Crashes on defining a recursive function about shadershop HOT 7 CLOSED

containsCircularDep = (fn_to_add, existing) ->                                      
  if fn_to_add instanceof C.BuiltInFn                                               
      return false                                                                  
  fn_to_add = fn_to_add.childFns[0].fn                                              
  recurse = (fn) ->                                                                 
    if fn.__id == fn_to_add.__id                                                    
        return true                                                                 
    if fn instanceof C.CompoundFn                                                   
        fn.childFns.some recurse                                                    
    else                                                                            
        false                                                                       
  recurse(existing) 

  if containsCircularDep fn, parent                                              
      console.log "CIRCULAR DEP"                                                 
      return 

containsCircularDep = (fn_to_add, existing) ->                                      
  if fn_to_add instanceof C.BuiltInFn                                               
      return false                                                                  
  recurse = (fn) ->                                                                 
    if fn instanceof C.DefinedFn or fn instanceof C.CompoundFn                      
        fn == existing or fn.childFns.some recurse                                  
    else if fn instanceof C.ChildFn                                                 
        recurse fn.fn                                                               
    else # C.BuiltInFn                                                              
        false                                                                       
  recurse(fn_to_add)