I am not aware of any tools that would warn about that. I do not even recall
using any version of lint that would warn about that (but it is been quite
awhile, so that is not really saying much), and probably would not use that
feature if I did. There is too much code running around with that pattern
where the code is correct (i.e. someone just did not bother to put any blank
lines in their code) and dealing with all the false-positives would be IMHO
more trouble than it is worth.
Of course, YMMV. I adhere to the philosophy that the code's not done until
you have stepped through every line of it at least once, and doing so would
immediately reveal an error in code like that. Additionally, a long
sequence of if/else if/else usually points to a situation that is better
handled either with a switch statement or polymorphism. Others without
those philosophies might find such problems come up in their own code more
often and would find a lint warning more valuable.
All that said, if you are thinking about writing such a tool, the new
make it somewhat easier to implement such a thing.