Python: switch dataflow library to new (shared) CFG + SSA

Flips the Python dataflow trunk from the legacy CFG (semmle/python/Flow.qll)
and legacy ESSA SSA (semmle/python/essa/*) to the new shared CFG facade
(semmle.python.controlflow.internal.Cfg) and the new SSA adapter
(semmle.python.dataflow.new.internal.SsaImpl), both introduced
additively in the preceding PRs in this stack.

This is the trunk-flip equivalent of the original draft PR #21894 (kept
around as documentation), rebased on top of the four preparatory PRs:

  P1: Remove AstNode.getAFlowNode() and rewrite callers (#21919).
  P2: Qualify Flow.qll's AST references with Py:: prefix (#21920).
  P3: Add new shared-CFG-backed control flow graph (#21921).
  P4: Add new shared-SSA-backed SSA adapter (#21923).

The Python dataflow library (semmle/python/dataflow/new/) now imports
the new CFG facade and SSA adapter. All CFG-typed predicates
(ControlFlowNode, CallNode, BasicBlock, NameNode, AttrNode, ...) are
qualified with the Cfg:: prefix; SSA references switch from
EssaVariable/EssaDefinition to SsaImpl::Definition/SourceVariable.

GuardNode is redesigned to use the new CFG's outcome-node model
(isAfterTrue / isAfterFalse) instead of the legacy ConditionBlock +
flipped indirection. Only BarrierGuard<...> is preserved as public
API.

Framework files (Bottle, FastApi, Django, Tornado, Pyramid, Stdlib,
...) are updated to take CFG nodes from the new facade.

A handful of dataflow consistency tweaks for the new CFG:
- Augmented-assignment targets are treated as both load and store.
- 'from X import *' produces uncertain SSA writes for unknown names.
- CFG nodes are canonicalised so dataflow does not see equivalent
  pre/post-order pairs as distinct nodes.

Two AST tweaks for the new CFG:
- AstNodeImpl: omit PEP 695 type-parameter names from
  FunctionDefExpr / ClassDefExpr children.
- ImportResolution: drop the legacy essa import.

Test churn (~175 files): reblessed library- and query-test .expected
files reflect slightly different CFG granularity, different toString
output, and a handful of true alert deltas in security queries.

Verification: all 367 lib + src + consistency-queries compile clean.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

config/identical-files.json

@@ -11,6 +11,10 @@
     "java/ql/lib/semmle/code/java/dataflow/internal/rangeanalysis/SignAnalysisCommon.qll",
     "csharp/ql/lib/semmle/code/csharp/dataflow/internal/rangeanalysis/SignAnalysisCommon.qll"
   ],
+  "Bound Java/C#": [
+    "java/ql/lib/semmle/code/java/dataflow/Bound.qll",
+    "csharp/ql/lib/semmle/code/csharp/dataflow/Bound.qll"
+  ],
   "ModulusAnalysis Java/C#": [
     "java/ql/lib/semmle/code/java/dataflow/ModulusAnalysis.qll",
     "csharp/ql/lib/semmle/code/csharp/dataflow/ModulusAnalysis.qll"

csharp/ql/lib/qlpack.yml

@@ -9,7 +9,6 @@ dependencies:
   codeql/controlflow: ${workspace}
   codeql/dataflow: ${workspace}
   codeql/mad: ${workspace}
-  codeql/rangeanalysis: ${workspace}
   codeql/ssa: ${workspace}
   codeql/threat-models: ${workspace}
   codeql/tutorial: ${workspace}

csharp/ql/lib/semmle/code/csharp/dataflow/Bound.qll

@@ -4,11 +4,67 @@
 overlay[local?]
 module;
 
-private import csharp as CS
 private import internal.rangeanalysis.BoundSpecific
-private import internal.rangeanalysis.BoundSpecific as BoundSpecific
-private import codeql.rangeanalysis.Bound as SharedBound
 
-private module BoundImpl = SharedBound::Bound<CS::Location, BoundSpecific::BoundDefs>;
+private newtype TBound =
+  TBoundZero() or
+  TBoundSsa(SsaVariable v) { v.getSourceVariable().getType() instanceof IntegralType } or
+  TBoundExpr(Expr e) {
+    interestingExprBound(e) and
+    not exists(SsaVariable v | e = v.getAUse())
+  }
 
-import BoundImpl
+/**
+ * A bound that may be inferred for an expression plus/minus an integer delta.
+ */
+abstract class Bound extends TBound {
+  /** Gets a textual representation of this bound. */
+  abstract string toString();
+
+  /** Gets an expression that equals this bound plus `delta`. */
+  abstract Expr getExpr(int delta);
+
+  /** Gets an expression that equals this bound. */
+  Expr getExpr() { result = this.getExpr(0) }
+
+  /** Gets the location of this bound. */
+  abstract Location getLocation();
+}
+
+/**
+ * The bound that corresponds to the integer 0. This is used to represent all
+ * integer bounds as bounds are always accompanied by an added integer delta.
+ */
+class ZeroBound extends Bound, TBoundZero {
+  override string toString() { result = "0" }
+
+  override Expr getExpr(int delta) { result.(ConstantIntegerExpr).getIntValue() = delta }
+
+  override Location getLocation() { result.hasLocationInfo("", 0, 0, 0, 0) }
+}
+
+/**
+ * A bound corresponding to the value of an SSA variable.
+ */
+class SsaBound extends Bound, TBoundSsa {
+  /** Gets the SSA variable that equals this bound. */
+  SsaVariable getSsa() { this = TBoundSsa(result) }
+
+  override string toString() { result = this.getSsa().toString() }
+
+  override Expr getExpr(int delta) { result = this.getSsa().getAUse() and delta = 0 }
+
+  override Location getLocation() { result = this.getSsa().getLocation() }
+}
+
+/**
+ * A bound that corresponds to the value of a specific expression that might be
+ * interesting, but isn't otherwise represented by the value of an SSA variable.
+ */
+class ExprBound extends Bound, TBoundExpr {
+  override string toString() { result = this.getExpr().toString() }
+
+  override Expr getExpr(int delta) { this = TBoundExpr(result) and delta = 0 }
+
+  override Location getLocation() { result = this.getExpr().getLocation() }
+}

csharp/ql/lib/semmle/code/csharp/dataflow/internal/rangeanalysis/BoundSpecific.qll

@@ -1,30 +1,22 @@
 /**
  * Provides C#-specific definitions for bounds.
  */
-overlay[local?]
-module;
 
 private import csharp as CS
 private import semmle.code.csharp.dataflow.SSA::Ssa as Ssa
 private import semmle.code.csharp.dataflow.internal.rangeanalysis.ConstantUtils as CU
 private import semmle.code.csharp.dataflow.internal.rangeanalysis.RangeUtils as RU
 private import semmle.code.csharp.dataflow.internal.rangeanalysis.SsaUtils as SU
-private import codeql.rangeanalysis.Bound as SharedBound
 
-/** Provides C#-specific definitions for bounds. */
-module BoundDefs implements SharedBound::BoundDefinitions<CS::Location> {
-  class Type = CS::Type;
+class SsaVariable = SU::SsaVariable;
 
-  class SsaVariable = SU::SsaVariable;
+class Expr = CS::ControlFlowNodes::ExprNode;
 
-  class SsaSourceVariable = Ssa::SourceVariable;
+class Location = CS::Location;
 
-  class Expr = CS::ControlFlowNodes::ExprNode;
+class IntegralType = CS::IntegralType;
 
-  class IntegralType = CS::IntegralType;
+class ConstantIntegerExpr = CU::ConstantIntegerExpr;
 
-  class ConstantIntegerExpr = CU::ConstantIntegerExpr;
-
-  /** Holds if `e` is a bound expression and it is not an SSA variable read. */
-  predicate interestingExprBound(Expr e) { CU::systemArrayLengthAccess(e.getExpr()) }
-}
+/** Holds if `e` is a bound expression and it is not an SSA variable read. */
+predicate interestingExprBound(Expr e) { CU::systemArrayLengthAccess(e.getExpr()) }

java/ql/lib/semmle/code/java/dataflow/Bound.qll

@@ -4,10 +4,67 @@
 overlay[local?]
 module;
 
-private import java as J
-private import internal.rangeanalysis.BoundSpecific as BoundSpecific
-private import codeql.rangeanalysis.Bound as SharedBound
+private import internal.rangeanalysis.BoundSpecific
 
-private module BoundImpl = SharedBound::Bound<J::Location, BoundSpecific::BoundDefs>;
+private newtype TBound =
+  TBoundZero() or
+  TBoundSsa(SsaVariable v) { v.getSourceVariable().getType() instanceof IntegralType } or
+  TBoundExpr(Expr e) {
+    interestingExprBound(e) and
+    not exists(SsaVariable v | e = v.getAUse())
+  }
 
-import BoundImpl
+/**
+ * A bound that may be inferred for an expression plus/minus an integer delta.
+ */
+abstract class Bound extends TBound {
+  /** Gets a textual representation of this bound. */
+  abstract string toString();
+
+  /** Gets an expression that equals this bound plus `delta`. */
+  abstract Expr getExpr(int delta);
+
+  /** Gets an expression that equals this bound. */
+  Expr getExpr() { result = this.getExpr(0) }
+
+  /** Gets the location of this bound. */
+  abstract Location getLocation();
+}
+
+/**
+ * The bound that corresponds to the integer 0. This is used to represent all
+ * integer bounds as bounds are always accompanied by an added integer delta.
+ */
+class ZeroBound extends Bound, TBoundZero {
+  override string toString() { result = "0" }
+
+  override Expr getExpr(int delta) { result.(ConstantIntegerExpr).getIntValue() = delta }
+
+  override Location getLocation() { result.hasLocationInfo("", 0, 0, 0, 0) }
+}
+
+/**
+ * A bound corresponding to the value of an SSA variable.
+ */
+class SsaBound extends Bound, TBoundSsa {
+  /** Gets the SSA variable that equals this bound. */
+  SsaVariable getSsa() { this = TBoundSsa(result) }
+
+  override string toString() { result = this.getSsa().toString() }
+
+  override Expr getExpr(int delta) { result = this.getSsa().getAUse() and delta = 0 }
+
+  override Location getLocation() { result = this.getSsa().getLocation() }
+}
+
+/**
+ * A bound that corresponds to the value of a specific expression that might be
+ * interesting, but isn't otherwise represented by the value of an SSA variable.
+ */
+class ExprBound extends Bound, TBoundExpr {
+  override string toString() { result = this.getExpr().toString() }
+
+  override Expr getExpr(int delta) { this = TBoundExpr(result) and delta = 0 }
+
+  override Location getLocation() { result = this.getExpr().getLocation() }
+}

java/ql/lib/semmle/code/java/dataflow/internal/rangeanalysis/BoundSpecific.qll

@@ -7,26 +7,21 @@ module;
 private import java as J
 private import semmle.code.java.dataflow.SSA as Ssa
 private import semmle.code.java.dataflow.RangeUtils as RU
-private import codeql.rangeanalysis.Bound as SharedBound
 
-module BoundDefs implements SharedBound::BoundDefinitions<J::Location> {
-  class SsaVariable extends Ssa::SsaDefinition {
-    /** Gets a use of this variable. */
-    Expr getAUse() { result = super.getARead() }
-  }
-
-  class SsaSourceVariable = Ssa::SourceVariable;
-
-  class Type = J::Type;
-
-  class Expr = J::Expr;
-
-  class IntegralType = J::IntegralType;
-
-  class ConstantIntegerExpr = RU::ConstantIntegerExpr;
-
-  /** Holds if `e` is a bound expression and it is not an SSA variable read. */
-  predicate interestingExprBound(Expr e) {
-    e.(J::FieldRead).getField() instanceof J::ArrayLengthField
-  }
+class SsaVariable extends Ssa::SsaDefinition {
+  /** Gets a use of this variable. */
+  Expr getAUse() { result = super.getARead() }
+}
+
+class Expr = J::Expr;
+
+class Location = J::Location;
+
+class IntegralType = J::IntegralType;
+
+class ConstantIntegerExpr = RU::ConstantIntegerExpr;
+
+/** Holds if `e` is a bound expression and it is not an SSA variable read. */
+predicate interestingExprBound(Expr e) {
+  e.(J::FieldRead).getField() instanceof J::ArrayLengthField
 }

python/ql/consistency-queries/CfgConsistency.ql

@@ -0,0 +1,2 @@
+import semmle.python.controlflow.internal.AstNodeImpl
+import ControlFlow::Consistency

python/ql/consistency-queries/DataFlowConsistency.ql

@@ -9,6 +9,7 @@ private import semmle.python.dataflow.new.internal.DataFlowImplSpecific
 private import semmle.python.dataflow.new.internal.DataFlowDispatch
 private import semmle.python.dataflow.new.internal.TaintTrackingImplSpecific
 private import codeql.dataflow.internal.DataFlowImplConsistency
+private import semmle.python.controlflow.internal.Cfg as Cfg
 
 private module Input implements InputSig<Location, PythonDataFlow> {
   private import Private
@@ -72,7 +73,7 @@ private module Input implements InputSig<Location, PythonDataFlow> {
     // resolve to multiple functions), but we only make _one_ ArgumentNode for each
     // argument in the CallNode, we end up violating this consistency check in those
     // cases. (see `getCallArg` in DataFlowDispatch.qll)
-    exists(DataFlowCall other, CallNode cfgCall | other != call |
+    exists(DataFlowCall other, Cfg::CallNode cfgCall | other != call |
       call.getNode() = cfgCall and
       other.getNode() = cfgCall and
       isArgumentNode(arg, call, _) and
@@ -88,16 +89,16 @@ private module Input implements InputSig<Location, PythonDataFlow> {
       // allow it instead.
       (
         call.getScope() = attr.getScope() and
-        any(CfgNode n | n.asCfgNode() = call.getNode().(CallNode).getFunction()).getALocalSource() =
-          attr
+        any(CfgNode n | n.asCfgNode() = call.getNode().(Cfg::CallNode).getFunction())
+            .getALocalSource() = attr
         or
         not exists(call.getScope().(Function).getDefinition()) and
         call.getScope().getScope+() = attr.getScope()
       ) and
       (
         other.getScope() = attr.getScope() and
-        any(CfgNode n | n.asCfgNode() = other.getNode().(CallNode).getFunction()).getALocalSource() =
-          attr
+        any(CfgNode n | n.asCfgNode() = other.getNode().(Cfg::CallNode).getFunction())
+            .getALocalSource() = attr
         or
         not exists(other.getScope().(Function).getDefinition()) and
         other.getScope().getScope+() = attr.getScope()

python/ql/lib/LegacyPointsTo.qll

@@ -213,9 +213,11 @@ class ExprWithPointsTo extends Expr {
    * Gets what this expression might "refer-to" in the given `context`.
    */
   predicate refersTo(Context context, Object obj, ClassObject cls, AstNode origin) {
-    this.getAFlowNode()
-        .(ControlFlowNodeWithPointsTo)
-        .refersTo(context, obj, cls, origin.getAFlowNode())
+    exists(ControlFlowNode this_, ControlFlowNode origin_ |
+      this_.getNode() = this and origin_.getNode() = origin
+    |
+      this_.(ControlFlowNodeWithPointsTo).refersTo(context, obj, cls, origin_)
+    )
   }
 
