Null-pointer exception cascade

[Pytheas01]

The following code causes a cascade of null pointer exceptions in SymphonyTool 0.4.0.

channels
tick

class ClockSt = begin
 state
public s: nat

initial
    Init()
     frame wr s
     post s = 0

operations

public increment()
frame wr s
post s = s~ + 1

end

process SimpleClock = begin
state c: ClockSt
 actions
 Ticking = Wait 1; c.increment(); tick -> Skip
 @
 c := new ClockSt(); c.Init(); mu X @ (Ticking; X)
 end