------ ----------------------------------------------------------------------- 
  Line   stubs/ext-ds.stub                                                      
 ------ ----------------------------------------------------------------------- 
  46     Return type Ds\Deque of method Ds\Deque::copy() is not compatible      
         with return type Ds\Collection of method Ds\Collection::copy().        
  55     Return type Ds\Deque of method Ds\Deque::merge() is not compatible     
         with return type Ds\Sequence of method Ds\Sequence::merge().           
  63     Return type Ds\Deque of method Ds\Deque::filter() is not compatible    
         with return type Ds\Sequence of method Ds\Sequence::filter().          
  72     Return type Ds\Deque of method Ds\Deque::map() is not compatible with  
         return type Ds\Sequence of method Ds\Sequence::map().                  
  79     Return type Ds\Deque of method Ds\Deque::reversed() is not compatible  
         with return type Ds\Sequence of method Ds\Sequence::reversed().        
  86     Return type Ds\Deque of method Ds\Deque::slice() is not compatible     
         with return type Ds\Sequence of method Ds\Sequence::slice().           
  108    Return type Ds\Map of method Ds\Map::copy() is not compatible with     
         return type Ds\Collection of method Ds\Collection::copy().             
  539    Return type Ds\Vector of method Ds\Vector::copy() is not compatible    
         with return type Ds\Collection of method Ds\Collection::copy().        
  546    Return type Ds\Vector of method Ds\Vector::reversed() is not           
         compatible with return type Ds\Sequence of method                      
         Ds\Sequence::reversed().                                               
  553    Return type Ds\Vector of method Ds\Vector::slice() is not compatible   
         with return type Ds\Sequence of method Ds\Sequence::slice().           
  561    Return type Ds\Vector of method Ds\Vector::sorted() is not compatible  
         with return type Ds\Sequence of method Ds\Sequence::sorted().          
  569    Return type Ds\Vector of method Ds\Vector::filter() is not compatible  
         with return type Ds\Sequence of method Ds\Sequence::filter().          
  578    Return type Ds\Vector of method Ds\Vector::map() is not compatible     
         with return type Ds\Sequence of method Ds\Sequence::map().             
  587    Return type Ds\Vector of method Ds\Vector::merge() is not compatible   
         with return type Ds\Sequence of method Ds\Sequence::merge().           
  622    Return type Ds\Set of method Ds\Set::copy() is not compatible with     
         return type Ds\Collection of method Ds\Collection::copy().             
  763    Return type Ds\Stack of method Ds\Stack::copy() is not compatible      
         with return type Ds\Collection of method Ds\Collection::copy().        
  815    Return type Ds\Queue of method Ds\Queue::copy() is not compatible      
         with return type Ds\Collection of method Ds\Collection::copy().        
  859    Return type Ds\PriorityQueue of method Ds\PriorityQueue::copy() is     
         not compatible with return type Ds\Collection of method                
         Ds\Collection::copy().                                                 
 ------ -----------------------------------------------------------------------