   /**
@@ -226,7 +228,11 @@ class ExprWithPointsTo extends Expr {
    */
   pragma[nomagic]
   predicate refersTo(Object obj, AstNode origin) {
-    this.getAFlowNode().(ControlFlowNodeWithPointsTo).refersTo(obj, origin.getAFlowNode())
+    exists(ControlFlowNode this_, ControlFlowNode origin_ |
+      this_.getNode() = this and origin_.getNode() = origin
+    |
+      this_.(ControlFlowNodeWithPointsTo).refersTo(obj, origin_)
+    )
   }
 
   /**
@@ -240,16 +246,22 @@ class ExprWithPointsTo extends Expr {
    * in the given `context`.
    */
   predicate pointsTo(Context context, Value value, AstNode origin) {
-    this.getAFlowNode()
-        .(ControlFlowNodeWithPointsTo)
-        .pointsTo(context, value, origin.getAFlowNode())
+    exists(ControlFlowNode this_, ControlFlowNode origin_ |
+      this_.getNode() = this and origin_.getNode() = origin
+    |
+      this_.(ControlFlowNodeWithPointsTo).pointsTo(context, value, origin_)
+    )
   }
 
   /**
    * Holds if this expression might "point-to" to `value` which is from `origin`.
    */
   predicate pointsTo(Value value, AstNode origin) {
-    this.getAFlowNode().(ControlFlowNodeWithPointsTo).pointsTo(value, origin.getAFlowNode())
+    exists(ControlFlowNode this_, ControlFlowNode origin_ |
+      this_.getNode() = this and origin_.getNode() = origin
+    |
+      this_.(ControlFlowNodeWithPointsTo).pointsTo(value, origin_)
+    )
   }
 
   /**
@@ -475,7 +487,10 @@ class FunctionMetricsWithPointsTo extends FunctionMetrics {
     not non_coupling_method(result) and
     exists(Call call | call.getScope() = this |
       exists(FunctionObject callee | callee.getFunction() = result |
-        call.getAFlowNode().getFunction().(ControlFlowNodeWithPointsTo).refersTo(callee)
+        exists(CallNode call_ |
+          call_.getNode() = call and
+          call_.getFunction().(ControlFlowNodeWithPointsTo).refersTo(callee)
+        )
       )
       or
       exists(Attribute a | call.getFunc() = a |

python/ql/lib/analysis/DefinitionTracking.qll

@@ -64,7 +64,7 @@ private predicate jump_to_defn(ControlFlowNode use, Definition defn) {
 private predicate preferred_jump_to_defn(Expr use, Definition def) {
   not use instanceof ClassExpr and
   not use instanceof FunctionExpr and
-  jump_to_defn(use.getAFlowNode(), def)
+  exists(ControlFlowNode useNode | useNode.getNode() = use | jump_to_defn(useNode, def))
 }
 
 private predicate unique_jump_to_defn(Expr use, Definition def) {
@@ -452,7 +452,7 @@ private predicate self_parameter_jump_to_defn_attribute(
  * This exists primarily for testing use `getPreferredDefinition()` instead.
  */
 Definition getADefinition(Expr use) {
-  jump_to_defn(use.getAFlowNode(), result) and
+  exists(ControlFlowNode useNode | useNode.getNode() = use | jump_to_defn(useNode, result)) and
   not use instanceof Call and
   not use.isArtificial() and
   // Not the use itself

python/ql/lib/change-notes/2026-05-19-add-shared-cfg.md

@@ -0,0 +1,4 @@
+---
+category: minorAnalysis
+---
+* A new Python control flow graph implementation has been added under `semmle.python.controlflow.internal.Cfg` (backed by `AstNodeImpl.qll`), built on the shared `codeql.controlflow.ControlFlowGraph` library. It is not yet used by the dataflow library or any production query; the legacy CFG in `semmle/python/Flow.qll` remains the default. The new library is exposed for tests and for upcoming migrations.

python/ql/lib/change-notes/2026-05-19-add-shared-ssa.md

@@ -0,0 +1,4 @@
+---
+category: minorAnalysis
+---
+* A new SSA adapter has been added under `semmle.python.dataflow.new.internal.SsaImpl`, built on the shared `codeql.ssa.Ssa` library and the new shared CFG (`semmle.python.controlflow.internal.Cfg`). It is not yet used by the dataflow library or any production query; the legacy ESSA SSA in `semmle/python/essa/*` remains the default. The new SSA adapter is exposed for tests and for the upcoming dataflow migration.

python/ql/lib/change-notes/2026-05-19-deprecate-getAFlowNode.md

@@ -0,0 +1,5 @@
+---
+category: deprecated
+---
+* The `AstNode.getAFlowNode()` predicate has been deprecated. Use `ControlFlowNode.getNode()` from the other direction instead: replace `e.getAFlowNode() = n` with `n.getNode() = e`. This is a preparatory step towards migrating the dataflow library off the legacy CFG; it has no semantic effect.
+

python/ql/lib/change-notes/2026-06-01-decorator-predicate-simplification.md

@@ -0,0 +1,4 @@
+---
+category: minorAnalysis
+---
+* Simplified the internal predicates that detect `@staticmethod`, `@classmethod` and `@property` decorators to match the decorator's AST `Name` directly, rather than going through the CFG and requiring the name to resolve globally. Code that shadows these three builtin decorators at the module-scope will now be classified by the decorator name alone; in practice, shadowing these names is extremely rare and the call-graph results are unchanged.

python/ql/lib/change-notes/2026-06-01-deprecate-getAReturnValueFlowNode.md

@@ -0,0 +1,4 @@
+---
+category: deprecated
+---
+* The `Function.getAReturnValueFlowNode()` predicate has been deprecated. Bind a `Return` node explicitly instead — `exists(Return ret | ret.getScope() = f and n.getNode() = ret.getValue())`. This is a preparatory step towards migrating the dataflow library off the legacy CFG; it has no semantic effect.

python/ql/lib/change-notes/2026-06-02-deprecated-flow-nodes-use-new-cfg.md

@@ -0,0 +1,4 @@
+---
+category: breaking
+---
+* The deprecated `AstNode.getAFlowNode()` and `Function.getAReturnValueFlowNode()` predicates now return nodes from the new shared CFG (`Cfg::ControlFlowNode`) rather than from the legacy CFG (`ControlFlowNode`). Callers that still rely on these deprecated APIs and feed the result into legacy-CFG-aware predicates will no longer type-check; migrate to `n.getNode() = e` (or, for return values, the explicit `Return` pattern shown in the deprecation message) to get nodes from the dataflow library's current CFG.

python/ql/lib/printCfgNew.ql

@@ -0,0 +1,45 @@
+/**
+ * @name Print CFG (New)
+ * @description Produces a representation of a file's Control Flow Graph
+ *              using the new shared control flow library.
+ *              This query is used by the VS Code extension.
+ * @id python/print-cfg
+ * @kind graph
+ * @tags ide-contextual-queries/print-cfg
+ */
+
+private import python as Py
+import semmle.python.controlflow.internal.AstNodeImpl
+
+external string selectedSourceFile();
+
+private predicate selectedSourceFileAlias = selectedSourceFile/0;
+
+external int selectedSourceLine();
+
+private predicate selectedSourceLineAlias = selectedSourceLine/0;
+
+external int selectedSourceColumn();
+
+private predicate selectedSourceColumnAlias = selectedSourceColumn/0;
+
+module ViewCfgQueryInput implements ControlFlow::ViewCfgQueryInputSig<Py::File> {
+  predicate selectedSourceFile = selectedSourceFileAlias/0;
+
+  predicate selectedSourceLine = selectedSourceLineAlias/0;
+
+  predicate selectedSourceColumn = selectedSourceColumnAlias/0;
+
+  predicate cfgScopeSpan(
+    Ast::Callable callable, Py::File file, int startLine, int startColumn, int endLine,
+    int endColumn
+  ) {
+    exists(Py::Scope scope |
+      scope = callable.asScope() and
+      file = scope.getLocation().getFile() and
+      scope.getLocation().hasLocationInfo(_, startLine, startColumn, endLine, endColumn)
+    )
+  }
+}
+
+import ControlFlow::ViewCfgQuery<Py::File, ViewCfgQueryInput>

python/ql/lib/semmle/python/ApiGraphs.qll

@@ -6,8 +6,9 @@
  * directed and labeled; they specify how the components represented by nodes relate to each other.
  */
 
-// Importing python under the `py` namespace to avoid importing `CallNode` from `Flow.qll` and thereby having a naming conflict with `API::CallNode`.
+// Importing python under the `PY` namespace to avoid pulling in `CallNode` from `Flow.qll` (via `import python`) and thereby having a naming conflict with `API::CallNode`.
 private import python as PY
+private import semmle.python.controlflow.internal.Cfg as Cfg
 import semmle.python.dataflow.new.DataFlow
 private import semmle.python.internal.CachedStages
 
@@ -282,7 +283,7 @@ module API {
       index = this.getIndex() and
       (
         // subscripting
-        exists(PY::SubscriptNode subscript |
+        exists(Cfg::SubscriptNode subscript |
           subscript.getObject() = this.getAValueReachableFromSource().asCfgNode() and
           subscript.getIndex() = index.asSink().asCfgNode()
         |
@@ -290,7 +291,7 @@ module API {
           subscript = result.asSource().asCfgNode()
           or
           // writing
-          subscript.(PY::DefinitionNode).getValue() = result.asSink().asCfgNode()
+          subscript.(Cfg::DefinitionNode).getValue() = result.asSink().asCfgNode()
         )
         or
         // dictionary literals
@@ -684,7 +685,7 @@ module API {
      * Ignores relative imports, such as `from ..foo.bar import baz`.
      */
     private predicate imports(DataFlow::CfgNode imp, string name) {
-      exists(PY::ImportExprNode iexpr |
+      exists(Cfg::ImportExprNode iexpr |
         imp.getNode() = iexpr and
         not iexpr.getNode().isRelative() and
         name = iexpr.getNode().getImportedModuleName()
@@ -775,7 +776,7 @@ module API {
         // list literals, from `x` to `[x]`
         // TODO: once convenient, this should be done at a higher level than the AST,
         // at least at the CFG layer, to take splitting into account.
-        // Also consider `SequenceNode for generality.
+        // Also consider `Cfg::SequenceNode` for generality.
         exists(PY::List list | list = pred.(DataFlow::ExprNode).getNode().getNode() |
           rhs.(DataFlow::ExprNode).getNode().getNode() = list.getAnElt() and
           lbl = Label::subscript()
@@ -805,7 +806,7 @@ module API {
         subscript = trackUseNode(src).getSubscript(index)
       |
         // from `x` to a definition of `x[...]`
-        rhs.asCfgNode() = subscript.asCfgNode().(PY::DefinitionNode).getValue() and
+        rhs.asCfgNode() = subscript.asCfgNode().(Cfg::DefinitionNode).getValue() and
         lbl = Label::subscript()
         or
         // from `x` to `"key"` in `x["key"]`

python/ql/lib/semmle/python/AstExtended.qll

@@ -3,6 +3,7 @@ module;
 
 import python
 private import semmle.python.internal.CachedStages
+private import semmle.python.controlflow.internal.Cfg as Cfg
 
 /** A syntactic node (Class, Function, Module, Expr, Stmt or Comprehension) corresponding to a flow node */
 abstract class AstNode extends AstNode_ {
@@ -16,21 +17,25 @@ abstract class AstNode extends AstNode_ {
   /** Gets the scope that this node occurs in */
   abstract Scope getScope();
 
-  /**
-   * Gets a flow node corresponding directly to this node.
-   * NOTE: For some statements and other purely syntactic elements,
-   * there may not be a `ControlFlowNode`
-   */
-  cached
-  ControlFlowNode getAFlowNode() {
-    Stages::AST::ref() and
-    py_flow_bb_node(result, this, _, _)
-  }
-
   /** Gets the location for this AST node */
   cached
   Location getLocation() { none() }
 
