Previously, as the check was done on the token and not on the ast,
`i <= v.size()` and `i <= v.size() - 2` would both raise the same
warning.
This patch fixes this, but this mean the check is only done when the
condition if `i <= v.size()`. Any other (more complex) condition is
ignore, and so we have false negative for instance with
`i <= v.size() + 1`.
