From 9630feb5e417dd5d4b1c918c0789ce8a94a0106e Mon Sep 17 00:00:00 2001
From: Kasper Svendsen <kaspersv@github.com>
Date: Mon, 20 Mar 2023 09:04:35 +0100
Subject: [PATCH 1/3] Dataflow: Remove revFlowAlias trick

---
 .../cpp/dataflow/internal/DataFlowImpl.qll    | 30 +++++++------------
 .../cpp/ir/dataflow/internal/DataFlowImpl.qll | 30 +++++++------------
 .../csharp/dataflow/internal/DataFlowImpl.qll | 30 +++++++------------
 .../go/dataflow/internal/DataFlowImpl.qll     | 30 +++++++------------
 .../java/dataflow/internal/DataFlowImpl.qll   | 30 +++++++------------
 .../dataflow/new/internal/DataFlowImpl.qll    | 30 +++++++------------
 .../ruby/dataflow/internal/DataFlowImpl.qll   | 30 +++++++------------
 .../swift/dataflow/internal/DataFlowImpl.qll  | 30 +++++++------------
 8 files changed, 80 insertions(+), 160 deletions(-)

diff --git a/cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowImpl.qll b/cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowImpl.qll
index b7cb98deaf9..f02728b9e18 100644
--- a/cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowImpl.qll
+++ b/cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowImpl.qll
@@ -1695,16 +1695,6 @@ module Impl<FullStateConfigSig Config> {
       pragma[nomagic]
       predicate revFlowAp(NodeEx node, Ap ap) { revFlow(node, _, _, _, ap) }
 
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      additional predicate revFlowAlias(NodeEx node) { revFlow(node, _, _, _, _) }
-
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      additional predicate revFlowAlias(NodeEx node, FlowState state, Ap ap) {
-        revFlow(node, state, ap)
-      }
-
       private predicate fwdConsCand(TypedContent tc, Ap ap) { storeStepFwd(_, ap, tc, _, _) }
 
       private predicate revConsCand(TypedContent tc, Ap ap) { storeStepCand(_, ap, tc, _, _) }
@@ -1978,7 +1968,7 @@ module Impl<FullStateConfigSig Config> {
   ) {
     flowOutOfCallNodeCand1(call, node1, kind, node2, allowsFieldFlow) and
     Stage2::revFlow(node2) and
-    Stage2::revFlowAlias(node1)
+    Stage2::revFlow(node1)
   }
 
   pragma[nomagic]
@@ -1987,7 +1977,7 @@ module Impl<FullStateConfigSig Config> {
   ) {
     flowIntoCallNodeCand1(call, node1, node2, allowsFieldFlow) and
     Stage2::revFlow(node2) and
-    Stage2::revFlowAlias(node1)
+    Stage2::revFlow(node1)
   }
 
   private module LocalFlowBigStep {
@@ -2069,11 +2059,11 @@ module Impl<FullStateConfigSig Config> {
       additionalLocalFlowStepNodeCand1(node1, node2) and
       state1 = state2 and
       Stage2::revFlow(node1, pragma[only_bind_into](state1), false) and
-      Stage2::revFlowAlias(node2, pragma[only_bind_into](state2), false)
+      Stage2::revFlow(node2, pragma[only_bind_into](state2), false)
       or
       additionalLocalStateStep(node1, state1, node2, state2) and
       Stage2::revFlow(node1, state1, false) and
-      Stage2::revFlowAlias(node2, state2, false)
+      Stage2::revFlow(node2, state2, false)
     }
 
     /**
@@ -2266,7 +2256,7 @@ module Impl<FullStateConfigSig Config> {
     ) {
       localFlowBigStep(node1, state1, node2, state2, preservesValue, ap.getType(), _) and
       PrevStage::revFlow(node1, pragma[only_bind_into](state1), _) and
-      PrevStage::revFlowAlias(node2, pragma[only_bind_into](state2), _) and
+      PrevStage::revFlow(node2, pragma[only_bind_into](state2), _) and
       exists(lcc)
     }
 
@@ -2277,7 +2267,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowOutOfCallNodeCand2(call, node1, kind, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2288,7 +2278,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowIntoCallNodeCand2(call, node1, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2590,7 +2580,7 @@ module Impl<FullStateConfigSig Config> {
     ) {
       localFlowBigStep(node1, state1, node2, state2, preservesValue, ap.getType(), lcc) and
       PrevStage::revFlow(node1, pragma[only_bind_into](state1), _) and
-      PrevStage::revFlowAlias(node2, pragma[only_bind_into](state2), _)
+      PrevStage::revFlow(node2, pragma[only_bind_into](state2), _)
     }
 
     pragma[nomagic]
@@ -2600,7 +2590,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowOutOfCallNodeCand2(call, node1, kind, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2611,7 +2601,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowIntoCallNodeCand2(call, node1, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
diff --git a/cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl.qll b/cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl.qll
index b7cb98deaf9..f02728b9e18 100644
--- a/cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl.qll
+++ b/cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl.qll
@@ -1695,16 +1695,6 @@ module Impl<FullStateConfigSig Config> {
       pragma[nomagic]
       predicate revFlowAp(NodeEx node, Ap ap) { revFlow(node, _, _, _, ap) }
 
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      additional predicate revFlowAlias(NodeEx node) { revFlow(node, _, _, _, _) }
-
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      additional predicate revFlowAlias(NodeEx node, FlowState state, Ap ap) {
-        revFlow(node, state, ap)
-      }
-
       private predicate fwdConsCand(TypedContent tc, Ap ap) { storeStepFwd(_, ap, tc, _, _) }
 
       private predicate revConsCand(TypedContent tc, Ap ap) { storeStepCand(_, ap, tc, _, _) }
@@ -1978,7 +1968,7 @@ module Impl<FullStateConfigSig Config> {
   ) {
     flowOutOfCallNodeCand1(call, node1, kind, node2, allowsFieldFlow) and
     Stage2::revFlow(node2) and
-    Stage2::revFlowAlias(node1)
+    Stage2::revFlow(node1)
   }
 
   pragma[nomagic]
@@ -1987,7 +1977,7 @@ module Impl<FullStateConfigSig Config> {
   ) {
     flowIntoCallNodeCand1(call, node1, node2, allowsFieldFlow) and
     Stage2::revFlow(node2) and
-    Stage2::revFlowAlias(node1)
+    Stage2::revFlow(node1)
   }
 
   private module LocalFlowBigStep {
@@ -2069,11 +2059,11 @@ module Impl<FullStateConfigSig Config> {
       additionalLocalFlowStepNodeCand1(node1, node2) and
       state1 = state2 and
       Stage2::revFlow(node1, pragma[only_bind_into](state1), false) and
-      Stage2::revFlowAlias(node2, pragma[only_bind_into](state2), false)
+      Stage2::revFlow(node2, pragma[only_bind_into](state2), false)
       or
       additionalLocalStateStep(node1, state1, node2, state2) and
       Stage2::revFlow(node1, state1, false) and
-      Stage2::revFlowAlias(node2, state2, false)
+      Stage2::revFlow(node2, state2, false)
     }
 
