Merge pull request #22249 from MathiasVP/python-explicit-fasttc-local-flow-step

Python: Use fastTC explicitly in `localFlow`

Author: MathiasVP

python/ql/lib/semmle/python/dataflow/new/internal/DataFlowUtil.qll

@@ -20,9 +20,11 @@ predicate localFlowStep(Node nodeFrom, Node nodeTo) {
   FlowSummaryImpl::Private::Steps::summaryThroughStepValue(nodeFrom, nodeTo, _)
 }
 
+private predicate localFlowStepPlus(Node node1, Node node2) = fastTC(localFlowStep/2)(node1, node2)
+
 /**
  * Holds if data flows from `source` to `sink` in zero or more local
  * (intra-procedural) steps.
  */
 pragma[inline]
-predicate localFlow(Node source, Node sink) { localFlowStep*(source, sink) }
+predicate localFlow(Node source, Node sink) { source = sink or localFlowStepPlus(source, sink) }