chokes on `rb"literal"` about yapf

[bwendling]

The problem is that the original code isn't correct. "rb" isn't accepted by "br" is. One of the limitations of lib2to3 (and therefore YAPF) is that it requires the code to be well-formed. Here's what I saw:

>>> rb'hello world'
  File "<stdin>", line 1
    rb'hello world'
                  ^
SyntaxError: invalid syntax
>>> br'hello world'
'hello world'
>>> 

[jab]

$ python3
Python 3.4.3 (default, Mar  1 2015, 15:44:16)
[GCC 4.2.1 Compatible Apple LLVM 6.0 (clang-600.0.56)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> rb'this is valid python3 syntax'
b'this is valid python3 syntax'

Useful for e.g. not having to escape backslashes in bytestrings.

[bwendling]

Ah! My mistake. I was using 2.7.

[bwendling]

Marking this as a bug, but I'm not sure what we can do here. Might be the same issue as yield from?

[eliben]

Yeah, I'll have to see what we do about places where lib2to3 fails. Maybe deeper monkey-patching will help

[eliben]

This is an upstream lib2to3 bug. Reported http://bugs.python.org/issue23894

Monkey patching this in lib2to3 is pretty complex -- I don't see this as very high priority at this time.

[eliben]

Adding a lib2to3 bug label.

[bwendling]

Python 3 seems to have fixed this.