python: make ArgumentNode publicly usable

- add `getCall`

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

@@ -322,6 +322,9 @@ SourceParameterNode parameterNode(Parameter p) { result.getParameter() = p }
 abstract class ArgumentNode extends Node {
   /** Holds if this argument occurs at the given position in the given call. */
   abstract predicate argumentOf(DataFlowCall call, ArgumentPosition pos);
+
+  /** Gets the call in which this node is an argument, if any. */
+  final DataFlowSourceCall getCall() { this.argumentOf(result, _) }
 }
 
 /** A data flow node that represents a call argument. */
@@ -335,9 +338,6 @@ class ArgumentSourceNode extends ArgumentNode {
   predicate sourceArgumentOf(DataFlowSourceCall call, ArgumentPosition pos) {
     this = call.getArg(pos)
   }
-
-  /** Gets the call in which this node is an argument. */
-  final DataFlowSourceCall getCall() { this.argumentOf(result, _) }
 }
 
 /**

python/ql/test/experimental/dataflow/TestUtil/MaximalFlowTest.qll

@@ -35,7 +35,7 @@ class MaximalFlowsConfig extends DataFlow::Configuration {
   override predicate isSink(DataFlow::Node node) {
     exists(node.getLocation().getFile().getRelativePath()) and
     not any(CallNode c).getArg(_) = node.asCfgNode() and
-    not node instanceof DataFlow::ArgumentSourceNode and
+    not node instanceof DataFlow::ArgumentNode and
     not node.asCfgNode().(NameNode).getId().matches("SINK%") and
     not exists(DataFlow::Node succ | DataFlow::localFlowStep(node, succ))
   }

python/ql/test/experimental/dataflow/TestUtil/RoutingTest.qll

@@ -43,7 +43,7 @@ abstract class RoutingTest extends InlineExpectationsTest {
   }
 
   pragma[inline]
-  private string fromFunc(DataFlow::ArgumentSourceNode fromNode) {
+  private string fromFunc(DataFlow::ArgumentNode fromNode) {
     result = fromNode.getCall().getNode().(CallNode).getFunction().getNode().(Name).getId()
   }
 

python/ql/test/experimental/dataflow/callGraphConfig.qll

@@ -11,7 +11,7 @@ class CallGraphConfig extends DataFlow::Configuration {
   override predicate isSource(DataFlow::Node node) {
     node instanceof DataFlowPrivate::ReturnNode
     or
-    node instanceof DataFlow::ArgumentSourceNode
+    node instanceof DataFlow::ArgumentNode
   }
 
   override predicate isSink(DataFlow::Node node) {

python/ql/test/experimental/dataflow/coverage/classesCallGraph.ql

@@ -11,7 +11,7 @@ class CallGraphConfig extends DataFlow::Configuration {
     node instanceof DataFlowPrivate::ReturnNode
     or
     // These sources should allow for the non-standard call syntax
-    node instanceof DataFlow::ArgumentSourceNode
+    node instanceof DataFlow::ArgumentNode
   }
 
   override predicate isSink(DataFlow::Node node) {