod
              svcBar.diamter2 = self.diameter
              svcBar.forceBarWall2 = self.forceBarWall
  
              println("testing from bar viewcontroller1")
          }
      }
  }
  </code></pre>