Merge pull request #7401 from github/release-prep/2.7.4

Release preparation for version 2.7.4

.github/workflows/ruby-dataset-measure.yml

@@ -24,7 +24,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        repo: [rails/rails, discourse/discourse, spree/spree]
+        repo: [rails/rails, discourse/discourse, spree/spree, ruby/ruby]
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2

cpp/change-notes/2021-11-01-isFromSystemMacroDefinition.md

@@ -1,4 +0,0 @@
-lgtm,codescanning
-* The QL library `semmle.code.cpp.commons.Exclusions` now contains a predicate
-  `isFromSystemMacroDefinition` for identifying code that originates from a
-  macro outside the project being analyzed.

cpp/change-notes/2021-11-09-use-of-http.md

@@ -1,2 +0,0 @@
-lgtm,codescanning
-* A new query `cpp/non-https-url` has been added for C/C++. The query flags uses of `http` URLs that might be better replaced with `https`.

cpp/ql/lib/CHANGELOG.md

@@ -1,3 +1,5 @@
+## 0.0.5
+
 ## 0.0.4
 
 ### New Features

cpp/ql/lib/change-notes/released/0.0.5.md

@@ -0,0 +1 @@
+## 0.0.5

cpp/ql/lib/codeql-pack.release.yml

@@ -1,2 +1,2 @@
 ---
-lastReleaseVersion: 0.0.4
+lastReleaseVersion: 0.0.5

cpp/ql/lib/qlpack.yml

@@ -1,8 +1,8 @@
 name: codeql/cpp-all
-version: 0.0.5-dev
+version: 0.0.5
 groups: cpp
 dbscheme: semmlecode.cpp.dbscheme
 extractor: cpp
 library: true
 dependencies:
-  codeql/cpp-upgrades: 0.0.3
+  codeql/cpp-upgrades: ^0.0.3

cpp/ql/lib/semmle/code/cpp/controlflow/internal/ConstantExprs.qll

@@ -626,9 +626,9 @@ library class ExprEvaluator extends int {
       // All assignments must have the same int value
       result =
         unique(Expr value |
-          value = v.getAnAssignedValue() and not ignoreVariableAssignment(e, v, value)
+          value = v.getAnAssignedValue() and not this.ignoreVariableAssignment(e, v, value)
         |
-          getValueInternalNonSubExpr(value)
+          this.getValueInternalNonSubExpr(value)
         )
     )
   }

cpp/ql/lib/semmle/code/cpp/dataflow/internal/DataFlowDispatch.qll

@@ -1,4 +1,6 @@
 private import cpp
+private import semmle.code.cpp.dataflow.internal.DataFlowPrivate
+private import semmle.code.cpp.dataflow.internal.DataFlowUtil
 
 /**
  * Gets a function that might be called by `call`.
@@ -63,3 +65,17 @@ predicate mayBenefitFromCallContext(Call call, Function f) { none() }
  * restricted to those `call`s for which a context might make a difference.
  */
 Function viableImplInCallContext(Call call, Call ctx) { none() }
+
+/** A parameter position represented by an integer. */
+class ParameterPosition extends int {
+  ParameterPosition() { any(ParameterNode p).isParameterOf(_, this) }
+}
+
+/** An argument position represented by an integer. */
+class ArgumentPosition extends int {
+  ArgumentPosition() { any(ArgumentNode a).argumentOf(_, this) }
+}
+
+/** Holds if arguments at position `apos` match parameters at position `ppos`. */
+pragma[inline]
+predicate parameterMatch(ParameterPosition ppos, ArgumentPosition apos) { ppos = apos }

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

@@ -256,11 +256,11 @@ private class ArgNodeEx extends NodeEx {
 private class ParamNodeEx extends NodeEx {
   ParamNodeEx() { this.asNode() instanceof ParamNode }
 
-  predicate isParameterOf(DataFlowCallable c, int i) {
-    this.asNode().(ParamNode).isParameterOf(c, i)
+  predicate isParameterOf(DataFlowCallable c, ParameterPosition pos) {
+    this.asNode().(ParamNode).isParameterOf(c, pos)
   }
 
-  int getPosition() { this.isParameterOf(_, result) }
+  ParameterPosition getPosition() { this.isParameterOf(_, result) }
 
   predicate allowParameterReturnInSelf() { allowParameterReturnInSelfCached(this.asNode()) }
 }
@@ -1012,6 +1012,9 @@ private module Stage2 {
 
   private predicate flowIntoCall = flowIntoCallNodeCand1/5;
 
+  bindingset[node, ap]
+  private predicate filter(NodeEx node, Ap ap) { any() }
+
   bindingset[ap, contentType]
   private predicate typecheckStore(Ap ap, DataFlowType contentType) { any() }
 
@@ -1020,6 +1023,13 @@ private module Stage2 {
     PrevStage::revFlow(node, _, _, apa, config)
   }
 
+  bindingset[result, apa]
+  private ApApprox unbindApa(ApApprox apa) {
+    exists(ApApprox apa0 |
+      apa = pragma[only_bind_into](apa0) and result = pragma[only_bind_into](apa0)
+    )
+  }
+
   pragma[nomagic]
   private predicate flowThroughOutOfCall(
     DataFlowCall call, CcCall ccc, RetNodeEx ret, NodeEx out, boolean allowsFieldFlow,
@@ -1042,6 +1052,13 @@ private module Stage2 {
    */
   pragma[nomagic]
   predicate fwdFlow(NodeEx node, Cc cc, ApOption argAp, Ap ap, Configuration config) {
+    fwdFlow0(node, cc, argAp, ap, config) and
+    flowCand(node, unbindApa(getApprox(ap)), config) and
+    filter(node, ap)
+  }
+
+  pragma[nomagic]
+  private predicate fwdFlow0(NodeEx node, Cc cc, ApOption argAp, Ap ap, Configuration config) {
     flowCand(node, _, config) and
     sourceNode(node, config) and
     (if hasSourceCallCtx(config) then cc = ccSomeCall() else cc = ccNone()) and
@@ -1112,7 +1129,7 @@ private module Stage2 {
   ) {
     exists(DataFlowType contentType |
       fwdFlow(node1, cc, argAp, ap1, config) and
-      PrevStage::storeStepCand(node1, getApprox(ap1), tc, node2, contentType, config) and
+      PrevStage::storeStepCand(node1, unbindApa(getApprox(ap1)), tc, node2, contentType, config) and
       typecheckStore(ap1, contentType)
     )
   }
@@ -1189,7 +1206,7 @@ private module Stage2 {
   ) {
     exists(ParamNodeEx p |
       fwdFlowIn(call, p, cc, _, argAp, ap, config) and
-      PrevStage::parameterMayFlowThrough(p, _, getApprox(ap), config)
+      PrevStage::parameterMayFlowThrough(p, _, unbindApa(getApprox(ap)), config)
     )
   }
 
@@ -1430,7 +1447,7 @@ private module Stage2 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2125,7 +2142,7 @@ private module Stage3 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2891,7 +2908,7 @@ private module Stage4 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2975,7 +2992,7 @@ private class SummaryCtxSome extends SummaryCtx, TSummaryCtxSome {
 
   SummaryCtxSome() { this = TSummaryCtxSome(p, ap) }
 
-  int getParameterPos() { p.isParameterOf(_, result) }
+  ParameterPosition getParameterPos() { p.isParameterOf(_, result) }
 
   ParamNodeEx getParamNode() { result = p }
 
@@ -3622,39 +3639,40 @@ private predicate pathOutOfCallable(PathNodeMid mid, NodeEx out, CallContext cc)
  */
 pragma[noinline]
 private predicate pathIntoArg(
-  PathNodeMid mid, int i, CallContext cc, DataFlowCall call, AccessPath ap, AccessPathApprox apa,
-  Configuration config
+  PathNodeMid mid, ParameterPosition ppos, CallContext cc, DataFlowCall call, AccessPath ap,
+  AccessPathApprox apa, Configuration config
 ) {
-  exists(ArgNode arg |
+  exists(ArgNode arg, ArgumentPosition apos |
     arg = mid.getNodeEx().asNode() and
     cc = mid.getCallContext() and
-    arg.argumentOf(call, i) and
+    arg.argumentOf(call, apos) and
     ap = mid.getAp() and
     apa = ap.getApprox() and
-    config = mid.getConfiguration()
+    config = mid.getConfiguration() and
+    parameterMatch(ppos, apos)
   )
 }
 
 pragma[nomagic]
 private predicate parameterCand(
-  DataFlowCallable callable, int i, AccessPathApprox apa, Configuration config
+  DataFlowCallable callable, ParameterPosition pos, AccessPathApprox apa, Configuration config
 ) {
   exists(ParamNodeEx p |
     Stage4::revFlow(p, _, _, apa, config) and
-    p.isParameterOf(callable, i)
+    p.isParameterOf(callable, pos)
   )
 }
 
 pragma[nomagic]
 private predicate pathIntoCallable0(
-  PathNodeMid mid, DataFlowCallable callable, int i, CallContext outercc, DataFlowCall call,
-  AccessPath ap, Configuration config
+  PathNodeMid mid, DataFlowCallable callable, ParameterPosition pos, CallContext outercc,
+  DataFlowCall call, AccessPath ap, Configuration config
 ) {
   exists(AccessPathApprox apa |
-    pathIntoArg(mid, pragma[only_bind_into](i), outercc, call, ap, pragma[only_bind_into](apa),
+    pathIntoArg(mid, pragma[only_bind_into](pos), outercc, call, ap, pragma[only_bind_into](apa),
       pragma[only_bind_into](config)) and
     callable = resolveCall(call, outercc) and
-    parameterCand(callable, pragma[only_bind_into](i), pragma[only_bind_into](apa),
+    parameterCand(callable, pragma[only_bind_into](pos), pragma[only_bind_into](apa),
       pragma[only_bind_into](config))
   )
 }
@@ -3669,9 +3687,9 @@ private predicate pathIntoCallable(
   PathNodeMid mid, ParamNodeEx p, CallContext outercc, CallContextCall innercc, SummaryCtx sc,
   DataFlowCall call, Configuration config
 ) {
-  exists(int i, DataFlowCallable callable, AccessPath ap |
-    pathIntoCallable0(mid, callable, i, outercc, call, ap, config) and
-    p.isParameterOf(callable, i) and
+  exists(ParameterPosition pos, DataFlowCallable callable, AccessPath ap |
+    pathIntoCallable0(mid, callable, pos, outercc, call, ap, config) and
+    p.isParameterOf(callable, pos) and
     (
       sc = TSummaryCtxSome(p, ap)
       or
@@ -3695,7 +3713,7 @@ private predicate paramFlowsThrough(
   ReturnKindExt kind, CallContextCall cc, SummaryCtxSome sc, AccessPath ap, AccessPathApprox apa,
   Configuration config
 ) {
-  exists(PathNodeMid mid, RetNodeEx ret, int pos |
+  exists(PathNodeMid mid, RetNodeEx ret, ParameterPosition pos |
     mid.getNodeEx() = ret and
     kind = ret.getKind() and
     cc = mid.getCallContext() and
@@ -4424,24 +4442,25 @@ private module FlowExploration {
 
   pragma[noinline]
   private predicate partialPathIntoArg(
-    PartialPathNodeFwd mid, int i, CallContext cc, DataFlowCall call, PartialAccessPath ap,
-    Configuration config
+    PartialPathNodeFwd mid, ParameterPosition ppos, CallContext cc, DataFlowCall call,
+    PartialAccessPath ap, Configuration config
   ) {
-    exists(ArgNode arg |
+    exists(ArgNode arg, ArgumentPosition apos |
       arg = mid.getNodeEx().asNode() and
       cc = mid.getCallContext() and
-      arg.argumentOf(call, i) and
+      arg.argumentOf(call, apos) and
       ap = mid.getAp() and
-      config = mid.getConfiguration()
+      config = mid.getConfiguration() and
+      parameterMatch(ppos, apos)
     )
   }
 
   pragma[nomagic]
   private predicate partialPathIntoCallable0(
-    PartialPathNodeFwd mid, DataFlowCallable callable, int i, CallContext outercc,
+    PartialPathNodeFwd mid, DataFlowCallable callable, ParameterPosition pos, CallContext outercc,
     DataFlowCall call, PartialAccessPath ap, Configuration config
   ) {
-    partialPathIntoArg(mid, i, outercc, call, ap, config) and
+    partialPathIntoArg(mid, pos, outercc, call, ap, config) and
     callable = resolveCall(call, outercc)
   }
 
@@ -4450,9 +4469,9 @@ private module FlowExploration {
     TSummaryCtx1 sc1, TSummaryCtx2 sc2, DataFlowCall call, PartialAccessPath ap,
     Configuration config
   ) {
-    exists(int i, DataFlowCallable callable |
-      partialPathIntoCallable0(mid, callable, i, outercc, call, ap, config) and
-      p.isParameterOf(callable, i) and
+    exists(ParameterPosition pos, DataFlowCallable callable |
+      partialPathIntoCallable0(mid, callable, pos, outercc, call, ap, config) and
+      p.isParameterOf(callable, pos) and
       sc1 = TSummaryCtx1Param(p) and
       sc2 = TSummaryCtx2Some(ap)
     |
@@ -4616,22 +4635,23 @@ private module FlowExploration {
 
   pragma[nomagic]
   private predicate revPartialPathFlowsThrough(
-    int pos, TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2, RevPartialAccessPath ap,
-    Configuration config
+    ArgumentPosition apos, TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2,
+    RevPartialAccessPath ap, Configuration config
   ) {
-    exists(PartialPathNodeRev mid, ParamNodeEx p |
+    exists(PartialPathNodeRev mid, ParamNodeEx p, ParameterPosition ppos |
       mid.getNodeEx() = p and
-      p.getPosition() = pos and
+      p.getPosition() = ppos and
       sc1 = mid.getSummaryCtx1() and
       sc2 = mid.getSummaryCtx2() and
       ap = mid.getAp() and
-      config = mid.getConfiguration()
+      config = mid.getConfiguration() and
+      parameterMatch(ppos, apos)
     )
   }
 
   pragma[nomagic]
   private predicate revPartialPathThroughCallable0(
-    DataFlowCall call, PartialPathNodeRev mid, int pos, RevPartialAccessPath ap,
+    DataFlowCall call, PartialPathNodeRev mid, ArgumentPosition pos, RevPartialAccessPath ap,
     Configuration config
   ) {
     exists(TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2 |
@@ -4644,7 +4664,7 @@ private module FlowExploration {
   private predicate revPartialPathThroughCallable(
     PartialPathNodeRev mid, ArgNodeEx node, RevPartialAccessPath ap, Configuration config
   ) {
-    exists(DataFlowCall call, int pos |
+    exists(DataFlowCall call, ArgumentPosition pos |
       revPartialPathThroughCallable0(call, mid, pos, ap, config) and
       node.asNode().(ArgNode).argumentOf(call, pos)
     )

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

@@ -256,11 +256,11 @@ private class ArgNodeEx extends NodeEx {
 private class ParamNodeEx extends NodeEx {
   ParamNodeEx() { this.asNode() instanceof ParamNode }
 
-  predicate isParameterOf(DataFlowCallable c, int i) {
-    this.asNode().(ParamNode).isParameterOf(c, i)
+  predicate isParameterOf(DataFlowCallable c, ParameterPosition pos) {
+    this.asNode().(ParamNode).isParameterOf(c, pos)
   }
 
-  int getPosition() { this.isParameterOf(_, result) }
+  ParameterPosition getPosition() { this.isParameterOf(_, result) }
 
   predicate allowParameterReturnInSelf() { allowParameterReturnInSelfCached(this.asNode()) }
 }
@@ -1012,6 +1012,9 @@ private module Stage2 {
 
   private predicate flowIntoCall = flowIntoCallNodeCand1/5;
 
+  bindingset[node, ap]
+  private predicate filter(NodeEx node, Ap ap) { any() }
+
   bindingset[ap, contentType]
   private predicate typecheckStore(Ap ap, DataFlowType contentType) { any() }
 
@@ -1020,6 +1023,13 @@ private module Stage2 {
     PrevStage::revFlow(node, _, _, apa, config)
   }
 
+  bindingset[result, apa]
+  private ApApprox unbindApa(ApApprox apa) {
+    exists(ApApprox apa0 |
+      apa = pragma[only_bind_into](apa0) and result = pragma[only_bind_into](apa0)
+    )
+  }
+
   pragma[nomagic]
   private predicate flowThroughOutOfCall(
     DataFlowCall call, CcCall ccc, RetNodeEx ret, NodeEx out, boolean allowsFieldFlow,
@@ -1042,6 +1052,13 @@ private module Stage2 {
    */
   pragma[nomagic]
   predicate fwdFlow(NodeEx node, Cc cc, ApOption argAp, Ap ap, Configuration config) {
+    fwdFlow0(node, cc, argAp, ap, config) and
+    flowCand(node, unbindApa(getApprox(ap)), config) and
+    filter(node, ap)
+  }
+
+  pragma[nomagic]
+  private predicate fwdFlow0(NodeEx node, Cc cc, ApOption argAp, Ap ap, Configuration config) {
     flowCand(node, _, config) and
     sourceNode(node, config) and
     (if hasSourceCallCtx(config) then cc = ccSomeCall() else cc = ccNone()) and
@@ -1112,7 +1129,7 @@ private module Stage2 {
   ) {
     exists(DataFlowType contentType |
       fwdFlow(node1, cc, argAp, ap1, config) and
-      PrevStage::storeStepCand(node1, getApprox(ap1), tc, node2, contentType, config) and
+      PrevStage::storeStepCand(node1, unbindApa(getApprox(ap1)), tc, node2, contentType, config) and
       typecheckStore(ap1, contentType)
     )
   }
@@ -1189,7 +1206,7 @@ private module Stage2 {
   ) {
     exists(ParamNodeEx p |
       fwdFlowIn(call, p, cc, _, argAp, ap, config) and
-      PrevStage::parameterMayFlowThrough(p, _, getApprox(ap), config)
+      PrevStage::parameterMayFlowThrough(p, _, unbindApa(getApprox(ap)), config)
     )
   }
 
@@ -1430,7 +1447,7 @@ private module Stage2 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2125,7 +2142,7 @@ private module Stage3 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2891,7 +2908,7 @@ private module Stage4 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2975,7 +2992,7 @@ private class SummaryCtxSome extends SummaryCtx, TSummaryCtxSome {
 
   SummaryCtxSome() { this = TSummaryCtxSome(p, ap) }
 
-  int getParameterPos() { p.isParameterOf(_, result) }
+  ParameterPosition getParameterPos() { p.isParameterOf(_, result) }
 
