7.8 blockers

Bug 4377 is bogus. (It doesn't seem possible to comment bug reports...)

[^] is not a negated empty set, just as [] is not an empty set. They are sets which contain (or does not contain, in the case of ^) the character "]". So we have e.g.

"[^]]" = Any character except "]" "[^][^]" = Any character except "]", "[", or "^". "[]]" = Only "]" "[][]" = Either "]" or "["

Thus the statement that there is no conflicting interpretation is invalid, and the bug report is bogus. (Even if there is no _valid_ conflicting interpretation in the example given in the bug report, example 2 above for example would be valid (but mean different things) in both interpretations.)