+  /**
+   * DEPRECATED: use `ControlFlowNode.getNode()` from the other direction instead;
+   * that is, replace `e.getAFlowNode() = n` with `n.getNode() = e`. This API is
+   * being removed to untangle the AST and CFG hierarchies.
+   *
+   * Gets a flow node corresponding directly to this node, from the new
+   * (shared) CFG. NOTE: For some statements and other purely syntactic
+   * elements, there may not be a `ControlFlowNode`.
+   */
+  cached
+  deprecated Cfg::ControlFlowNode getAFlowNode() {
+    Stages::AST::ref() and
+    result.getNode() = this
+  }
+
   /**
    * Whether this syntactic element is artificial, that is it is generated
    * by the compiler and is not present in the source

python/ql/lib/semmle/python/Concepts.qll

@@ -5,6 +5,7 @@
  */
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import semmle.python.dataflow.new.DataFlow
 private import semmle.python.dataflow.new.internal.DataFlowImplSpecific
 private import semmle.python.dataflow.new.RemoteFlowSources
@@ -214,7 +215,7 @@ module Path {
     SafeAccessCheck() { this = DataFlow::BarrierGuard<safeAccessCheck/3>::getABarrierNode() }
   }
 
-  private predicate safeAccessCheck(DataFlow::GuardNode g, ControlFlowNode node, boolean branch) {
+  private predicate safeAccessCheck(DataFlow::GuardNode g, Cfg::ControlFlowNode node, boolean branch) {
     g.(SafeAccessCheck::Range).checks(node, branch)
   }
 
@@ -223,7 +224,7 @@ module Path {
     /** A data-flow node that checks that a path is safe to access in some way, for example by having a controlled prefix. */
     abstract class Range extends DataFlow::GuardNode {
       /** Holds if this guard validates `node` upon evaluating to `branch`. */
-      abstract predicate checks(ControlFlowNode node, boolean branch);
+      abstract predicate checks(Cfg::ControlFlowNode node, boolean branch);
     }
   }
 }

python/ql/lib/semmle/python/Exprs.qll

@@ -28,7 +28,9 @@ class Expr extends Expr_, AstNode {
   /** Whether this expression may have a side effect (as determined purely from its syntax) */
   predicate hasSideEffects() {
     /* If an exception raised by this expression handled, count that as a side effect */
-    this.getAFlowNode().getASuccessor().getNode() instanceof ExceptStmt
+    exists(ControlFlowNode n | n.getNode() = this |
+      n.getASuccessor().getNode() instanceof ExceptStmt
+    )
     or
     this.getASubExpression().hasSideEffects()
   }
@@ -68,8 +70,6 @@ class Attribute extends Attribute_ {
   /* syntax: Expr.name */
   override Expr getASubExpression() { result = this.getObject() }
 
-  override AttrNode getAFlowNode() { result = super.getAFlowNode() }
-
   /** Gets the name of this attribute. That is the `name` in `obj.name` */
   string getName() { result = Attribute_.super.getAttr() }
 
@@ -96,8 +96,6 @@ class Subscript extends Subscript_ {
   }
 
   Expr getObject() { result = Subscript_.super.getValue() }
-
-  override SubscriptNode getAFlowNode() { result = super.getAFlowNode() }
 }
 
 /** A call expression, such as `func(...)` */
@@ -113,8 +111,6 @@ class Call extends Call_ {
 
   override string toString() { result = this.getFunc().toString() + "()" }
 
-  override CallNode getAFlowNode() { result = super.getAFlowNode() }
-
   /** Gets a tuple (*) argument of this call. */
   Expr getStarargs() { result = this.getAPositionalArg().(Starred).getValue() }
 
@@ -200,8 +196,6 @@ class IfExp extends IfExp_ {
   override Expr getASubExpression() {
     result = this.getTest() or result = this.getBody() or result = this.getOrelse()
   }
-
-  override IfExprNode getAFlowNode() { result = super.getAFlowNode() }
 }
 
 /** A starred expression, such as the `*rest` in the assignment `first, *rest = seq` */
@@ -410,8 +404,6 @@ class PlaceHolder extends PlaceHolder_ {
   override Expr getASubExpression() { none() }
 
   override string toString() { result = "$" + this.getId() }
-
-  override NameNode getAFlowNode() { result = super.getAFlowNode() }
 }
 
 /** A tuple expression such as `( 1, 3, 5, 7, 9 )` */
@@ -478,8 +470,6 @@ class Name extends Name_ {
 
   override string toString() { result = this.getId() }
 
-  override NameNode getAFlowNode() { result = super.getAFlowNode() }
-
   override predicate isArtificial() {
     /* Artificial variable names in comprehensions all start with "." */
     this.getId().charAt(0) = "."
@@ -585,8 +575,6 @@ abstract class NameConstant extends Name, ImmutableLiteral {
 
   override predicate isConstant() { any() }
 
-  override NameConstantNode getAFlowNode() { result = Name.super.getAFlowNode() }
-
   override predicate isArtificial() { none() }
 }
 

python/ql/lib/semmle/python/Flow.qll

@@ -1,7 +1,7 @@
 overlay[local]
 module;
 
-import python
+import python as Py
 private import semmle.python.internal.CachedStages
 private import codeql.controlflow.BasicBlock as BB
 
@@ -17,7 +17,7 @@ private import codeql.controlflow.BasicBlock as BB
  */
 
 private predicate augstore(ControlFlowNode load, ControlFlowNode store) {
-  exists(Expr load_store | exists(AugAssign aa | aa.getTarget() = load_store) |
+  exists(Py::Expr load_store | exists(Py::AugAssign aa | aa.getTarget() = load_store) |
     toAst(load) = load_store and
     toAst(store) = load_store and
     load.strictlyDominates(store)
@@ -25,7 +25,7 @@ private predicate augstore(ControlFlowNode load, ControlFlowNode store) {
 }
 
 /** A non-dispatched getNode() to avoid negative recursion issues */
-private AstNode toAst(ControlFlowNode n) { py_flow_bb_node(n, result, _, _) }
+private Py::AstNode toAst(ControlFlowNode n) { py_flow_bb_node(n, result, _, _) }
 
 /**
  * A control flow node. Control flow nodes have a many-to-one relation with syntactic nodes,
@@ -35,19 +35,19 @@ private AstNode toAst(ControlFlowNode n) { py_flow_bb_node(n, result, _, _) }
 class ControlFlowNode extends @py_flow_node {
   /** Whether this control flow node is a load (including those in augmented assignments) */
   predicate isLoad() {
-    exists(Expr e | e = toAst(this) | py_expr_contexts(_, 3, e) and not augstore(_, this))
+    exists(Py::Expr e | e = toAst(this) | py_expr_contexts(_, 3, e) and not augstore(_, this))
   }
 
   /** Whether this control flow node is a store (including those in augmented assignments) */
   predicate isStore() {
-    exists(Expr e | e = toAst(this) | py_expr_contexts(_, 5, e) or augstore(_, this))
+    exists(Py::Expr e | e = toAst(this) | py_expr_contexts(_, 5, e) or augstore(_, this))
   }
 
   /** Whether this control flow node is a delete */
-  predicate isDelete() { exists(Expr e | e = toAst(this) | py_expr_contexts(_, 2, e)) }
+  predicate isDelete() { exists(Py::Expr e | e = toAst(this) | py_expr_contexts(_, 2, e)) }
 
   /** Whether this control flow node is a parameter */
-  predicate isParameter() { exists(Expr e | e = toAst(this) | py_expr_contexts(_, 4, e)) }
+  predicate isParameter() { exists(Py::Expr e | e = toAst(this) | py_expr_contexts(_, 4, e)) }
 
   /** Whether this control flow node is a store in an augmented assignment */
   predicate isAugStore() { augstore(_, this) }
@@ -57,61 +57,61 @@ class ControlFlowNode extends @py_flow_node {
 
   /** Whether this flow node corresponds to a literal */
   predicate isLiteral() {
-    toAst(this) instanceof Bytes
+    toAst(this) instanceof Py::Bytes
     or
-    toAst(this) instanceof Dict
+    toAst(this) instanceof Py::Dict
     or
-    toAst(this) instanceof DictComp
+    toAst(this) instanceof Py::DictComp
     or
-    toAst(this) instanceof Set
+    toAst(this) instanceof Py::Set
     or
-    toAst(this) instanceof SetComp
+    toAst(this) instanceof Py::SetComp
     or
-    toAst(this) instanceof Ellipsis
+    toAst(this) instanceof Py::Ellipsis
     or
-    toAst(this) instanceof GeneratorExp
+    toAst(this) instanceof Py::GeneratorExp
     or
-    toAst(this) instanceof Lambda
+    toAst(this) instanceof Py::Lambda
     or
-    toAst(this) instanceof ListComp
+    toAst(this) instanceof Py::ListComp
     or
-    toAst(this) instanceof List
+    toAst(this) instanceof Py::List
     or
-    toAst(this) instanceof Num
+    toAst(this) instanceof Py::Num
     or
-    toAst(this) instanceof Tuple
+    toAst(this) instanceof Py::Tuple
     or
-    toAst(this) instanceof Unicode
+    toAst(this) instanceof Py::Unicode
     or
-    toAst(this) instanceof NameConstant
+    toAst(this) instanceof Py::NameConstant
   }
 
   /** Whether this flow node corresponds to an attribute expression */
-  predicate isAttribute() { toAst(this) instanceof Attribute }
+  predicate isAttribute() { toAst(this) instanceof Py::Attribute }
 
   /** Whether this flow node corresponds to an subscript expression */
-  predicate isSubscript() { toAst(this) instanceof Subscript }
+  predicate isSubscript() { toAst(this) instanceof Py::Subscript }
 
   /** Whether this flow node corresponds to an import member */
-  predicate isImportMember() { toAst(this) instanceof ImportMember }
+  predicate isImportMember() { toAst(this) instanceof Py::ImportMember }
 
   /** Whether this flow node corresponds to a call */
-  predicate isCall() { toAst(this) instanceof Call }
+  predicate isCall() { toAst(this) instanceof Py::Call }
 
   /** Whether this flow node is the first in a module */
-  predicate isModuleEntry() { this.isEntryNode() and toAst(this) instanceof Module }
+  predicate isModuleEntry() { this.isEntryNode() and toAst(this) instanceof Py::Module }
 
   /** Whether this flow node corresponds to an import */
-  predicate isImport() { toAst(this) instanceof ImportExpr }
+  predicate isImport() { toAst(this) instanceof Py::ImportExpr }
 
   /** Whether this flow node corresponds to a conditional expression */
-  predicate isIfExp() { toAst(this) instanceof IfExp }
+  predicate isIfExp() { toAst(this) instanceof Py::IfExp }
 
   /** Whether this flow node corresponds to a function definition expression */
-  predicate isFunction() { toAst(this) instanceof FunctionExpr }
+  predicate isFunction() { toAst(this) instanceof Py::FunctionExpr }
 
   /** Whether this flow node corresponds to a class definition expression */
-  predicate isClass() { toAst(this) instanceof ClassExpr }
+  predicate isClass() { toAst(this) instanceof Py::ClassExpr }
 
   /** Gets a predecessor of this flow node */
   ControlFlowNode getAPredecessor() { this = result.getASuccessor() }
@@ -123,25 +123,25 @@ class ControlFlowNode extends @py_flow_node {
   ControlFlowNode getImmediateDominator() { py_idoms(this, result) }
 
   /** Gets the syntactic element corresponding to this flow node */
-  AstNode getNode() { py_flow_bb_node(this, result, _, _) }
+  Py::AstNode getNode() { py_flow_bb_node(this, result, _, _) }
 
   /** Gets a textual representation of this element. */
   cached
   string toString() {
     Stages::AST::ref() and
     // Since modules can have ambigous names, entry nodes can too, if we do not collate them.
-    exists(Scope s | s.getEntryNode() = this |
+    exists(Py::Scope s | s.getEntryNode() = this |
       result = "Entry node for " + concat( | | s.toString(), ",")
     )
     or
-    exists(Scope s | s.getANormalExit() = this | result = "Exit node for " + s.toString())
+    exists(Py::Scope s | s.getANormalExit() = this | result = "Exit node for " + s.toString())
     or
-    not exists(Scope s | s.getEntryNode() = this or s.getANormalExit() = this) and
+    not exists(Py::Scope s | s.getEntryNode() = this or s.getANormalExit() = this) and
     result = "ControlFlowNode for " + this.getNode().toString()
   }
 
   /** Gets the location of this ControlFlowNode */
-  Location getLocation() { result = this.getNode().getLocation() }
+  Py::Location getLocation() { result = this.getNode().getLocation() }
 
   /** Whether this flow node is the first in its scope */
   predicate isEntryNode() { py_scope_flow(this, _, -1) }
@@ -151,9 +151,9 @@ class ControlFlowNode extends @py_flow_node {
 
   /** Gets the scope containing this flow node */
   cached
-  Scope getScope() {
+  Py::Scope getScope() {
     Stages::AST::ref() and
-    if this.getNode() instanceof Scope
+    if this.getNode() instanceof Py::Scope
     then
       /* Entry or exit node */
       result = this.getNode()
@@ -161,7 +161,7 @@ class ControlFlowNode extends @py_flow_node {
   }
 
   /** Gets the enclosing module */
-  Module getEnclosingModule() { result = this.getScope().getEnclosingModule() }
+  Py::Module getEnclosingModule() { result = this.getScope().getEnclosingModule() }
 
   /** Gets a successor for this node if the relevant condition is True. */
   ControlFlowNode getATrueSuccessor() {
@@ -188,7 +188,7 @@ class ControlFlowNode extends @py_flow_node {
   }
 
   /** Whether the scope may be exited as a result of this node raising an exception */
-  predicate isExceptionalExit(Scope s) { py_scope_flow(this, s, 1) }
+  predicate isExceptionalExit(Py::Scope s) { py_scope_flow(this, s, 1) }
 