   ParamNodeEx getParamNode() { result = p }
 
@@ -3622,39 +3639,40 @@ private predicate pathOutOfCallable(PathNodeMid mid, NodeEx out, CallContext cc)
  */
 pragma[noinline]
 private predicate pathIntoArg(
-  PathNodeMid mid, int i, CallContext cc, DataFlowCall call, AccessPath ap, AccessPathApprox apa,
-  Configuration config
+  PathNodeMid mid, ParameterPosition ppos, CallContext cc, DataFlowCall call, AccessPath ap,
+  AccessPathApprox apa, Configuration config
 ) {
-  exists(ArgNode arg |
+  exists(ArgNode arg, ArgumentPosition apos |
     arg = mid.getNodeEx().asNode() and
     cc = mid.getCallContext() and
-    arg.argumentOf(call, i) and
+    arg.argumentOf(call, apos) and
     ap = mid.getAp() and
     apa = ap.getApprox() and
-    config = mid.getConfiguration()
+    config = mid.getConfiguration() and
+    parameterMatch(ppos, apos)
   )
 }
 
 pragma[nomagic]
 private predicate parameterCand(
-  DataFlowCallable callable, int i, AccessPathApprox apa, Configuration config
+  DataFlowCallable callable, ParameterPosition pos, AccessPathApprox apa, Configuration config
 ) {
   exists(ParamNodeEx p |
     Stage4::revFlow(p, _, _, apa, config) and
-    p.isParameterOf(callable, i)
+    p.isParameterOf(callable, pos)
   )
 }
 
 pragma[nomagic]
 private predicate pathIntoCallable0(
-  PathNodeMid mid, DataFlowCallable callable, int i, CallContext outercc, DataFlowCall call,
-  AccessPath ap, Configuration config
+  PathNodeMid mid, DataFlowCallable callable, ParameterPosition pos, CallContext outercc,
+  DataFlowCall call, AccessPath ap, Configuration config
 ) {
   exists(AccessPathApprox apa |
-    pathIntoArg(mid, pragma[only_bind_into](i), outercc, call, ap, pragma[only_bind_into](apa),
+    pathIntoArg(mid, pragma[only_bind_into](pos), outercc, call, ap, pragma[only_bind_into](apa),
       pragma[only_bind_into](config)) and
     callable = resolveCall(call, outercc) and
-    parameterCand(callable, pragma[only_bind_into](i), pragma[only_bind_into](apa),
+    parameterCand(callable, pragma[only_bind_into](pos), pragma[only_bind_into](apa),
       pragma[only_bind_into](config))
   )
 }
@@ -3669,9 +3687,9 @@ private predicate pathIntoCallable(
   PathNodeMid mid, ParamNodeEx p, CallContext outercc, CallContextCall innercc, SummaryCtx sc,
   DataFlowCall call, Configuration config
 ) {
-  exists(int i, DataFlowCallable callable, AccessPath ap |
-    pathIntoCallable0(mid, callable, i, outercc, call, ap, config) and
-    p.isParameterOf(callable, i) and
+  exists(ParameterPosition pos, DataFlowCallable callable, AccessPath ap |
+    pathIntoCallable0(mid, callable, pos, outercc, call, ap, config) and
+    p.isParameterOf(callable, pos) and
     (
       sc = TSummaryCtxSome(p, ap)
       or
@@ -3695,7 +3713,7 @@ private predicate paramFlowsThrough(
   ReturnKindExt kind, CallContextCall cc, SummaryCtxSome sc, AccessPath ap, AccessPathApprox apa,
   Configuration config
 ) {
-  exists(PathNodeMid mid, RetNodeEx ret, int pos |
+  exists(PathNodeMid mid, RetNodeEx ret, ParameterPosition pos |
     mid.getNodeEx() = ret and
     kind = ret.getKind() and
     cc = mid.getCallContext() and
@@ -4424,24 +4442,25 @@ private module FlowExploration {
 
   pragma[noinline]
   private predicate partialPathIntoArg(
-    PartialPathNodeFwd mid, int i, CallContext cc, DataFlowCall call, PartialAccessPath ap,
-    Configuration config
+    PartialPathNodeFwd mid, ParameterPosition ppos, CallContext cc, DataFlowCall call,
+    PartialAccessPath ap, Configuration config
   ) {
-    exists(ArgNode arg |
+    exists(ArgNode arg, ArgumentPosition apos |
       arg = mid.getNodeEx().asNode() and
       cc = mid.getCallContext() and
-      arg.argumentOf(call, i) and
+      arg.argumentOf(call, apos) and
       ap = mid.getAp() and
-      config = mid.getConfiguration()
+      config = mid.getConfiguration() and
+      parameterMatch(ppos, apos)
     )
   }
 
   pragma[nomagic]
   private predicate partialPathIntoCallable0(
-    PartialPathNodeFwd mid, DataFlowCallable callable, int i, CallContext outercc,
+    PartialPathNodeFwd mid, DataFlowCallable callable, ParameterPosition pos, CallContext outercc,
     DataFlowCall call, PartialAccessPath ap, Configuration config
   ) {
-    partialPathIntoArg(mid, i, outercc, call, ap, config) and
+    partialPathIntoArg(mid, pos, outercc, call, ap, config) and
     callable = resolveCall(call, outercc)
   }
 
@@ -4450,9 +4469,9 @@ private module FlowExploration {
     TSummaryCtx1 sc1, TSummaryCtx2 sc2, DataFlowCall call, PartialAccessPath ap,
     Configuration config
   ) {
-    exists(int i, DataFlowCallable callable |
-      partialPathIntoCallable0(mid, callable, i, outercc, call, ap, config) and
-      p.isParameterOf(callable, i) and
+    exists(ParameterPosition pos, DataFlowCallable callable |
+      partialPathIntoCallable0(mid, callable, pos, outercc, call, ap, config) and
+      p.isParameterOf(callable, pos) and
       sc1 = TSummaryCtx1Param(p) and
       sc2 = TSummaryCtx2Some(ap)
     |
@@ -4616,22 +4635,23 @@ private module FlowExploration {
 
   pragma[nomagic]
   private predicate revPartialPathFlowsThrough(
-    int pos, TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2, RevPartialAccessPath ap,
-    Configuration config
+    ArgumentPosition apos, TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2,
+    RevPartialAccessPath ap, Configuration config
   ) {
-    exists(PartialPathNodeRev mid, ParamNodeEx p |
+    exists(PartialPathNodeRev mid, ParamNodeEx p, ParameterPosition ppos |
       mid.getNodeEx() = p and
-      p.getPosition() = pos and
+      p.getPosition() = ppos and
       sc1 = mid.getSummaryCtx1() and
       sc2 = mid.getSummaryCtx2() and
       ap = mid.getAp() and
-      config = mid.getConfiguration()
+      config = mid.getConfiguration() and
+      parameterMatch(ppos, apos)
     )
   }
 
   pragma[nomagic]
   private predicate revPartialPathThroughCallable0(
-    DataFlowCall call, PartialPathNodeRev mid, int pos, RevPartialAccessPath ap,
+    DataFlowCall call, PartialPathNodeRev mid, ArgumentPosition pos, RevPartialAccessPath ap,
     Configuration config
   ) {
     exists(TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2 |
@@ -4644,7 +4664,7 @@ private module FlowExploration {
   private predicate revPartialPathThroughCallable(
     PartialPathNodeRev mid, ArgNodeEx node, RevPartialAccessPath ap, Configuration config
   ) {
-    exists(DataFlowCall call, int pos |
+    exists(DataFlowCall call, ArgumentPosition pos |
       revPartialPathThroughCallable0(call, mid, pos, ap, config) and
       node.asNode().(ArgNode).argumentOf(call, pos)
     )

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

@@ -256,11 +256,11 @@ private class ArgNodeEx extends NodeEx {
 private class ParamNodeEx extends NodeEx {
   ParamNodeEx() { this.asNode() instanceof ParamNode }
 
-  predicate isParameterOf(DataFlowCallable c, int i) {
-    this.asNode().(ParamNode).isParameterOf(c, i)
+  predicate isParameterOf(DataFlowCallable c, ParameterPosition pos) {
+    this.asNode().(ParamNode).isParameterOf(c, pos)
   }
 
-  int getPosition() { this.isParameterOf(_, result) }
+  ParameterPosition getPosition() { this.isParameterOf(_, result) }
 
   predicate allowParameterReturnInSelf() { allowParameterReturnInSelfCached(this.asNode()) }
 }
@@ -1012,6 +1012,9 @@ private module Stage2 {
 
   private predicate flowIntoCall = flowIntoCallNodeCand1/5;
 
+  bindingset[node, ap]
+  private predicate filter(NodeEx node, Ap ap) { any() }
+
   bindingset[ap, contentType]
   private predicate typecheckStore(Ap ap, DataFlowType contentType) { any() }
 
@@ -1020,6 +1023,13 @@ private module Stage2 {
     PrevStage::revFlow(node, _, _, apa, config)
   }
 
+  bindingset[result, apa]
+  private ApApprox unbindApa(ApApprox apa) {
+    exists(ApApprox apa0 |
+      apa = pragma[only_bind_into](apa0) and result = pragma[only_bind_into](apa0)
+    )
+  }
+
   pragma[nomagic]
   private predicate flowThroughOutOfCall(
     DataFlowCall call, CcCall ccc, RetNodeEx ret, NodeEx out, boolean allowsFieldFlow,
@@ -1042,6 +1052,13 @@ private module Stage2 {
    */
   pragma[nomagic]
   predicate fwdFlow(NodeEx node, Cc cc, ApOption argAp, Ap ap, Configuration config) {
+    fwdFlow0(node, cc, argAp, ap, config) and
+    flowCand(node, unbindApa(getApprox(ap)), config) and
+    filter(node, ap)
+  }
+
+  pragma[nomagic]
+  private predicate fwdFlow0(NodeEx node, Cc cc, ApOption argAp, Ap ap, Configuration config) {
     flowCand(node, _, config) and
     sourceNode(node, config) and
     (if hasSourceCallCtx(config) then cc = ccSomeCall() else cc = ccNone()) and
@@ -1112,7 +1129,7 @@ private module Stage2 {
   ) {
     exists(DataFlowType contentType |
       fwdFlow(node1, cc, argAp, ap1, config) and
-      PrevStage::storeStepCand(node1, getApprox(ap1), tc, node2, contentType, config) and
+      PrevStage::storeStepCand(node1, unbindApa(getApprox(ap1)), tc, node2, contentType, config) and
       typecheckStore(ap1, contentType)
     )
   }
@@ -1189,7 +1206,7 @@ private module Stage2 {
   ) {
     exists(ParamNodeEx p |
       fwdFlowIn(call, p, cc, _, argAp, ap, config) and
-      PrevStage::parameterMayFlowThrough(p, _, getApprox(ap), config)
+      PrevStage::parameterMayFlowThrough(p, _, unbindApa(getApprox(ap)), config)
     )
   }
 
@@ -1430,7 +1447,7 @@ private module Stage2 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2125,7 +2142,7 @@ private module Stage3 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2891,7 +2908,7 @@ private module Stage4 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2975,7 +2992,7 @@ private class SummaryCtxSome extends SummaryCtx, TSummaryCtxSome {
 
   SummaryCtxSome() { this = TSummaryCtxSome(p, ap) }
 
-  int getParameterPos() { p.isParameterOf(_, result) }
+  ParameterPosition getParameterPos() { p.isParameterOf(_, result) }
 
   ParamNodeEx getParamNode() { result = p }
 
@@ -3622,39 +3639,40 @@ private predicate pathOutOfCallable(PathNodeMid mid, NodeEx out, CallContext cc)
  */
 pragma[noinline]
 private predicate pathIntoArg(
-  PathNodeMid mid, int i, CallContext cc, DataFlowCall call, AccessPath ap, AccessPathApprox apa,
-  Configuration config
+  PathNodeMid mid, ParameterPosition ppos, CallContext cc, DataFlowCall call, AccessPath ap,
+  AccessPathApprox apa, Configuration config
 ) {
-  exists(ArgNode arg |
+  exists(ArgNode arg, ArgumentPosition apos |
     arg = mid.getNodeEx().asNode() and
     cc = mid.getCallContext() and
-    arg.argumentOf(call, i) and
+    arg.argumentOf(call, apos) and
     ap = mid.getAp() and
     apa = ap.getApprox() and
-    config = mid.getConfiguration()
+    config = mid.getConfiguration() and
+    parameterMatch(ppos, apos)
   )
 }
 
 pragma[nomagic]
 private predicate parameterCand(
-  DataFlowCallable callable, int i, AccessPathApprox apa, Configuration config
+  DataFlowCallable callable, ParameterPosition pos, AccessPathApprox apa, Configuration config
 ) {
   exists(ParamNodeEx p |
     Stage4::revFlow(p, _, _, apa, config) and
-    p.isParameterOf(callable, i)
+    p.isParameterOf(callable, pos)
   )
 }
 
 pragma[nomagic]
 private predicate pathIntoCallable0(
-  PathNodeMid mid, DataFlowCallable callable, int i, CallContext outercc, DataFlowCall call,
-  AccessPath ap, Configuration config
+  PathNodeMid mid, DataFlowCallable callable, ParameterPosition pos, CallContext outercc,
+  DataFlowCall call, AccessPath ap, Configuration config
 ) {
   exists(AccessPathApprox apa |
-    pathIntoArg(mid, pragma[only_bind_into](i), outercc, call, ap, pragma[only_bind_into](apa),
+    pathIntoArg(mid, pragma[only_bind_into](pos), outercc, call, ap, pragma[only_bind_into](apa),
       pragma[only_bind_into](config)) and
     callable = resolveCall(call, outercc) and
-    parameterCand(callable, pragma[only_bind_into](i), pragma[only_bind_into](apa),
+    parameterCand(callable, pragma[only_bind_into](pos), pragma[only_bind_into](apa),
       pragma[only_bind_into](config))
   )
 }
@@ -3669,9 +3687,9 @@ private predicate pathIntoCallable(
   PathNodeMid mid, ParamNodeEx p, CallContext outercc, CallContextCall innercc, SummaryCtx sc,
   DataFlowCall call, Configuration config
 ) {
-  exists(int i, DataFlowCallable callable, AccessPath ap |
-    pathIntoCallable0(mid, callable, i, outercc, call, ap, config) and
-    p.isParameterOf(callable, i) and
+  exists(ParameterPosition pos, DataFlowCallable callable, AccessPath ap |
+    pathIntoCallable0(mid, callable, pos, outercc, call, ap, config) and
+    p.isParameterOf(callable, pos) and
     (
       sc = TSummaryCtxSome(p, ap)
       or
@@ -3695,7 +3713,7 @@ private predicate paramFlowsThrough(
   ReturnKindExt kind, CallContextCall cc, SummaryCtxSome sc, AccessPath ap, AccessPathApprox apa,
   Configuration config
 ) {
-  exists(PathNodeMid mid, RetNodeEx ret, int pos |
+  exists(PathNodeMid mid, RetNodeEx ret, ParameterPosition pos |
     mid.getNodeEx() = ret and
     kind = ret.getKind() and
     cc = mid.getCallContext() and
@@ -4424,24 +4442,25 @@ private module FlowExploration {
 
   pragma[noinline]
   private predicate partialPathIntoArg(
-    PartialPathNodeFwd mid, int i, CallContext cc, DataFlowCall call, PartialAccessPath ap,
-    Configuration config
+    PartialPathNodeFwd mid, ParameterPosition ppos, CallContext cc, DataFlowCall call,
+    PartialAccessPath ap, Configuration config
   ) {
-    exists(ArgNode arg |
+    exists(ArgNode arg, ArgumentPosition apos |
       arg = mid.getNodeEx().asNode() and
       cc = mid.getCallContext() and
-      arg.argumentOf(call, i) and
+      arg.argumentOf(call, apos) and
       ap = mid.getAp() and
-      config = mid.getConfiguration()
+      config = mid.getConfiguration() and
+      parameterMatch(ppos, apos)
     )
   }
 
   pragma[nomagic]
   private predicate partialPathIntoCallable0(
-    PartialPathNodeFwd mid, DataFlowCallable callable, int i, CallContext outercc,
+    PartialPathNodeFwd mid, DataFlowCallable callable, ParameterPosition pos, CallContext outercc,
     DataFlowCall call, PartialAccessPath ap, Configuration config
   ) {
-    partialPathIntoArg(mid, i, outercc, call, ap, config) and
+    partialPathIntoArg(mid, pos, outercc, call, ap, config) and
     callable = resolveCall(call, outercc)
   }
 
@@ -4450,9 +4469,9 @@ private module FlowExploration {
     TSummaryCtx1 sc1, TSummaryCtx2 sc2, DataFlowCall call, PartialAccessPath ap,
     Configuration config
   ) {
-    exists(int i, DataFlowCallable callable |
-      partialPathIntoCallable0(mid, callable, i, outercc, call, ap, config) and
-      p.isParameterOf(callable, i) and
+    exists(ParameterPosition pos, DataFlowCallable callable |
+      partialPathIntoCallable0(mid, callable, pos, outercc, call, ap, config) and
+      p.isParameterOf(callable, pos) and
       sc1 = TSummaryCtx1Param(p) and
       sc2 = TSummaryCtx2Some(ap)
     |
@@ -4616,22 +4635,23 @@ private module FlowExploration {
 
   pragma[nomagic]
   private predicate revPartialPathFlowsThrough(
-    int pos, TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2, RevPartialAccessPath ap,
-    Configuration config
+    ArgumentPosition apos, TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2,
+    RevPartialAccessPath ap, Configuration config
   ) {
-    exists(PartialPathNodeRev mid, ParamNodeEx p |
+    exists(PartialPathNodeRev mid, ParamNodeEx p, ParameterPosition ppos |
       mid.getNodeEx() = p and
-      p.getPosition() = pos and
+      p.getPosition() = ppos and
       sc1 = mid.getSummaryCtx1() and
       sc2 = mid.getSummaryCtx2() and
       ap = mid.getAp() and
-      config = mid.getConfiguration()
+      config = mid.getConfiguration() and
+      parameterMatch(ppos, apos)
     )
   }
 
   pragma[nomagic]
   private predicate revPartialPathThroughCallable0(
-    DataFlowCall call, PartialPathNodeRev mid, int pos, RevPartialAccessPath ap,
+    DataFlowCall call, PartialPathNodeRev mid, ArgumentPosition pos, RevPartialAccessPath ap,
     Configuration config
   ) {
     exists(TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2 |
@@ -4644,7 +4664,7 @@ private module FlowExploration {
   private predicate revPartialPathThroughCallable(
     PartialPathNodeRev mid, ArgNodeEx node, RevPartialAccessPath ap, Configuration config
   ) {
-    exists(DataFlowCall call, int pos |
+    exists(DataFlowCall call, ArgumentPosition pos |
       revPartialPathThroughCallable0(call, mid, pos, ap, config) and
       node.asNode().(ArgNode).argumentOf(call, pos)
     )

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

@@ -256,11 +256,11 @@ private class ArgNodeEx extends NodeEx {
 private class ParamNodeEx extends NodeEx {
   ParamNodeEx() { this.asNode() instanceof ParamNode }
 
-  predicate isParameterOf(DataFlowCallable c, int i) {
-    this.asNode().(ParamNode).isParameterOf(c, i)
+  predicate isParameterOf(DataFlowCallable c, ParameterPosition pos) {
+    this.asNode().(ParamNode).isParameterOf(c, pos)
   }
 
-  int getPosition() { this.isParameterOf(_, result) }
+  ParameterPosition getPosition() { this.isParameterOf(_, result) }
 
   predicate allowParameterReturnInSelf() { allowParameterReturnInSelfCached(this.asNode()) }
 }
@@ -1012,6 +1012,9 @@ private module Stage2 {
 
   private predicate flowIntoCall = flowIntoCallNodeCand1/5;
 
