.E
======================================================================
ERROR: testVarOps (__main__.VarOpTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/uke/oil/osh/cmd_eval_test.py", line 51, in testVarOps
    ev._EvalWordPart(unset_sub, part_vals, 0)
  File "/home/uke/oil/osh/word_eval.py", line 1767, in _EvalWordPart
    self._EvalBracedVarSub(part, part_vals, quoted)
  File "/home/uke/oil/osh/word_eval.py", line 1410, in _EvalBracedVarSub
    if part.name_tok.id == Id.VSub_Name:
AttributeError: 'NoneType' object has no attribute 'id'

----------------------------------------------------------------------
Ran 2 tests in 0.005s

FAILED (errors=1)
(command.Simple
  blame_tok:(Token
    id:Lit_Chars
    length:4
    col:0
    line:(SourceLine
      line_num:1
      content:"echo _{a,b}_"
      src:(source.MainFile path:"<cmd_eval_test.py>")
    )
  )
  more_env:[]
  words:[
    (CompoundWord parts:[...0x7f3bd2f2d808])
    (word.BracedTree
      parts:[
        (Token id:Lit_Chars length:1 col:5 line:...0x7f3bd2f3d3c0)
        (word_part.BracedTuple
          words:[
            (CompoundWord
              parts:[(Token id:Lit_Chars length:1 col:7 line:...0x7f3bd2f3d3c0)]
            )
            (CompoundWord
              parts:[(Token id:Lit_Chars length:1 col:9 line:...0x7f3bd2f3d3c0)]
            )
          ]
        )
        (Token id:Lit_Chars length:1 col:11 line:...0x7f3bd2f3d3c0)
      ]
    )
  ]
  is_last_cmd:F
)