     /**
@@ -2266,7 +2256,7 @@ module Impl<FullStateConfigSig Config> {
     ) {
       localFlowBigStep(node1, state1, node2, state2, preservesValue, ap.getType(), _) and
       PrevStage::revFlow(node1, pragma[only_bind_into](state1), _) and
-      PrevStage::revFlowAlias(node2, pragma[only_bind_into](state2), _) and
+      PrevStage::revFlow(node2, pragma[only_bind_into](state2), _) and
       exists(lcc)
     }
 
@@ -2277,7 +2267,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowOutOfCallNodeCand2(call, node1, kind, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2288,7 +2278,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowIntoCallNodeCand2(call, node1, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2590,7 +2580,7 @@ module Impl<FullStateConfigSig Config> {
     ) {
       localFlowBigStep(node1, state1, node2, state2, preservesValue, ap.getType(), lcc) and
       PrevStage::revFlow(node1, pragma[only_bind_into](state1), _) and
-      PrevStage::revFlowAlias(node2, pragma[only_bind_into](state2), _)
+      PrevStage::revFlow(node2, pragma[only_bind_into](state2), _)
     }
 
     pragma[nomagic]
@@ -2600,7 +2590,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowOutOfCallNodeCand2(call, node1, kind, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2611,7 +2601,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowIntoCallNodeCand2(call, node1, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
diff --git a/csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowImpl.qll b/csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowImpl.qll
index b7cb98deaf9..f02728b9e18 100644
--- a/csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowImpl.qll
+++ b/csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowImpl.qll
@@ -1695,16 +1695,6 @@ module Impl<FullStateConfigSig Config> {
       pragma[nomagic]
       predicate revFlowAp(NodeEx node, Ap ap) { revFlow(node, _, _, _, ap) }
 
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      additional predicate revFlowAlias(NodeEx node) { revFlow(node, _, _, _, _) }
-
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      additional predicate revFlowAlias(NodeEx node, FlowState state, Ap ap) {
-        revFlow(node, state, ap)
-      }
-
       private predicate fwdConsCand(TypedContent tc, Ap ap) { storeStepFwd(_, ap, tc, _, _) }
 
       private predicate revConsCand(TypedContent tc, Ap ap) { storeStepCand(_, ap, tc, _, _) }
@@ -1978,7 +1968,7 @@ module Impl<FullStateConfigSig Config> {
   ) {
     flowOutOfCallNodeCand1(call, node1, kind, node2, allowsFieldFlow) and
     Stage2::revFlow(node2) and
-    Stage2::revFlowAlias(node1)
+    Stage2::revFlow(node1)
   }
 
   pragma[nomagic]
@@ -1987,7 +1977,7 @@ module Impl<FullStateConfigSig Config> {
   ) {
     flowIntoCallNodeCand1(call, node1, node2, allowsFieldFlow) and
     Stage2::revFlow(node2) and
-    Stage2::revFlowAlias(node1)
+    Stage2::revFlow(node1)
   }
 
   private module LocalFlowBigStep {
@@ -2069,11 +2059,11 @@ module Impl<FullStateConfigSig Config> {
       additionalLocalFlowStepNodeCand1(node1, node2) and
       state1 = state2 and
       Stage2::revFlow(node1, pragma[only_bind_into](state1), false) and
-      Stage2::revFlowAlias(node2, pragma[only_bind_into](state2), false)
+      Stage2::revFlow(node2, pragma[only_bind_into](state2), false)
       or
       additionalLocalStateStep(node1, state1, node2, state2) and
       Stage2::revFlow(node1, state1, false) and
-      Stage2::revFlowAlias(node2, state2, false)
+      Stage2::revFlow(node2, state2, false)
     }
 
     /**
@@ -2266,7 +2256,7 @@ module Impl<FullStateConfigSig Config> {
     ) {
       localFlowBigStep(node1, state1, node2, state2, preservesValue, ap.getType(), _) and
       PrevStage::revFlow(node1, pragma[only_bind_into](state1), _) and
-      PrevStage::revFlowAlias(node2, pragma[only_bind_into](state2), _) and
+      PrevStage::revFlow(node2, pragma[only_bind_into](state2), _) and
       exists(lcc)
     }
 
@@ -2277,7 +2267,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowOutOfCallNodeCand2(call, node1, kind, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2288,7 +2278,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowIntoCallNodeCand2(call, node1, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2590,7 +2580,7 @@ module Impl<FullStateConfigSig Config> {
     ) {
       localFlowBigStep(node1, state1, node2, state2, preservesValue, ap.getType(), lcc) and
       PrevStage::revFlow(node1, pragma[only_bind_into](state1), _) and
-      PrevStage::revFlowAlias(node2, pragma[only_bind_into](state2), _)
+      PrevStage::revFlow(node2, pragma[only_bind_into](state2), _)
     }
 
     pragma[nomagic]
@@ -2600,7 +2590,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowOutOfCallNodeCand2(call, node1, kind, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2611,7 +2601,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowIntoCallNodeCand2(call, node1, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
diff --git a/go/ql/lib/semmle/go/dataflow/internal/DataFlowImpl.qll b/go/ql/lib/semmle/go/dataflow/internal/DataFlowImpl.qll
index b7cb98deaf9..f02728b9e18 100644
--- a/go/ql/lib/semmle/go/dataflow/internal/DataFlowImpl.qll
+++ b/go/ql/lib/semmle/go/dataflow/internal/DataFlowImpl.qll
@@ -1695,16 +1695,6 @@ module Impl<FullStateConfigSig Config> {
       pragma[nomagic]
       predicate revFlowAp(NodeEx node, Ap ap) { revFlow(node, _, _, _, ap) }
 
