Python: Move typePreservingStep into Private

Author: tausbn

python/ql/src/experimental/typetracking/TypeTracker.qll

@@ -78,12 +78,6 @@ module StepSummary {
   }
 }
 
-/** Holds if it's reasonable to expect the data flow step from `nodeFrom` to `nodeTo` to preserve types. */
-private predicate typePreservingStep(Node nodeFrom, Node nodeTo) {
-  simpleLocalFlowStep(nodeFrom, nodeTo) or
-  jumpStep(nodeFrom, nodeTo)
-}
-
 /**
  * A utility class that is equivalent to `boolean` but does not require type joining.
  */

python/ql/src/experimental/typetracking/TypeTrackerPrivate.qll

@@ -6,9 +6,11 @@ class Node = DataFlowPublic::Node;
 
 class LocalSourceNode = DataFlowPublic::LocalSourceNode;
 
-predicate jumpStep = DataFlowPrivate::jumpStep/2;
-
-predicate simpleLocalFlowStep = DataFlowPrivate::simpleLocalFlowStep/2;
+/** Holds if it's reasonable to expect the data flow step from `nodeFrom` to `nodeTo` to preserve types. */
+predicate typePreservingStep(Node nodeFrom, Node nodeTo) {
+  DataFlowPrivate::simpleLocalFlowStep(nodeFrom, nodeTo) or
+  DataFlowPrivate::jumpStep(nodeFrom, nodeTo)
+}
 
 /**
  * Gets the name of a possible piece of content. This will usually include things like