C++: Def is only used in defToNode, which doesn't include phi reads nodes.

Author: aschackmull

cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowPrivate.qll

@@ -1834,15 +1834,15 @@ module IteratorFlow {
 
   private module IteratorSsa = SsaImpl::Make<Location, SsaInput>;
 
-  private class Def extends IteratorSsa::DefinitionExt {
+  private class Def extends IteratorSsa::Definition {
     final override Location getLocation() { result = this.getImpl().getLocation() }
 
     /**
      * Holds if this definition (or use) has index `index` in block `block`,
      * and is a definition (or use) of the variable `sv`.
      */
     predicate hasIndexInBlock(IRBlock block, int index, SourceVariable sv) {
-      super.definesAt(sv, block, index, _)
+      super.definesAt(sv, block, index)
     }
 
     private Ssa::DefImpl getImpl() {