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      additional predicate revFlowAlias(NodeEx node) { revFlow(node, _, _, _, _) }
-
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      additional predicate revFlowAlias(NodeEx node, FlowState state, Ap ap) {
-        revFlow(node, state, ap)
-      }
-
       private predicate fwdConsCand(TypedContent tc, Ap ap) { storeStepFwd(_, ap, tc, _, _) }
 
       private predicate revConsCand(TypedContent tc, Ap ap) { storeStepCand(_, ap, tc, _, _) }
@@ -1978,7 +1968,7 @@ module Impl<FullStateConfigSig Config> {
   ) {
     flowOutOfCallNodeCand1(call, node1, kind, node2, allowsFieldFlow) and
     Stage2::revFlow(node2) and
-    Stage2::revFlowAlias(node1)
+    Stage2::revFlow(node1)
   }
 
   pragma[nomagic]
@@ -1987,7 +1977,7 @@ module Impl<FullStateConfigSig Config> {
   ) {
     flowIntoCallNodeCand1(call, node1, node2, allowsFieldFlow) and
     Stage2::revFlow(node2) and
-    Stage2::revFlowAlias(node1)
+    Stage2::revFlow(node1)
   }
 
   private module LocalFlowBigStep {
@@ -2069,11 +2059,11 @@ module Impl<FullStateConfigSig Config> {
       additionalLocalFlowStepNodeCand1(node1, node2) and
       state1 = state2 and
       Stage2::revFlow(node1, pragma[only_bind_into](state1), false) and
-      Stage2::revFlowAlias(node2, pragma[only_bind_into](state2), false)
+      Stage2::revFlow(node2, pragma[only_bind_into](state2), false)
       or
       additionalLocalStateStep(node1, state1, node2, state2) and
       Stage2::revFlow(node1, state1, false) and
-      Stage2::revFlowAlias(node2, state2, false)
+      Stage2::revFlow(node2, state2, false)
     }
 
     /**
@@ -2266,7 +2256,7 @@ module Impl<FullStateConfigSig Config> {
     ) {
       localFlowBigStep(node1, state1, node2, state2, preservesValue, ap.getType(), _) and
       PrevStage::revFlow(node1, pragma[only_bind_into](state1), _) and
-      PrevStage::revFlowAlias(node2, pragma[only_bind_into](state2), _) and
+      PrevStage::revFlow(node2, pragma[only_bind_into](state2), _) and
       exists(lcc)
     }
 
@@ -2277,7 +2267,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowOutOfCallNodeCand2(call, node1, kind, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2288,7 +2278,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowIntoCallNodeCand2(call, node1, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2590,7 +2580,7 @@ module Impl<FullStateConfigSig Config> {
     ) {
       localFlowBigStep(node1, state1, node2, state2, preservesValue, ap.getType(), lcc) and
       PrevStage::revFlow(node1, pragma[only_bind_into](state1), _) and
-      PrevStage::revFlowAlias(node2, pragma[only_bind_into](state2), _)
+      PrevStage::revFlow(node2, pragma[only_bind_into](state2), _)
     }
 
     pragma[nomagic]
@@ -2600,7 +2590,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowOutOfCallNodeCand2(call, node1, kind, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2611,7 +2601,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowIntoCallNodeCand2(call, node1, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
diff --git a/java/ql/lib/semmle/code/java/dataflow/internal/DataFlowImpl.qll b/java/ql/lib/semmle/code/java/dataflow/internal/DataFlowImpl.qll
index b7cb98deaf9..f02728b9e18 100644
--- a/java/ql/lib/semmle/code/java/dataflow/internal/DataFlowImpl.qll
+++ b/java/ql/lib/semmle/code/java/dataflow/internal/DataFlowImpl.qll
@@ -1695,16 +1695,6 @@ module Impl<FullStateConfigSig Config> {
       pragma[nomagic]
       predicate revFlowAp(NodeEx node, Ap ap) { revFlow(node, _, _, _, ap) }
 
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      additional predicate revFlowAlias(NodeEx node) { revFlow(node, _, _, _, _) }
-
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      additional predicate revFlowAlias(NodeEx node, FlowState state, Ap ap) {
-        revFlow(node, state, ap)
-      }
-
       private predicate fwdConsCand(TypedContent tc, Ap ap) { storeStepFwd(_, ap, tc, _, _) }
 
       private predicate revConsCand(TypedContent tc, Ap ap) { storeStepCand(_, ap, tc, _, _) }
@@ -1978,7 +1968,7 @@ module Impl<FullStateConfigSig Config> {
   ) {
     flowOutOfCallNodeCand1(call, node1, kind, node2, allowsFieldFlow) and
     Stage2::revFlow(node2) and
-    Stage2::revFlowAlias(node1)
+    Stage2::revFlow(node1)
   }
 
   pragma[nomagic]
@@ -1987,7 +1977,7 @@ module Impl<FullStateConfigSig Config> {
   ) {
     flowIntoCallNodeCand1(call, node1, node2, allowsFieldFlow) and
     Stage2::revFlow(node2) and
-    Stage2::revFlowAlias(node1)
+    Stage2::revFlow(node1)
   }
 
   private module LocalFlowBigStep {
@@ -2069,11 +2059,11 @@ module Impl<FullStateConfigSig Config> {
       additionalLocalFlowStepNodeCand1(node1, node2) and
       state1 = state2 and
       Stage2::revFlow(node1, pragma[only_bind_into](state1), false) and
-      Stage2::revFlowAlias(node2, pragma[only_bind_into](state2), false)
+      Stage2::revFlow(node2, pragma[only_bind_into](state2), false)
       or
       additionalLocalStateStep(node1, state1, node2, state2) and
       Stage2::revFlow(node1, state1, false) and
-      Stage2::revFlowAlias(node2, state2, false)
+      Stage2::revFlow(node2, state2, false)
     }
 
     /**
@@ -2266,7 +2256,7 @@ module Impl<FullStateConfigSig Config> {
     ) {
       localFlowBigStep(node1, state1, node2, state2, preservesValue, ap.getType(), _) and
       PrevStage::revFlow(node1, pragma[only_bind_into](state1), _) and
-      PrevStage::revFlowAlias(node2, pragma[only_bind_into](state2), _) and
+      PrevStage::revFlow(node2, pragma[only_bind_into](state2), _) and
       exists(lcc)
     }
 
@@ -2277,7 +2267,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowOutOfCallNodeCand2(call, node1, kind, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2288,7 +2278,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowIntoCallNodeCand2(call, node1, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2590,7 +2580,7 @@ module Impl<FullStateConfigSig Config> {
     ) {
       localFlowBigStep(node1, state1, node2, state2, preservesValue, ap.getType(), lcc) and
       PrevStage::revFlow(node1, pragma[only_bind_into](state1), _) and
-      PrevStage::revFlowAlias(node2, pragma[only_bind_into](state2), _)
+      PrevStage::revFlow(node2, pragma[only_bind_into](state2), _)
     }
 
     pragma[nomagic]
@@ -2600,7 +2590,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowOutOfCallNodeCand2(call, node1, kind, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2611,7 +2601,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowIntoCallNodeCand2(call, node1, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
diff --git a/python/ql/lib/semmle/python/dataflow/new/internal/DataFlowImpl.qll b/python/ql/lib/semmle/python/dataflow/new/internal/DataFlowImpl.qll
index b7cb98deaf9..f02728b9e18 100644
--- a/python/ql/lib/semmle/python/dataflow/new/internal/DataFlowImpl.qll
+++ b/python/ql/lib/semmle/python/dataflow/new/internal/DataFlowImpl.qll
@@ -1695,16 +1695,6 @@ module Impl<FullStateConfigSig Config> {
       pragma[nomagic]
       predicate revFlowAp(NodeEx node, Ap ap) { revFlow(node, _, _, _, ap) }
 
