seattlerb/ruby_parser — pull request #107 by stormbrew (2013-03-27 01:48:24+00:00)
Title: Add test case for and fix behaviour when given 'a[] += b'.

Currently the behaviour on hitting a code fragment like 'a[] += b' is to throw an error as val[2] has nil in it. The code is valid and ripper accepts it, leaving a nil in the field where the arguments would go, so I made this do the same.