+  bindingset[node, ap]
+  private predicate filter(NodeEx node, Ap ap) { any() }
+
   bindingset[ap, contentType]
   private predicate typecheckStore(Ap ap, DataFlowType contentType) { any() }
 
@@ -1020,6 +1023,13 @@ private module Stage2 {
     PrevStage::revFlow(node, _, _, apa, config)
   }
 
+  bindingset[result, apa]
+  private ApApprox unbindApa(ApApprox apa) {
+    exists(ApApprox apa0 |
+      apa = pragma[only_bind_into](apa0) and result = pragma[only_bind_into](apa0)
+    )
+  }
+
   pragma[nomagic]
   private predicate flowThroughOutOfCall(
     DataFlowCall call, CcCall ccc, RetNodeEx ret, NodeEx out, boolean allowsFieldFlow,
@@ -1042,6 +1052,13 @@ private module Stage2 {
    */
   pragma[nomagic]
   predicate fwdFlow(NodeEx node, Cc cc, ApOption argAp, Ap ap, Configuration config) {
+    fwdFlow0(node, cc, argAp, ap, config) and
+    flowCand(node, unbindApa(getApprox(ap)), config) and
+    filter(node, ap)
+  }
+
+  pragma[nomagic]
+  private predicate fwdFlow0(NodeEx node, Cc cc, ApOption argAp, Ap ap, Configuration config) {
     flowCand(node, _, config) and
     sourceNode(node, config) and
     (if hasSourceCallCtx(config) then cc = ccSomeCall() else cc = ccNone()) and
@@ -1112,7 +1129,7 @@ private module Stage2 {
   ) {
     exists(DataFlowType contentType |
       fwdFlow(node1, cc, argAp, ap1, config) and
-      PrevStage::storeStepCand(node1, getApprox(ap1), tc, node2, contentType, config) and
+      PrevStage::storeStepCand(node1, unbindApa(getApprox(ap1)), tc, node2, contentType, config) and
       typecheckStore(ap1, contentType)
     )
   }
@@ -1189,7 +1206,7 @@ private module Stage2 {
   ) {
     exists(ParamNodeEx p |
       fwdFlowIn(call, p, cc, _, argAp, ap, config) and
-      PrevStage::parameterMayFlowThrough(p, _, getApprox(ap), config)
+      PrevStage::parameterMayFlowThrough(p, _, unbindApa(getApprox(ap)), config)
     )
   }
 
@@ -1430,7 +1447,7 @@ private module Stage2 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2125,7 +2142,7 @@ private module Stage3 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2891,7 +2908,7 @@ private module Stage4 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2975,7 +2992,7 @@ private class SummaryCtxSome extends SummaryCtx, TSummaryCtxSome {
 
   SummaryCtxSome() { this = TSummaryCtxSome(p, ap) }
 
-  int getParameterPos() { p.isParameterOf(_, result) }
+  ParameterPosition getParameterPos() { p.isParameterOf(_, result) }
 
   ParamNodeEx getParamNode() { result = p }
 
@@ -3622,39 +3639,40 @@ private predicate pathOutOfCallable(PathNodeMid mid, NodeEx out, CallContext cc)
  */
 pragma[noinline]
 private predicate pathIntoArg(
-  PathNodeMid mid, int i, CallContext cc, DataFlowCall call, AccessPath ap, AccessPathApprox apa,
-  Configuration config
+  PathNodeMid mid, ParameterPosition ppos, CallContext cc, DataFlowCall call, AccessPath ap,
+  AccessPathApprox apa, Configuration config
 ) {
-  exists(ArgNode arg |
+  exists(ArgNode arg, ArgumentPosition apos |
     arg = mid.getNodeEx().asNode() and
     cc = mid.getCallContext() and
-    arg.argumentOf(call, i) and
+    arg.argumentOf(call, apos) and
     ap = mid.getAp() and
     apa = ap.getApprox() and
-    config = mid.getConfiguration()
+    config = mid.getConfiguration() and
+    parameterMatch(ppos, apos)
   )
 }
 
 pragma[nomagic]
 private predicate parameterCand(
-  DataFlowCallable callable, int i, AccessPathApprox apa, Configuration config
+  DataFlowCallable callable, ParameterPosition pos, AccessPathApprox apa, Configuration config
 ) {
   exists(ParamNodeEx p |
     Stage4::revFlow(p, _, _, apa, config) and
-    p.isParameterOf(callable, i)
+    p.isParameterOf(callable, pos)
   )
 }
 
 pragma[nomagic]
 private predicate pathIntoCallable0(
-  PathNodeMid mid, DataFlowCallable callable, int i, CallContext outercc, DataFlowCall call,
-  AccessPath ap, Configuration config
+  PathNodeMid mid, DataFlowCallable callable, ParameterPosition pos, CallContext outercc,
+  DataFlowCall call, AccessPath ap, Configuration config
 ) {
   exists(AccessPathApprox apa |
-    pathIntoArg(mid, pragma[only_bind_into](i), outercc, call, ap, pragma[only_bind_into](apa),
+    pathIntoArg(mid, pragma[only_bind_into](pos), outercc, call, ap, pragma[only_bind_into](apa),
       pragma[only_bind_into](config)) and
     callable = resolveCall(call, outercc) and
-    parameterCand(callable, pragma[only_bind_into](i), pragma[only_bind_into](apa),
+    parameterCand(callable, pragma[only_bind_into](pos), pragma[only_bind_into](apa),
       pragma[only_bind_into](config))
   )
 }
@@ -3669,9 +3687,9 @@ private predicate pathIntoCallable(
   PathNodeMid mid, ParamNodeEx p, CallContext outercc, CallContextCall innercc, SummaryCtx sc,
   DataFlowCall call, Configuration config
 ) {
-  exists(int i, DataFlowCallable callable, AccessPath ap |
-    pathIntoCallable0(mid, callable, i, outercc, call, ap, config) and
-    p.isParameterOf(callable, i) and
+  exists(ParameterPosition pos, DataFlowCallable callable, AccessPath ap |
+    pathIntoCallable0(mid, callable, pos, outercc, call, ap, config) and
+    p.isParameterOf(callable, pos) and
     (
       sc = TSummaryCtxSome(p, ap)
       or
@@ -3695,7 +3713,7 @@ private predicate paramFlowsThrough(
   ReturnKindExt kind, CallContextCall cc, SummaryCtxSome sc, AccessPath ap, AccessPathApprox apa,
   Configuration config
 ) {
-  exists(PathNodeMid mid, RetNodeEx ret, int pos |
+  exists(PathNodeMid mid, RetNodeEx ret, ParameterPosition pos |
     mid.getNodeEx() = ret and
     kind = ret.getKind() and
     cc = mid.getCallContext() and
@@ -4424,24 +4442,25 @@ private module FlowExploration {
 
   pragma[noinline]
   private predicate partialPathIntoArg(
-    PartialPathNodeFwd mid, int i, CallContext cc, DataFlowCall call, PartialAccessPath ap,
-    Configuration config
+    PartialPathNodeFwd mid, ParameterPosition ppos, CallContext cc, DataFlowCall call,
+    PartialAccessPath ap, Configuration config
   ) {
-    exists(ArgNode arg |
+    exists(ArgNode arg, ArgumentPosition apos |
       arg = mid.getNodeEx().asNode() and
       cc = mid.getCallContext() and
-      arg.argumentOf(call, i) and
+      arg.argumentOf(call, apos) and
       ap = mid.getAp() and
-      config = mid.getConfiguration()
+      config = mid.getConfiguration() and
+      parameterMatch(ppos, apos)
     )
   }
 
   pragma[nomagic]
   private predicate partialPathIntoCallable0(
-    PartialPathNodeFwd mid, DataFlowCallable callable, int i, CallContext outercc,
+    PartialPathNodeFwd mid, DataFlowCallable callable, ParameterPosition pos, CallContext outercc,
     DataFlowCall call, PartialAccessPath ap, Configuration config
   ) {
-    partialPathIntoArg(mid, i, outercc, call, ap, config) and
+    partialPathIntoArg(mid, pos, outercc, call, ap, config) and
     callable = resolveCall(call, outercc)
   }
 
@@ -4450,9 +4469,9 @@ private module FlowExploration {
     TSummaryCtx1 sc1, TSummaryCtx2 sc2, DataFlowCall call, PartialAccessPath ap,
     Configuration config
   ) {
-    exists(int i, DataFlowCallable callable |
-      partialPathIntoCallable0(mid, callable, i, outercc, call, ap, config) and
-      p.isParameterOf(callable, i) and
+    exists(ParameterPosition pos, DataFlowCallable callable |
+      partialPathIntoCallable0(mid, callable, pos, outercc, call, ap, config) and
+      p.isParameterOf(callable, pos) and
       sc1 = TSummaryCtx1Param(p) and
       sc2 = TSummaryCtx2Some(ap)
     |
@@ -4616,22 +4635,23 @@ private module FlowExploration {
 
   pragma[nomagic]
   private predicate revPartialPathFlowsThrough(
-    int pos, TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2, RevPartialAccessPath ap,
-    Configuration config
+    ArgumentPosition apos, TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2,
+    RevPartialAccessPath ap, Configuration config
   ) {
-    exists(PartialPathNodeRev mid, ParamNodeEx p |
+    exists(PartialPathNodeRev mid, ParamNodeEx p, ParameterPosition ppos |
       mid.getNodeEx() = p and
-      p.getPosition() = pos and
+      p.getPosition() = ppos and
       sc1 = mid.getSummaryCtx1() and
       sc2 = mid.getSummaryCtx2() and
       ap = mid.getAp() and
-      config = mid.getConfiguration()
+      config = mid.getConfiguration() and
+      parameterMatch(ppos, apos)
     )
   }
 
   pragma[nomagic]
   private predicate revPartialPathThroughCallable0(
-    DataFlowCall call, PartialPathNodeRev mid, int pos, RevPartialAccessPath ap,
+    DataFlowCall call, PartialPathNodeRev mid, ArgumentPosition pos, RevPartialAccessPath ap,
     Configuration config
   ) {
     exists(TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2 |
@@ -4644,7 +4664,7 @@ private module FlowExploration {
   private predicate revPartialPathThroughCallable(
     PartialPathNodeRev mid, ArgNodeEx node, RevPartialAccessPath ap, Configuration config
   ) {
-    exists(DataFlowCall call, int pos |
+    exists(DataFlowCall call, ArgumentPosition pos |
       revPartialPathThroughCallable0(call, mid, pos, ap, config) and
       node.asNode().(ArgNode).argumentOf(call, pos)
     )

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

@@ -62,6 +62,18 @@ predicate accessPathCostLimits(int apLimit, int tupleLimit) {
   tupleLimit = 1000
 }
 
+/**
+ * Holds if `arg` is an argument of `call` with an argument position that matches
+ * parameter position `ppos`.
+ */
+pragma[noinline]
+predicate argumentPositionMatch(DataFlowCall call, ArgNode arg, ParameterPosition ppos) {
+  exists(ArgumentPosition apos |
+    arg.argumentOf(call, apos) and
+    parameterMatch(ppos, apos)
+  )
+}
+
 /**
  * Provides a simple data-flow analysis for resolving lambda calls. The analysis
  * currently excludes read-steps, store-steps, and flow-through.
@@ -71,25 +83,27 @@ predicate accessPathCostLimits(int apLimit, int tupleLimit) {
  * calls. For this reason, we cannot reuse the code from `DataFlowImpl.qll` directly.
  */
 private module LambdaFlow {
-  private predicate viableParamNonLambda(DataFlowCall call, int i, ParamNode p) {
-    p.isParameterOf(viableCallable(call), i)
+  pragma[noinline]
+  private predicate viableParamNonLambda(DataFlowCall call, ParameterPosition ppos, ParamNode p) {
+    p.isParameterOf(viableCallable(call), ppos)
   }
 
-  private predicate viableParamLambda(DataFlowCall call, int i, ParamNode p) {
-    p.isParameterOf(viableCallableLambda(call, _), i)
+  pragma[noinline]
+  private predicate viableParamLambda(DataFlowCall call, ParameterPosition ppos, ParamNode p) {
+    p.isParameterOf(viableCallableLambda(call, _), ppos)
   }
 
   private predicate viableParamArgNonLambda(DataFlowCall call, ParamNode p, ArgNode arg) {
-    exists(int i |
-      viableParamNonLambda(call, i, p) and
-      arg.argumentOf(call, i)
+    exists(ParameterPosition ppos |
+      viableParamNonLambda(call, ppos, p) and
+      argumentPositionMatch(call, arg, ppos)
     )
   }
 
   private predicate viableParamArgLambda(DataFlowCall call, ParamNode p, ArgNode arg) {
-    exists(int i |
-      viableParamLambda(call, i, p) and
-      arg.argumentOf(call, i)
+    exists(ParameterPosition ppos |
+      viableParamLambda(call, ppos, p) and
+      argumentPositionMatch(call, arg, ppos)
     )
   }
 
@@ -322,7 +336,7 @@ private module Cached {
     or
     exists(ArgNode arg |
       result.(PostUpdateNode).getPreUpdateNode() = arg and
-      arg.argumentOf(call, k.(ParamUpdateReturnKind).getPosition())
+      arg.argumentOf(call, k.(ParamUpdateReturnKind).getAMatchingArgumentPosition())
     )
   }
 
@@ -330,7 +344,7 @@ private module Cached {
   predicate returnNodeExt(Node n, ReturnKindExt k) {
     k = TValueReturn(n.(ReturnNode).getKind())
     or
-    exists(ParamNode p, int pos |
+    exists(ParamNode p, ParameterPosition pos |
       parameterValueFlowsToPreUpdate(p, n) and
       p.isParameterOf(_, pos) and
       k = TParamUpdate(pos)
@@ -352,11 +366,13 @@ private module Cached {
   }
 
   cached
-  predicate parameterNode(Node p, DataFlowCallable c, int pos) { isParameterNode(p, c, pos) }
+  predicate parameterNode(Node p, DataFlowCallable c, ParameterPosition pos) {
+    isParameterNode(p, c, pos)
+  }
 
   cached
-  predicate argumentNode(Node n, DataFlowCall call, int pos) {
-    n.(ArgumentNode).argumentOf(call, pos)
+  predicate argumentNode(Node n, DataFlowCall call, ArgumentPosition pos) {
+    isArgumentNode(n, call, pos)
   }
 
   /**
@@ -374,12 +390,12 @@ private module Cached {
   }
 
   /**
-   * Holds if `p` is the `i`th parameter of a viable dispatch target of `call`.
-   * The instance parameter is considered to have index `-1`.
+   * Holds if `p` is the parameter of a viable dispatch target of `call`,
+   * and `p` has position `ppos`.
    */
   pragma[nomagic]
-  private predicate viableParam(DataFlowCall call, int i, ParamNode p) {
-    p.isParameterOf(viableCallableExt(call), i)
+  private predicate viableParam(DataFlowCall call, ParameterPosition ppos, ParamNode p) {
+    p.isParameterOf(viableCallableExt(call), ppos)
   }
 
   /**
@@ -388,9 +404,9 @@ private module Cached {
    */
   cached
   predicate viableParamArg(DataFlowCall call, ParamNode p, ArgNode arg) {
-    exists(int i |
-      viableParam(call, i, p) and
-      arg.argumentOf(call, i) and
+    exists(ParameterPosition ppos |
+      viableParam(call, ppos, p) and
+      argumentPositionMatch(call, arg, ppos) and
       compatibleTypes(getNodeDataFlowType(arg), getNodeDataFlowType(p))
     )
   }
@@ -862,7 +878,7 @@ private module Cached {
   cached
   newtype TReturnKindExt =
     TValueReturn(ReturnKind kind) or
-    TParamUpdate(int pos) { exists(ParamNode p | p.isParameterOf(_, pos)) }
+    TParamUpdate(ParameterPosition pos) { exists(ParamNode p | p.isParameterOf(_, pos)) }
 
   cached
   newtype TBooleanOption =
@@ -1054,9 +1070,9 @@ class ParamNode extends Node {
 
   /**
    * Holds if this node is the parameter of callable `c` at the specified
-   * (zero-based) position.
+   * position.
    */
-  predicate isParameterOf(DataFlowCallable c, int i) { parameterNode(this, c, i) }
+  predicate isParameterOf(DataFlowCallable c, ParameterPosition pos) { parameterNode(this, c, pos) }
 }
 
 /** A data-flow node that represents a call argument. */
@@ -1064,7 +1080,9 @@ class ArgNode extends Node {
   ArgNode() { argumentNode(this, _, _) }
 
   /** Holds if this argument occurs at the given position in the given call. */
-  final predicate argumentOf(DataFlowCall call, int pos) { argumentNode(this, call, pos) }
+  final predicate argumentOf(DataFlowCall call, ArgumentPosition pos) {
+    argumentNode(this, call, pos)
+  }
 }
 
 /**
@@ -1110,11 +1128,14 @@ class ValueReturnKind extends ReturnKindExt, TValueReturn {
 }
 
 class ParamUpdateReturnKind extends ReturnKindExt, TParamUpdate {
-  private int pos;
+  private ParameterPosition pos;
 
   ParamUpdateReturnKind() { this = TParamUpdate(pos) }
 
-  int getPosition() { result = pos }
+  ParameterPosition getPosition() { result = pos }
+
+  pragma[nomagic]
+  ArgumentPosition getAMatchingArgumentPosition() { parameterMatch(pos, result) }
 
   override string toString() { result = "param update " + pos }
 }

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

@@ -256,11 +256,11 @@ private class ArgNodeEx extends NodeEx {
 private class ParamNodeEx extends NodeEx {
   ParamNodeEx() { this.asNode() instanceof ParamNode }
 
-  predicate isParameterOf(DataFlowCallable c, int i) {
-    this.asNode().(ParamNode).isParameterOf(c, i)
+  predicate isParameterOf(DataFlowCallable c, ParameterPosition pos) {
+    this.asNode().(ParamNode).isParameterOf(c, pos)
   }
 
-  int getPosition() { this.isParameterOf(_, result) }
+  ParameterPosition getPosition() { this.isParameterOf(_, result) }
 
   predicate allowParameterReturnInSelf() { allowParameterReturnInSelfCached(this.asNode()) }
 }
@@ -1012,6 +1012,9 @@ private module Stage2 {
 
   private predicate flowIntoCall = flowIntoCallNodeCand1/5;
 
+  bindingset[node, ap]
+  private predicate filter(NodeEx node, Ap ap) { any() }
+
   bindingset[ap, contentType]
   private predicate typecheckStore(Ap ap, DataFlowType contentType) { any() }
 
@@ -1020,6 +1023,13 @@ private module Stage2 {
     PrevStage::revFlow(node, _, _, apa, config)
   }
 
