old_contents: print(','.join(()))
  print(','.join(('a',)))
  print(','.join(('a', 'b')))
  
  print(','.join([]))
  print(','.join(['a']))
  print(','.join(['a', 'b']))
  
  print(''.join(''))
  print(''.join('abc'))
  print(','.join('abc'))
  print(','.join('abc' for i in range(5)))
  
  print(b','.join([b'abc', b'123']))
  
  try:
      print(b','.join(['abc', b'123']))
  except TypeError:
      print("TypeError")
  
  try:
      print(','.join([b'abc', b'123']))
  except TypeError:
      print("TypeError")
  
  # joined by the compiler
  print("a" "b")
  print("a" '''b''')
  print("a" # inline comment
      "b")
  print("a" \
      "b")
  
  # the following should not be joined by the compiler
  x = 'a'
  'b'
  print(x)
  
new_contents: print(','.join(()))
  print(','.join(('a',)))
  print(','.join(('a', 'b')))
  
  print(','.join([]))
  print(','.join(['a']))
  print(','.join(['a', 'b']))
  
  print(''.join(''))
  print(''.join('abc'))
  print(','.join('abc'))
  print(','.join('abc' for i in range(5)))
  
  print(b','.join([b'abc', b'123']))
  
  try:
      ''.join(None)
  except TypeError:
      print("TypeError")
  
  try:
      print(b','.join(['abc', b'123']))
  except TypeError:
      print("TypeError")
  
  try:
      print(','.join([b'abc', b'123']))
  except TypeError:
      print("TypeError")
  
  # joined by the compiler
  print("a" "b")
  print("a" '''b''')
  print("a" # inline comment
      "b")
  print("a" \
      "b")
  
  # the following should not be joined by the compiler
  x = 'a'
  'b'
  print(x)
  
subject: Add test case where argument is not iterable.