Address review comments

Author: hvitved

shared/dataflow/codeql/dataflow/internal/DataFlowImpl.qll

@@ -3932,6 +3932,8 @@ module MakeImpl<LocationSig Location, InputSig<Location> Lang> {
       override predicate isSource() { none() }
 
       override string toString() { result = sourceGroup }
+
+      override Location getLocation() { result.hasLocationInfo("", 0, 0, 0, 0) }
     }
 
     private class PathNodeSinkGroup extends PathNodeImpl, TPathNodeSinkGroup {
@@ -3948,6 +3950,8 @@ module MakeImpl<LocationSig Location, InputSig<Location> Lang> {
       override predicate isSource() { none() }
 
       override string toString() { result = sinkGroup }
+
+      override Location getLocation() { result.hasLocationInfo("", 0, 0, 0, 0) }
     }
 
     private predicate pathNode(

shared/dataflow/codeql/dataflow/internal/DataFlowImplCommon.qll

@@ -1650,8 +1650,6 @@ module MakeImplCommon<LocationSig Location, InputSig<Location> Lang> {
    */
   class CastingNode extends NodeFinal {
     CastingNode() { castingNode(this) }
-
-    string toString() { result = super.toString() }
   }
 
   private predicate readStepWithTypes(
@@ -1800,8 +1798,6 @@ module MakeImplCommon<LocationSig Location, InputSig<Location> Lang> {
   class ParamNode extends NodeFinal {
     ParamNode() { parameterNode(this, _, _) }
 
-    string toString() { result = super.toString() }
-
     /**
      * Holds if this node is the parameter of callable `c` at the specified
      * position.
@@ -1815,8 +1811,6 @@ module MakeImplCommon<LocationSig Location, InputSig<Location> Lang> {
   class ArgNode extends NodeFinal {
     ArgNode() { argumentNode(this, _, _) }
 
-    string toString() { result = super.toString() }
-
     /** Holds if this argument occurs at the given position in the given call. */
     final predicate argumentOf(DataFlowCall call, ArgumentPosition pos) {
       argumentNode(this, call, pos)
@@ -1830,8 +1824,6 @@ module MakeImplCommon<LocationSig Location, InputSig<Location> Lang> {
   class ReturnNodeExt extends NodeFinal {
     ReturnNodeExt() { returnNodeExt(this, _) }
 
-    string toString() { result = super.toString() }
-
     /** Gets the kind of this returned value. */
     ReturnKindExt getKind() { returnNodeExt(this, result) }
   }
@@ -1842,8 +1834,6 @@ module MakeImplCommon<LocationSig Location, InputSig<Location> Lang> {
    */
   class OutNodeExt extends NodeFinal {
     OutNodeExt() { outNodeExt(this) }
-
-    string toString() { result = super.toString() }
   }
 
   /**