Holds if the intermediate node
node is a taint sanitizer, that is,
tainted values can not flow into or out of
Note that this only blocks flow through nodes that operate directly on the tainted value.
An object containing a tainted value in a property can still flow into and out of
To block such objects, override
isBarrier or use a labeled sanitizer to block the
data flow label.
For operations that check if a value is tainted or safe, use