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      additional predicate revFlowAlias(NodeEx node) { revFlow(node, _, _, _, _) }
-
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      additional predicate revFlowAlias(NodeEx node, FlowState state, Ap ap) {
-        revFlow(node, state, ap)
-      }
-
       private predicate fwdConsCand(TypedContent tc, Ap ap) { storeStepFwd(_, ap, tc, _, _) }
 
       private predicate revConsCand(TypedContent tc, Ap ap) { storeStepCand(_, ap, tc, _, _) }
@@ -1978,7 +1968,7 @@ module Impl<FullStateConfigSig Config> {
   ) {
     flowOutOfCallNodeCand1(call, node1, kind, node2, allowsFieldFlow) and
     Stage2::revFlow(node2) and
-    Stage2::revFlowAlias(node1)
+    Stage2::revFlow(node1)
   }
 
   pragma[nomagic]
@@ -1987,7 +1977,7 @@ module Impl<FullStateConfigSig Config> {
   ) {
     flowIntoCallNodeCand1(call, node1, node2, allowsFieldFlow) and
     Stage2::revFlow(node2) and
-    Stage2::revFlowAlias(node1)
+    Stage2::revFlow(node1)
   }
 
   private module LocalFlowBigStep {
@@ -2069,11 +2059,11 @@ module Impl<FullStateConfigSig Config> {
       additionalLocalFlowStepNodeCand1(node1, node2) and
       state1 = state2 and
       Stage2::revFlow(node1, pragma[only_bind_into](state1), false) and
-      Stage2::revFlowAlias(node2, pragma[only_bind_into](state2), false)
+      Stage2::revFlow(node2, pragma[only_bind_into](state2), false)
       or
       additionalLocalStateStep(node1, state1, node2, state2) and
       Stage2::revFlow(node1, state1, false) and
-      Stage2::revFlowAlias(node2, state2, false)
+      Stage2::revFlow(node2, state2, false)
     }
 
     /**
@@ -2266,7 +2256,7 @@ module Impl<FullStateConfigSig Config> {
     ) {
       localFlowBigStep(node1, state1, node2, state2, preservesValue, ap.getType(), _) and
       PrevStage::revFlow(node1, pragma[only_bind_into](state1), _) and
-      PrevStage::revFlowAlias(node2, pragma[only_bind_into](state2), _) and
+      PrevStage::revFlow(node2, pragma[only_bind_into](state2), _) and
       exists(lcc)
     }
 
@@ -2277,7 +2267,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowOutOfCallNodeCand2(call, node1, kind, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2288,7 +2278,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowIntoCallNodeCand2(call, node1, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2590,7 +2580,7 @@ module Impl<FullStateConfigSig Config> {
     ) {
       localFlowBigStep(node1, state1, node2, state2, preservesValue, ap.getType(), lcc) and
       PrevStage::revFlow(node1, pragma[only_bind_into](state1), _) and
-      PrevStage::revFlowAlias(node2, pragma[only_bind_into](state2), _)
+      PrevStage::revFlow(node2, pragma[only_bind_into](state2), _)
     }
 
     pragma[nomagic]
@@ -2600,7 +2590,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowOutOfCallNodeCand2(call, node1, kind, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2611,7 +2601,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowIntoCallNodeCand2(call, node1, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
diff --git a/ruby/ql/lib/codeql/ruby/dataflow/internal/DataFlowImpl.qll b/ruby/ql/lib/codeql/ruby/dataflow/internal/DataFlowImpl.qll
index b7cb98deaf9..f02728b9e18 100644
--- a/ruby/ql/lib/codeql/ruby/dataflow/internal/DataFlowImpl.qll
+++ b/ruby/ql/lib/codeql/ruby/dataflow/internal/DataFlowImpl.qll
@@ -1695,16 +1695,6 @@ module Impl<FullStateConfigSig Config> {
       pragma[nomagic]
       predicate revFlowAp(NodeEx node, Ap ap) { revFlow(node, _, _, _, ap) }
 
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      additional predicate revFlowAlias(NodeEx node) { revFlow(node, _, _, _, _) }
-
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      additional predicate revFlowAlias(NodeEx node, FlowState state, Ap ap) {
-        revFlow(node, state, ap)
-      }
-
       private predicate fwdConsCand(TypedContent tc, Ap ap) { storeStepFwd(_, ap, tc, _, _) }
 
       private predicate revConsCand(TypedContent tc, Ap ap) { storeStepCand(_, ap, tc, _, _) }
@@ -1978,7 +1968,7 @@ module Impl<FullStateConfigSig Config> {
   ) {
     flowOutOfCallNodeCand1(call, node1, kind, node2, allowsFieldFlow) and
     Stage2::revFlow(node2) and
-    Stage2::revFlowAlias(node1)
+    Stage2::revFlow(node1)
   }
 
   pragma[nomagic]
@@ -1987,7 +1977,7 @@ module Impl<FullStateConfigSig Config> {
   ) {
     flowIntoCallNodeCand1(call, node1, node2, allowsFieldFlow) and
     Stage2::revFlow(node2) and
-    Stage2::revFlowAlias(node1)
+    Stage2::revFlow(node1)
   }
 
   private module LocalFlowBigStep {
@@ -2069,11 +2059,11 @@ module Impl<FullStateConfigSig Config> {
       additionalLocalFlowStepNodeCand1(node1, node2) and
       state1 = state2 and
       Stage2::revFlow(node1, pragma[only_bind_into](state1), false) and
-      Stage2::revFlowAlias(node2, pragma[only_bind_into](state2), false)
+      Stage2::revFlow(node2, pragma[only_bind_into](state2), false)
       or
       additionalLocalStateStep(node1, state1, node2, state2) and
       Stage2::revFlow(node1, state1, false) and
-      Stage2::revFlowAlias(node2, state2, false)
+      Stage2::revFlow(node2, state2, false)
     }
 
     /**
@@ -2266,7 +2256,7 @@ module Impl<FullStateConfigSig Config> {
     ) {
       localFlowBigStep(node1, state1, node2, state2, preservesValue, ap.getType(), _) and
       PrevStage::revFlow(node1, pragma[only_bind_into](state1), _) and
-      PrevStage::revFlowAlias(node2, pragma[only_bind_into](state2), _) and
+      PrevStage::revFlow(node2, pragma[only_bind_into](state2), _) and
       exists(lcc)
     }
 