+  bindingset[result, apa]
+  private ApApprox unbindApa(ApApprox apa) {
+    exists(ApApprox apa0 |
+      apa = pragma[only_bind_into](apa0) and result = pragma[only_bind_into](apa0)
+    )
+  }
+
   pragma[nomagic]
   private predicate flowThroughOutOfCall(
     DataFlowCall call, CcCall ccc, RetNodeEx ret, NodeEx out, boolean allowsFieldFlow,
@@ -1042,6 +1052,13 @@ private module Stage2 {
    */
   pragma[nomagic]
   predicate fwdFlow(NodeEx node, Cc cc, ApOption argAp, Ap ap, Configuration config) {
+    fwdFlow0(node, cc, argAp, ap, config) and
+    flowCand(node, unbindApa(getApprox(ap)), config) and
+    filter(node, ap)
+  }
+
+  pragma[nomagic]
+  private predicate fwdFlow0(NodeEx node, Cc cc, ApOption argAp, Ap ap, Configuration config) {
     flowCand(node, _, config) and
     sourceNode(node, config) and
     (if hasSourceCallCtx(config) then cc = ccSomeCall() else cc = ccNone()) and
@@ -1112,7 +1129,7 @@ private module Stage2 {
   ) {
     exists(DataFlowType contentType |
       fwdFlow(node1, cc, argAp, ap1, config) and
-      PrevStage::storeStepCand(node1, getApprox(ap1), tc, node2, contentType, config) and
+      PrevStage::storeStepCand(node1, unbindApa(getApprox(ap1)), tc, node2, contentType, config) and
       typecheckStore(ap1, contentType)
     )
   }
@@ -1189,7 +1206,7 @@ private module Stage2 {
   ) {
     exists(ParamNodeEx p |
       fwdFlowIn(call, p, cc, _, argAp, ap, config) and
-      PrevStage::parameterMayFlowThrough(p, _, getApprox(ap), config)
+      PrevStage::parameterMayFlowThrough(p, _, unbindApa(getApprox(ap)), config)
     )
   }
 
@@ -1430,7 +1447,7 @@ private module Stage2 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2125,7 +2142,7 @@ private module Stage3 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2891,7 +2908,7 @@ private module Stage4 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2975,7 +2992,7 @@ private class SummaryCtxSome extends SummaryCtx, TSummaryCtxSome {
 
   SummaryCtxSome() { this = TSummaryCtxSome(p, ap) }
 
-  int getParameterPos() { p.isParameterOf(_, result) }
+  ParameterPosition getParameterPos() { p.isParameterOf(_, result) }
 
   ParamNodeEx getParamNode() { result = p }
 
@@ -3622,39 +3639,40 @@ private predicate pathOutOfCallable(PathNodeMid mid, NodeEx out, CallContext cc)
  */
 pragma[noinline]
 private predicate pathIntoArg(
-  PathNodeMid mid, int i, CallContext cc, DataFlowCall call, AccessPath ap, AccessPathApprox apa,
-  Configuration config
+  PathNodeMid mid, ParameterPosition ppos, CallContext cc, DataFlowCall call, AccessPath ap,
+  AccessPathApprox apa, Configuration config
 ) {
-  exists(ArgNode arg |
+  exists(ArgNode arg, ArgumentPosition apos |
     arg = mid.getNodeEx().asNode() and
     cc = mid.getCallContext() and
-    arg.argumentOf(call, i) and
+    arg.argumentOf(call, apos) and
     ap = mid.getAp() and
     apa = ap.getApprox() and
-    config = mid.getConfiguration()
+    config = mid.getConfiguration() and
+    parameterMatch(ppos, apos)
   )
 }
 
 pragma[nomagic]
 private predicate parameterCand(
-  DataFlowCallable callable, int i, AccessPathApprox apa, Configuration config
+  DataFlowCallable callable, ParameterPosition pos, AccessPathApprox apa, Configuration config
 ) {
   exists(ParamNodeEx p |
     Stage4::revFlow(p, _, _, apa, config) and
-    p.isParameterOf(callable, i)
+    p.isParameterOf(callable, pos)
   )
 }
 
 pragma[nomagic]
 private predicate pathIntoCallable0(
-  PathNodeMid mid, DataFlowCallable callable, int i, CallContext outercc, DataFlowCall call,
-  AccessPath ap, Configuration config
+  PathNodeMid mid, DataFlowCallable callable, ParameterPosition pos, CallContext outercc,
+  DataFlowCall call, AccessPath ap, Configuration config
 ) {
   exists(AccessPathApprox apa |
-    pathIntoArg(mid, pragma[only_bind_into](i), outercc, call, ap, pragma[only_bind_into](apa),
+    pathIntoArg(mid, pragma[only_bind_into](pos), outercc, call, ap, pragma[only_bind_into](apa),
       pragma[only_bind_into](config)) and
     callable = resolveCall(call, outercc) and
-    parameterCand(callable, pragma[only_bind_into](i), pragma[only_bind_into](apa),
+    parameterCand(callable, pragma[only_bind_into](pos), pragma[only_bind_into](apa),
       pragma[only_bind_into](config))
   )
 }
@@ -3669,9 +3687,9 @@ private predicate pathIntoCallable(
   PathNodeMid mid, ParamNodeEx p, CallContext outercc, CallContextCall innercc, SummaryCtx sc,
   DataFlowCall call, Configuration config
 ) {
-  exists(int i, DataFlowCallable callable, AccessPath ap |
-    pathIntoCallable0(mid, callable, i, outercc, call, ap, config) and
-    p.isParameterOf(callable, i) and
+  exists(ParameterPosition pos, DataFlowCallable callable, AccessPath ap |
+    pathIntoCallable0(mid, callable, pos, outercc, call, ap, config) and
+    p.isParameterOf(callable, pos) and
     (
       sc = TSummaryCtxSome(p, ap)
       or
@@ -3695,7 +3713,7 @@ private predicate paramFlowsThrough(
   ReturnKindExt kind, CallContextCall cc, SummaryCtxSome sc, AccessPath ap, AccessPathApprox apa,
   Configuration config
 ) {
-  exists(PathNodeMid mid, RetNodeEx ret, int pos |
+  exists(PathNodeMid mid, RetNodeEx ret, ParameterPosition pos |
     mid.getNodeEx() = ret and
     kind = ret.getKind() and
     cc = mid.getCallContext() and
@@ -4424,24 +4442,25 @@ private module FlowExploration {
 
   pragma[noinline]
   private predicate partialPathIntoArg(
-    PartialPathNodeFwd mid, int i, CallContext cc, DataFlowCall call, PartialAccessPath ap,
-    Configuration config
+    PartialPathNodeFwd mid, ParameterPosition ppos, CallContext cc, DataFlowCall call,
+    PartialAccessPath ap, Configuration config
   ) {
-    exists(ArgNode arg |
+    exists(ArgNode arg, ArgumentPosition apos |
       arg = mid.getNodeEx().asNode() and
       cc = mid.getCallContext() and
-      arg.argumentOf(call, i) and
+      arg.argumentOf(call, apos) and
       ap = mid.getAp() and
-      config = mid.getConfiguration()
+      config = mid.getConfiguration() and
+      parameterMatch(ppos, apos)
     )
   }
 
   pragma[nomagic]
   private predicate partialPathIntoCallable0(
-    PartialPathNodeFwd mid, DataFlowCallable callable, int i, CallContext outercc,
+    PartialPathNodeFwd mid, DataFlowCallable callable, ParameterPosition pos, CallContext outercc,
     DataFlowCall call, PartialAccessPath ap, Configuration config
   ) {
-    partialPathIntoArg(mid, i, outercc, call, ap, config) and
+    partialPathIntoArg(mid, pos, outercc, call, ap, config) and
     callable = resolveCall(call, outercc)
   }
 
@@ -4450,9 +4469,9 @@ private module FlowExploration {
     TSummaryCtx1 sc1, TSummaryCtx2 sc2, DataFlowCall call, PartialAccessPath ap,
     Configuration config
   ) {
-    exists(int i, DataFlowCallable callable |
-      partialPathIntoCallable0(mid, callable, i, outercc, call, ap, config) and
-      p.isParameterOf(callable, i) and
+    exists(ParameterPosition pos, DataFlowCallable callable |
+      partialPathIntoCallable0(mid, callable, pos, outercc, call, ap, config) and
+      p.isParameterOf(callable, pos) and
       sc1 = TSummaryCtx1Param(p) and
       sc2 = TSummaryCtx2Some(ap)
     |
@@ -4616,22 +4635,23 @@ private module FlowExploration {
 
   pragma[nomagic]
   private predicate revPartialPathFlowsThrough(
-    int pos, TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2, RevPartialAccessPath ap,
-    Configuration config
+    ArgumentPosition apos, TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2,
+    RevPartialAccessPath ap, Configuration config
   ) {
-    exists(PartialPathNodeRev mid, ParamNodeEx p |
+    exists(PartialPathNodeRev mid, ParamNodeEx p, ParameterPosition ppos |
       mid.getNodeEx() = p and
-      p.getPosition() = pos and
+      p.getPosition() = ppos and
       sc1 = mid.getSummaryCtx1() and
       sc2 = mid.getSummaryCtx2() and
       ap = mid.getAp() and
-      config = mid.getConfiguration()
+      config = mid.getConfiguration() and
+      parameterMatch(ppos, apos)
     )
   }
 
   pragma[nomagic]
   private predicate revPartialPathThroughCallable0(
-    DataFlowCall call, PartialPathNodeRev mid, int pos, RevPartialAccessPath ap,
+    DataFlowCall call, PartialPathNodeRev mid, ArgumentPosition pos, RevPartialAccessPath ap,
     Configuration config
   ) {
     exists(TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2 |
@@ -4644,7 +4664,7 @@ private module FlowExploration {
   private predicate revPartialPathThroughCallable(
     PartialPathNodeRev mid, ArgNodeEx node, RevPartialAccessPath ap, Configuration config
   ) {
-    exists(DataFlowCall call, int pos |
+    exists(DataFlowCall call, ArgumentPosition pos |
       revPartialPathThroughCallable0(call, mid, pos, ap, config) and
       node.asNode().(ArgNode).argumentOf(call, pos)
     )

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

@@ -8,7 +8,14 @@ private import DataFlowImplConsistency
 DataFlowCallable nodeGetEnclosingCallable(Node n) { result = n.getEnclosingCallable() }
 
 /** Holds if `p` is a `ParameterNode` of `c` with position `pos`. */
-predicate isParameterNode(ParameterNode p, DataFlowCallable c, int pos) { p.isParameterOf(c, pos) }
+predicate isParameterNode(ParameterNode p, DataFlowCallable c, ParameterPosition pos) {
+  p.isParameterOf(c, pos)
+}
+
+/** Holds if `arg` is an `ArgumentNode` of `c` with position `pos`. */
+predicate isArgumentNode(ArgumentNode arg, DataFlowCall c, ArgumentPosition pos) {
+  arg.argumentOf(c, pos)
+}
 
 /** Gets the instance argument of a non-static call. */
 private Node getInstanceArgument(Call call) {

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

@@ -2,6 +2,7 @@ private import cpp
 private import semmle.code.cpp.ir.IR
 private import semmle.code.cpp.ir.dataflow.DataFlow
 private import semmle.code.cpp.ir.dataflow.internal.DataFlowPrivate
+private import semmle.code.cpp.ir.dataflow.internal.DataFlowUtil
 private import DataFlowImplCommon as DataFlowImplCommon
 
 /**
@@ -266,3 +267,17 @@ Function viableImplInCallContext(CallInstruction call, CallInstruction ctx) {
     result = ctx.getArgument(i).getUnconvertedResultExpression().(FunctionAccess).getTarget()
   )
 }
+
+/** A parameter position represented by an integer. */
+class ParameterPosition extends int {
+  ParameterPosition() { any(ParameterNode p).isParameterOf(_, this) }
+}
+
+/** An argument position represented by an integer. */
+class ArgumentPosition extends int {
+  ArgumentPosition() { any(ArgumentNode a).argumentOf(_, this) }
+}
+
+/** Holds if arguments at position `apos` match parameters at position `ppos`. */
+pragma[inline]
+predicate parameterMatch(ParameterPosition ppos, ArgumentPosition apos) { ppos = apos }

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

@@ -256,11 +256,11 @@ private class ArgNodeEx extends NodeEx {
 private class ParamNodeEx extends NodeEx {
   ParamNodeEx() { this.asNode() instanceof ParamNode }
 
-  predicate isParameterOf(DataFlowCallable c, int i) {
-    this.asNode().(ParamNode).isParameterOf(c, i)
+  predicate isParameterOf(DataFlowCallable c, ParameterPosition pos) {
+    this.asNode().(ParamNode).isParameterOf(c, pos)
   }
 
-  int getPosition() { this.isParameterOf(_, result) }
+  ParameterPosition getPosition() { this.isParameterOf(_, result) }
 
   predicate allowParameterReturnInSelf() { allowParameterReturnInSelfCached(this.asNode()) }
 }
@@ -1012,6 +1012,9 @@ private module Stage2 {
 
   private predicate flowIntoCall = flowIntoCallNodeCand1/5;
 
+  bindingset[node, ap]
+  private predicate filter(NodeEx node, Ap ap) { any() }
+
   bindingset[ap, contentType]
   private predicate typecheckStore(Ap ap, DataFlowType contentType) { any() }
 
@@ -1020,6 +1023,13 @@ private module Stage2 {
     PrevStage::revFlow(node, _, _, apa, config)
   }
 
+  bindingset[result, apa]
+  private ApApprox unbindApa(ApApprox apa) {
+    exists(ApApprox apa0 |
+      apa = pragma[only_bind_into](apa0) and result = pragma[only_bind_into](apa0)
+    )
+  }
+
   pragma[nomagic]
   private predicate flowThroughOutOfCall(
     DataFlowCall call, CcCall ccc, RetNodeEx ret, NodeEx out, boolean allowsFieldFlow,
@@ -1042,6 +1052,13 @@ private module Stage2 {
    */
   pragma[nomagic]
   predicate fwdFlow(NodeEx node, Cc cc, ApOption argAp, Ap ap, Configuration config) {
+    fwdFlow0(node, cc, argAp, ap, config) and
+    flowCand(node, unbindApa(getApprox(ap)), config) and
+    filter(node, ap)
+  }
+
+  pragma[nomagic]
+  private predicate fwdFlow0(NodeEx node, Cc cc, ApOption argAp, Ap ap, Configuration config) {
     flowCand(node, _, config) and
     sourceNode(node, config) and
     (if hasSourceCallCtx(config) then cc = ccSomeCall() else cc = ccNone()) and
@@ -1112,7 +1129,7 @@ private module Stage2 {
   ) {
     exists(DataFlowType contentType |
       fwdFlow(node1, cc, argAp, ap1, config) and
-      PrevStage::storeStepCand(node1, getApprox(ap1), tc, node2, contentType, config) and
+      PrevStage::storeStepCand(node1, unbindApa(getApprox(ap1)), tc, node2, contentType, config) and
       typecheckStore(ap1, contentType)
     )
   }
@@ -1189,7 +1206,7 @@ private module Stage2 {
   ) {
     exists(ParamNodeEx p |
       fwdFlowIn(call, p, cc, _, argAp, ap, config) and
-      PrevStage::parameterMayFlowThrough(p, _, getApprox(ap), config)
+      PrevStage::parameterMayFlowThrough(p, _, unbindApa(getApprox(ap)), config)
     )
   }
 
@@ -1430,7 +1447,7 @@ private module Stage2 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2125,7 +2142,7 @@ private module Stage3 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2891,7 +2908,7 @@ private module Stage4 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2975,7 +2992,7 @@ private class SummaryCtxSome extends SummaryCtx, TSummaryCtxSome {
 
   SummaryCtxSome() { this = TSummaryCtxSome(p, ap) }
 
-  int getParameterPos() { p.isParameterOf(_, result) }
+  ParameterPosition getParameterPos() { p.isParameterOf(_, result) }
 
   ParamNodeEx getParamNode() { result = p }
 
@@ -3622,39 +3639,40 @@ private predicate pathOutOfCallable(PathNodeMid mid, NodeEx out, CallContext cc)
  */
 pragma[noinline]
 private predicate pathIntoArg(
-  PathNodeMid mid, int i, CallContext cc, DataFlowCall call, AccessPath ap, AccessPathApprox apa,
-  Configuration config
+  PathNodeMid mid, ParameterPosition ppos, CallContext cc, DataFlowCall call, AccessPath ap,
+  AccessPathApprox apa, Configuration config
 ) {
-  exists(ArgNode arg |
+  exists(ArgNode arg, ArgumentPosition apos |
     arg = mid.getNodeEx().asNode() and
     cc = mid.getCallContext() and
-    arg.argumentOf(call, i) and
+    arg.argumentOf(call, apos) and
     ap = mid.getAp() and
     apa = ap.getApprox() and
-    config = mid.getConfiguration()
+    config = mid.getConfiguration() and
+    parameterMatch(ppos, apos)
   )
 }
 
 pragma[nomagic]
 private predicate parameterCand(
-  DataFlowCallable callable, int i, AccessPathApprox apa, Configuration config
+  DataFlowCallable callable, ParameterPosition pos, AccessPathApprox apa, Configuration config
 ) {
   exists(ParamNodeEx p |
     Stage4::revFlow(p, _, _, apa, config) and
-    p.isParameterOf(callable, i)
+    p.isParameterOf(callable, pos)
   )
 }
 
 pragma[nomagic]
 private predicate pathIntoCallable0(
-  PathNodeMid mid, DataFlowCallable callable, int i, CallContext outercc, DataFlowCall call,
-  AccessPath ap, Configuration config
+  PathNodeMid mid, DataFlowCallable callable, ParameterPosition pos, CallContext outercc,
+  DataFlowCall call, AccessPath ap, Configuration config
 ) {
   exists(AccessPathApprox apa |
-    pathIntoArg(mid, pragma[only_bind_into](i), outercc, call, ap, pragma[only_bind_into](apa),
+    pathIntoArg(mid, pragma[only_bind_into](pos), outercc, call, ap, pragma[only_bind_into](apa),
       pragma[only_bind_into](config)) and
     callable = resolveCall(call, outercc) and
-    parameterCand(callable, pragma[only_bind_into](i), pragma[only_bind_into](apa),
+    parameterCand(callable, pragma[only_bind_into](pos), pragma[only_bind_into](apa),
       pragma[only_bind_into](config))
   )
 }
@@ -3669,9 +3687,9 @@ private predicate pathIntoCallable(
   PathNodeMid mid, ParamNodeEx p, CallContext outercc, CallContextCall innercc, SummaryCtx sc,
   DataFlowCall call, Configuration config
 ) {
-  exists(int i, DataFlowCallable callable, AccessPath ap |
-    pathIntoCallable0(mid, callable, i, outercc, call, ap, config) and
-    p.isParameterOf(callable, i) and
+  exists(ParameterPosition pos, DataFlowCallable callable, AccessPath ap |
+    pathIntoCallable0(mid, callable, pos, outercc, call, ap, config) and
+    p.isParameterOf(callable, pos) and
     (
       sc = TSummaryCtxSome(p, ap)
       or
@@ -3695,7 +3713,7 @@ private predicate paramFlowsThrough(
   ReturnKindExt kind, CallContextCall cc, SummaryCtxSome sc, AccessPath ap, AccessPathApprox apa,
   Configuration config
 ) {
-  exists(PathNodeMid mid, RetNodeEx ret, int pos |
+  exists(PathNodeMid mid, RetNodeEx ret, ParameterPosition pos |
     mid.getNodeEx() = ret and
     kind = ret.getKind() and
     cc = mid.getCallContext() and
@@ -4424,24 +4442,25 @@ private module FlowExploration {
 
   pragma[noinline]
   private predicate partialPathIntoArg(
-    PartialPathNodeFwd mid, int i, CallContext cc, DataFlowCall call, PartialAccessPath ap,
-    Configuration config
+    PartialPathNodeFwd mid, ParameterPosition ppos, CallContext cc, DataFlowCall call,
+    PartialAccessPath ap, Configuration config
   ) {
-    exists(ArgNode arg |
+    exists(ArgNode arg, ArgumentPosition apos |
       arg = mid.getNodeEx().asNode() and
       cc = mid.getCallContext() and
-      arg.argumentOf(call, i) and
+      arg.argumentOf(call, apos) and
       ap = mid.getAp() and
-      config = mid.getConfiguration()
+      config = mid.getConfiguration() and
+      parameterMatch(ppos, apos)
     )
   }
 
   pragma[nomagic]
   private predicate partialPathIntoCallable0(
-    PartialPathNodeFwd mid, DataFlowCallable callable, int i, CallContext outercc,
+    PartialPathNodeFwd mid, DataFlowCallable callable, ParameterPosition pos, CallContext outercc,
     DataFlowCall call, PartialAccessPath ap, Configuration config
   ) {
-    partialPathIntoArg(mid, i, outercc, call, ap, config) and
+    partialPathIntoArg(mid, pos, outercc, call, ap, config) and
     callable = resolveCall(call, outercc)
   }
 
