C++: Fix duplication for indirect exprs similar to how we fixed it in #15410.

Author: MathiasVP

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

@@ -1484,12 +1484,17 @@ private module IndirectNodeToIndirectExpr<IndirectNodeToIndirectExprSig Sig> {
       indirectNodeHasIndirectExpr(node, e, n, indirectionIndex) and
       not exists(Expr conv, int adjustedIndirectionIndex |
         adjustForReference(e, indirectionIndex, conv, adjustedIndirectionIndex) and
-        indirectNodeHasIndirectExpr(_, conv, n + 1, adjustedIndirectionIndex)
+        indirectExprNodeShouldBe(conv, n + 1, adjustedIndirectionIndex)
       )
     )
   }
 }
 
+private predicate indirectExprNodeShouldBe(Expr e, int n, int indirectionIndex) {
+  indirectExprNodeShouldBeIndirectOperand(_, e, n, indirectionIndex) or
+  indirectExprNodeShouldBeIndirectInstruction(_, e, n, indirectionIndex)
+}
+
 private module IndirectOperandIndirectExprNodeImpl implements IndirectNodeToIndirectExprSig {
   class IndirectNode = IndirectOperand;
 

cpp/ql/test/library-tests/dataflow/asExpr/test.cpp

@@ -2,7 +2,7 @@ void take_const_ref_int(const int &);
 
 void test_materialize_temp_int()
 {
-  take_const_ref_int(42); // $ asExpr=42 numberOfNodes="42: 2" asIndirectExpr=42 numberOfIndirectNodes="42: 2"
+  take_const_ref_int(42); // $ asExpr=42 numberOfNodes="42: 2" asIndirectExpr=42
 }
 
 struct A {};
@@ -11,7 +11,7 @@ A get();
 void take_const_ref(const A &);
 
 void test1(){
-  take_const_ref(get()); // $ asExpr="call to get" numberOfNodes="call to get: 2" asIndirectExpr="call to get" numberOfIndirectNodes="call to get: 2"
+  take_const_ref(get()); // $ asExpr="call to get" numberOfNodes="call to get: 2" asIndirectExpr="call to get"
 }
 
 void take_ref(A &);