regex.compile("^(?:a(?:(?:))+)+") causes "_regex_core.error: nothing to repeat"

What steps will reproduce the problem?
>>> import regex
>>> regex.compile("^(?:a(?:(?:))+)+")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Python32\3.2.2\lib\site-packages\regex.py", line 289, in compile
    return _compile(pattern, flags, kwargs)
  File "C:\Python32\3.2.2\lib\site-packages\regex.py", line 423, in _compile
    parsed = parse_pattern(source, info)
  File "C:\Python32\3.2.2\lib\site-packages\_regex_core.py", line 336, in parse_
pattern
    branches = [parse_sequence(source, info)]
  File "C:\Python32\3.2.2\lib\site-packages\_regex_core.py", line 355, in parse_
sequence
    item = parse_item(source, info)
  File "C:\Python32\3.2.2\lib\site-packages\_regex_core.py", line 365, in parse_
item
    element = parse_element(source, info)
  File "C:\Python32\3.2.2\lib\site-packages\_regex_core.py", line 649, in parse_
element
    element = parse_paren(source, info)
  File "C:\Python32\3.2.2\lib\site-packages\_regex_core.py", line 783, in parse_
paren
    return parse_flags_subpattern(source, info)
  File "C:\Python32\3.2.2\lib\site-packages\_regex_core.py", line 998, in parse_
flags_subpattern
    subpattern = parse_pattern(source, info)
  File "C:\Python32\3.2.2\lib\site-packages\_regex_core.py", line 336, in parse_
pattern
    branches = [parse_sequence(source, info)]
  File "C:\Python32\3.2.2\lib\site-packages\_regex_core.py", line 355, in parse_
sequence
    item = parse_item(source, info)
  File "C:\Python32\3.2.2\lib\site-packages\_regex_core.py", line 365, in parse_
item
    element = parse_element(source, info)
  File "C:\Python32\3.2.2\lib\site-packages\_regex_core.py", line 698, in parse_
element
    raise error("nothing to repeat")
_regex_core.error: nothing to repeat
>>>

What is the expected output? What do you see instead?
>>> import regex
>>> regex.compile("^(?:a(?:(?:))+)+")
regex.Regex('^(?:a(?:(?:))+)+', flags=regex.V0)
>>>

What version of the product are you using? On what operating system?
Windows XP Home SP3 (32-bit version)
Python 3.2.2 (default, Sep  4 2011, 09:51:08) [MSC v.1500 32 bit (Intel)] on win
32
regex 0.1.20120119

Please provide any additional information below.

Original issue reported on code.google.com by msm...@gmail.com on 20 Jan 2012 at 1:54

Forever-Young / mrab-regex-hg

regex.compile("^(?:a(?:(?:))+)+") causes "_regex_core.error: nothing to repeat" #45