   /** Whether this node is a normal (non-exceptional) exit */
   predicate isNormalExit() { py_scope_flow(this, _, 0) or py_scope_flow(this, _, 2) }
@@ -236,7 +236,7 @@ class ControlFlowNode extends @py_flow_node {
   /* join-ordering helper for `getAChild() */
   pragma[noinline]
   private ControlFlowNode getExprChild(BasicBlock dom) {
-    this.getNode().(Expr).getAChildNode() = result.getNode() and
+    this.getNode().(Py::Expr).getAChildNode() = result.getNode() and
     result.getBasicBlock().dominates(dom) and
     not this instanceof UnaryExprNode
   }
@@ -249,16 +249,16 @@ class ControlFlowNode extends @py_flow_node {
  */
 
 private class AnyNode extends ControlFlowNode {
-  override AstNode getNode() { result = super.getNode() }
+  override Py::AstNode getNode() { result = super.getNode() }
 }
 
 /** A control flow node corresponding to a call expression, such as `func(...)` */
 class CallNode extends ControlFlowNode {
-  CallNode() { toAst(this) instanceof Call }
+  CallNode() { toAst(this) instanceof Py::Call }
 
   /** Gets the flow node corresponding to the function expression for the call corresponding to this flow node */
   ControlFlowNode getFunction() {
-    exists(Call c |
+    exists(Py::Call c |
       this.getNode() = c and
       c.getFunc() = result.getNode() and
       result.getBasicBlock().dominates(this.getBasicBlock())
@@ -267,7 +267,7 @@ class CallNode extends ControlFlowNode {
 
   /** Gets the flow node corresponding to the n'th positional argument of the call corresponding to this flow node */
   ControlFlowNode getArg(int n) {
-    exists(Call c |
+    exists(Py::Call c |
       this.getNode() = c and
       c.getArg(n) = result.getNode() and
       result.getBasicBlock().dominates(this.getBasicBlock())
@@ -276,7 +276,7 @@ class CallNode extends ControlFlowNode {
 
   /** Gets the flow node corresponding to the named argument of the call corresponding to this flow node */
   ControlFlowNode getArgByName(string name) {
-    exists(Call c, Keyword k |
+    exists(Py::Call c, Py::Keyword k |
       this.getNode() = c and
       k = c.getANamedArg() and
       k.getValue() = result.getNode() and
@@ -292,7 +292,7 @@ class CallNode extends ControlFlowNode {
     result = this.getArgByName(_)
   }
 
-  override Call getNode() { result = super.getNode() }
+  override Py::Call getNode() { result = super.getNode() }
 
   predicate isDecoratorCall() {
     this.isClassDecoratorCall()
@@ -301,11 +301,11 @@ class CallNode extends ControlFlowNode {
   }
 
   predicate isClassDecoratorCall() {
-    exists(ClassExpr cls | this.getNode() = cls.getADecoratorCall())
+    exists(Py::ClassExpr cls | this.getNode() = cls.getADecoratorCall())
   }
 
   predicate isFunctionDecoratorCall() {
-    exists(FunctionExpr func | this.getNode() = func.getADecoratorCall())
+    exists(Py::FunctionExpr func | this.getNode() = func.getADecoratorCall())
   }
 
   /** Gets the first tuple (*) argument of this call, if any. */
@@ -323,11 +323,11 @@ class CallNode extends ControlFlowNode {
 
 /** A control flow corresponding to an attribute expression, such as `value.attr` */
 class AttrNode extends ControlFlowNode {
-  AttrNode() { toAst(this) instanceof Attribute }
+  AttrNode() { toAst(this) instanceof Py::Attribute }
 
   /** Gets the flow node corresponding to the object of the attribute expression corresponding to this flow node */
   ControlFlowNode getObject() {
-    exists(Attribute a |
+    exists(Py::Attribute a |
       this.getNode() = a and
       a.getObject() = result.getNode() and
       result.getBasicBlock().dominates(this.getBasicBlock())
@@ -339,7 +339,7 @@ class AttrNode extends ControlFlowNode {
    * with the matching name
    */
   ControlFlowNode getObject(string name) {
-    exists(Attribute a |
+    exists(Py::Attribute a |
       this.getNode() = a and
       a.getObject() = result.getNode() and
       a.getName() = name and
@@ -348,57 +348,57 @@ class AttrNode extends ControlFlowNode {
   }
 
   /** Gets the attribute name of the attribute expression corresponding to this flow node */
-  string getName() { exists(Attribute a | this.getNode() = a and a.getName() = result) }
+  string getName() { exists(Py::Attribute a | this.getNode() = a and a.getName() = result) }
 
-  override Attribute getNode() { result = super.getNode() }
+  override Py::Attribute getNode() { result = super.getNode() }
 }
 
 /** A control flow node corresponding to a `from ... import ...` expression */
 class ImportMemberNode extends ControlFlowNode {
-  ImportMemberNode() { toAst(this) instanceof ImportMember }
+  ImportMemberNode() { toAst(this) instanceof Py::ImportMember }
 
   /**
    * Gets the flow node corresponding to the module in the import-member expression corresponding to this flow node,
    * with the matching name
    */
   ControlFlowNode getModule(string name) {
-    exists(ImportMember i | this.getNode() = i and i.getModule() = result.getNode() |
+    exists(Py::ImportMember i | this.getNode() = i and i.getModule() = result.getNode() |
       i.getName() = name and
       result.getBasicBlock().dominates(this.getBasicBlock())
     )
   }
 
-  override ImportMember getNode() { result = super.getNode() }
+  override Py::ImportMember getNode() { result = super.getNode() }
 }
 
 /** A control flow node corresponding to an artificial expression representing an import */
 class ImportExprNode extends ControlFlowNode {
-  ImportExprNode() { toAst(this) instanceof ImportExpr }
+  ImportExprNode() { toAst(this) instanceof Py::ImportExpr }
 
-  override ImportExpr getNode() { result = super.getNode() }
+  override Py::ImportExpr getNode() { result = super.getNode() }
 }
 
 /** A control flow node corresponding to a `from ... import *` statement */
 class ImportStarNode extends ControlFlowNode {
-  ImportStarNode() { toAst(this) instanceof ImportStar }
+  ImportStarNode() { toAst(this) instanceof Py::ImportStar }
 
   /** Gets the flow node corresponding to the module in the import-star corresponding to this flow node */
   ControlFlowNode getModule() {
-    exists(ImportStar i | this.getNode() = i and i.getModuleExpr() = result.getNode() |
+    exists(Py::ImportStar i | this.getNode() = i and i.getModuleExpr() = result.getNode() |
       result.getBasicBlock().dominates(this.getBasicBlock())
     )
   }
 
-  override ImportStar getNode() { result = super.getNode() }
+  override Py::ImportStar getNode() { result = super.getNode() }
 }
 
 /** A control flow node corresponding to a subscript expression, such as `value[slice]` */
 class SubscriptNode extends ControlFlowNode {
-  SubscriptNode() { toAst(this) instanceof Subscript }
+  SubscriptNode() { toAst(this) instanceof Py::Subscript }
 
   /** flow node corresponding to the value of the sequence in a subscript operation */
   ControlFlowNode getObject() {
-    exists(Subscript s |
+    exists(Py::Subscript s |
       this.getNode() = s and
       s.getObject() = result.getNode() and
       result.getBasicBlock().dominates(this.getBasicBlock())
@@ -407,23 +407,23 @@ class SubscriptNode extends ControlFlowNode {
 
   /** flow node corresponding to the index in a subscript operation */
   ControlFlowNode getIndex() {
-    exists(Subscript s |
+    exists(Py::Subscript s |
       this.getNode() = s and
       s.getIndex() = result.getNode() and
       result.getBasicBlock().dominates(this.getBasicBlock())
     )
   }
 
-  override Subscript getNode() { result = super.getNode() }
+  override Py::Subscript getNode() { result = super.getNode() }
 }
 
 /** A control flow node corresponding to a comparison operation, such as `x<y` */
 class CompareNode extends ControlFlowNode {
-  CompareNode() { toAst(this) instanceof Compare }
+  CompareNode() { toAst(this) instanceof Py::Compare }
 
   /** Whether left and right are a pair of operands for this comparison */
-  predicate operands(ControlFlowNode left, Cmpop op, ControlFlowNode right) {
-    exists(Compare c, Expr eleft, Expr eright |
+  predicate operands(ControlFlowNode left, Py::Cmpop op, ControlFlowNode right) {
+    exists(Py::Compare c, Py::Expr eleft, Py::Expr eright |
       this.getNode() = c and left.getNode() = eleft and right.getNode() = eright
     |
       eleft = c.getLeft() and eright = c.getComparator(0) and op = c.getOp(0)
@@ -436,26 +436,26 @@ class CompareNode extends ControlFlowNode {
     right.getBasicBlock().dominates(this.getBasicBlock())
   }
 
-  override Compare getNode() { result = super.getNode() }
+  override Py::Compare getNode() { result = super.getNode() }
 }
 
 /** A control flow node corresponding to a conditional expression such as, `body if test else orelse` */
 class IfExprNode extends ControlFlowNode {
-  IfExprNode() { toAst(this) instanceof IfExp }
+  IfExprNode() { toAst(this) instanceof Py::IfExp }
 
   /** flow node corresponding to one of the operands of an if-expression */
   ControlFlowNode getAnOperand() { result = this.getAPredecessor() }
 
-  override IfExp getNode() { result = super.getNode() }
+  override Py::IfExp getNode() { result = super.getNode() }
 }
 
 /** A control flow node corresponding to an assignment expression such as `lhs := rhs`. */
 class AssignmentExprNode extends ControlFlowNode {
-  AssignmentExprNode() { toAst(this) instanceof AssignExpr }
+  AssignmentExprNode() { toAst(this) instanceof Py::AssignExpr }
 
   /** Gets the flow node corresponding to the left-hand side of the assignment expression */
   ControlFlowNode getTarget() {
-    exists(AssignExpr a |
+    exists(Py::AssignExpr a |
       this.getNode() = a and
       a.getTarget() = result.getNode() and
       result.getBasicBlock().dominates(this.getBasicBlock())
@@ -464,27 +464,27 @@ class AssignmentExprNode extends ControlFlowNode {
 
   /** Gets the flow node corresponding to the right-hand side of the assignment expression */
   ControlFlowNode getValue() {
-    exists(AssignExpr a |
+    exists(Py::AssignExpr a |
       this.getNode() = a and
       a.getValue() = result.getNode() and
       result.getBasicBlock().dominates(this.getBasicBlock())
     )
   }
 
-  override AssignExpr getNode() { result = super.getNode() }
+  override Py::AssignExpr getNode() { result = super.getNode() }
 }
 
 /** A control flow node corresponding to a binary expression, such as `x + y` */
 class BinaryExprNode extends ControlFlowNode {
-  BinaryExprNode() { toAst(this) instanceof BinaryExpr }
+  BinaryExprNode() { toAst(this) instanceof Py::BinaryExpr }
 
   /** flow node corresponding to one of the operands of a binary expression */
   ControlFlowNode getAnOperand() { result = this.getLeft() or result = this.getRight() }
 
-  override BinaryExpr getNode() { result = super.getNode() }
+  override Py::BinaryExpr getNode() { result = super.getNode() }
 
   ControlFlowNode getLeft() {
-    exists(BinaryExpr b |
+    exists(Py::BinaryExpr b |
       this.getNode() = b and
       result.getNode() = b.getLeft() and
       result.getBasicBlock().dominates(this.getBasicBlock())
@@ -492,7 +492,7 @@ class BinaryExprNode extends ControlFlowNode {
   }
 
   ControlFlowNode getRight() {
-    exists(BinaryExpr b |
+    exists(Py::BinaryExpr b |
       this.getNode() = b and
       result.getNode() = b.getRight() and
       result.getBasicBlock().dominates(this.getBasicBlock())
@@ -500,11 +500,11 @@ class BinaryExprNode extends ControlFlowNode {
   }
 
   /** Gets the operator of this binary expression node. */
-  Operator getOp() { result = this.getNode().getOp() }
+  Py::Operator getOp() { result = this.getNode().getOp() }
 
   /** Whether left and right are a pair of operands for this binary expression */
-  predicate operands(ControlFlowNode left, Operator op, ControlFlowNode right) {
-    exists(BinaryExpr b, Expr eleft, Expr eright |
+  predicate operands(ControlFlowNode left, Py::Operator op, ControlFlowNode right) {
+    exists(Py::BinaryExpr b, Py::Expr eleft, Py::Expr eright |
       this.getNode() = b and left.getNode() = eleft and right.getNode() = eright
     |
       eleft = b.getLeft() and eright = b.getRight() and op = b.getOp()
@@ -516,20 +516,20 @@ class BinaryExprNode extends ControlFlowNode {
 
 /** A control flow node corresponding to a boolean shortcut (and/or) operation */
 class BoolExprNode extends ControlFlowNode {
-  BoolExprNode() { toAst(this) instanceof BoolExpr }
+  BoolExprNode() { toAst(this) instanceof Py::BoolExpr }
 
   /** flow node corresponding to one of the operands of a boolean expression */
   ControlFlowNode getAnOperand() {
-    exists(BoolExpr b | this.getNode() = b and result.getNode() = b.getAValue()) and
+    exists(Py::BoolExpr b | this.getNode() = b and result.getNode() = b.getAValue()) and
     this.getBasicBlock().dominates(result.getBasicBlock())
   }
 
-  override BoolExpr getNode() { result = super.getNode() }
+  override Py::BoolExpr getNode() { result = super.getNode() }
 }
 
 /** A control flow node corresponding to a unary expression: (`+x`), (`-x`) or (`~x`) */
 class UnaryExprNode extends ControlFlowNode {
-  UnaryExprNode() { toAst(this) instanceof UnaryExpr }
+  UnaryExprNode() { toAst(this) instanceof Py::UnaryExpr }
 