@@ -4450,9 +4469,9 @@ private module FlowExploration {
     TSummaryCtx1 sc1, TSummaryCtx2 sc2, DataFlowCall call, PartialAccessPath ap,
     Configuration config
   ) {
-    exists(int i, DataFlowCallable callable |
-      partialPathIntoCallable0(mid, callable, i, outercc, call, ap, config) and
-      p.isParameterOf(callable, i) and
+    exists(ParameterPosition pos, DataFlowCallable callable |
+      partialPathIntoCallable0(mid, callable, pos, outercc, call, ap, config) and
+      p.isParameterOf(callable, pos) and
       sc1 = TSummaryCtx1Param(p) and
       sc2 = TSummaryCtx2Some(ap)
     |
@@ -4616,22 +4635,23 @@ private module FlowExploration {
 
   pragma[nomagic]
   private predicate revPartialPathFlowsThrough(
-    int pos, TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2, RevPartialAccessPath ap,
-    Configuration config
+    ArgumentPosition apos, TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2,
+    RevPartialAccessPath ap, Configuration config
   ) {
-    exists(PartialPathNodeRev mid, ParamNodeEx p |
+    exists(PartialPathNodeRev mid, ParamNodeEx p, ParameterPosition ppos |
       mid.getNodeEx() = p and
-      p.getPosition() = pos and
+      p.getPosition() = ppos and
       sc1 = mid.getSummaryCtx1() and
       sc2 = mid.getSummaryCtx2() and
       ap = mid.getAp() and
-      config = mid.getConfiguration()
+      config = mid.getConfiguration() and
+      parameterMatch(ppos, apos)
     )
   }
 
   pragma[nomagic]
   private predicate revPartialPathThroughCallable0(
-    DataFlowCall call, PartialPathNodeRev mid, int pos, RevPartialAccessPath ap,
+    DataFlowCall call, PartialPathNodeRev mid, ArgumentPosition pos, RevPartialAccessPath ap,
     Configuration config
   ) {
     exists(TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2 |
@@ -4644,7 +4664,7 @@ private module FlowExploration {
   private predicate revPartialPathThroughCallable(
     PartialPathNodeRev mid, ArgNodeEx node, RevPartialAccessPath ap, Configuration config
   ) {
-    exists(DataFlowCall call, int pos |
+    exists(DataFlowCall call, ArgumentPosition pos |
       revPartialPathThroughCallable0(call, mid, pos, ap, config) and
       node.asNode().(ArgNode).argumentOf(call, pos)
     )

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

@@ -256,11 +256,11 @@ private class ArgNodeEx extends NodeEx {
 private class ParamNodeEx extends NodeEx {
   ParamNodeEx() { this.asNode() instanceof ParamNode }
 
-  predicate isParameterOf(DataFlowCallable c, int i) {
-    this.asNode().(ParamNode).isParameterOf(c, i)
+  predicate isParameterOf(DataFlowCallable c, ParameterPosition pos) {
+    this.asNode().(ParamNode).isParameterOf(c, pos)
   }
 
-  int getPosition() { this.isParameterOf(_, result) }
+  ParameterPosition getPosition() { this.isParameterOf(_, result) }
 
   predicate allowParameterReturnInSelf() { allowParameterReturnInSelfCached(this.asNode()) }
 }
@@ -1012,6 +1012,9 @@ private module Stage2 {
 
   private predicate flowIntoCall = flowIntoCallNodeCand1/5;
 
+  bindingset[node, ap]
+  private predicate filter(NodeEx node, Ap ap) { any() }
+
   bindingset[ap, contentType]
   private predicate typecheckStore(Ap ap, DataFlowType contentType) { any() }
 
@@ -1020,6 +1023,13 @@ private module Stage2 {
     PrevStage::revFlow(node, _, _, apa, config)
   }
 
+  bindingset[result, apa]
+  private ApApprox unbindApa(ApApprox apa) {
+    exists(ApApprox apa0 |
+      apa = pragma[only_bind_into](apa0) and result = pragma[only_bind_into](apa0)
+    )
+  }
+
   pragma[nomagic]
   private predicate flowThroughOutOfCall(
     DataFlowCall call, CcCall ccc, RetNodeEx ret, NodeEx out, boolean allowsFieldFlow,
@@ -1042,6 +1052,13 @@ private module Stage2 {
    */
   pragma[nomagic]
   predicate fwdFlow(NodeEx node, Cc cc, ApOption argAp, Ap ap, Configuration config) {
+    fwdFlow0(node, cc, argAp, ap, config) and
+    flowCand(node, unbindApa(getApprox(ap)), config) and
+    filter(node, ap)
+  }
+
+  pragma[nomagic]
+  private predicate fwdFlow0(NodeEx node, Cc cc, ApOption argAp, Ap ap, Configuration config) {
     flowCand(node, _, config) and
     sourceNode(node, config) and
     (if hasSourceCallCtx(config) then cc = ccSomeCall() else cc = ccNone()) and
@@ -1112,7 +1129,7 @@ private module Stage2 {
   ) {
     exists(DataFlowType contentType |
       fwdFlow(node1, cc, argAp, ap1, config) and
-      PrevStage::storeStepCand(node1, getApprox(ap1), tc, node2, contentType, config) and
+      PrevStage::storeStepCand(node1, unbindApa(getApprox(ap1)), tc, node2, contentType, config) and
       typecheckStore(ap1, contentType)
     )
   }
@@ -1189,7 +1206,7 @@ private module Stage2 {
   ) {
     exists(ParamNodeEx p |
       fwdFlowIn(call, p, cc, _, argAp, ap, config) and
-      PrevStage::parameterMayFlowThrough(p, _, getApprox(ap), config)
+      PrevStage::parameterMayFlowThrough(p, _, unbindApa(getApprox(ap)), config)
     )
   }
 
@@ -1430,7 +1447,7 @@ private module Stage2 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2125,7 +2142,7 @@ private module Stage3 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2891,7 +2908,7 @@ private module Stage4 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2975,7 +2992,7 @@ private class SummaryCtxSome extends SummaryCtx, TSummaryCtxSome {
 
   SummaryCtxSome() { this = TSummaryCtxSome(p, ap) }
 
-  int getParameterPos() { p.isParameterOf(_, result) }
+  ParameterPosition getParameterPos() { p.isParameterOf(_, result) }
 
   ParamNodeEx getParamNode() { result = p }
 
@@ -3622,39 +3639,40 @@ private predicate pathOutOfCallable(PathNodeMid mid, NodeEx out, CallContext cc)
  */
 pragma[noinline]
 private predicate pathIntoArg(
-  PathNodeMid mid, int i, CallContext cc, DataFlowCall call, AccessPath ap, AccessPathApprox apa,
-  Configuration config
+  PathNodeMid mid, ParameterPosition ppos, CallContext cc, DataFlowCall call, AccessPath ap,
+  AccessPathApprox apa, Configuration config
 ) {
-  exists(ArgNode arg |
+  exists(ArgNode arg, ArgumentPosition apos |
     arg = mid.getNodeEx().asNode() and
     cc = mid.getCallContext() and
-    arg.argumentOf(call, i) and
+    arg.argumentOf(call, apos) and
     ap = mid.getAp() and
     apa = ap.getApprox() and
-    config = mid.getConfiguration()
+    config = mid.getConfiguration() and
+    parameterMatch(ppos, apos)
   )
 }
 
 pragma[nomagic]
 private predicate parameterCand(
-  DataFlowCallable callable, int i, AccessPathApprox apa, Configuration config
+  DataFlowCallable callable, ParameterPosition pos, AccessPathApprox apa, Configuration config
 ) {
   exists(ParamNodeEx p |
     Stage4::revFlow(p, _, _, apa, config) and
-    p.isParameterOf(callable, i)
+    p.isParameterOf(callable, pos)
   )
 }
 
 pragma[nomagic]
 private predicate pathIntoCallable0(
-  PathNodeMid mid, DataFlowCallable callable, int i, CallContext outercc, DataFlowCall call,
-  AccessPath ap, Configuration config
+  PathNodeMid mid, DataFlowCallable callable, ParameterPosition pos, CallContext outercc,
+  DataFlowCall call, AccessPath ap, Configuration config
 ) {
   exists(AccessPathApprox apa |
-    pathIntoArg(mid, pragma[only_bind_into](i), outercc, call, ap, pragma[only_bind_into](apa),
+    pathIntoArg(mid, pragma[only_bind_into](pos), outercc, call, ap, pragma[only_bind_into](apa),
       pragma[only_bind_into](config)) and
     callable = resolveCall(call, outercc) and
-    parameterCand(callable, pragma[only_bind_into](i), pragma[only_bind_into](apa),
+    parameterCand(callable, pragma[only_bind_into](pos), pragma[only_bind_into](apa),
       pragma[only_bind_into](config))
   )
 }
@@ -3669,9 +3687,9 @@ private predicate pathIntoCallable(
   PathNodeMid mid, ParamNodeEx p, CallContext outercc, CallContextCall innercc, SummaryCtx sc,
   DataFlowCall call, Configuration config
 ) {
-  exists(int i, DataFlowCallable callable, AccessPath ap |
-    pathIntoCallable0(mid, callable, i, outercc, call, ap, config) and
-    p.isParameterOf(callable, i) and
+  exists(ParameterPosition pos, DataFlowCallable callable, AccessPath ap |
+    pathIntoCallable0(mid, callable, pos, outercc, call, ap, config) and
+    p.isParameterOf(callable, pos) and
     (
       sc = TSummaryCtxSome(p, ap)
       or
@@ -3695,7 +3713,7 @@ private predicate paramFlowsThrough(
   ReturnKindExt kind, CallContextCall cc, SummaryCtxSome sc, AccessPath ap, AccessPathApprox apa,
   Configuration config
 ) {
-  exists(PathNodeMid mid, RetNodeEx ret, int pos |
+  exists(PathNodeMid mid, RetNodeEx ret, ParameterPosition pos |
     mid.getNodeEx() = ret and
     kind = ret.getKind() and
     cc = mid.getCallContext() and
@@ -4424,24 +4442,25 @@ private module FlowExploration {
 
   pragma[noinline]
   private predicate partialPathIntoArg(
-    PartialPathNodeFwd mid, int i, CallContext cc, DataFlowCall call, PartialAccessPath ap,
-    Configuration config
+    PartialPathNodeFwd mid, ParameterPosition ppos, CallContext cc, DataFlowCall call,
+    PartialAccessPath ap, Configuration config
   ) {
-    exists(ArgNode arg |
+    exists(ArgNode arg, ArgumentPosition apos |
       arg = mid.getNodeEx().asNode() and
       cc = mid.getCallContext() and
-      arg.argumentOf(call, i) and
+      arg.argumentOf(call, apos) and
       ap = mid.getAp() and
-      config = mid.getConfiguration()
+      config = mid.getConfiguration() and
+      parameterMatch(ppos, apos)
     )
   }
 
   pragma[nomagic]
   private predicate partialPathIntoCallable0(
-    PartialPathNodeFwd mid, DataFlowCallable callable, int i, CallContext outercc,
+    PartialPathNodeFwd mid, DataFlowCallable callable, ParameterPosition pos, CallContext outercc,
     DataFlowCall call, PartialAccessPath ap, Configuration config
   ) {
-    partialPathIntoArg(mid, i, outercc, call, ap, config) and
+    partialPathIntoArg(mid, pos, outercc, call, ap, config) and
     callable = resolveCall(call, outercc)
   }
 
@@ -4450,9 +4469,9 @@ private module FlowExploration {
     TSummaryCtx1 sc1, TSummaryCtx2 sc2, DataFlowCall call, PartialAccessPath ap,
     Configuration config
   ) {
-    exists(int i, DataFlowCallable callable |
-      partialPathIntoCallable0(mid, callable, i, outercc, call, ap, config) and
-      p.isParameterOf(callable, i) and
+    exists(ParameterPosition pos, DataFlowCallable callable |
+      partialPathIntoCallable0(mid, callable, pos, outercc, call, ap, config) and
+      p.isParameterOf(callable, pos) and
       sc1 = TSummaryCtx1Param(p) and
       sc2 = TSummaryCtx2Some(ap)
     |
@@ -4616,22 +4635,23 @@ private module FlowExploration {
 
   pragma[nomagic]
   private predicate revPartialPathFlowsThrough(
-    int pos, TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2, RevPartialAccessPath ap,
-    Configuration config
+    ArgumentPosition apos, TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2,
+    RevPartialAccessPath ap, Configuration config
   ) {
-    exists(PartialPathNodeRev mid, ParamNodeEx p |
+    exists(PartialPathNodeRev mid, ParamNodeEx p, ParameterPosition ppos |
       mid.getNodeEx() = p and
-      p.getPosition() = pos and
+      p.getPosition() = ppos and
       sc1 = mid.getSummaryCtx1() and
       sc2 = mid.getSummaryCtx2() and
       ap = mid.getAp() and
-      config = mid.getConfiguration()
+      config = mid.getConfiguration() and
+      parameterMatch(ppos, apos)
     )
   }
 
   pragma[nomagic]
   private predicate revPartialPathThroughCallable0(
-    DataFlowCall call, PartialPathNodeRev mid, int pos, RevPartialAccessPath ap,
+    DataFlowCall call, PartialPathNodeRev mid, ArgumentPosition pos, RevPartialAccessPath ap,
     Configuration config
   ) {
     exists(TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2 |
@@ -4644,7 +4664,7 @@ private module FlowExploration {
   private predicate revPartialPathThroughCallable(
     PartialPathNodeRev mid, ArgNodeEx node, RevPartialAccessPath ap, Configuration config
   ) {
-    exists(DataFlowCall call, int pos |
+    exists(DataFlowCall call, ArgumentPosition pos |
       revPartialPathThroughCallable0(call, mid, pos, ap, config) and
       node.asNode().(ArgNode).argumentOf(call, pos)
     )

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

@@ -256,11 +256,11 @@ private class ArgNodeEx extends NodeEx {
 private class ParamNodeEx extends NodeEx {
   ParamNodeEx() { this.asNode() instanceof ParamNode }
 
-  predicate isParameterOf(DataFlowCallable c, int i) {
-    this.asNode().(ParamNode).isParameterOf(c, i)
+  predicate isParameterOf(DataFlowCallable c, ParameterPosition pos) {
+    this.asNode().(ParamNode).isParameterOf(c, pos)
   }
 
-  int getPosition() { this.isParameterOf(_, result) }
+  ParameterPosition getPosition() { this.isParameterOf(_, result) }
 
   predicate allowParameterReturnInSelf() { allowParameterReturnInSelfCached(this.asNode()) }
 }
@@ -1012,6 +1012,9 @@ private module Stage2 {
 
   private predicate flowIntoCall = flowIntoCallNodeCand1/5;
 
+  bindingset[node, ap]
+  private predicate filter(NodeEx node, Ap ap) { any() }
+
   bindingset[ap, contentType]
   private predicate typecheckStore(Ap ap, DataFlowType contentType) { any() }
 
@@ -1020,6 +1023,13 @@ private module Stage2 {
     PrevStage::revFlow(node, _, _, apa, config)
   }
 
+  bindingset[result, apa]
+  private ApApprox unbindApa(ApApprox apa) {
+    exists(ApApprox apa0 |
+      apa = pragma[only_bind_into](apa0) and result = pragma[only_bind_into](apa0)
+    )
+  }
+
   pragma[nomagic]
   private predicate flowThroughOutOfCall(
     DataFlowCall call, CcCall ccc, RetNodeEx ret, NodeEx out, boolean allowsFieldFlow,
@@ -1042,6 +1052,13 @@ private module Stage2 {
    */
   pragma[nomagic]
   predicate fwdFlow(NodeEx node, Cc cc, ApOption argAp, Ap ap, Configuration config) {
+    fwdFlow0(node, cc, argAp, ap, config) and
+    flowCand(node, unbindApa(getApprox(ap)), config) and
+    filter(node, ap)
+  }
+
+  pragma[nomagic]
+  private predicate fwdFlow0(NodeEx node, Cc cc, ApOption argAp, Ap ap, Configuration config) {
     flowCand(node, _, config) and
     sourceNode(node, config) and
     (if hasSourceCallCtx(config) then cc = ccSomeCall() else cc = ccNone()) and
@@ -1112,7 +1129,7 @@ private module Stage2 {
   ) {
     exists(DataFlowType contentType |
       fwdFlow(node1, cc, argAp, ap1, config) and
-      PrevStage::storeStepCand(node1, getApprox(ap1), tc, node2, contentType, config) and
+      PrevStage::storeStepCand(node1, unbindApa(getApprox(ap1)), tc, node2, contentType, config) and
       typecheckStore(ap1, contentType)
     )
   }
@@ -1189,7 +1206,7 @@ private module Stage2 {
   ) {
     exists(ParamNodeEx p |
       fwdFlowIn(call, p, cc, _, argAp, ap, config) and
-      PrevStage::parameterMayFlowThrough(p, _, getApprox(ap), config)
+      PrevStage::parameterMayFlowThrough(p, _, unbindApa(getApprox(ap)), config)
     )
   }
 
@@ -1430,7 +1447,7 @@ private module Stage2 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2125,7 +2142,7 @@ private module Stage3 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2891,7 +2908,7 @@ private module Stage4 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2975,7 +2992,7 @@ private class SummaryCtxSome extends SummaryCtx, TSummaryCtxSome {
 
   SummaryCtxSome() { this = TSummaryCtxSome(p, ap) }
 
-  int getParameterPos() { p.isParameterOf(_, result) }
+  ParameterPosition getParameterPos() { p.isParameterOf(_, result) }
 
