Re: highlight failed part of isearch input

[Stefan Monnier]

>> There may be performance issues (if the search text is long, the longest
>> prefix with a match is short (i.e. we need to iterate many times), and the
>> buffer is long (i.,e. each iteration's trial search takes a while))

> Binary search?

For plain strings it works, but for regexps it doesn't: the fact that
a prefix fails to match doesn't gurantee that some longer prefix will also
fail to match.


        Stefan