   /**
    * Gets flow node corresponding to the operand of a unary expression.
@@ -540,7 +540,7 @@ class UnaryExprNode extends ControlFlowNode {
    */
   ControlFlowNode getOperand() { result = this.getAPredecessor() }
 
-  override UnaryExpr getNode() { result = super.getNode() }
+  override Py::UnaryExpr getNode() { result = super.getNode() }
 
   override ControlFlowNode getAChild() { result = this.getAPredecessor() }
 }
@@ -555,27 +555,27 @@ class DefinitionNode extends ControlFlowNode {
   cached
   DefinitionNode() {
     Stages::AST::ref() and
-    exists(Assign a | a.getATarget().getAFlowNode() = this)
+    exists(Py::Assign a | this.getNode() = a.getATarget())
     or
-    exists(AssignExpr a | a.getTarget().getAFlowNode() = this)
+    exists(Py::AssignExpr a | this.getNode() = a.getTarget())
     or
-    exists(AnnAssign a | a.getTarget().getAFlowNode() = this and exists(a.getValue()))
+    exists(Py::AnnAssign a | this.getNode() = a.getTarget() and exists(a.getValue()))
     or
-    exists(Alias a | a.getAsname().getAFlowNode() = this)
+    exists(Py::Alias a | this.getNode() = a.getAsname())
     or
     augstore(_, this)
     or
     // `x, y = 1, 2` where LHS is a combination of list or tuples
-    exists(Assign a | list_or_tuple_nested_element(a.getATarget()).getAFlowNode() = this)
+    exists(Py::Assign a | this.getNode() = list_or_tuple_nested_element(a.getATarget()))
     or
-    exists(For for | for.getTarget().getAFlowNode() = this)
+    exists(Py::For for | this.getNode() = for.getTarget())
     or
-    exists(Parameter param | this = param.asName().getAFlowNode() and exists(param.getDefault()))
+    exists(Py::Parameter param | this.getNode() = param.asName() and exists(param.getDefault()))
   }
 
   /** flow node corresponding to the value assigned for the definition corresponding to this flow node */
   ControlFlowNode getValue() {
-    result = assigned_value(this.getNode()).getAFlowNode() and
+    result.getNode() = assigned_value(this.getNode()) and
     (
       result.getBasicBlock().dominates(this.getBasicBlock())
       or
@@ -584,16 +584,16 @@ class DefinitionNode extends ControlFlowNode {
       // since the default value for a parameter is evaluated in the same basic block as
       // the function definition, but the parameter belongs to the basic block of the function,
       // there is no dominance relationship between the two.
-      exists(Parameter param | this = param.asName().getAFlowNode())
+      exists(Py::Parameter param | this.getNode() = param.asName())
     )
   }
 }
 
-private Expr list_or_tuple_nested_element(Expr list_or_tuple) {
-  exists(Expr elt |
-    elt = list_or_tuple.(Tuple).getAnElt()
+private Py::Expr list_or_tuple_nested_element(Py::Expr list_or_tuple) {
+  exists(Py::Expr elt |
+    elt = list_or_tuple.(Py::Tuple).getAnElt()
     or
-    elt = list_or_tuple.(List).getAnElt()
+    elt = list_or_tuple.(Py::List).getAnElt()
   |
     result = elt
     or
@@ -603,12 +603,12 @@ private Expr list_or_tuple_nested_element(Expr list_or_tuple) {
 
 /**
  * A control flow node corresponding to a deletion statement, such as `del x`.
- * There can be multiple `DeletionNode`s for each `Delete` such that each
+ * There can be multiple `DeletionNode`s for each `Py::Delete` such that each
  * target has own `DeletionNode`. The CFG for `del a, x.y` looks like:
  * `NameNode('a') -> DeletionNode -> NameNode('b') -> AttrNode('y') -> DeletionNode`.
  */
 class DeletionNode extends ControlFlowNode {
-  DeletionNode() { toAst(this) instanceof Delete }
+  DeletionNode() { toAst(this) instanceof Py::Delete }
 
   /** Gets the unique target of this deletion node. */
   ControlFlowNode getTarget() { result.getASuccessor() = this }
@@ -617,9 +617,9 @@ class DeletionNode extends ControlFlowNode {
 /** A control flow node corresponding to a sequence (tuple or list) literal */
 abstract class SequenceNode extends ControlFlowNode {
   SequenceNode() {
-    toAst(this) instanceof Tuple
+    toAst(this) instanceof Py::Tuple
     or
-    toAst(this) instanceof List
+    toAst(this) instanceof Py::List
   }
 
   /** Gets the control flow node for an element of this sequence */
@@ -632,11 +632,11 @@ abstract class SequenceNode extends ControlFlowNode {
 
 /** A control flow node corresponding to a tuple expression such as `( 1, 3, 5, 7, 9 )` */
 class TupleNode extends SequenceNode {
-  TupleNode() { toAst(this) instanceof Tuple }
+  TupleNode() { toAst(this) instanceof Py::Tuple }
 
   override ControlFlowNode getElement(int n) {
     Stages::AST::ref() and
-    exists(Tuple t | this.getNode() = t and result.getNode() = t.getElt(n)) and
+    exists(Py::Tuple t | this.getNode() = t and result.getNode() = t.getElt(n)) and
     (
       result.getBasicBlock().dominates(this.getBasicBlock())
       or
@@ -647,10 +647,10 @@ class TupleNode extends SequenceNode {
 
 /** A control flow node corresponding to a list expression, such as `[ 1, 3, 5, 7, 9 ]` */
 class ListNode extends SequenceNode {
-  ListNode() { toAst(this) instanceof List }
+  ListNode() { toAst(this) instanceof Py::List }
 
   override ControlFlowNode getElement(int n) {
-    exists(List l | this.getNode() = l and result.getNode() = l.getElt(n)) and
+    exists(Py::List l | this.getNode() = l and result.getNode() = l.getElt(n)) and
     (
       result.getBasicBlock().dominates(this.getBasicBlock())
       or
@@ -661,10 +661,10 @@ class ListNode extends SequenceNode {
 
 /** A control flow node corresponding to a set expression, such as `{ 1, 3, 5, 7, 9 }` */
 class SetNode extends ControlFlowNode {
-  SetNode() { toAst(this) instanceof Set }
+  SetNode() { toAst(this) instanceof Py::Set }
 
   ControlFlowNode getAnElement() {
-    exists(Set s | this.getNode() = s and result.getNode() = s.getElt(_)) and
+    exists(Py::Set s | this.getNode() = s and result.getNode() = s.getElt(_)) and
     (
       result.getBasicBlock().dominates(this.getBasicBlock())
       or
@@ -675,20 +675,20 @@ class SetNode extends ControlFlowNode {
 
 /** A control flow node corresponding to a dictionary literal, such as `{ 'a': 1, 'b': 2 }` */
 class DictNode extends ControlFlowNode {
-  DictNode() { toAst(this) instanceof Dict }
+  DictNode() { toAst(this) instanceof Py::Dict }
 
   /**
    * Gets a key of this dictionary literal node, for those items that have keys
    * E.g, in {'a':1, **b} this returns only 'a'
    */
   ControlFlowNode getAKey() {
-    exists(Dict d | this.getNode() = d and result.getNode() = d.getAKey()) and
+    exists(Py::Dict d | this.getNode() = d and result.getNode() = d.getAKey()) and
     result.getBasicBlock().dominates(this.getBasicBlock())
   }
 
   /** Gets a value of this dictionary literal node */
   ControlFlowNode getAValue() {
-    exists(Dict d | this.getNode() = d and result.getNode() = d.getAValue()) and
+    exists(Py::Dict d | this.getNode() = d and result.getNode() = d.getAValue()) and
     result.getBasicBlock().dominates(this.getBasicBlock())
   }
 }
@@ -712,21 +712,23 @@ class IterableNode extends ControlFlowNode {
   }
 }
 
-private AstNode assigned_value(Expr lhs) {
+private Py::AstNode assigned_value(Py::Expr lhs) {
   /* lhs = result */
-  exists(Assign a | a.getATarget() = lhs and result = a.getValue())
+  exists(Py::Assign a | a.getATarget() = lhs and result = a.getValue())
   or
   /* lhs := result */
-  exists(AssignExpr a | a.getTarget() = lhs and result = a.getValue())
+  exists(Py::AssignExpr a | a.getTarget() = lhs and result = a.getValue())
   or
   /* lhs : annotation = result */
-  exists(AnnAssign a | a.getTarget() = lhs and result = a.getValue())
+  exists(Py::AnnAssign a | a.getTarget() = lhs and result = a.getValue())
   or
   /* import result as lhs */
-  exists(Alias a | a.getAsname() = lhs and result = a.getValue())
+  exists(Py::Alias a | a.getAsname() = lhs and result = a.getValue())
   or
   /* lhs += x  =>  result = (lhs + x) */
-  exists(AugAssign a, BinaryExpr b | b = a.getOperation() and result = b and lhs = b.getLeft())
+  exists(Py::AugAssign a, Py::BinaryExpr b |
+    b = a.getOperation() and result = b and lhs = b.getLeft()
+  )
   or
   /*
    * ..., lhs, ... = ..., result, ...
@@ -734,31 +736,31 @@ private AstNode assigned_value(Expr lhs) {
    * ..., (..., lhs, ...), ... = ..., (..., result, ...), ...
    */
 
-  exists(Assign a | nested_sequence_assign(a.getATarget(), a.getValue(), lhs, result))
+  exists(Py::Assign a | nested_sequence_assign(a.getATarget(), a.getValue(), lhs, result))
   or
   /* for lhs in seq: => `result` is the `for` node, representing the `iter(next(seq))` operation. */
-  result.(For).getTarget() = lhs
+  result.(Py::For).getTarget() = lhs
   or
-  exists(Parameter param | lhs = param.asName() and result = param.getDefault())
+  exists(Py::Parameter param | lhs = param.asName() and result = param.getDefault())
 }
 
 predicate nested_sequence_assign(
-  Expr left_parent, Expr right_parent, Expr left_result, Expr right_result
+  Py::Expr left_parent, Py::Expr right_parent, Py::Expr left_result, Py::Expr right_result
 ) {
-  exists(Assign a |
+  exists(Py::Assign a |
     a.getATarget().getASubExpression*() = left_parent and
     a.getValue().getASubExpression*() = right_parent
   ) and
-  exists(int i, Expr left_elem, Expr right_elem |
+  exists(int i, Py::Expr left_elem, Py::Expr right_elem |
     (
-      left_elem = left_parent.(Tuple).getElt(i)
+      left_elem = left_parent.(Py::Tuple).getElt(i)
       or
-      left_elem = left_parent.(List).getElt(i)
+      left_elem = left_parent.(Py::List).getElt(i)
     ) and
     (
-      right_elem = right_parent.(Tuple).getElt(i)
+      right_elem = right_parent.(Py::Tuple).getElt(i)
       or
-      right_elem = right_parent.(List).getElt(i)
+      right_elem = right_parent.(Py::List).getElt(i)
     )
   |
     left_result = left_elem and right_result = right_elem
@@ -769,9 +771,9 @@ predicate nested_sequence_assign(
 
 /** A flow node for a `for` statement. */
 class ForNode extends ControlFlowNode {
-  ForNode() { toAst(this) instanceof For }
+  ForNode() { toAst(this) instanceof Py::For }
 
-  override For getNode() { result = super.getNode() }
+  override Py::For getNode() { result = super.getNode() }
 
   /** Holds if this `for` statement causes iteration over `sequence` storing each step of the iteration in `target` */
   predicate iterates(ControlFlowNode target, ControlFlowNode sequence) {
@@ -782,7 +784,7 @@ class ForNode extends ControlFlowNode {
 
   /** Gets the sequence node for this `for` statement. */
   ControlFlowNode getSequence() {
-    exists(For for |
+    exists(Py::For for |
       toAst(this) = for and
       for.getIter() = result.getNode()
     |
@@ -792,7 +794,7 @@ class ForNode extends ControlFlowNode {
 
   /** A possible `target` for this `for` statement, not accounting for loop unrolling */
   private ControlFlowNode possibleTarget() {
-    exists(For for |
+    exists(Py::For for |
       toAst(this) = for and
       for.getTarget() = result.getNode() and
       this.getBasicBlock().dominates(result.getBasicBlock())
@@ -809,11 +811,11 @@ class ForNode extends ControlFlowNode {
 
 /** A flow node for a `raise` statement */
 class RaiseStmtNode extends ControlFlowNode {
-  RaiseStmtNode() { toAst(this) instanceof Raise }
+  RaiseStmtNode() { toAst(this) instanceof Py::Raise }
 
   /** Gets the control flow node for the exception raised by this raise statement */
   ControlFlowNode getException() {
-    exists(Raise r |
+    exists(Py::Raise r |
       r = toAst(this) and
       r.getException() = toAst(result) and
       result.getBasicBlock().dominates(this.getBasicBlock())
@@ -827,36 +829,36 @@ class RaiseStmtNode extends ControlFlowNode {
  */
 class NameNode extends ControlFlowNode {
   NameNode() {
-    exists(Name n | py_flow_bb_node(this, n, _, _))
+    exists(Py::Name n | py_flow_bb_node(this, n, _, _))
     or
-    exists(PlaceHolder p | py_flow_bb_node(this, p, _, _))
+    exists(Py::PlaceHolder p | py_flow_bb_node(this, p, _, _))
   }
 
   /** Whether this flow node defines the variable `v`. */
-  predicate defines(Variable v) {
-    exists(Name d | this.getNode() = d and d.defines(v)) and
+  predicate defines(Py::Variable v) {
+    exists(Py::Name d | this.getNode() = d and d.defines(v)) and
     not this.isLoad()
   }
 