@@ -2277,7 +2267,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowOutOfCallNodeCand2(call, node1, kind, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2288,7 +2278,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowIntoCallNodeCand2(call, node1, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2590,7 +2580,7 @@ module Impl<FullStateConfigSig Config> {
     ) {
       localFlowBigStep(node1, state1, node2, state2, preservesValue, ap.getType(), lcc) and
       PrevStage::revFlow(node1, pragma[only_bind_into](state1), _) and
-      PrevStage::revFlowAlias(node2, pragma[only_bind_into](state2), _)
+      PrevStage::revFlow(node2, pragma[only_bind_into](state2), _)
     }
 
     pragma[nomagic]
@@ -2600,7 +2590,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowOutOfCallNodeCand2(call, node1, kind, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2611,7 +2601,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowIntoCallNodeCand2(call, node1, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
diff --git a/swift/ql/lib/codeql/swift/dataflow/internal/DataFlowImpl.qll b/swift/ql/lib/codeql/swift/dataflow/internal/DataFlowImpl.qll
index b7cb98deaf9..f02728b9e18 100644
--- a/swift/ql/lib/codeql/swift/dataflow/internal/DataFlowImpl.qll
+++ b/swift/ql/lib/codeql/swift/dataflow/internal/DataFlowImpl.qll
@@ -1695,16 +1695,6 @@ module Impl<FullStateConfigSig Config> {
       pragma[nomagic]
       predicate revFlowAp(NodeEx node, Ap ap) { revFlow(node, _, _, _, ap) }
 
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      additional predicate revFlowAlias(NodeEx node) { revFlow(node, _, _, _, _) }
-
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      additional predicate revFlowAlias(NodeEx node, FlowState state, Ap ap) {
-        revFlow(node, state, ap)
-      }
-
       private predicate fwdConsCand(TypedContent tc, Ap ap) { storeStepFwd(_, ap, tc, _, _) }
 
       private predicate revConsCand(TypedContent tc, Ap ap) { storeStepCand(_, ap, tc, _, _) }
@@ -1978,7 +1968,7 @@ module Impl<FullStateConfigSig Config> {
   ) {
     flowOutOfCallNodeCand1(call, node1, kind, node2, allowsFieldFlow) and
     Stage2::revFlow(node2) and
-    Stage2::revFlowAlias(node1)
+    Stage2::revFlow(node1)
   }
 
   pragma[nomagic]
@@ -1987,7 +1977,7 @@ module Impl<FullStateConfigSig Config> {
   ) {
     flowIntoCallNodeCand1(call, node1, node2, allowsFieldFlow) and
     Stage2::revFlow(node2) and
-    Stage2::revFlowAlias(node1)
+    Stage2::revFlow(node1)
   }
 
   private module LocalFlowBigStep {
@@ -2069,11 +2059,11 @@ module Impl<FullStateConfigSig Config> {
       additionalLocalFlowStepNodeCand1(node1, node2) and
       state1 = state2 and
       Stage2::revFlow(node1, pragma[only_bind_into](state1), false) and
-      Stage2::revFlowAlias(node2, pragma[only_bind_into](state2), false)
+      Stage2::revFlow(node2, pragma[only_bind_into](state2), false)
       or
       additionalLocalStateStep(node1, state1, node2, state2) and
       Stage2::revFlow(node1, state1, false) and
-      Stage2::revFlowAlias(node2, state2, false)
+      Stage2::revFlow(node2, state2, false)
     }
 
     /**
@@ -2266,7 +2256,7 @@ module Impl<FullStateConfigSig Config> {
     ) {
       localFlowBigStep(node1, state1, node2, state2, preservesValue, ap.getType(), _) and
       PrevStage::revFlow(node1, pragma[only_bind_into](state1), _) and
-      PrevStage::revFlowAlias(node2, pragma[only_bind_into](state2), _) and
+      PrevStage::revFlow(node2, pragma[only_bind_into](state2), _) and
       exists(lcc)
     }
 
@@ -2277,7 +2267,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowOutOfCallNodeCand2(call, node1, kind, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2288,7 +2278,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowIntoCallNodeCand2(call, node1, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2590,7 +2580,7 @@ module Impl<FullStateConfigSig Config> {
     ) {
       localFlowBigStep(node1, state1, node2, state2, preservesValue, ap.getType(), lcc) and
       PrevStage::revFlow(node1, pragma[only_bind_into](state1), _) and
-      PrevStage::revFlowAlias(node2, pragma[only_bind_into](state2), _)
+      PrevStage::revFlow(node2, pragma[only_bind_into](state2), _)
     }
 
     pragma[nomagic]
@@ -2600,7 +2590,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowOutOfCallNodeCand2(call, node1, kind, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 
@@ -2611,7 +2601,7 @@ module Impl<FullStateConfigSig Config> {
       exists(FlowState state |
         flowIntoCallNodeCand2(call, node1, node2, allowsFieldFlow) and
         PrevStage::revFlow(node2, pragma[only_bind_into](state), _) and
-        PrevStage::revFlowAlias(node1, pragma[only_bind_into](state), _)
+        PrevStage::revFlow(node1, pragma[only_bind_into](state), _)
       )
     }
 

From e0e3a1d62161999b5d83f96602ad5bb99634a3f9 Mon Sep 17 00:00:00 2001
From: Kasper Svendsen <kaspersv@github.com>
Date: Mon, 20 Mar 2023 13:02:18 +0100
Subject: [PATCH 2/3] Dataflow: remove revFlowApAlias trick

---
 .../code/cpp/dataflow/internal/DataFlowImpl.qll       | 11 ++---------
 .../code/cpp/ir/dataflow/internal/DataFlowImpl.qll    | 11 ++---------
 .../code/csharp/dataflow/internal/DataFlowImpl.qll    | 11 ++---------
 .../lib/semmle/go/dataflow/internal/DataFlowImpl.qll  | 11 ++---------
 .../code/java/dataflow/internal/DataFlowImpl.qll      | 11 ++---------
 .../python/dataflow/new/internal/DataFlowImpl.qll     | 11 ++---------
 .../codeql/ruby/dataflow/internal/DataFlowImpl.qll    | 11 ++---------
 .../codeql/swift/dataflow/internal/DataFlowImpl.qll   | 11 ++---------
 8 files changed, 16 insertions(+), 72 deletions(-)

diff --git a/cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowImpl.qll b/cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowImpl.qll
index f02728b9e18..a2af8508265 100644
--- a/cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowImpl.qll
+++ b/cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowImpl.qll
@@ -1144,20 +1144,13 @@ module Impl<FullStateConfigSig Config> {
     module Stage<StageParam Param> implements StageSig {
       import Param
 
