re.compile('foo[a-') raises a TypeError exception
instead of re.error.

Python 2.2.1 (#1, Apr  4 2002, 17:22:15) 
[GCC 2.96 20000731 (Mandrake Linux 8.2 2.96-0.76mdk)]
on linux2
Type "help", "copyright", "credits" or "license" for
more information.
>>> import re
>>> re.compile('foo[a-')
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "/usr/local/lib/python2.2/sre.py", line 178, in
compile
    return _compile(pattern, flags)
  File "/usr/local/lib/python2.2/sre.py", line 226, in
_compile
    p = sre_compile.compile(pattern, flags)
  File "/usr/local/lib/python2.2/sre_compile.py", line
430, in compile
    p = sre_parse.parse(p, flags)
  File "/usr/local/lib/python2.2/sre_parse.py", line
623, in parse
    p = _parse_sub(source, pattern, 0)
  File "/usr/local/lib/python2.2/sre_parse.py", line
318, in _parse_sub
    items.append(_parse(source, state))
  File "/usr/local/lib/python2.2/sre_parse.py", line
424, in _parse
    if this[0] == "\\":
TypeError: unsubscriptable object