   /** Whether this flow node deletes the variable `v`. */
-  predicate deletes(Variable v) { exists(Name d | this.getNode() = d and d.deletes(v)) }
+  predicate deletes(Py::Variable v) { exists(Py::Name d | this.getNode() = d and d.deletes(v)) }
 
   /** Whether this flow node uses the variable `v`. */
-  predicate uses(Variable v) {
+  predicate uses(Py::Variable v) {
     this.isLoad() and
-    exists(Name u | this.getNode() = u and u.uses(v))
+    exists(Py::Name u | this.getNode() = u and u.uses(v))
     or
-    exists(PlaceHolder u |
-      this.getNode() = u and u.getVariable() = v and u.getCtx() instanceof Load
+    exists(Py::PlaceHolder u |
+      this.getNode() = u and u.getVariable() = v and u.getCtx() instanceof Py::Load
     )
     or
     Scopes::use_of_global_variable(this, v.getScope(), v.getId())
   }
 
   string getId() {
-    result = this.getNode().(Name).getId()
+    result = this.getNode().(Py::Name).getId()
     or
-    result = this.getNode().(PlaceHolder).getId()
+    result = this.getNode().(Py::PlaceHolder).getId()
   }
 
   /** Whether this is a use of a local variable. */
@@ -868,82 +870,84 @@ class NameNode extends ControlFlowNode {
   /** Whether this is a use of a global (including builtin) variable. */
   predicate isGlobal() { Scopes::use_of_global_variable(this, _, _) }
 
-  predicate isSelf() { exists(SsaVariable selfvar | selfvar.isSelf() and selfvar.getAUse() = this) }
+  predicate isSelf() {
+    exists(Py::SsaVariable selfvar | selfvar.isSelf() and selfvar.getAUse() = this)
+  }
 }
 
 /** A control flow node corresponding to a named constant, one of `None`, `True` or `False`. */
 class NameConstantNode extends NameNode {
-  NameConstantNode() { exists(NameConstant n | py_flow_bb_node(this, n, _, _)) }
+  NameConstantNode() { exists(Py::NameConstant n | py_flow_bb_node(this, n, _, _)) }
   /*
    * We ought to override uses as well, but that has
    * a serious performance impact.
-   *    deprecated predicate uses(Variable v) { none() }
+   *    deprecated predicate uses(Py::Variable v) { none() }
    */
 
   }
 
 /** A control flow node corresponding to a starred expression, `*a`. */
 class StarredNode extends ControlFlowNode {
-  StarredNode() { toAst(this) instanceof Starred }
+  StarredNode() { toAst(this) instanceof Py::Starred }
 
-  ControlFlowNode getValue() { toAst(result) = toAst(this).(Starred).getValue() }
+  ControlFlowNode getValue() { toAst(result) = toAst(this).(Py::Starred).getValue() }
 }
 
 /** The ControlFlowNode for an 'except' statement. */
 class ExceptFlowNode extends ControlFlowNode {
-  ExceptFlowNode() { this.getNode() instanceof ExceptStmt }
+  ExceptFlowNode() { this.getNode() instanceof Py::ExceptStmt }
 
   /**
    * Gets the type handled by this exception handler.
-   * `ExceptionType` in `except ExceptionType as e:`
+   * `Py::ExceptionType` in `except Py::ExceptionType as e:`
    */
   ControlFlowNode getType() {
-    exists(ExceptStmt ex |
+    exists(Py::ExceptStmt ex |
       this.getBasicBlock().dominates(result.getBasicBlock()) and
       ex = this.getNode() and
-      result = ex.getType().getAFlowNode()
+      result.getNode() = ex.getType()
     )
   }
 
   /**
    * Gets the name assigned to the handled exception, if any.
-   * `e` in `except ExceptionType as e:`
+   * `e` in `except Py::ExceptionType as e:`
    */
   ControlFlowNode getName() {
-    exists(ExceptStmt ex |
+    exists(Py::ExceptStmt ex |
       this.getBasicBlock().dominates(result.getBasicBlock()) and
       ex = this.getNode() and
-      result = ex.getName().getAFlowNode()
+      result.getNode() = ex.getName()
     )
   }
 }
 
 /** The ControlFlowNode for an 'except*' statement. */
 class ExceptGroupFlowNode extends ControlFlowNode {
-  ExceptGroupFlowNode() { this.getNode() instanceof ExceptGroupStmt }
+  ExceptGroupFlowNode() { this.getNode() instanceof Py::ExceptGroupStmt }
 
   /**
    * Gets the type handled by this exception handler.
-   * `ExceptionType` in `except* ExceptionType as e:`
+   * `Py::ExceptionType` in `except* Py::ExceptionType as e:`
    */
   ControlFlowNode getType() {
     this.getBasicBlock().dominates(result.getBasicBlock()) and
-    result = this.getNode().(ExceptGroupStmt).getType().getAFlowNode()
+    result.getNode() = this.getNode().(Py::ExceptGroupStmt).getType()
   }
 
   /**
    * Gets the name assigned to the handled exception, if any.
-   * `e` in `except* ExceptionType as e:`
+   * `e` in `except* Py::ExceptionType as e:`
    */
   ControlFlowNode getName() {
     this.getBasicBlock().dominates(result.getBasicBlock()) and
-    result = this.getNode().(ExceptGroupStmt).getName().getAFlowNode()
+    result.getNode() = this.getNode().(Py::ExceptGroupStmt).getName()
   }
 }
 
 private module Scopes {
   private predicate fast_local(NameNode n) {
-    exists(FastLocalVariable v |
+    exists(Py::FastLocalVariable v |
       n.uses(v) and
       v.getScope() = n.getScope()
     )
@@ -952,15 +956,15 @@ private module Scopes {
   predicate local(NameNode n) {
     fast_local(n)
     or
-    exists(SsaVariable var |
+    exists(Py::SsaVariable var |
       var.getAUse() = n and
-      n.getScope() instanceof Class and
+      n.getScope() instanceof Py::Class and
       exists(var.getDefinition())
     )
   }
 
   predicate non_local(NameNode n) {
-    exists(FastLocalVariable flv |
+    exists(Py::FastLocalVariable flv |
       flv.getALoad() = n.getNode() and
       not flv.getScope() = n.getScope()
     )
@@ -968,20 +972,20 @@ private module Scopes {
 
   // magic is fine, but we get questionable join-ordering of it
   pragma[nomagic]
-  predicate use_of_global_variable(NameNode n, Module scope, string name) {
+  predicate use_of_global_variable(NameNode n, Py::Module scope, string name) {
     n.isLoad() and
     not non_local(n) and
-    not exists(SsaVariable var | var.getAUse() = n |
-      var.getVariable() instanceof FastLocalVariable
+    not exists(Py::SsaVariable var | var.getAUse() = n |
+      var.getVariable() instanceof Py::FastLocalVariable
       or
-      n.getScope() instanceof Class and
+      n.getScope() instanceof Py::Class and
       not maybe_undefined(var)
     ) and
     name = n.getId() and
     scope = n.getEnclosingModule()
   }
 
-  private predicate maybe_undefined(SsaVariable var) {
+  private predicate maybe_undefined(Py::SsaVariable var) {
     not exists(var.getDefinition()) and not py_ssa_phi(var, _)
     or
     var.getDefinition().isDelete()
@@ -1058,13 +1062,13 @@ class BasicBlock extends @py_flow_node {
   private predicate oneNodeBlock() { this.firstNode() = this.getLastNode() }
 
   private predicate startLocationInfo(string file, int line, int col) {
-    if this.firstNode().getNode() instanceof Scope
+    if this.firstNode().getNode() instanceof Py::Scope
     then this.firstNode().getASuccessor().getLocation().hasLocationInfo(file, line, col, _, _)
     else this.firstNode().getLocation().hasLocationInfo(file, line, col, _, _)
   }
 
   private predicate endLocationInfo(int endl, int endc) {
-    if this.getLastNode().getNode() instanceof Scope and not this.oneNodeBlock()
+    if this.getLastNode().getNode() instanceof Py::Scope and not this.oneNodeBlock()
     then this.getLastNode().getAPredecessor().getLocation().hasLocationInfo(_, _, _, endl, endc)
     else this.getLastNode().getLocation().hasLocationInfo(_, _, _, endl, endc)
   }
@@ -1081,7 +1085,7 @@ class BasicBlock extends @py_flow_node {
 
   /** Whether flow from this basic block reaches a normal exit from its scope */
   predicate reachesExit() {
-    exists(Scope s | s.getANormalExit().getBasicBlock() = this)
+    exists(Py::Scope s | s.getANormalExit().getBasicBlock() = this)
     or
     this.getASuccessor().reachesExit()
   }
@@ -1122,7 +1126,7 @@ class BasicBlock extends @py_flow_node {
 
   /** Gets the scope of this block */
   pragma[nomagic]
-  Scope getScope() {
+  Py::Scope getScope() {
     exists(ControlFlowNode n | n.getBasicBlock() = this |
       /* Take care not to use an entry or exit node as that node's scope will be the outer scope */
       not py_scope_flow(n, _, -1) and
@@ -1145,17 +1149,17 @@ class BasicBlock extends @py_flow_node {
   predicate reaches(BasicBlock other) { this = other or this.strictlyReaches(other) }
 
   /**
-   * Gets the `ConditionBlock`, if any, that controls this block and
-   * does not control any other `ConditionBlock`s that control this block.
-   * That is the `ConditionBlock` that is closest dominator.
+   * Gets the `Py::ConditionBlock`, if any, that controls this block and
+   * does not control any other `Py::ConditionBlock`s that control this block.
+   * That is the `Py::ConditionBlock` that is closest dominator.
    */
-  ConditionBlock getImmediatelyControllingBlock() {
+  Py::ConditionBlock getImmediatelyControllingBlock() {
     result = this.nonControllingImmediateDominator*().getImmediateDominator()
   }
 
   private BasicBlock nonControllingImmediateDominator() {
     result = this.getImmediateDominator() and
-    not result.(ConditionBlock).controls(this, _)
+    not result.(Py::ConditionBlock).controls(this, _)
   }
 
   /**
@@ -1175,7 +1179,7 @@ private class ControlFlowNodeAlias = ControlFlowNode;
 
 final private class FinalBasicBlock = BasicBlock;
 
-module Cfg implements BB::CfgSig<Location> {
+module Cfg implements BB::CfgSig<Py::Location> {
   private import codeql.controlflow.SuccessorType
 
   class ControlFlowNode = ControlFlowNodeAlias;
@@ -1186,7 +1190,7 @@ module Cfg implements BB::CfgSig<Location> {
     // Using the location of the first node is simple
     // and we just need a way to identify the basic block
     // during debugging, so this will be serviceable.
-    Location getLocation() { result = super.getNode(0).getLocation() }
+    Py::Location getLocation() { result = super.getNode(0).getLocation() }
 
     int length() { result = count(int i | exists(this.getNode(i))) }
 

python/ql/lib/semmle/python/Function.qll

@@ -2,6 +2,7 @@ overlay[local]
 module;
 
 import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 
 /**
  * A function, independent of defaults and binding.
@@ -153,8 +154,16 @@ class Function extends Function_, Scope, AstNode {
 
   override predicate contains(AstNode inner) { Scope.super.contains(inner) }
 
-  /** Gets a control flow node for a return value of this function */
-  ControlFlowNode getAReturnValueFlowNode() {
+  /**
+   * DEPRECATED: bind a `Return` node explicitly instead, e.g.
+   * `exists(Return ret | ret.getScope() = this and n.getNode() = ret.getValue())`.
+   * This API is being phased out together with `AstNode.getAFlowNode()` to
+   * untangle the AST and CFG hierarchies.
+   *
+   * Gets a control flow node for a return value of this function, from the
+   * new (shared) CFG.
+   */
+  deprecated Cfg::ControlFlowNode getAReturnValueFlowNode() {
     exists(Return ret |
       ret.getScope() = this and
       ret.getValue() = result.getNode()

python/ql/lib/semmle/python/Import.qll

@@ -162,8 +162,6 @@ class ImportMember extends ImportMember_ {
   string getImportedModuleName() {
     result = this.getModule().(ImportExpr).getImportedModuleName() + "." + this.getName()
   }
-
-  override ImportMemberNode getAFlowNode() { result = super.getAFlowNode() }
 }
 
 /** An import statement */

python/ql/lib/semmle/python/SelfAttribute.qll

@@ -46,20 +46,23 @@ class SelfAttributeRead extends SelfAttribute {
   }
 
   predicate guardedByHasattr() {
-    exists(Variable var, ControlFlowNode n |
-      var.getAUse() = this.getObject().getAFlowNode() and
+    exists(Variable var, ControlFlowNode n, ControlFlowNode this_, ControlFlowNode obj_ |
+      this_.getNode() = this and obj_.getNode() = this.getObject()
+    |
+      var.getAUse() = obj_ and
       hasattr(n, var.getAUse(), this.getName()) and
-      n.strictlyDominates(this.getAFlowNode())
+      n.strictlyDominates(this_)
     )
   }
 
   pragma[noinline]
   predicate locallyDefined() {
-    exists(SelfAttributeStore store |
-      this.getName() = store.getName() and
-      this.getScope() = store.getScope()
+    exists(SelfAttributeStore store, ControlFlowNode store_, ControlFlowNode this_ |
+      store_.getNode() = store and this_.getNode() = this
     |
-      store.getAFlowNode().strictlyDominates(this.getAFlowNode())
+      this.getName() = store.getName() and
+      this.getScope() = store.getScope() and
+      store_.strictlyDominates(this_)
     )
   }
 }

python/ql/lib/semmle/python/dataflow/new/BarrierGuards.qll

@@ -1,36 +1,43 @@
 /** Provides commonly used BarrierGuards. */
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import semmle.python.dataflow.new.DataFlow
 