-      /* Begin: Stage logic. */
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      private predicate revFlowApAlias(NodeEx node, ApApprox apa) {
-        PrevStage::revFlowAp(node, apa)
-      }
-
       pragma[nomagic]
       private predicate flowIntoCallApa(
         DataFlowCall call, ArgNodeEx arg, ParamNodeEx p, boolean allowsFieldFlow, ApApprox apa
       ) {
         flowIntoCall(call, arg, p, allowsFieldFlow) and
         PrevStage::revFlowAp(p, pragma[only_bind_into](apa)) and
-        revFlowApAlias(arg, pragma[only_bind_into](apa))
+        PrevStage::revFlowAp(arg, pragma[only_bind_into](apa))
       }
 
       pragma[nomagic]
@@ -1167,7 +1160,7 @@ module Impl<FullStateConfigSig Config> {
       ) {
         flowOutOfCall(call, ret, kind, out, allowsFieldFlow) and
         PrevStage::revFlowAp(out, pragma[only_bind_into](apa)) and
-        revFlowApAlias(ret, pragma[only_bind_into](apa))
+        PrevStage::revFlowAp(ret, pragma[only_bind_into](apa))
       }
 
       pragma[nomagic]
diff --git a/cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl.qll b/cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl.qll
index f02728b9e18..a2af8508265 100644
--- a/cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl.qll
+++ b/cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl.qll
@@ -1144,20 +1144,13 @@ module Impl<FullStateConfigSig Config> {
     module Stage<StageParam Param> implements StageSig {
       import Param
 
-      /* Begin: Stage logic. */
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      private predicate revFlowApAlias(NodeEx node, ApApprox apa) {
-        PrevStage::revFlowAp(node, apa)
-      }
-
       pragma[nomagic]
       private predicate flowIntoCallApa(
         DataFlowCall call, ArgNodeEx arg, ParamNodeEx p, boolean allowsFieldFlow, ApApprox apa
       ) {
         flowIntoCall(call, arg, p, allowsFieldFlow) and
         PrevStage::revFlowAp(p, pragma[only_bind_into](apa)) and
-        revFlowApAlias(arg, pragma[only_bind_into](apa))
+        PrevStage::revFlowAp(arg, pragma[only_bind_into](apa))
       }
 
       pragma[nomagic]
@@ -1167,7 +1160,7 @@ module Impl<FullStateConfigSig Config> {
       ) {
         flowOutOfCall(call, ret, kind, out, allowsFieldFlow) and
         PrevStage::revFlowAp(out, pragma[only_bind_into](apa)) and
-        revFlowApAlias(ret, pragma[only_bind_into](apa))
+        PrevStage::revFlowAp(ret, pragma[only_bind_into](apa))
       }
 
       pragma[nomagic]
diff --git a/csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowImpl.qll b/csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowImpl.qll
index f02728b9e18..a2af8508265 100644
--- a/csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowImpl.qll
+++ b/csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowImpl.qll
@@ -1144,20 +1144,13 @@ module Impl<FullStateConfigSig Config> {
     module Stage<StageParam Param> implements StageSig {
       import Param
 
-      /* Begin: Stage logic. */
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      private predicate revFlowApAlias(NodeEx node, ApApprox apa) {
-        PrevStage::revFlowAp(node, apa)
-      }
-
       pragma[nomagic]
       private predicate flowIntoCallApa(
         DataFlowCall call, ArgNodeEx arg, ParamNodeEx p, boolean allowsFieldFlow, ApApprox apa
       ) {
         flowIntoCall(call, arg, p, allowsFieldFlow) and
         PrevStage::revFlowAp(p, pragma[only_bind_into](apa)) and
-        revFlowApAlias(arg, pragma[only_bind_into](apa))
+        PrevStage::revFlowAp(arg, pragma[only_bind_into](apa))
       }
 
       pragma[nomagic]
@@ -1167,7 +1160,7 @@ module Impl<FullStateConfigSig Config> {
       ) {
         flowOutOfCall(call, ret, kind, out, allowsFieldFlow) and
         PrevStage::revFlowAp(out, pragma[only_bind_into](apa)) and
-        revFlowApAlias(ret, pragma[only_bind_into](apa))
+        PrevStage::revFlowAp(ret, pragma[only_bind_into](apa))
       }
 
       pragma[nomagic]
diff --git a/go/ql/lib/semmle/go/dataflow/internal/DataFlowImpl.qll b/go/ql/lib/semmle/go/dataflow/internal/DataFlowImpl.qll
index f02728b9e18..a2af8508265 100644
--- a/go/ql/lib/semmle/go/dataflow/internal/DataFlowImpl.qll
+++ b/go/ql/lib/semmle/go/dataflow/internal/DataFlowImpl.qll
@@ -1144,20 +1144,13 @@ module Impl<FullStateConfigSig Config> {
     module Stage<StageParam Param> implements StageSig {
       import Param
 
-      /* Begin: Stage logic. */
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      private predicate revFlowApAlias(NodeEx node, ApApprox apa) {
-        PrevStage::revFlowAp(node, apa)
-      }
-
       pragma[nomagic]
       private predicate flowIntoCallApa(
         DataFlowCall call, ArgNodeEx arg, ParamNodeEx p, boolean allowsFieldFlow, ApApprox apa
       ) {
         flowIntoCall(call, arg, p, allowsFieldFlow) and
         PrevStage::revFlowAp(p, pragma[only_bind_into](apa)) and
-        revFlowApAlias(arg, pragma[only_bind_into](apa))
+        PrevStage::revFlowAp(arg, pragma[only_bind_into](apa))
       }
 
       pragma[nomagic]
@@ -1167,7 +1160,7 @@ module Impl<FullStateConfigSig Config> {
       ) {
         flowOutOfCall(call, ret, kind, out, allowsFieldFlow) and
         PrevStage::revFlowAp(out, pragma[only_bind_into](apa)) and
-        revFlowApAlias(ret, pragma[only_bind_into](apa))
+        PrevStage::revFlowAp(ret, pragma[only_bind_into](apa))
       }
 
       pragma[nomagic]
diff --git a/java/ql/lib/semmle/code/java/dataflow/internal/DataFlowImpl.qll b/java/ql/lib/semmle/code/java/dataflow/internal/DataFlowImpl.qll
index f02728b9e18..a2af8508265 100644
--- a/java/ql/lib/semmle/code/java/dataflow/internal/DataFlowImpl.qll
+++ b/java/ql/lib/semmle/code/java/dataflow/internal/DataFlowImpl.qll
@@ -1144,20 +1144,13 @@ module Impl<FullStateConfigSig Config> {
     module Stage<StageParam Param> implements StageSig {
       import Param
 