   ParamNodeEx getParamNode() { result = p }
 
@@ -3622,39 +3639,40 @@ private predicate pathOutOfCallable(PathNodeMid mid, NodeEx out, CallContext cc)
  */
 pragma[noinline]
 private predicate pathIntoArg(
-  PathNodeMid mid, int i, CallContext cc, DataFlowCall call, AccessPath ap, AccessPathApprox apa,
-  Configuration config
+  PathNodeMid mid, ParameterPosition ppos, CallContext cc, DataFlowCall call, AccessPath ap,
+  AccessPathApprox apa, Configuration config
 ) {
-  exists(ArgNode arg |
+  exists(ArgNode arg, ArgumentPosition apos |
     arg = mid.getNodeEx().asNode() and
     cc = mid.getCallContext() and
-    arg.argumentOf(call, i) and
+    arg.argumentOf(call, apos) and
     ap = mid.getAp() and
     apa = ap.getApprox() and
-    config = mid.getConfiguration()
+    config = mid.getConfiguration() and
+    parameterMatch(ppos, apos)
   )
 }
 
 pragma[nomagic]
 private predicate parameterCand(
-  DataFlowCallable callable, int i, AccessPathApprox apa, Configuration config
+  DataFlowCallable callable, ParameterPosition pos, AccessPathApprox apa, Configuration config
 ) {
   exists(ParamNodeEx p |
     Stage4::revFlow(p, _, _, apa, config) and
-    p.isParameterOf(callable, i)
+    p.isParameterOf(callable, pos)
   )
 }
 
 pragma[nomagic]
 private predicate pathIntoCallable0(
-  PathNodeMid mid, DataFlowCallable callable, int i, CallContext outercc, DataFlowCall call,
-  AccessPath ap, Configuration config
+  PathNodeMid mid, DataFlowCallable callable, ParameterPosition pos, CallContext outercc,
+  DataFlowCall call, AccessPath ap, Configuration config
 ) {
   exists(AccessPathApprox apa |
-    pathIntoArg(mid, pragma[only_bind_into](i), outercc, call, ap, pragma[only_bind_into](apa),
+    pathIntoArg(mid, pragma[only_bind_into](pos), outercc, call, ap, pragma[only_bind_into](apa),
       pragma[only_bind_into](config)) and
     callable = resolveCall(call, outercc) and
-    parameterCand(callable, pragma[only_bind_into](i), pragma[only_bind_into](apa),
+    parameterCand(callable, pragma[only_bind_into](pos), pragma[only_bind_into](apa),
       pragma[only_bind_into](config))
   )
 }
@@ -3669,9 +3687,9 @@ private predicate pathIntoCallable(
   PathNodeMid mid, ParamNodeEx p, CallContext outercc, CallContextCall innercc, SummaryCtx sc,
   DataFlowCall call, Configuration config
 ) {
-  exists(int i, DataFlowCallable callable, AccessPath ap |
-    pathIntoCallable0(mid, callable, i, outercc, call, ap, config) and
-    p.isParameterOf(callable, i) and
+  exists(ParameterPosition pos, DataFlowCallable callable, AccessPath ap |
+    pathIntoCallable0(mid, callable, pos, outercc, call, ap, config) and
+    p.isParameterOf(callable, pos) and
     (
       sc = TSummaryCtxSome(p, ap)
       or
@@ -3695,7 +3713,7 @@ private predicate paramFlowsThrough(
   ReturnKindExt kind, CallContextCall cc, SummaryCtxSome sc, AccessPath ap, AccessPathApprox apa,
   Configuration config
 ) {
-  exists(PathNodeMid mid, RetNodeEx ret, int pos |
+  exists(PathNodeMid mid, RetNodeEx ret, ParameterPosition pos |
     mid.getNodeEx() = ret and
     kind = ret.getKind() and
     cc = mid.getCallContext() and
@@ -4424,24 +4442,25 @@ private module FlowExploration {
 
   pragma[noinline]
   private predicate partialPathIntoArg(
-    PartialPathNodeFwd mid, int i, CallContext cc, DataFlowCall call, PartialAccessPath ap,
-    Configuration config
+    PartialPathNodeFwd mid, ParameterPosition ppos, CallContext cc, DataFlowCall call,
+    PartialAccessPath ap, Configuration config
   ) {
-    exists(ArgNode arg |
+    exists(ArgNode arg, ArgumentPosition apos |
       arg = mid.getNodeEx().asNode() and
       cc = mid.getCallContext() and
-      arg.argumentOf(call, i) and
+      arg.argumentOf(call, apos) and
       ap = mid.getAp() and
-      config = mid.getConfiguration()
+      config = mid.getConfiguration() and
+      parameterMatch(ppos, apos)
     )
   }
 
   pragma[nomagic]
   private predicate partialPathIntoCallable0(
-    PartialPathNodeFwd mid, DataFlowCallable callable, int i, CallContext outercc,
+    PartialPathNodeFwd mid, DataFlowCallable callable, ParameterPosition pos, CallContext outercc,
     DataFlowCall call, PartialAccessPath ap, Configuration config
   ) {
-    partialPathIntoArg(mid, i, outercc, call, ap, config) and
+    partialPathIntoArg(mid, pos, outercc, call, ap, config) and
     callable = resolveCall(call, outercc)
   }
 
@@ -4450,9 +4469,9 @@ private module FlowExploration {
     TSummaryCtx1 sc1, TSummaryCtx2 sc2, DataFlowCall call, PartialAccessPath ap,
     Configuration config
   ) {
-    exists(int i, DataFlowCallable callable |
-      partialPathIntoCallable0(mid, callable, i, outercc, call, ap, config) and
-      p.isParameterOf(callable, i) and
+    exists(ParameterPosition pos, DataFlowCallable callable |
+      partialPathIntoCallable0(mid, callable, pos, outercc, call, ap, config) and
+      p.isParameterOf(callable, pos) and
       sc1 = TSummaryCtx1Param(p) and
       sc2 = TSummaryCtx2Some(ap)
     |
@@ -4616,22 +4635,23 @@ private module FlowExploration {
 
   pragma[nomagic]
   private predicate revPartialPathFlowsThrough(
-    int pos, TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2, RevPartialAccessPath ap,
-    Configuration config
+    ArgumentPosition apos, TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2,
+    RevPartialAccessPath ap, Configuration config
   ) {
-    exists(PartialPathNodeRev mid, ParamNodeEx p |
+    exists(PartialPathNodeRev mid, ParamNodeEx p, ParameterPosition ppos |
       mid.getNodeEx() = p and
-      p.getPosition() = pos and
+      p.getPosition() = ppos and
       sc1 = mid.getSummaryCtx1() and
       sc2 = mid.getSummaryCtx2() and
       ap = mid.getAp() and
-      config = mid.getConfiguration()
+      config = mid.getConfiguration() and
+      parameterMatch(ppos, apos)
     )
   }
 
   pragma[nomagic]
   private predicate revPartialPathThroughCallable0(
-    DataFlowCall call, PartialPathNodeRev mid, int pos, RevPartialAccessPath ap,
+    DataFlowCall call, PartialPathNodeRev mid, ArgumentPosition pos, RevPartialAccessPath ap,
     Configuration config
   ) {
     exists(TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2 |
@@ -4644,7 +4664,7 @@ private module FlowExploration {
   private predicate revPartialPathThroughCallable(
     PartialPathNodeRev mid, ArgNodeEx node, RevPartialAccessPath ap, Configuration config
   ) {
-    exists(DataFlowCall call, int pos |
+    exists(DataFlowCall call, ArgumentPosition pos |
       revPartialPathThroughCallable0(call, mid, pos, ap, config) and
       node.asNode().(ArgNode).argumentOf(call, pos)
     )

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

@@ -256,11 +256,11 @@ private class ArgNodeEx extends NodeEx {
 private class ParamNodeEx extends NodeEx {
   ParamNodeEx() { this.asNode() instanceof ParamNode }
 
-  predicate isParameterOf(DataFlowCallable c, int i) {
-    this.asNode().(ParamNode).isParameterOf(c, i)
+  predicate isParameterOf(DataFlowCallable c, ParameterPosition pos) {
+    this.asNode().(ParamNode).isParameterOf(c, pos)
   }
 
-  int getPosition() { this.isParameterOf(_, result) }
+  ParameterPosition getPosition() { this.isParameterOf(_, result) }
 
   predicate allowParameterReturnInSelf() { allowParameterReturnInSelfCached(this.asNode()) }
 }
@@ -1012,6 +1012,9 @@ private module Stage2 {
 
   private predicate flowIntoCall = flowIntoCallNodeCand1/5;
 
+  bindingset[node, ap]
+  private predicate filter(NodeEx node, Ap ap) { any() }
+
   bindingset[ap, contentType]
   private predicate typecheckStore(Ap ap, DataFlowType contentType) { any() }
 
@@ -1020,6 +1023,13 @@ private module Stage2 {
     PrevStage::revFlow(node, _, _, apa, config)
   }
 
+  bindingset[result, apa]
+  private ApApprox unbindApa(ApApprox apa) {
+    exists(ApApprox apa0 |
+      apa = pragma[only_bind_into](apa0) and result = pragma[only_bind_into](apa0)
+    )
+  }
+
   pragma[nomagic]
   private predicate flowThroughOutOfCall(
     DataFlowCall call, CcCall ccc, RetNodeEx ret, NodeEx out, boolean allowsFieldFlow,
@@ -1042,6 +1052,13 @@ private module Stage2 {
    */
   pragma[nomagic]
   predicate fwdFlow(NodeEx node, Cc cc, ApOption argAp, Ap ap, Configuration config) {
+    fwdFlow0(node, cc, argAp, ap, config) and
+    flowCand(node, unbindApa(getApprox(ap)), config) and
+    filter(node, ap)
+  }
+
+  pragma[nomagic]
+  private predicate fwdFlow0(NodeEx node, Cc cc, ApOption argAp, Ap ap, Configuration config) {
     flowCand(node, _, config) and
     sourceNode(node, config) and
     (if hasSourceCallCtx(config) then cc = ccSomeCall() else cc = ccNone()) and
@@ -1112,7 +1129,7 @@ private module Stage2 {
   ) {
     exists(DataFlowType contentType |
       fwdFlow(node1, cc, argAp, ap1, config) and
-      PrevStage::storeStepCand(node1, getApprox(ap1), tc, node2, contentType, config) and
+      PrevStage::storeStepCand(node1, unbindApa(getApprox(ap1)), tc, node2, contentType, config) and
       typecheckStore(ap1, contentType)
     )
   }
@@ -1189,7 +1206,7 @@ private module Stage2 {
   ) {
     exists(ParamNodeEx p |
       fwdFlowIn(call, p, cc, _, argAp, ap, config) and
-      PrevStage::parameterMayFlowThrough(p, _, getApprox(ap), config)
+      PrevStage::parameterMayFlowThrough(p, _, unbindApa(getApprox(ap)), config)
     )
   }
 
@@ -1430,7 +1447,7 @@ private module Stage2 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2125,7 +2142,7 @@ private module Stage3 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2891,7 +2908,7 @@ private module Stage4 {
   }
 
   predicate parameterMayFlowThrough(ParamNodeEx p, DataFlowCallable c, Ap ap, Configuration config) {
-    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, int pos |
+    exists(RetNodeEx ret, Ap ap0, ReturnKindExt kind, ParameterPosition pos |
       parameterFlow(p, ap, ap0, c, config) and
       c = ret.getEnclosingCallable() and
       revFlow(pragma[only_bind_into](ret), true, apSome(_), pragma[only_bind_into](ap0),
@@ -2975,7 +2992,7 @@ private class SummaryCtxSome extends SummaryCtx, TSummaryCtxSome {
 
   SummaryCtxSome() { this = TSummaryCtxSome(p, ap) }
 
-  int getParameterPos() { p.isParameterOf(_, result) }
+  ParameterPosition getParameterPos() { p.isParameterOf(_, result) }
 
   ParamNodeEx getParamNode() { result = p }
 
@@ -3622,39 +3639,40 @@ private predicate pathOutOfCallable(PathNodeMid mid, NodeEx out, CallContext cc)
  */
 pragma[noinline]
 private predicate pathIntoArg(
-  PathNodeMid mid, int i, CallContext cc, DataFlowCall call, AccessPath ap, AccessPathApprox apa,
-  Configuration config
+  PathNodeMid mid, ParameterPosition ppos, CallContext cc, DataFlowCall call, AccessPath ap,
+  AccessPathApprox apa, Configuration config
 ) {
-  exists(ArgNode arg |
+  exists(ArgNode arg, ArgumentPosition apos |
     arg = mid.getNodeEx().asNode() and
     cc = mid.getCallContext() and
-    arg.argumentOf(call, i) and
+    arg.argumentOf(call, apos) and
     ap = mid.getAp() and
     apa = ap.getApprox() and
-    config = mid.getConfiguration()
+    config = mid.getConfiguration() and
+    parameterMatch(ppos, apos)
   )
 }
 
 pragma[nomagic]
 private predicate parameterCand(
-  DataFlowCallable callable, int i, AccessPathApprox apa, Configuration config
+  DataFlowCallable callable, ParameterPosition pos, AccessPathApprox apa, Configuration config
 ) {
   exists(ParamNodeEx p |
     Stage4::revFlow(p, _, _, apa, config) and
-    p.isParameterOf(callable, i)
+    p.isParameterOf(callable, pos)
   )
 }
 
 pragma[nomagic]
 private predicate pathIntoCallable0(
-  PathNodeMid mid, DataFlowCallable callable, int i, CallContext outercc, DataFlowCall call,
-  AccessPath ap, Configuration config
+  PathNodeMid mid, DataFlowCallable callable, ParameterPosition pos, CallContext outercc,
+  DataFlowCall call, AccessPath ap, Configuration config
 ) {
   exists(AccessPathApprox apa |
-    pathIntoArg(mid, pragma[only_bind_into](i), outercc, call, ap, pragma[only_bind_into](apa),
+    pathIntoArg(mid, pragma[only_bind_into](pos), outercc, call, ap, pragma[only_bind_into](apa),
       pragma[only_bind_into](config)) and
     callable = resolveCall(call, outercc) and
-    parameterCand(callable, pragma[only_bind_into](i), pragma[only_bind_into](apa),
+    parameterCand(callable, pragma[only_bind_into](pos), pragma[only_bind_into](apa),
       pragma[only_bind_into](config))
   )
 }
@@ -3669,9 +3687,9 @@ private predicate pathIntoCallable(
   PathNodeMid mid, ParamNodeEx p, CallContext outercc, CallContextCall innercc, SummaryCtx sc,
   DataFlowCall call, Configuration config
 ) {
-  exists(int i, DataFlowCallable callable, AccessPath ap |
-    pathIntoCallable0(mid, callable, i, outercc, call, ap, config) and
-    p.isParameterOf(callable, i) and
+  exists(ParameterPosition pos, DataFlowCallable callable, AccessPath ap |
+    pathIntoCallable0(mid, callable, pos, outercc, call, ap, config) and
+    p.isParameterOf(callable, pos) and
     (
       sc = TSummaryCtxSome(p, ap)
       or
@@ -3695,7 +3713,7 @@ private predicate paramFlowsThrough(
   ReturnKindExt kind, CallContextCall cc, SummaryCtxSome sc, AccessPath ap, AccessPathApprox apa,
   Configuration config
 ) {
-  exists(PathNodeMid mid, RetNodeEx ret, int pos |
+  exists(PathNodeMid mid, RetNodeEx ret, ParameterPosition pos |
     mid.getNodeEx() = ret and
     kind = ret.getKind() and
     cc = mid.getCallContext() and
@@ -4424,24 +4442,25 @@ private module FlowExploration {
 
   pragma[noinline]
   private predicate partialPathIntoArg(
-    PartialPathNodeFwd mid, int i, CallContext cc, DataFlowCall call, PartialAccessPath ap,
-    Configuration config
+    PartialPathNodeFwd mid, ParameterPosition ppos, CallContext cc, DataFlowCall call,
+    PartialAccessPath ap, Configuration config
   ) {
-    exists(ArgNode arg |
+    exists(ArgNode arg, ArgumentPosition apos |
       arg = mid.getNodeEx().asNode() and
       cc = mid.getCallContext() and
-      arg.argumentOf(call, i) and
+      arg.argumentOf(call, apos) and
       ap = mid.getAp() and
-      config = mid.getConfiguration()
+      config = mid.getConfiguration() and
+      parameterMatch(ppos, apos)
     )
   }
 
   pragma[nomagic]
   private predicate partialPathIntoCallable0(
-    PartialPathNodeFwd mid, DataFlowCallable callable, int i, CallContext outercc,
+    PartialPathNodeFwd mid, DataFlowCallable callable, ParameterPosition pos, CallContext outercc,
     DataFlowCall call, PartialAccessPath ap, Configuration config
   ) {
-    partialPathIntoArg(mid, i, outercc, call, ap, config) and
+    partialPathIntoArg(mid, pos, outercc, call, ap, config) and
     callable = resolveCall(call, outercc)
   }
 
@@ -4450,9 +4469,9 @@ private module FlowExploration {
     TSummaryCtx1 sc1, TSummaryCtx2 sc2, DataFlowCall call, PartialAccessPath ap,
     Configuration config
   ) {
-    exists(int i, DataFlowCallable callable |
-      partialPathIntoCallable0(mid, callable, i, outercc, call, ap, config) and
-      p.isParameterOf(callable, i) and
+    exists(ParameterPosition pos, DataFlowCallable callable |
+      partialPathIntoCallable0(mid, callable, pos, outercc, call, ap, config) and
+      p.isParameterOf(callable, pos) and
       sc1 = TSummaryCtx1Param(p) and
       sc2 = TSummaryCtx2Some(ap)
     |
@@ -4616,22 +4635,23 @@ private module FlowExploration {
 
   pragma[nomagic]
   private predicate revPartialPathFlowsThrough(
-    int pos, TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2, RevPartialAccessPath ap,
-    Configuration config
+    ArgumentPosition apos, TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2,
+    RevPartialAccessPath ap, Configuration config
   ) {
-    exists(PartialPathNodeRev mid, ParamNodeEx p |
+    exists(PartialPathNodeRev mid, ParamNodeEx p, ParameterPosition ppos |
       mid.getNodeEx() = p and
-      p.getPosition() = pos and
+      p.getPosition() = ppos and
       sc1 = mid.getSummaryCtx1() and
       sc2 = mid.getSummaryCtx2() and
       ap = mid.getAp() and
-      config = mid.getConfiguration()
+      config = mid.getConfiguration() and
+      parameterMatch(ppos, apos)
     )
   }
 
   pragma[nomagic]
   private predicate revPartialPathThroughCallable0(
-    DataFlowCall call, PartialPathNodeRev mid, int pos, RevPartialAccessPath ap,
+    DataFlowCall call, PartialPathNodeRev mid, ArgumentPosition pos, RevPartialAccessPath ap,
     Configuration config
   ) {
     exists(TRevSummaryCtx1Some sc1, TRevSummaryCtx2Some sc2 |
@@ -4644,7 +4664,7 @@ private module FlowExploration {
   private predicate revPartialPathThroughCallable(
     PartialPathNodeRev mid, ArgNodeEx node, RevPartialAccessPath ap, Configuration config
   ) {
-    exists(DataFlowCall call, int pos |
+    exists(DataFlowCall call, ArgumentPosition pos |
       revPartialPathThroughCallable0(call, mid, pos, ap, config) and
       node.asNode().(ArgNode).argumentOf(call, pos)
     )