-private predicate constCompare(DataFlow::GuardNode g, ControlFlowNode node, boolean branch) {
-  exists(CompareNode cn | cn = g |
-    exists(ImmutableLiteral const, Cmpop op |
-      op = any(Eq eq) and branch = true
-      or
-      op = any(NotEq ne) and branch = false
+private predicate constCompare(DataFlow::GuardNode g, Cfg::ControlFlowNode node, boolean branch) {
+  exists(Cfg::CompareNode cn | cn = g |
+    exists(ImmutableLiteral const, Cmpop op, Cfg::ControlFlowNode c |
+      c.getNode() = const and
+      (
+        op = any(Eq eq) and branch = true
+        or
+        op = any(NotEq ne) and branch = false
+      )
     |
-      cn.operands(const.getAFlowNode(), op, node)
+      cn.operands(c, op, node)
       or
-      cn.operands(node, op, const.getAFlowNode())
+      cn.operands(node, op, c)
     )
     or
-    exists(NameConstant const, Cmpop op |
-      op = any(Is is_) and branch = true
-      or
-      op = any(IsNot isn) and branch = false
+    exists(NameConstant const, Cmpop op, Cfg::ControlFlowNode c |
+      c.getNode() = const and
+      (
+        op = any(Is is_) and branch = true
+        or
+        op = any(IsNot isn) and branch = false
+      )
     |
-      cn.operands(const.getAFlowNode(), op, node)
+      cn.operands(c, op, node)
       or
-      cn.operands(node, op, const.getAFlowNode())
+      cn.operands(node, op, c)
     )
     or
-    exists(IterableNode const_iterable, Cmpop op |
+    exists(Cfg::IterableNode const_iterable, Cmpop op |
       op = any(In in_) and branch = true
       or
       op = any(NotIn ni) and branch = false
     |
-      forall(ControlFlowNode elem | elem = const_iterable.getAnElement() |
+      forall(Cfg::ControlFlowNode elem | elem = const_iterable.getAnElement() |
         elem.getNode() instanceof ImmutableLiteral
       ) and
       cn.operands(node, op, const_iterable)

python/ql/lib/semmle/python/dataflow/new/SensitiveDataSources.qll

@@ -4,6 +4,7 @@
  */
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import semmle.python.dataflow.new.DataFlow
 // Need to import `semmle.python.Frameworks` since frameworks can extend `SensitiveDataSource::Range`
 private import semmle.python.Frameworks
@@ -105,7 +106,7 @@ private module SensitiveDataModeling {
       or
       // to cover functions that we don't have the definition for, and where the
       // reference to the function has not already been marked as being sensitive
-      this.getFunction().asCfgNode().(NameNode).getId() = sensitiveString(classification)
+      this.getFunction().asCfgNode().(Cfg::NameNode).getId() = sensitiveString(classification)
     }
 
     override SensitiveDataClassification getClassification() { result = classification }
@@ -251,12 +252,12 @@ private module SensitiveDataModeling {
     SensitiveDataClassification classification;
 
     SensitiveVariableAssignment() {
-      exists(DefinitionNode def |
-        def.(NameNode).getId() = sensitiveString(classification) and
+      exists(Cfg::DefinitionNode def |
+        def.(Cfg::NameNode).getId() = sensitiveString(classification) and
         (
           this.asCfgNode() = def.getValue()
           or
-          this.asCfgNode() = def.getValue().(ForNode).getSequence()
+          this.asCfgNode() = def.getValue().(Cfg::ForNode).getSequence()
         ) and
         not this.asExpr() instanceof FunctionExpr and
         not this.asExpr() instanceof ClassExpr
@@ -293,7 +294,7 @@ private module SensitiveDataModeling {
     SensitiveDataClassification classification;
 
     SensitiveSubscript() {
-      this.asCfgNode().(SubscriptNode).getIndex() =
+      this.asCfgNode().(Cfg::SubscriptNode).getIndex() =
         sensitiveLookupStringConst(classification).asCfgNode()
     }
 

python/ql/lib/semmle/python/dataflow/new/internal/Attributes.qll

@@ -3,6 +3,7 @@ overlay[local]
 module;
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 import DataFlowUtil
 import DataFlowPublic
 private import DataFlowPrivate
@@ -83,9 +84,9 @@ abstract class AttrWrite extends AttrRef {
  * ```python
  * object.attr = value
  * ```
- * Also gives access to the `value` being written, by extending `DefinitionNode`.
+ * Also gives access to the `value` being written, by extending `Cfg::DefinitionNode`.
  */
-private class AttributeAssignmentNode extends DefinitionNode, AttrNode { }
+private class AttributeAssignmentNode extends Cfg::DefinitionNode, Cfg::AttrNode { }
 
 /** A simple attribute assignment: `object.attr = value`. */
 private class AttributeAssignmentAsAttrWrite extends AttrWrite, CfgNode {
@@ -131,13 +132,13 @@ private class GlobalAttributeAssignmentAsAttrWrite extends AttrWrite, CfgNode {
   override string getAttributeName() { result = node.getName() }
 }
 
-/** Represents `CallNode`s that may refer to calls to built-in functions or classes. */
-private class BuiltInCallNode extends CallNode {
+/** Represents `Cfg::CallNode`s that may refer to calls to built-in functions or classes. */
+private class BuiltInCallNode extends Cfg::CallNode {
   string name;
 
   BuiltInCallNode() {
     // TODO disallow instances where the name of the built-in may refer to an in-scope variable of that name.
-    exists(NameNode id |
+    exists(Cfg::NameNode id |
       name = Builtins::getBuiltinName() and
       this.getFunction() = id and
       id.getId() = name and
@@ -145,7 +146,7 @@ private class BuiltInCallNode extends CallNode {
     )
   }
 
-  /** Gets the name of the built-in function that is called at this `CallNode` */
+  /** Gets the name of the built-in function that is called at this `Cfg::CallNode` */
   string getBuiltinName() { result = name }
 }
 
@@ -157,20 +158,20 @@ private class BuiltinAttrCallNode extends BuiltInCallNode {
   BuiltinAttrCallNode() { name in ["setattr", "getattr", "hasattr", "delattr"] }
 
   /** Gets the control flow node for object on which the attribute is accessed. */
-  ControlFlowNode getObject() { result in [this.getArg(0), this.getArgByName("object")] }
+  Cfg::ControlFlowNode getObject() { result in [this.getArg(0), this.getArgByName("object")] }
 
   /**
    * Gets the control flow node for the value that is being written to the attribute.
    * Only relevant for `setattr` calls.
    */
-  ControlFlowNode getValue() {
+  Cfg::ControlFlowNode getValue() {
     // only valid for `setattr`
     name = "setattr" and
     result in [this.getArg(2), this.getArgByName("value")]
   }
 
   /** Gets the control flow node that defines the name of the attribute being accessed. */
-  ControlFlowNode getName() { result in [this.getArg(1), this.getArgByName("name")] }
+  Cfg::ControlFlowNode getName() { result in [this.getArg(1), this.getArgByName("name")] }
 }
 