-      /* Begin: Stage logic. */
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      private predicate revFlowApAlias(NodeEx node, ApApprox apa) {
-        PrevStage::revFlowAp(node, apa)
-      }
-
       pragma[nomagic]
       private predicate flowIntoCallApa(
         DataFlowCall call, ArgNodeEx arg, ParamNodeEx p, boolean allowsFieldFlow, ApApprox apa
       ) {
         flowIntoCall(call, arg, p, allowsFieldFlow) and
         PrevStage::revFlowAp(p, pragma[only_bind_into](apa)) and
-        revFlowApAlias(arg, pragma[only_bind_into](apa))
+        PrevStage::revFlowAp(arg, pragma[only_bind_into](apa))
       }
 
       pragma[nomagic]
@@ -1167,7 +1160,7 @@ module Impl<FullStateConfigSig Config> {
       ) {
         flowOutOfCall(call, ret, kind, out, allowsFieldFlow) and
         PrevStage::revFlowAp(out, pragma[only_bind_into](apa)) and
-        revFlowApAlias(ret, pragma[only_bind_into](apa))
+        PrevStage::revFlowAp(ret, pragma[only_bind_into](apa))
       }
 
       pragma[nomagic]
diff --git a/python/ql/lib/semmle/python/dataflow/new/internal/DataFlowImpl.qll b/python/ql/lib/semmle/python/dataflow/new/internal/DataFlowImpl.qll
index f02728b9e18..a2af8508265 100644
--- a/python/ql/lib/semmle/python/dataflow/new/internal/DataFlowImpl.qll
+++ b/python/ql/lib/semmle/python/dataflow/new/internal/DataFlowImpl.qll
@@ -1144,20 +1144,13 @@ module Impl<FullStateConfigSig Config> {
     module Stage<StageParam Param> implements StageSig {
       import Param
 
-      /* Begin: Stage logic. */
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      private predicate revFlowApAlias(NodeEx node, ApApprox apa) {
-        PrevStage::revFlowAp(node, apa)
-      }
-
       pragma[nomagic]
       private predicate flowIntoCallApa(
         DataFlowCall call, ArgNodeEx arg, ParamNodeEx p, boolean allowsFieldFlow, ApApprox apa
       ) {
         flowIntoCall(call, arg, p, allowsFieldFlow) and
         PrevStage::revFlowAp(p, pragma[only_bind_into](apa)) and
-        revFlowApAlias(arg, pragma[only_bind_into](apa))
+        PrevStage::revFlowAp(arg, pragma[only_bind_into](apa))
       }
 
       pragma[nomagic]
@@ -1167,7 +1160,7 @@ module Impl<FullStateConfigSig Config> {
       ) {
         flowOutOfCall(call, ret, kind, out, allowsFieldFlow) and
         PrevStage::revFlowAp(out, pragma[only_bind_into](apa)) and
-        revFlowApAlias(ret, pragma[only_bind_into](apa))
+        PrevStage::revFlowAp(ret, pragma[only_bind_into](apa))
       }
 
       pragma[nomagic]
diff --git a/ruby/ql/lib/codeql/ruby/dataflow/internal/DataFlowImpl.qll b/ruby/ql/lib/codeql/ruby/dataflow/internal/DataFlowImpl.qll
index f02728b9e18..a2af8508265 100644
--- a/ruby/ql/lib/codeql/ruby/dataflow/internal/DataFlowImpl.qll
+++ b/ruby/ql/lib/codeql/ruby/dataflow/internal/DataFlowImpl.qll
@@ -1144,20 +1144,13 @@ module Impl<FullStateConfigSig Config> {
     module Stage<StageParam Param> implements StageSig {
       import Param
 
-      /* Begin: Stage logic. */
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      private predicate revFlowApAlias(NodeEx node, ApApprox apa) {
-        PrevStage::revFlowAp(node, apa)
-      }
-
       pragma[nomagic]
       private predicate flowIntoCallApa(
         DataFlowCall call, ArgNodeEx arg, ParamNodeEx p, boolean allowsFieldFlow, ApApprox apa
       ) {
         flowIntoCall(call, arg, p, allowsFieldFlow) and
         PrevStage::revFlowAp(p, pragma[only_bind_into](apa)) and
-        revFlowApAlias(arg, pragma[only_bind_into](apa))
+        PrevStage::revFlowAp(arg, pragma[only_bind_into](apa))
       }
 
       pragma[nomagic]
@@ -1167,7 +1160,7 @@ module Impl<FullStateConfigSig Config> {
       ) {
         flowOutOfCall(call, ret, kind, out, allowsFieldFlow) and
         PrevStage::revFlowAp(out, pragma[only_bind_into](apa)) and
-        revFlowApAlias(ret, pragma[only_bind_into](apa))
+        PrevStage::revFlowAp(ret, pragma[only_bind_into](apa))
       }
 
       pragma[nomagic]
diff --git a/swift/ql/lib/codeql/swift/dataflow/internal/DataFlowImpl.qll b/swift/ql/lib/codeql/swift/dataflow/internal/DataFlowImpl.qll
index f02728b9e18..a2af8508265 100644
--- a/swift/ql/lib/codeql/swift/dataflow/internal/DataFlowImpl.qll
+++ b/swift/ql/lib/codeql/swift/dataflow/internal/DataFlowImpl.qll
@@ -1144,20 +1144,13 @@ module Impl<FullStateConfigSig Config> {
     module Stage<StageParam Param> implements StageSig {
       import Param
 
-      /* Begin: Stage logic. */
-      // use an alias as a workaround for bad functionality-induced joins
-      pragma[nomagic]
-      private predicate revFlowApAlias(NodeEx node, ApApprox apa) {
-        PrevStage::revFlowAp(node, apa)
-      }
-
       pragma[nomagic]
       private predicate flowIntoCallApa(
         DataFlowCall call, ArgNodeEx arg, ParamNodeEx p, boolean allowsFieldFlow, ApApprox apa
       ) {
         flowIntoCall(call, arg, p, allowsFieldFlow) and
         PrevStage::revFlowAp(p, pragma[only_bind_into](apa)) and
-        revFlowApAlias(arg, pragma[only_bind_into](apa))
+        PrevStage::revFlowAp(arg, pragma[only_bind_into](apa))
       }
 
       pragma[nomagic]
@@ -1167,7 +1160,7 @@ module Impl<FullStateConfigSig Config> {
       ) {
         flowOutOfCall(call, ret, kind, out, allowsFieldFlow) and
         PrevStage::revFlowAp(out, pragma[only_bind_into](apa)) and
-        revFlowApAlias(ret, pragma[only_bind_into](apa))
+        PrevStage::revFlowAp(ret, pragma[only_bind_into](apa))
       }
 
       pragma[nomagic]

From 1d2f1b6ae6982228d71854d1aa689d960dde90ed Mon Sep 17 00:00:00 2001
From: Kasper Svendsen <kaspersv@github.com>
Date: Mon, 20 Mar 2023 13:34:14 +0100
Subject: [PATCH 3/3] Address comments

