Address review comments

Author: hvitved

cpp/ql/src/semmle/code/cpp/dataflow/internal/DataFlowImpl.qll

@@ -765,7 +765,7 @@ private module Stage2 {
   bindingset[result, ap]
   private ApApprox getApprox(Ap ap) { any() }
 
-  private Ap getApNil(Node node) { PrevStage::revFlow(node, _) and result instanceof ApNil }
+  private ApNil getApNil(Node node) { PrevStage::revFlow(node, _) and exists(result) }
 
   bindingset[tc, tail]
   private Ap apCons(TypedContent tc, Ap tail) { result = true and exists(tc) and exists(tail) }

cpp/ql/src/semmle/code/cpp/dataflow/internal/DataFlowImpl2.qll

@@ -765,7 +765,7 @@ private module Stage2 {
   bindingset[result, ap]
   private ApApprox getApprox(Ap ap) { any() }
 
-  private Ap getApNil(Node node) { PrevStage::revFlow(node, _) and result instanceof ApNil }
+  private ApNil getApNil(Node node) { PrevStage::revFlow(node, _) and exists(result) }
 
   bindingset[tc, tail]
   private Ap apCons(TypedContent tc, Ap tail) { result = true and exists(tc) and exists(tail) }

cpp/ql/src/semmle/code/cpp/dataflow/internal/DataFlowImpl3.qll

@@ -765,7 +765,7 @@ private module Stage2 {
   bindingset[result, ap]
   private ApApprox getApprox(Ap ap) { any() }
 
-  private Ap getApNil(Node node) { PrevStage::revFlow(node, _) and result instanceof ApNil }
+  private ApNil getApNil(Node node) { PrevStage::revFlow(node, _) and exists(result) }
 
   bindingset[tc, tail]
   private Ap apCons(TypedContent tc, Ap tail) { result = true and exists(tc) and exists(tail) }

cpp/ql/src/semmle/code/cpp/dataflow/internal/DataFlowImpl4.qll

@@ -765,7 +765,7 @@ private module Stage2 {
   bindingset[result, ap]
   private ApApprox getApprox(Ap ap) { any() }
 
-  private Ap getApNil(Node node) { PrevStage::revFlow(node, _) and result instanceof ApNil }
+  private ApNil getApNil(Node node) { PrevStage::revFlow(node, _) and exists(result) }
 
   bindingset[tc, tail]
   private Ap apCons(TypedContent tc, Ap tail) { result = true and exists(tc) and exists(tail) }

cpp/ql/src/semmle/code/cpp/dataflow/internal/DataFlowImplCommon.qll

@@ -753,10 +753,7 @@ class ReturnPosition extends TReturnPosition0 {
  */
 pragma[inline]
 DataFlowCallable getNodeEnclosingCallable(Node n) {
-  exists(Node n0 |
-    pragma[only_bind_into](n0) = n and
-    result = n0.getEnclosingCallable()
-  )
+  pragma[only_bind_into](result) = n.getEnclosingCallable()
 }
 
 pragma[noinline]

cpp/ql/src/semmle/code/cpp/dataflow/internal/DataFlowImplLocal.qll

@@ -765,7 +765,7 @@ private module Stage2 {
   bindingset[result, ap]
   private ApApprox getApprox(Ap ap) { any() }
 
-  private Ap getApNil(Node node) { PrevStage::revFlow(node, _) and result instanceof ApNil }
+  private ApNil getApNil(Node node) { PrevStage::revFlow(node, _) and exists(result) }
 
   bindingset[tc, tail]
   private Ap apCons(TypedContent tc, Ap tail) { result = true and exists(tc) and exists(tail) }

cpp/ql/src/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl.qll

@@ -765,7 +765,7 @@ private module Stage2 {
   bindingset[result, ap]
   private ApApprox getApprox(Ap ap) { any() }
 
-  private Ap getApNil(Node node) { PrevStage::revFlow(node, _) and result instanceof ApNil }
+  private ApNil getApNil(Node node) { PrevStage::revFlow(node, _) and exists(result) }
 
   bindingset[tc, tail]
   private Ap apCons(TypedContent tc, Ap tail) { result = true and exists(tc) and exists(tail) }

cpp/ql/src/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl2.qll

@@ -765,7 +765,7 @@ private module Stage2 {
   bindingset[result, ap]
   private ApApprox getApprox(Ap ap) { any() }
 
-  private Ap getApNil(Node node) { PrevStage::revFlow(node, _) and result instanceof ApNil }
+  private ApNil getApNil(Node node) { PrevStage::revFlow(node, _) and exists(result) }
 
   bindingset[tc, tail]
   private Ap apCons(TypedContent tc, Ap tail) { result = true and exists(tc) and exists(tail) }

cpp/ql/src/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl3.qll

@@ -765,7 +765,7 @@ private module Stage2 {
   bindingset[result, ap]
   private ApApprox getApprox(Ap ap) { any() }
 
-  private Ap getApNil(Node node) { PrevStage::revFlow(node, _) and result instanceof ApNil }
+  private ApNil getApNil(Node node) { PrevStage::revFlow(node, _) and exists(result) }
 
   bindingset[tc, tail]
   private Ap apCons(TypedContent tc, Ap tail) { result = true and exists(tc) and exists(tail) }

cpp/ql/src/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl4.qll

@@ -765,7 +765,7 @@ private module Stage2 {
   bindingset[result, ap]
   private ApApprox getApprox(Ap ap) { any() }
 
-  private Ap getApNil(Node node) { PrevStage::revFlow(node, _) and result instanceof ApNil }
+  private ApNil getApNil(Node node) { PrevStage::revFlow(node, _) and exists(result) }
 
   bindingset[tc, tail]
   private Ap apCons(TypedContent tc, Ap tail) { result = true and exists(tc) and exists(tail) }