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

@@ -62,6 +62,18 @@ predicate accessPathCostLimits(int apLimit, int tupleLimit) {
   tupleLimit = 1000
 }
 
+/**
+ * Holds if `arg` is an argument of `call` with an argument position that matches
+ * parameter position `ppos`.
+ */
+pragma[noinline]
+predicate argumentPositionMatch(DataFlowCall call, ArgNode arg, ParameterPosition ppos) {
+  exists(ArgumentPosition apos |
+    arg.argumentOf(call, apos) and
+    parameterMatch(ppos, apos)
+  )
+}
+
 /**
  * Provides a simple data-flow analysis for resolving lambda calls. The analysis
  * currently excludes read-steps, store-steps, and flow-through.
@@ -71,25 +83,27 @@ predicate accessPathCostLimits(int apLimit, int tupleLimit) {
  * calls. For this reason, we cannot reuse the code from `DataFlowImpl.qll` directly.
  */
 private module LambdaFlow {
-  private predicate viableParamNonLambda(DataFlowCall call, int i, ParamNode p) {
-    p.isParameterOf(viableCallable(call), i)
+  pragma[noinline]
+  private predicate viableParamNonLambda(DataFlowCall call, ParameterPosition ppos, ParamNode p) {
+    p.isParameterOf(viableCallable(call), ppos)
   }
 
-  private predicate viableParamLambda(DataFlowCall call, int i, ParamNode p) {
-    p.isParameterOf(viableCallableLambda(call, _), i)
+  pragma[noinline]
+  private predicate viableParamLambda(DataFlowCall call, ParameterPosition ppos, ParamNode p) {
+    p.isParameterOf(viableCallableLambda(call, _), ppos)
   }
 
   private predicate viableParamArgNonLambda(DataFlowCall call, ParamNode p, ArgNode arg) {
-    exists(int i |
-      viableParamNonLambda(call, i, p) and
-      arg.argumentOf(call, i)
+    exists(ParameterPosition ppos |
+      viableParamNonLambda(call, ppos, p) and
+      argumentPositionMatch(call, arg, ppos)
     )
   }
 
   private predicate viableParamArgLambda(DataFlowCall call, ParamNode p, ArgNode arg) {
-    exists(int i |
-      viableParamLambda(call, i, p) and
-      arg.argumentOf(call, i)
+    exists(ParameterPosition ppos |
+      viableParamLambda(call, ppos, p) and
+      argumentPositionMatch(call, arg, ppos)
     )
   }
 
@@ -322,7 +336,7 @@ private module Cached {
     or
     exists(ArgNode arg |
       result.(PostUpdateNode).getPreUpdateNode() = arg and
-      arg.argumentOf(call, k.(ParamUpdateReturnKind).getPosition())
+      arg.argumentOf(call, k.(ParamUpdateReturnKind).getAMatchingArgumentPosition())
     )
   }
 
@@ -330,7 +344,7 @@ private module Cached {
   predicate returnNodeExt(Node n, ReturnKindExt k) {
     k = TValueReturn(n.(ReturnNode).getKind())
     or
-    exists(ParamNode p, int pos |
+    exists(ParamNode p, ParameterPosition pos |
       parameterValueFlowsToPreUpdate(p, n) and
       p.isParameterOf(_, pos) and
       k = TParamUpdate(pos)
@@ -352,11 +366,13 @@ private module Cached {
   }
 
   cached
-  predicate parameterNode(Node p, DataFlowCallable c, int pos) { isParameterNode(p, c, pos) }
+  predicate parameterNode(Node p, DataFlowCallable c, ParameterPosition pos) {
+    isParameterNode(p, c, pos)
+  }
 
   cached
-  predicate argumentNode(Node n, DataFlowCall call, int pos) {
-    n.(ArgumentNode).argumentOf(call, pos)
+  predicate argumentNode(Node n, DataFlowCall call, ArgumentPosition pos) {
+    isArgumentNode(n, call, pos)
   }
 
   /**
@@ -374,12 +390,12 @@ private module Cached {
   }
 
   /**
-   * Holds if `p` is the `i`th parameter of a viable dispatch target of `call`.
-   * The instance parameter is considered to have index `-1`.
+   * Holds if `p` is the parameter of a viable dispatch target of `call`,
+   * and `p` has position `ppos`.
    */
   pragma[nomagic]
-  private predicate viableParam(DataFlowCall call, int i, ParamNode p) {
-    p.isParameterOf(viableCallableExt(call), i)
+  private predicate viableParam(DataFlowCall call, ParameterPosition ppos, ParamNode p) {
+    p.isParameterOf(viableCallableExt(call), ppos)
   }
 
   /**
@@ -388,9 +404,9 @@ private module Cached {
    */
   cached
   predicate viableParamArg(DataFlowCall call, ParamNode p, ArgNode arg) {
-    exists(int i |
-      viableParam(call, i, p) and
-      arg.argumentOf(call, i) and
+    exists(ParameterPosition ppos |
+      viableParam(call, ppos, p) and
+      argumentPositionMatch(call, arg, ppos) and
       compatibleTypes(getNodeDataFlowType(arg), getNodeDataFlowType(p))
     )
   }
@@ -862,7 +878,7 @@ private module Cached {
   cached
   newtype TReturnKindExt =
     TValueReturn(ReturnKind kind) or
-    TParamUpdate(int pos) { exists(ParamNode p | p.isParameterOf(_, pos)) }
+    TParamUpdate(ParameterPosition pos) { exists(ParamNode p | p.isParameterOf(_, pos)) }
 
   cached
   newtype TBooleanOption =
@@ -1054,9 +1070,9 @@ class ParamNode extends Node {
 
   /**
    * Holds if this node is the parameter of callable `c` at the specified
-   * (zero-based) position.
+   * position.
    */
-  predicate isParameterOf(DataFlowCallable c, int i) { parameterNode(this, c, i) }
+  predicate isParameterOf(DataFlowCallable c, ParameterPosition pos) { parameterNode(this, c, pos) }
 }
 
 /** A data-flow node that represents a call argument. */
@@ -1064,7 +1080,9 @@ class ArgNode extends Node {
   ArgNode() { argumentNode(this, _, _) }
 
   /** Holds if this argument occurs at the given position in the given call. */
-  final predicate argumentOf(DataFlowCall call, int pos) { argumentNode(this, call, pos) }
+  final predicate argumentOf(DataFlowCall call, ArgumentPosition pos) {
+    argumentNode(this, call, pos)
+  }
 }
 
 /**
@@ -1110,11 +1128,14 @@ class ValueReturnKind extends ReturnKindExt, TValueReturn {
 }
 
 class ParamUpdateReturnKind extends ReturnKindExt, TParamUpdate {
-  private int pos;
+  private ParameterPosition pos;
 
   ParamUpdateReturnKind() { this = TParamUpdate(pos) }
 
-  int getPosition() { result = pos }
+  ParameterPosition getPosition() { result = pos }
+
+  pragma[nomagic]
+  ArgumentPosition getAMatchingArgumentPosition() { parameterMatch(pos, result) }
 
   override string toString() { result = "param update " + pos }
 }

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

@@ -8,7 +8,14 @@ private import DataFlowImplConsistency
 DataFlowCallable nodeGetEnclosingCallable(Node n) { result = n.getEnclosingCallable() }
 
 /** Holds if `p` is a `ParameterNode` of `c` with position `pos`. */
-predicate isParameterNode(ParameterNode p, DataFlowCallable c, int pos) { p.isParameterOf(c, pos) }
+predicate isParameterNode(ParameterNode p, DataFlowCallable c, ParameterPosition pos) {
+  p.isParameterOf(c, pos)
+}
+
+/** Holds if `arg` is an `ArgumentNode` of `c` with position `pos`. */
+predicate isArgumentNode(ArgumentNode arg, DataFlowCall c, ArgumentPosition pos) {
+  arg.argumentOf(c, pos)
+}
 
 /**
  * A data flow node that occurs as the argument of a call and is passed as-is

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

@@ -452,7 +452,7 @@ class SsaPhiNode extends Node, TSsaPhiNode {
 
   /** Holds if this phi node has input from the `rnk`'th write operation in block `block`. */
   final predicate hasInputAtRankInBlock(IRBlock block, int rnk) {
-    hasInputAtRankInBlock(block, rnk, _)
+    this.hasInputAtRankInBlock(block, rnk, _)
   }
 
   /**

cpp/ql/lib/semmle/code/cpp/ir/implementation/aliased_ssa/Operand.qll

@@ -307,7 +307,7 @@ class NonPhiMemoryOperand extends NonPhiOperand, MemoryOperand, TNonPhiMemoryOpe
   final override string toString() { result = tag.toString() }
 
   final override Instruction getAnyDef() {
-    result = unique(Instruction defInstr | hasDefinition(defInstr, _))
+    result = unique(Instruction defInstr | this.hasDefinition(defInstr, _))
   }
 
   final override Overlap getDefinitionOverlap() { this.hasDefinition(_, result) }

cpp/ql/lib/semmle/code/cpp/ir/implementation/raw/Operand.qll

@@ -307,7 +307,7 @@ class NonPhiMemoryOperand extends NonPhiOperand, MemoryOperand, TNonPhiMemoryOpe
   final override string toString() { result = tag.toString() }
 
   final override Instruction getAnyDef() {
-    result = unique(Instruction defInstr | hasDefinition(defInstr, _))
+    result = unique(Instruction defInstr | this.hasDefinition(defInstr, _))
   }
 
   final override Overlap getDefinitionOverlap() { this.hasDefinition(_, result) }

cpp/ql/lib/semmle/code/cpp/ir/implementation/unaliased_ssa/Operand.qll

@@ -307,7 +307,7 @@ class NonPhiMemoryOperand extends NonPhiOperand, MemoryOperand, TNonPhiMemoryOpe
   final override string toString() { result = tag.toString() }
 
   final override Instruction getAnyDef() {
-    result = unique(Instruction defInstr | hasDefinition(defInstr, _))
+    result = unique(Instruction defInstr | this.hasDefinition(defInstr, _))
   }
 
   final override Overlap getDefinitionOverlap() { this.hasDefinition(_, result) }

cpp/ql/src/AlertSuppression.ql

@@ -18,12 +18,12 @@ class SuppressionComment extends Comment {
     (
       this instanceof CppStyleComment and
       // strip the beginning slashes
-      text = getContents().suffix(2)
+      text = this.getContents().suffix(2)
       or
       this instanceof CStyleComment and
       // strip both the beginning /* and the end */ the comment
       exists(string text0 |
-        text0 = getContents().suffix(2) and
+        text0 = this.getContents().suffix(2) and
         text = text0.prefix(text0.length() - 2)
       ) and
       // The /* */ comment must be a single-line comment

cpp/ql/src/Architecture/Refactoring Opportunities/ClassesWithManyFields.ql

@@ -153,12 +153,12 @@ class ExtClass extends Class {
   }
 
   predicate hasLocationInfo(string path, int startline, int startcol, int endline, int endcol) {
-    if hasOneVariableGroup()
+    if this.hasOneVariableGroup()
     then
       exists(VariableDeclarationGroup vdg | vdg.getClass() = this |
         vdg.hasLocationInfo(path, startline, startcol, endline, endcol)
       )
-    else getLocation().hasLocationInfo(path, startline, startcol, endline, endcol)
+    else this.getLocation().hasLocationInfo(path, startline, startcol, endline, endcol)
   }
 }
 

cpp/ql/src/Best Practices/Unused Entities/UnusedStaticFunctions.ql

@@ -50,6 +50,16 @@ predicate reachableThing(Thing t) {
   exists(Thing mid | reachableThing(mid) and mid.callsOrAccesses() = t)
 }
 
+pragma[nomagic]
+predicate callsOrAccessesPlus(Thing thing1, FunctionToRemove thing2) {
+  thing1.callsOrAccesses() = thing2
+  or
+  exists(Thing mid |
+    thing1.callsOrAccesses() = mid and
+    callsOrAccessesPlus(mid, thing2)
+  )
+}
+
 class Thing extends Locatable {
   Thing() {
     this instanceof Function or
@@ -81,7 +91,7 @@ class FunctionToRemove extends Function {
   }
 
   Thing getOther() {
-    result.callsOrAccesses+() = this and
+    callsOrAccessesPlus(result, this) and
     this != result and
     // We will already be reporting the enclosing function of a
     // local variable, so don't also report the variable

cpp/ql/src/CHANGELOG.md

@@ -1,3 +1,10 @@
+## 0.0.5
+
+### New Queries
+
+* A new query `cpp/certificate-not-checked` has been added for C/C++. The query flags unsafe use of OpenSSL and similar libraries.
+* A new query `cpp/certificate-result-conflation` has been added for C/C++. The query flags unsafe use of OpenSSL and similar libraries.
+
 ## 0.0.4
 
 ### New Queries

cpp/ql/src/Critical/OverflowStatic.ql

@@ -103,9 +103,9 @@ class CallWithBufferSize extends FunctionCall {
     // `upperBound(e)` defaults to `exprMaxVal(e)` when `e` isn't analyzable. So to get a meaningful
     // result in this case we pick the minimum value obtainable from dataflow and range analysis.
     result =
-      upperBound(statedSizeExpr())
+      upperBound(this.statedSizeExpr())
           .minimum(min(Expr statedSizeSrc |
-              DataFlow::localExprFlow(statedSizeSrc, statedSizeExpr())
+              DataFlow::localExprFlow(statedSizeSrc, this.statedSizeExpr())
             |
               statedSizeSrc.getValue().toInt()
             ))

cpp/ql/src/JPL_C/LOC-2/Rule 09/Semaphores.qll

@@ -22,7 +22,7 @@ abstract class LockOperation extends FunctionCall {
   ControlFlowNode getAReachedNode() {
     result = this
     or
-    exists(ControlFlowNode mid | mid = getAReachedNode() |
+    exists(ControlFlowNode mid | mid = this.getAReachedNode() |
       not mid != this.getMatchingUnlock() and
       result = mid.getASuccessor()
     )

cpp/ql/src/Likely Bugs/Leap Year/LeapYear.qll

@@ -156,8 +156,8 @@ abstract class LeapYearFieldAccess extends YearFieldAccess {
     //
     // https://aa.usno.navy.mil/faq/docs/calendars.php
     this.isUsedInMod4Operation() and
-    additionalModulusCheckForLeapYear(400) and
-    additionalModulusCheckForLeapYear(100)
+    this.additionalModulusCheckForLeapYear(400) and
+    this.additionalModulusCheckForLeapYear(100)
   }
 }
 
@@ -176,17 +176,17 @@ class StructTmLeapYearFieldAccess extends LeapYearFieldAccess {
 
   override predicate isUsedInCorrectLeapYearCheck() {
     this.isUsedInMod4Operation() and
-    additionalModulusCheckForLeapYear(400) and
-    additionalModulusCheckForLeapYear(100) and
+    this.additionalModulusCheckForLeapYear(400) and
+    this.additionalModulusCheckForLeapYear(100) and
     // tm_year represents years since 1900
     (
-      additionalAdditionOrSubstractionCheckForLeapYear(1900)
+      this.additionalAdditionOrSubstractionCheckForLeapYear(1900)
       or
       // some systems may use 2000 for 2-digit year conversions
-      additionalAdditionOrSubstractionCheckForLeapYear(2000)
+      this.additionalAdditionOrSubstractionCheckForLeapYear(2000)
       or
       // converting from/to Unix epoch
-      additionalAdditionOrSubstractionCheckForLeapYear(1970)
+      this.additionalAdditionOrSubstractionCheckForLeapYear(1970)
     )
   }
 }

cpp/ql/src/Likely Bugs/Memory Management/AllocaInLoop.ql

@@ -57,7 +57,7 @@ class LoopWithAlloca extends Stmt {
     or
     // `e == 0`
     exists(EQExpr eq |
-      conditionRequires(eq, truth.booleanNot()) and
+      this.conditionRequires(eq, truth.booleanNot()) and
       eq.getAnOperand().getValue().toInt() = 0 and
       e = eq.getAnOperand() and
       not exists(e.getValue())
@@ -65,7 +65,7 @@ class LoopWithAlloca extends Stmt {
     or
     // `e != 0`
     exists(NEExpr eq |
-      conditionRequires(eq, truth) and
+      this.conditionRequires(eq, truth) and
       eq.getAnOperand().getValue().toInt() = 0 and
       e = eq.getAnOperand() and
       not exists(e.getValue())
@@ -73,7 +73,7 @@ class LoopWithAlloca extends Stmt {
     or
     // `(bool)e == true`
     exists(EQExpr eq |
-      conditionRequires(eq, truth) and
+      this.conditionRequires(eq, truth) and
       eq.getAnOperand().getValue().toInt() = 1 and
       e = eq.getAnOperand() and
       e.getUnspecifiedType() instanceof BoolType and
@@ -82,7 +82,7 @@ class LoopWithAlloca extends Stmt {
     or
     // `(bool)e != true`
     exists(NEExpr eq |
-      conditionRequires(eq, truth.booleanNot()) and
+      this.conditionRequires(eq, truth.booleanNot()) and
       eq.getAnOperand().getValue().toInt() = 1 and
       e = eq.getAnOperand() and
       e.getUnspecifiedType() instanceof BoolType and
@@ -90,7 +90,7 @@ class LoopWithAlloca extends Stmt {
     )
     or
     exists(NotExpr notExpr |
-      conditionRequires(notExpr, truth.booleanNot()) and
+      this.conditionRequires(notExpr, truth.booleanNot()) and
       e = notExpr.getOperand()
     )
     or
@@ -98,7 +98,7 @@ class LoopWithAlloca extends Stmt {
     // requires both of its operand to be true as well.
     exists(LogicalAndExpr andExpr |
       truth = true and
-      conditionRequires(andExpr, truth) and
+      this.conditionRequires(andExpr, truth) and
       e = andExpr.getAnOperand()
     )
     or
@@ -106,7 +106,7 @@ class LoopWithAlloca extends Stmt {
     // it requires both of its operand to be false as well.
     exists(LogicalOrExpr orExpr |
       truth = false and
-      conditionRequires(orExpr, truth) and
+      this.conditionRequires(orExpr, truth) and
       e = orExpr.getAnOperand()
     )
   }
@@ -141,9 +141,9 @@ class LoopWithAlloca extends Stmt {
    * `conditionRequiresInequality`.
    */
   private Variable getAControllingVariable() {
-    conditionRequires(result.getAnAccess(), _)
+    this.conditionRequires(result.getAnAccess(), _)
     or
-    conditionRequiresInequality(result.getAnAccess(), _, _)
+    this.conditionRequiresInequality(result.getAnAccess(), _, _)
   }
 
   /**

cpp/ql/src/Likely Bugs/Memory Management/NtohlArrayNoBound.qll

@@ -61,72 +61,72 @@ class PointerArithmeticAccess extends BufferAccess, Expr {
  * A pair of buffer accesses through a call to memcpy.
  */
 class MemCpy extends BufferAccess, FunctionCall {
-  MemCpy() { getTarget().hasName("memcpy") }
+  MemCpy() { this.getTarget().hasName("memcpy") }
 
   override Expr getPointer() {
-    result = getArgument(0) or
-    result = getArgument(1)
+    result = this.getArgument(0) or
+    result = this.getArgument(1)
   }
 