---
 cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowImpl.qll    | 1 +
 cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl.qll | 1 +
 .../ql/lib/semmle/code/csharp/dataflow/internal/DataFlowImpl.qll | 1 +
 go/ql/lib/semmle/go/dataflow/internal/DataFlowImpl.qll           | 1 +
 java/ql/lib/semmle/code/java/dataflow/internal/DataFlowImpl.qll  | 1 +
 .../ql/lib/semmle/python/dataflow/new/internal/DataFlowImpl.qll  | 1 +
 ruby/ql/lib/codeql/ruby/dataflow/internal/DataFlowImpl.qll       | 1 +
 swift/ql/lib/codeql/swift/dataflow/internal/DataFlowImpl.qll     | 1 +
 8 files changed, 8 insertions(+)

diff --git a/cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowImpl.qll b/cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowImpl.qll
index a2af8508265..c47b0308855 100644
--- a/cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowImpl.qll
+++ b/cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowImpl.qll
@@ -1144,6 +1144,7 @@ module Impl<FullStateConfigSig Config> {
     module Stage<StageParam Param> implements StageSig {
       import Param
 
+      /* Begin: Stage logic. */
       pragma[nomagic]
       private predicate flowIntoCallApa(
         DataFlowCall call, ArgNodeEx arg, ParamNodeEx p, boolean allowsFieldFlow, ApApprox apa
diff --git a/cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl.qll b/cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl.qll
index a2af8508265..c47b0308855 100644
--- a/cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl.qll
+++ b/cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowImpl.qll
@@ -1144,6 +1144,7 @@ module Impl<FullStateConfigSig Config> {
     module Stage<StageParam Param> implements StageSig {
       import Param
 
+      /* Begin: Stage logic. */
       pragma[nomagic]
       private predicate flowIntoCallApa(
         DataFlowCall call, ArgNodeEx arg, ParamNodeEx p, boolean allowsFieldFlow, ApApprox apa
diff --git a/csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowImpl.qll b/csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowImpl.qll
index a2af8508265..c47b0308855 100644
--- a/csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowImpl.qll
+++ b/csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowImpl.qll
@@ -1144,6 +1144,7 @@ module Impl<FullStateConfigSig Config> {
     module Stage<StageParam Param> implements StageSig {
       import Param
 
+      /* Begin: Stage logic. */
       pragma[nomagic]
       private predicate flowIntoCallApa(
         DataFlowCall call, ArgNodeEx arg, ParamNodeEx p, boolean allowsFieldFlow, ApApprox apa
diff --git a/go/ql/lib/semmle/go/dataflow/internal/DataFlowImpl.qll b/go/ql/lib/semmle/go/dataflow/internal/DataFlowImpl.qll
index a2af8508265..c47b0308855 100644
--- a/go/ql/lib/semmle/go/dataflow/internal/DataFlowImpl.qll
+++ b/go/ql/lib/semmle/go/dataflow/internal/DataFlowImpl.qll
@@ -1144,6 +1144,7 @@ module Impl<FullStateConfigSig Config> {
     module Stage<StageParam Param> implements StageSig {
       import Param
 
+      /* Begin: Stage logic. */
       pragma[nomagic]
       private predicate flowIntoCallApa(
         DataFlowCall call, ArgNodeEx arg, ParamNodeEx p, boolean allowsFieldFlow, ApApprox apa
diff --git a/java/ql/lib/semmle/code/java/dataflow/internal/DataFlowImpl.qll b/java/ql/lib/semmle/code/java/dataflow/internal/DataFlowImpl.qll
index a2af8508265..c47b0308855 100644
--- a/java/ql/lib/semmle/code/java/dataflow/internal/DataFlowImpl.qll
+++ b/java/ql/lib/semmle/code/java/dataflow/internal/DataFlowImpl.qll
@@ -1144,6 +1144,7 @@ module Impl<FullStateConfigSig Config> {
     module Stage<StageParam Param> implements StageSig {
       import Param
 
+      /* Begin: Stage logic. */
       pragma[nomagic]
       private predicate flowIntoCallApa(
         DataFlowCall call, ArgNodeEx arg, ParamNodeEx p, boolean allowsFieldFlow, ApApprox apa
diff --git a/python/ql/lib/semmle/python/dataflow/new/internal/DataFlowImpl.qll b/python/ql/lib/semmle/python/dataflow/new/internal/DataFlowImpl.qll
index a2af8508265..c47b0308855 100644
--- a/python/ql/lib/semmle/python/dataflow/new/internal/DataFlowImpl.qll
+++ b/python/ql/lib/semmle/python/dataflow/new/internal/DataFlowImpl.qll
@@ -1144,6 +1144,7 @@ module Impl<FullStateConfigSig Config> {
     module Stage<StageParam Param> implements StageSig {
       import Param
 
+      /* Begin: Stage logic. */
       pragma[nomagic]
       private predicate flowIntoCallApa(
         DataFlowCall call, ArgNodeEx arg, ParamNodeEx p, boolean allowsFieldFlow, ApApprox apa
diff --git a/ruby/ql/lib/codeql/ruby/dataflow/internal/DataFlowImpl.qll b/ruby/ql/lib/codeql/ruby/dataflow/internal/DataFlowImpl.qll
index a2af8508265..c47b0308855 100644
--- a/ruby/ql/lib/codeql/ruby/dataflow/internal/DataFlowImpl.qll
+++ b/ruby/ql/lib/codeql/ruby/dataflow/internal/DataFlowImpl.qll
@@ -1144,6 +1144,7 @@ module Impl<FullStateConfigSig Config> {
     module Stage<StageParam Param> implements StageSig {
       import Param
 
+      /* Begin: Stage logic. */
       pragma[nomagic]
       private predicate flowIntoCallApa(
         DataFlowCall call, ArgNodeEx arg, ParamNodeEx p, boolean allowsFieldFlow, ApApprox apa
diff --git a/swift/ql/lib/codeql/swift/dataflow/internal/DataFlowImpl.qll b/swift/ql/lib/codeql/swift/dataflow/internal/DataFlowImpl.qll
index a2af8508265..c47b0308855 100644
--- a/swift/ql/lib/codeql/swift/dataflow/internal/DataFlowImpl.qll
+++ b/swift/ql/lib/codeql/swift/dataflow/internal/DataFlowImpl.qll
@@ -1144,6 +1144,7 @@ module Impl<FullStateConfigSig Config> {
     module Stage<StageParam Param> implements StageSig {
       import Param
 
+      /* Begin: Stage logic. */
       pragma[nomagic]
       private predicate flowIntoCallApa(
         DataFlowCall call, ArgNodeEx arg, ParamNodeEx p, boolean allowsFieldFlow, ApApprox apa