JavaScript: Refactor argumentPassing.

javascript/ql/src/semmle/javascript/dataflow/Configuration.qll

@@ -502,10 +502,7 @@ private predicate callInputStep(
 ) {
   (
     isRelevant(pred, cfg) and
-    exists(Parameter parm |
-      argumentPassing(invk, pred, f, parm) and
-      succ = DataFlow::parameterNode(parm)
-    )
+    argumentPassing(invk, pred, f, succ)
     or
     isRelevant(pred, cfg) and
     exists(SsaDefinition prevDef, SsaDefinition def |

javascript/ql/src/semmle/javascript/dataflow/Nodes.qll

@@ -17,6 +17,9 @@ class ParameterNode extends DataFlow::SourceNode {
 
   /** Gets the name of this parameter. */
   string getName() { result = p.getName() }
+
+  /** Holds if this parameter is a rest parameter. */
+  predicate isRestParameter() { p.isRestParameter() }
 }
 
 /** A data flow node corresponding to a function invocation (with or without `new`). */

javascript/ql/src/semmle/javascript/dataflow/TaintTracking.qll

@@ -782,7 +782,7 @@ module TaintTracking {
    * A function that returns the result of a sanitizer check.
    */
   private class SanitizingFunction extends Function {
-    Parameter sanitizedParameter;
+    DataFlow::ParameterNode sanitizedParameter;
 
     SanitizerGuardNode sanitizer;
 
@@ -806,11 +806,11 @@ module TaintTracking {
           or
           returnExpr = getAReturnedExpr()
         ) and
-        DataFlow::parameterNode(sanitizedParameter).flowsToExpr(e) and
+        sanitizedParameter.flowsToExpr(e) and
         sanitizer.sanitizes(sanitizerOutcome, e)
       ) and
       getNumParameter() = 1 and
-      sanitizedParameter = getParameter(0)
+      sanitizedParameter.getParameter() = getParameter(0)
     }
 
     /**

javascript/ql/src/semmle/javascript/dataflow/TrackedNodes.qll

@@ -113,10 +113,7 @@ private module NodeTracking {
   ) {
     isRelevant(pred) and
     (
-      exists(Parameter parm |
-        argumentPassing(invk, pred, f, parm) and
-        succ = DataFlow::parameterNode(parm)
-      )
+      argumentPassing(invk, pred, f, succ)
       or
       exists(SsaDefinition prevDef, SsaDefinition def |
         pred = DataFlow::ssaDefinitionNode(prevDef) and

javascript/ql/src/semmle/javascript/dataflow/internal/FlowSteps.qll

@@ -87,11 +87,11 @@ predicate localFlowStep(
  * through invocation `invk` of function `f`.
  */
 predicate argumentPassing(
-  DataFlow::InvokeNode invk, DataFlow::ValueNode arg, Function f, Parameter parm
+  DataFlow::InvokeNode invk, DataFlow::ValueNode arg, Function f, DataFlow::ParameterNode parm
 ) {
   calls(invk, f) and
   exists(int i |
-    f.getParameter(i) = parm and
+    f.getParameter(i) = parm.getParameter() and
     not parm.isRestParameter() and
     arg = invk.getArgument(i)
   )
@@ -99,7 +99,7 @@ predicate argumentPassing(
   exists(DataFlow::Node callback, int i |
     invk.(DataFlow::AdditionalPartialInvokeNode).isPartialArgument(callback, arg, i) and
     partiallyCalls(invk, callback, f) and
-    parm = f.getParameter(i) and
+    parm.getParameter() = f.getParameter(i) and
     not parm.isRestParameter()
   )
 }
@@ -109,10 +109,7 @@ predicate argumentPassing(
  * to a function call.
  */
 predicate callStep(DataFlow::Node pred, DataFlow::Node succ) {
-  exists(Parameter parm |
-    argumentPassing(_, pred, _, parm) and
-    succ = DataFlow::parameterNode(parm)
-  )
+  argumentPassing(_, pred, _, succ)
 }
 
 /**