-  override Expr getAccessedLength() { result = getArgument(2) }
+  override Expr getAccessedLength() { result = this.getArgument(2) }
 }
 
 class StrncpySizeExpr extends BufferAccess, FunctionCall {
-  StrncpySizeExpr() { getTarget().hasName("strncpy") }
+  StrncpySizeExpr() { this.getTarget().hasName("strncpy") }
 
   override Expr getPointer() {
-    result = getArgument(0) or
-    result = getArgument(1)
+    result = this.getArgument(0) or
+    result = this.getArgument(1)
   }
 
-  override Expr getAccessedLength() { result = getArgument(2) }
+  override Expr getAccessedLength() { result = this.getArgument(2) }
 }
 
 class RecvSizeExpr extends BufferAccess, FunctionCall {
-  RecvSizeExpr() { getTarget().hasName("recv") }
+  RecvSizeExpr() { this.getTarget().hasName("recv") }
 
-  override Expr getPointer() { result = getArgument(1) }
+  override Expr getPointer() { result = this.getArgument(1) }
 
-  override Expr getAccessedLength() { result = getArgument(2) }
+  override Expr getAccessedLength() { result = this.getArgument(2) }
 }
 
 class SendSizeExpr extends BufferAccess, FunctionCall {
-  SendSizeExpr() { getTarget().hasName("send") }
+  SendSizeExpr() { this.getTarget().hasName("send") }
 
-  override Expr getPointer() { result = getArgument(1) }
+  override Expr getPointer() { result = this.getArgument(1) }
 
-  override Expr getAccessedLength() { result = getArgument(2) }
+  override Expr getAccessedLength() { result = this.getArgument(2) }
 }
 
 class SnprintfSizeExpr extends BufferAccess, FunctionCall {
-  SnprintfSizeExpr() { getTarget().hasName("snprintf") }
+  SnprintfSizeExpr() { this.getTarget().hasName("snprintf") }
 
-  override Expr getPointer() { result = getArgument(0) }
+  override Expr getPointer() { result = this.getArgument(0) }
 
-  override Expr getAccessedLength() { result = getArgument(1) }
+  override Expr getAccessedLength() { result = this.getArgument(1) }
 }
 
 class MemcmpSizeExpr extends BufferAccess, FunctionCall {
-  MemcmpSizeExpr() { getTarget().hasName("Memcmp") }
+  MemcmpSizeExpr() { this.getTarget().hasName("Memcmp") }
 
   override Expr getPointer() {
-    result = getArgument(0) or
-    result = getArgument(1)
+    result = this.getArgument(0) or
+    result = this.getArgument(1)
   }
 
-  override Expr getAccessedLength() { result = getArgument(2) }
+  override Expr getAccessedLength() { result = this.getArgument(2) }
 }
 
 class MallocSizeExpr extends BufferAccess, FunctionCall {
-  MallocSizeExpr() { getTarget().hasName("malloc") }
+  MallocSizeExpr() { this.getTarget().hasName("malloc") }
 
   override Expr getPointer() { none() }
 
-  override Expr getAccessedLength() { result = getArgument(0) }
+  override Expr getAccessedLength() { result = this.getArgument(0) }
 }
 
 class NetworkFunctionCall extends FunctionCall {
-  NetworkFunctionCall() { getTarget().hasName(["ntohd", "ntohf", "ntohl", "ntohll", "ntohs"]) }
+  NetworkFunctionCall() { this.getTarget().hasName(["ntohd", "ntohf", "ntohl", "ntohll", "ntohs"]) }
 }
 
 class NetworkToBufferSizeConfiguration extends DataFlow::Configuration {

cpp/ql/src/Likely Bugs/Protocols/TlsSettingsMisconfiguration.ql

@@ -3,8 +3,10 @@
  * @description Using the TLS or SSLv23 protocol from the boost::asio library, but not disabling deprecated protocols, or disabling minimum-recommended protocols.
  * @kind problem
  * @problem.severity error
+ * @security-severity 7.5
  * @id cpp/boost/tls-settings-misconfiguration
  * @tags security
+ *       external/cwe/cwe-326
  */
 
 import cpp

cpp/ql/src/Likely Bugs/Protocols/UseOfDeprecatedHardcodedProtocol.ql

@@ -3,8 +3,10 @@
  * @description Using a deprecated hard-coded protocol using the boost::asio library.
  * @kind problem
  * @problem.severity error
+ * @security-severity 7.5
  * @id cpp/boost/use-of-deprecated-hardcoded-security-protocol
  * @tags security
+ *       external/cwe/cwe-327
  */
 
 import cpp

cpp/ql/src/Power of 10/Rule 4/FunctionTooLong.ql

@@ -13,7 +13,7 @@ import cpp
 
 class MacroFunctionCall extends MacroInvocation {
   MacroFunctionCall() {
-    not exists(getParentInvocation()) and
+    not exists(this.getParentInvocation()) and
     this.getMacro().getHead().matches("%(%")
   }
 

cpp/ql/src/Power of 10/Rule 5/AssertionDensity.ql

@@ -13,7 +13,7 @@ import semmle.code.cpp.commons.Assertions
 
 class MacroFunctionCall extends MacroInvocation {
   MacroFunctionCall() {
-    not exists(getParentInvocation()) and
+    not exists(this.getParentInvocation()) and
     this.getMacro().getHead().matches("%(%")
   }
 

cpp/ql/src/Security/CWE/CWE-020/ExternalAPIsSpecific.qll

@@ -38,7 +38,7 @@ class ExternalAPIDataNode extends DataFlow::Node {
   int getIndex() { result = i }
 
   /** Gets the description of the function being called. */
-  string getFunctionDescription() { result = getExternalFunction().toString() }
+  string getFunctionDescription() { result = this.getExternalFunction().toString() }
 }
 
 /** A configuration for tracking flow from `RemoteFlowSource`s to `ExternalAPIDataNode`s. */

cpp/ql/src/Security/CWE/CWE-020/ir/ExternalAPIsSpecific.qll

@@ -38,7 +38,7 @@ class ExternalAPIDataNode extends DataFlow::Node {
   int getIndex() { result = i }
 
   /** Gets the description of the function being called. */
-  string getFunctionDescription() { result = getExternalFunction().toString() }
+  string getFunctionDescription() { result = this.getExternalFunction().toString() }
 }
 
 /** A configuration for tracking flow from `RemoteFlowSource`s to `ExternalAPIDataNode`s. */

cpp/ql/src/Security/CWE/CWE-121/UnterminatedVarargsCall.ql

@@ -42,7 +42,7 @@ class VarargsFunction extends Function {
   }
 
   private int trailingArgValueCount(string value) {
-    result = strictcount(FunctionCall fc | trailingArgValue(fc) = value)
+    result = strictcount(FunctionCall fc | this.trailingArgValue(fc) = value)
   }
 
   string nonTrailingVarArgValue(FunctionCall fc, int index) {
@@ -58,11 +58,11 @@ class VarargsFunction extends Function {
 
   string normalTerminator(int cnt) {
     result = ["0", "-1"] and
-    cnt = trailingArgValueCount(result) and
-    2 * cnt > totalCount() and
+    cnt = this.trailingArgValueCount(result) and
+    2 * cnt > this.totalCount() and
     not exists(FunctionCall fc, int index |
       // terminator value is used in a non-terminating position
-      nonTrailingVarArgValue(fc, index) = result
+      this.nonTrailingVarArgValue(fc, index) = result
     )
   }
 

cpp/ql/src/Security/CWE/CWE-170/ImproperNullTerminationTainted.ql

@@ -42,7 +42,7 @@ class TaintSource extends VariableAccess {
     definitionUsePair(_, this, va)
     or
     exists(VariableAccess mid, Expr def |
-      sourceReaches(mid) and
+      this.sourceReaches(mid) and
       exprDefinition(_, def, mid) and
       definitionUsePair(_, def, va)
     )
@@ -53,11 +53,11 @@ class TaintSource extends VariableAccess {
    * from `va`, possibly using intermediate reassignments.
    */
   private predicate reachesSink(VariableAccess va, VariableAccess sink) {
-    isSink(sink) and
+    this.isSink(sink) and
     va = sink
     or
     exists(VariableAccess mid, Expr def |
-      reachesSink(mid, sink) and
+      this.reachesSink(mid, sink) and
       exprDefinition(_, def, va) and
       definitionUsePair(_, def, mid)
     )
@@ -71,15 +71,15 @@ class TaintSource extends VariableAccess {
    * this source to `sink` found via `tainted(source, sink)`.)
    */
   predicate reaches(VariableAccess sink) {
-    isSink(sink) and
+    this.isSink(sink) and
     not exists(VariableAccess va |
       va != this and
       va != sink and
       mayAddNullTerminator(_, va)
     |
-      sourceReaches(va)
+      this.sourceReaches(va)
       or
-      reachesSink(va, sink)
+      this.reachesSink(va, sink)
     )
   }
 }

cpp/ql/src/Security/CWE/CWE-295/SSLResultConflation.qhelp

@@ -0,0 +1,28 @@
+<!DOCTYPE qhelp PUBLIC
+  "-//Semmle//qhelp//EN"
+  "qhelp.dtd">
+<qhelp>
+<overview>
+<p>When checking the result of SSL certificate verification, accepting any error code may allow an attacker to impersonate someone who is trusted.</p>
+
+</overview>
+<recommendation>
+
+<p>When checking an SSL certificate with <code>SSL_get_verify_result</code>, only <code>X509_V_OK</code> is a success code. If there is any other result the certificate should not be accepted.</p>
+
+</recommendation>
+<example>
+
+<p>In this example the error code <code>X509_V_ERR_CERT_HAS_EXPIRED</code> is treated the same as an OK result. An expired certificate should not be accepted as it is more likely to be compromised than a valid certificate.</p>
+
+<sample src="SSLResultConflationBad.cpp" />
+
+<p>In the corrected example, only a result of <code>X509_V_OK</code> is accepted.</p>
+
+<sample src="SSLResultConflationGood.cpp" />
+
+</example>
+<references>
+
+</references>
+</qhelp>

cpp/ql/src/Security/CWE/CWE-295/SSLResultConflation.ql

@@ -0,0 +1,50 @@
+/**
+ * @name Certificate result conflation
+ * @description Only accept SSL certificates that pass certificate verification.
+ * @kind problem
+ * @problem.severity error
+ * @security-severity 7.5
+ * @precision medium
+ * @id cpp/certificate-result-conflation
+ * @tags security
+ *       external/cwe/cwe-295
+ */
+
+import cpp
+import semmle.code.cpp.controlflow.Guards
+import semmle.code.cpp.dataflow.DataFlow
+
+/**
+ * A call to `SSL_get_verify_result`.
+ */
+class SSLGetVerifyResultCall extends FunctionCall {
+  SSLGetVerifyResultCall() { getTarget().getName() = "SSL_get_verify_result" }
+}
+
+/**
+ * Data flow from a call to `SSL_get_verify_result` to a guard condition
+ * that references the result.
+ */
+class VerifyResultConfig extends DataFlow::Configuration {
+  VerifyResultConfig() { this = "VerifyResultConfig" }
+
+  override predicate isSource(DataFlow::Node source) {
+    source.asExpr() instanceof SSLGetVerifyResultCall
+  }
+
+  override predicate isSink(DataFlow::Node sink) {
+    exists(GuardCondition guard | guard.getAChild*() = sink.asExpr())
+  }
+}
+
+from
+  VerifyResultConfig config, DataFlow::Node source, DataFlow::Node sink1, DataFlow::Node sink2,
+  GuardCondition guard, Expr c1, Expr c2, boolean testIsTrue
+where
+  config.hasFlow(source, sink1) and
+  config.hasFlow(source, sink2) and
+  guard.comparesEq(sink1.asExpr(), c1, 0, false, testIsTrue) and // (value != c1) => testIsTrue
+  guard.comparesEq(sink2.asExpr(), c2, 0, false, testIsTrue) and // (value != c2) => testIsTrue
+  c1.getValue().toInt() = 0 and
+  c2.getValue().toInt() != 0
+select guard, "This expression conflates OK and non-OK results from $@.", source, source.toString()

cpp/ql/src/Security/CWE/CWE-295/SSLResultConflationBad.cpp

@@ -0,0 +1,13 @@
+// ...
+
+if (cert = SSL_get_peer_certificate(ssl))
+{
+	result = SSL_get_verify_result(ssl);
+
+	if ((result == X509_V_OK) || (result == X509_V_ERR_CERT_HAS_EXPIRED)) // BAD (conflates OK and a non-OK codes)
+	{
+		do_ok();
+	} else {
+		do_error();
+	}
+}

cpp/ql/src/Security/CWE/CWE-295/SSLResultConflationGood.cpp

@@ -0,0 +1,13 @@
+// ...
+
+if (cert = SSL_get_peer_certificate(ssl))
+{
+	result = SSL_get_verify_result(ssl);
+
+	if (result == X509_V_OK) // GOOD
+	{
+		do_ok();
+	} else {
+		do_error();
+	}
+}

cpp/ql/src/Security/CWE/CWE-295/SSLResultNotChecked.qhelp

@@ -0,0 +1,28 @@
+<!DOCTYPE qhelp PUBLIC
+  "-//Semmle//qhelp//EN"
+  "qhelp.dtd">
+<qhelp>
+<overview>
+<p>After fetching an SSL certificate, always check the result of certificate verification.</p>
+
+</overview>
+<recommendation>
+
+<p>Always check the result of SSL certificate verification. A certificate that has been revoked may indicate that data is coming from an attacker, whereas a certificate that has expired or was self-signed may indicate an increased likelihood that the data is malicious.</p>
+
+</recommendation>
+<example>
+
+<p>In this example, the <code>SSL_get_peer_certificate</code> function is used to get the certificate of a peer. However it is unsafe to use that information without checking if the certificate is valid.</p>
+
+<sample src="SSLResultNotCheckedBad.cpp" />
+
+<p>In the corrected example, we use <code>SSL_get_verify_result</code> to check that certificate verification was successful.</p>
+
+<sample src="SSLResultNotCheckedGood.cpp" />
+
+</example>
+<references>
+
+</references>
+</qhelp>

cpp/ql/src/Security/CWE/CWE-295/SSLResultNotChecked.ql

@@ -0,0 +1,120 @@
+/**
+ * @name Certificate not checked
+ * @description Always check the result of certificate verification after fetching an SSL certificate.
+ * @kind problem
+ * @problem.severity error
+ * @security-severity 7.5
+ * @precision medium
+ * @id cpp/certificate-not-checked
+ * @tags security
+ *       external/cwe/cwe-295
+ */
+
+import cpp
+import semmle.code.cpp.valuenumbering.GlobalValueNumbering
+import semmle.code.cpp.controlflow.IRGuards
+
+/**
+ * A call to `SSL_get_peer_certificate`.
+ */
+class SSLGetPeerCertificateCall extends FunctionCall {
+  SSLGetPeerCertificateCall() {
+    getTarget().getName() = "SSL_get_peer_certificate" // SSL_get_peer_certificate(ssl)
+  }
+
+  Expr getSSLArgument() { result = getArgument(0) }
+}
+
+/**
+ * A call to `SSL_get_verify_result`.
+ */
+class SSLGetVerifyResultCall extends FunctionCall {
+  SSLGetVerifyResultCall() {
+    getTarget().getName() = "SSL_get_verify_result" // SSL_get_peer_certificate(ssl)
+  }
+
+  Expr getSSLArgument() { result = getArgument(0) }
+}
+
+/**
+ * Holds if the SSL object passed into `SSL_get_peer_certificate` is checked with
+ * `SSL_get_verify_result` entering `node`.
+ */
+predicate resultIsChecked(SSLGetPeerCertificateCall getCertCall, ControlFlowNode node) {
+  exists(Expr ssl, SSLGetVerifyResultCall check |
+    ssl = globalValueNumber(getCertCall.getSSLArgument()).getAnExpr() and
+    ssl = check.getSSLArgument() and
+    node = check
+  )
+}
+
+/**
+ * Holds if the certificate returned by `SSL_get_peer_certificate` is found to be
+ * `0` on the edge `node1` to `node2`.
+ */
+predicate certIsZero(
+  SSLGetPeerCertificateCall getCertCall, ControlFlowNode node1, ControlFlowNode node2
+) {
+  exists(Expr cert | cert = globalValueNumber(getCertCall).getAnExpr() |
+    exists(GuardCondition guard, Expr zero |
+      zero.getValue().toInt() = 0 and
+      node1 = guard and
+      (
+        // if (cert == zero) {
+        guard.comparesEq(cert, zero, 0, true, true) and
+        node2 = guard.getATrueSuccessor()
+        or
+        // if (cert != zero) { }
+        guard.comparesEq(cert, zero, 0, false, true) and
+        node2 = guard.getAFalseSuccessor()
+      )
+    )
+    or
+    (
+      // if (cert) { }
+      node1 = cert
+      or
+      // if (!cert) {
+      node1.(NotExpr).getAChild() = cert
+    ) and
+    node2 = node1.getASuccessor() and
+    not cert.(GuardCondition).controls(node2, true) // cert may be false
+  )
+}
+
+/**
+ * Holds if the SSL object passed into `SSL_get_peer_certificate` has not been checked with
+ * `SSL_get_verify_result` at `node`. Note that this is only computed at the call to
+ * `SSL_get_peer_certificate` and at the start and end of `BasicBlock`s.
+ */
+predicate certNotChecked(SSLGetPeerCertificateCall getCertCall, ControlFlowNode node) {
+  // cert is not checked at the call to `SSL_get_peer_certificate`
+  node = getCertCall
+  or
+  exists(BasicBlock bb, int pos |
+    // flow to end of a `BasicBlock`
+    certNotChecked(getCertCall, bb.getNode(pos)) and
+    node = bb.getEnd() and
+    // check for barrier node
+    not exists(int pos2 |
+      pos2 > pos and
+      resultIsChecked(getCertCall, bb.getNode(pos2))
+    )
+  )
+  or
+  exists(BasicBlock pred, BasicBlock bb |
+    // flow from the end of one `BasicBlock` to the beginning of a successor
+    certNotChecked(getCertCall, pred.getEnd()) and
+    bb = pred.getASuccessor() and
+    node = bb.getStart() and
+    // check for barrier bb
+    not certIsZero(getCertCall, pred.getEnd(), bb.getStart())
+  )
+}
+
+from SSLGetPeerCertificateCall getCertCall, ControlFlowNode node
+where
+  certNotChecked(getCertCall, node) and
+  node instanceof Function // (function exit)
+select getCertCall,
+  "This " + getCertCall.toString() + " is not followed by a call to SSL_get_verify_result."

cpp/ql/src/Security/CWE/CWE-295/SSLResultNotCheckedBad.cpp

@@ -0,0 +1,5 @@
+// ...
+
+X509 *cert = SSL_get_peer_certificate(ssl); // BAD (SSL_get_verify_result is never called)
+
+// ...