 /** Represents calls to the built-in `setattr`. */
@@ -205,10 +206,10 @@ private class SetAttrCallAsAttrWrite extends AttrWrite, CfgNode {
  *     attr = value
  *     ...
  * ```
- * Instances of this class correspond to the `NameNode` for `attr`, and also gives access to `value` by
- * virtue of being a `DefinitionNode`.
+ * Instances of this class correspond to the `Cfg::NameNode` for `attr`, and also gives access to `value` by
+ * virtue of being a `Cfg::DefinitionNode`.
  */
-private class ClassAttributeAssignmentNode extends DefinitionNode, NameNode {
+private class ClassAttributeAssignmentNode extends Cfg::DefinitionNode, Cfg::NameNode {
   ClassAttributeAssignmentNode() { this.getScope() = any(ClassExpr c).getInnerScope() }
 }
 
@@ -228,7 +229,7 @@ private class ClassDefinitionAsAttrWrite extends AttrWrite, CfgNode {
 
   override Node getValue() { result.asCfgNode() = node.getValue() }
 
-  override Node getObject() { result.asCfgNode() = cls.getAFlowNode() }
+  override Node getObject() { result.asCfgNode().getNode() = cls }
 
   override ExprNode getAttributeNameExpr() { none() }
 
@@ -248,7 +249,7 @@ abstract class AttrRead extends AttrRef, Node, LocalSourceNode {
 
 /** A simple attribute read, e.g. `object.attr` */
 private class AttributeReadAsAttrRead extends AttrRead, CfgNode {
-  override AttrNode node;
+  override Cfg::AttrNode node;
 
   AttributeReadAsAttrRead() { node.isLoad() }
 
@@ -285,7 +286,7 @@ private class GetAttrCallAsAttrRead extends AttrRead, CfgNode {
  * is treated as if it is a read of the attribute `module.attr`, even if `module` is not imported directly.
  */
 private class ModuleAttributeImportAsAttrRead extends AttrRead, CfgNode {
-  override ImportMemberNode node;
+  override Cfg::ImportMemberNode node;
 
   override Node getObject() { result.asCfgNode() = node.getModule(_) }
 

python/ql/lib/semmle/python/dataflow/new/internal/Builtins.qll

@@ -3,6 +3,7 @@ overlay[local]
 module;
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import semmle.python.dataflow.new.DataFlow
 private import semmle.python.dataflow.new.internal.ImportStar
 
@@ -67,7 +68,7 @@ module Builtins {
   DataFlow::CfgNode likelyBuiltin(string name) {
     exists(Module m |
       result.getNode() =
-        any(NameNode n |
+        any(Cfg::NameNode n |
           possible_builtin_accessed_in_module(n, name, m) and
           not possible_builtin_defined_in_module(name, m)
         )
@@ -87,7 +88,7 @@ module Builtins {
    * Holds if `n` is an access of a global variable called `name` (which is also the name of a
    * built-in) inside the module `m`.
    */
-  private predicate possible_builtin_accessed_in_module(NameNode n, string name, Module m) {
+  private predicate possible_builtin_accessed_in_module(Cfg::NameNode n, string name, Module m) {
     n.isGlobal() and
     n.isLoad() and
     name = n.getId() and

python/ql/lib/semmle/python/dataflow/new/internal/DataFlowDispatch.qll

@@ -25,7 +25,7 @@
  * what callable this call might end up targeting.
  *
  * Specifically this means that we cannot use type-backtrackers from the function of a
- * `CallNode`, since there is no `CallNode` to backtrack from for `func` in the example
+ * `Cfg::CallNode`, since there is no `Cfg::CallNode` to backtrack from for `func` in the example
  * above.
  *
  * Note: This hasn't been 100% realized yet, so we don't currently expose a predicate to
@@ -35,6 +35,7 @@ overlay[local?]
 module;
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import DataFlowPublic
 private import DataFlowPrivate
 private import FlowSummaryImpl as FlowSummaryImpl
@@ -162,7 +163,7 @@ newtype TArgumentPosition =
    */
   TLambdaSelfArgumentPosition() or
   TPositionalArgumentPosition(int index) {
-    exists(any(CallNode c).getArg(index))
+    exists(any(Cfg::CallNode c).getArg(index))
     or
     // since synthetic calls within a summarized callable could use a unique argument
     // position, we need to ensure we make these available (these are specified as
@@ -174,7 +175,7 @@ newtype TArgumentPosition =
     index = 0
   } or
   TKeywordArgumentPosition(string name) {
-    exists(any(CallNode c).getArgByName(name))
+    exists(any(Cfg::CallNode c).getArgByName(name))
     or
     // see comment for TPositionalArgumentPosition
     FlowSummaryImpl::ParsePositions::isParsedKeywordParameterPosition(_, name)
@@ -256,9 +257,12 @@ predicate parameterMatch(ParameterPosition ppos, ArgumentPosition apos) {
  */
 overlay[local]
 predicate isStaticmethod(Function func) {
-  exists(NameNode id | id.getId() = "staticmethod" and id.isGlobal() |
-    func.getADecorator() = id.getNode()
-  )
+  // The decorator is *syntactically* a `Name` "staticmethod" — we don't
+  // care which variable it resolves to. `staticmethod` is a builtin and
+  // is almost never shadowed in a module-level scope; even if a class
+  // redefines `staticmethod` in its body, the class body has not started
+  // executing yet at the decorator position, so Python uses the builtin.
+  func.getADecorator().(Name).getId() = "staticmethod"
 }
 
 /**
@@ -268,9 +272,9 @@ predicate isStaticmethod(Function func) {
  */
 overlay[local]
 predicate isClassmethod(Function func) {
-  exists(NameNode id | id.getId() = "classmethod" and id.isGlobal() |
-    func.getADecorator() = id.getNode()
-  )
+  // See `isStaticmethod` for the rationale for matching on the AST `Name`
+  // rather than going via the CFG and `isGlobal()`.
+  func.getADecorator().(Name).getId() = "classmethod"
   or
   exists(Class cls |
     cls.getAMethod() = func and
@@ -285,9 +289,8 @@ predicate isClassmethod(Function func) {
 /** Holds if the function `func` has a `property` decorator. */
 overlay[local]
 predicate hasPropertyDecorator(Function func) {
-  exists(NameNode id | id.getId() = "property" and id.isGlobal() |
-    func.getADecorator() = id.getNode()
-  )
+  // See `isStaticmethod` for the rationale for matching on the AST `Name`.
+  func.getADecorator().(Name).getId() = "property"
 }
 
 /**
@@ -295,10 +298,12 @@ predicate hasPropertyDecorator(Function func) {
  */
 overlay[local]
 predicate hasContextmanagerDecorator(Function func) {
-  exists(ControlFlowNode contextmanager |
-    contextmanager.(NameNode).getId() = "contextmanager" and contextmanager.(NameNode).isGlobal()
+  exists(Cfg::ControlFlowNode contextmanager |
+    contextmanager.(Cfg::NameNode).getId() = "contextmanager" and
+    contextmanager.(Cfg::NameNode).isGlobal()
     or
-    contextmanager.(AttrNode).getObject("contextmanager").(NameNode).getId() = "contextlib"
+    contextmanager.(Cfg::AttrNode).getObject("contextmanager").(Cfg::NameNode).getId() =
+      "contextlib"
   |
     func.getADecorator() = contextmanager.getNode()
   )
@@ -314,10 +319,10 @@ predicate hasContextmanagerDecorator(Function func) {
  */
 overlay[local]
 private predicate hasOverloadDecorator(Function func) {
-  exists(ControlFlowNode overload |
-    overload.(NameNode).getId() = "overload" and overload.(NameNode).isGlobal()
+  exists(Cfg::ControlFlowNode overload |
+    overload.(Cfg::NameNode).getId() = "overload" and overload.(Cfg::NameNode).isGlobal()
     or
-    overload.(AttrNode).getObject("overload").(NameNode).isGlobal()
+    overload.(Cfg::AttrNode).getObject("overload").(Cfg::NameNode).isGlobal()
   |
     func.getADecorator() = overload.getNode()
   )
@@ -536,7 +541,7 @@ class LibraryCallableValue extends DataFlowCallable, TLibraryCallable {
 // =============================================================================
 /** Gets a call to `type`. */
 private CallCfgNode getTypeCall() {
-  exists(NameNode id | id.getId() = "type" and id.isGlobal() |
+  exists(Cfg::NameNode id | id.getId() = "type" and id.isGlobal() |
     result.getFunction().asCfgNode() = id
   )
 }
@@ -548,7 +553,7 @@ private CallCfgNode getSuperCall() {
   // link below), but otherwise only 2 edgecases. Overall it seems ok to ignore this complexity.
   //
   // https://github.com/python/cpython/blob/18b1782192f85bd26db89f5bc850f8bee4247c1a/Lib/unittest/mock.py#L48-L50
-  exists(NameNode id | id.getId() = "super" and id.isGlobal() |
+  exists(Cfg::NameNode id | id.getId() = "super" and id.isGlobal() |
     result.getFunction().asCfgNode() = id
   )
 }
@@ -1034,7 +1039,7 @@ private module MethodCalls {
    */
   pragma[nomagic]
   private predicate directCall(
-    CallNode call, Function target, string functionName, Class cls, AttrRead attr, Node self
+    Cfg::CallNode call, Function target, string functionName, Class cls, AttrRead attr, Node self
   ) {
     target = findFunctionAccordingToMroKnownStartingClass(cls, functionName) and
     directCall_join(call, functionName, cls, attr, self)
@@ -1043,7 +1048,7 @@ private module MethodCalls {
   /** Extracted to give good join order */
   pragma[nomagic]
   private predicate directCall_join(
-    CallNode call, string functionName, Class cls, AttrRead attr, Node self
+    Cfg::CallNode call, string functionName, Class cls, AttrRead attr, Node self
   ) {
     call.getFunction() = attrReadTracker(attr).asCfgNode() and
     attr.accesses(self, functionName) and
@@ -1060,7 +1065,7 @@ private module MethodCalls {
    */
   pragma[nomagic]
   private predicate callWithinMethodImplicitSelfOrCls(
-    CallNode call, Function target, string functionName, Class classWithMethod, AttrRead attr,
+    Cfg::CallNode call, Function target, string functionName, Class classWithMethod, AttrRead attr,
     Node self
   ) {
     target = findFunctionAccordingToMro(getADirectSubclass*(classWithMethod), functionName) and
@@ -1070,7 +1075,7 @@ private module MethodCalls {
   /** Extracted to give good join order */
   pragma[nomagic]
   private predicate callWithinMethodImplicitSelfOrCls_join(
-    CallNode call, string functionName, Class classWithMethod, AttrRead attr, Node self
+    Cfg::CallNode call, string functionName, Class classWithMethod, AttrRead attr, Node self
   ) {
     call.getFunction() = attrReadTracker(attr).asCfgNode() and
     attr.accesses(self, functionName) and
@@ -1082,7 +1087,7 @@ private module MethodCalls {
    * resolve the call to a known target (since the only super class might be the
    * builtin `object`, so we never have the implementation of `__new__` in the DB).
    */
-  predicate fromSuperNewCall(CallNode call, Class classUsedInSuper, AttrRead attr, Node self) {
+  predicate fromSuperNewCall(Cfg::CallNode call, Class classUsedInSuper, AttrRead attr, Node self) {
     fromSuper_join(call, "__new__", classUsedInSuper, attr, self) and
     self in [classTracker(_), clsArgumentTracker(_)]
   }
@@ -1104,7 +1109,7 @@ private module MethodCalls {
    */
   pragma[nomagic]
   predicate fromSuper(
-    CallNode call, Function target, string functionName, Class classUsedInSuper, AttrRead attr,
+    Cfg::CallNode call, Function target, string functionName, Class classUsedInSuper, AttrRead attr,
     Node self
   ) {
     target = findFunctionAccordingToMro(getNextClassInMro(classUsedInSuper), functionName) and
@@ -1114,7 +1119,7 @@ private module MethodCalls {
   /** Extracted to give good join order */
   pragma[nomagic]
   private predicate fromSuper_join(
-    CallNode call, string functionName, Class classUsedInSuper, AttrRead attr, Node self
+    Cfg::CallNode call, string functionName, Class classUsedInSuper, AttrRead attr, Node self
   ) {
     call.getFunction() = attrReadTracker(attr).asCfgNode() and
     (
@@ -1133,7 +1138,7 @@ private module MethodCalls {
     )
   }
 
-  predicate resolveMethodCall(CallNode call, Function target, CallType type, Node self) {
+  predicate resolveMethodCall(Cfg::CallNode call, Function target, CallType type, Node self) {
     (
       directCall(call, target, _, _, _, self)
       or
@@ -1180,7 +1185,7 @@ import MethodCalls
  * NOTE: We have this predicate mostly to be able to compare with old point-to
  * call-graph resolution. So it could be removed in the future.
  */
-predicate resolveClassCall(CallNode call, Class cls) {
+predicate resolveClassCall(Cfg::CallNode call, Class cls) {
   call.getFunction() = classTracker(cls).asCfgNode()
   or
   // `cls()` inside a classmethod (which also contains `type(self)()` inside a method)
@@ -1210,7 +1215,7 @@ Function invokedFunctionFromClassConstruction(Class cls, string funcName) {
  *
  * See https://docs.python.org/3/reference/datamodel.html#object.__call__
  */
-predicate resolveClassInstanceCall(CallNode call, Function target, Node self) {
+predicate resolveClassInstanceCall(Cfg::CallNode call, Function target, Node self) {
   exists(Class cls |
     call.getFunction() = classInstanceTracker(cls).asCfgNode() and
     target = findFunctionAccordingToMroKnownStartingClass(cls, "__call__")
@@ -1229,7 +1234,7 @@ predicate resolveClassInstanceCall(CallNode call, Function target, Node self) {
  * Holds if `call` is a call to the `target`, with call-type `type`.
  */
 cached
-predicate resolveCall(CallNode call, Function target, CallType type) {
+predicate resolveCall(Cfg::CallNode call, Function target, CallType type) {
   Stages::DataFlow::ref() and
   (
     type instanceof CallTypePlainFunction and
@@ -1254,11 +1259,11 @@ predicate resolveCall(CallNode call, Function target, CallType type) {
 // =============================================================================
 /**
  * Holds if the argument of `call` at position `apos` is `arg`. This is just a helper
- * predicate that maps ArgumentPositions to the arguments of the underlying `CallNode`.
+ * predicate that maps ArgumentPositions to the arguments of the underlying `Cfg::CallNode`.
  */
 overlay[local]
 cached
-predicate normalCallArg(CallNode call, Node arg, ArgumentPosition apos) {
+predicate normalCallArg(Cfg::CallNode call, Node arg, ArgumentPosition apos) {
   exists(int index |
     apos.isPositional(index) and
     arg.asCfgNode() = call.getArg(index)
@@ -1273,7 +1278,7 @@ predicate normalCallArg(CallNode call, Node arg, ArgumentPosition apos) {
   exists(int index |
     apos.isStarArgs(index) and
     arg.asCfgNode() = call.getStarArg() and
-    // since `CallNode.getArg` doesn't include `*args`, we need to drop to the AST level
+    // since `Cfg::CallNode.getArg` doesn't include `*args`, we need to drop to the AST level
     // to get the index. Notice that we only use the AST for getting the index, so we
     // don't need to check for dominance in regards to splitting.
     call.getStarArg().getNode() = call.getNode().getPositionalArg(index).(Starred).getValue()
@@ -1347,7 +1352,9 @@ predicate normalCallArg(CallNode call, Node arg, ArgumentPosition apos) {
  * translated into `l.clear()`, and we can still have use-use flow.
  */
 cached
-predicate getCallArg(CallNode call, Function target, CallType type, Node arg, ArgumentPosition apos) {
+predicate getCallArg(
+  Cfg::CallNode call, Function target, CallType type, Node arg, ArgumentPosition apos
+) {
   Stages::DataFlow::ref() and
   resolveCall(call, target, type) and
   (
@@ -1440,10 +1447,13 @@ private predicate sameEnclosingCallable(Node node1, Node node2) {
 // DataFlowCall
 // =============================================================================
 newtype TDataFlowCall =
-  TNormalCall(CallNode call, Function target, CallType type) { resolveCall(call, target, type) } or
+  TNormalCall(Cfg::CallNode call, Function target, CallType type) {
+    resolveCall(call, target, type) and
+    Cfg::isCanonicalAstNodeRepresentative(call)
+  } or
   /** A call to the generated function inside a comprehension */
   TComprehensionCall(Comp c) or
-  TPotentialLibraryCall(CallNode call) or
+  TPotentialLibraryCall(Cfg::CallNode call) { Cfg::isCanonicalAstNodeRepresentative(call) } or
   /** A synthesized call inside a summarized callable */
   TSummaryCall(
     FlowSummaryImpl::Public::SummarizedCallable c, FlowSummaryImpl::Private::SummaryNode receiver
@@ -1463,7 +1473,7 @@ abstract class DataFlowCall extends TDataFlowCall {
   abstract ArgumentNode getArgument(ArgumentPosition apos);
 
   /** Get the control flow node representing this call, if any. */
-  abstract ControlFlowNode getNode();
+  abstract Cfg::ControlFlowNode getNode();
 
   /** Gets the enclosing callable of this call. */
   DataFlowCallable getEnclosingCallable() { result = getCallableScope(this.getScope()) }
@@ -1494,28 +1504,28 @@ abstract class ExtractedDataFlowCall extends DataFlowCall {
 }
 
 /**
- * A resolved call in source code with an underlying `CallNode`.
+ * A resolved call in source code with an underlying `Cfg::CallNode`.
  *
  * This is considered normal, compared with special calls such as `obj[0]` calling the
  * `__getitem__` method on the object. However, this also includes calls that go to the
  * `__call__` special method.
  */
 class NormalCall extends ExtractedDataFlowCall, TNormalCall {
-  CallNode call;
+  Cfg::CallNode call;
   Function target;
   CallType type;
 
   NormalCall() { this = TNormalCall(call, target, type) }
 
   override string toString() {
-    // note: if we used toString directly on the CallNode we would get
-    //     `ControlFlowNode for func()`
-    // but the `ControlFlowNode` part is just clutter, so we go directly to the AST node
+    // note: if we used toString directly on the Cfg::CallNode we would get
+    //     `Cfg::ControlFlowNode for func()`
+    // but the `Cfg::ControlFlowNode` part is just clutter, so we go directly to the AST node
     // instead.
     result = call.getNode().toString()
   }
 
-  override ControlFlowNode getNode() { result = call }
+  override Cfg::ControlFlowNode getNode() { result = call }
 
   override Scope getScope() { result = call.getScope() }
 
@@ -1543,7 +1553,7 @@ class ComprehensionCall extends ExtractedDataFlowCall, TComprehensionCall {
 
   override string toString() { result = "comprehension call" }
 
-  override ControlFlowNode getNode() { result.getNode() = c }
+  override Cfg::ControlFlowNode getNode() { result.getNode() = c }
 
   override Scope getScope() { result = c.getScope() }
 
@@ -1566,14 +1576,14 @@ class ComprehensionCall extends ExtractedDataFlowCall, TComprehensionCall {
  * in this class.
  */
 class PotentialLibraryCall extends ExtractedDataFlowCall, TPotentialLibraryCall {
-  CallNode call;
+  Cfg::CallNode call;
 
   PotentialLibraryCall() { this = TPotentialLibraryCall(call) }
 
   override string toString() {
-    // note: if we used toString directly on the CallNode we would get
-    //     `ControlFlowNode for func()`
-    // but the `ControlFlowNode` part is just clutter, so we go directly to the AST node
+    // note: if we used toString directly on the Cfg::CallNode we would get
+    //     `Cfg::ControlFlowNode for func()`
+    // but the `Cfg::ControlFlowNode` part is just clutter, so we go directly to the AST node
     // instead.
     result = call.getNode().toString()
   }
@@ -1590,10 +1600,10 @@ class PotentialLibraryCall extends ExtractedDataFlowCall, TPotentialLibraryCall
     // potential self argument, from `foo.bar()` -- note that this could also just be a
     // module reference, but we really don't have a good way of knowing :|
     apos.isSelf() and
-    result.asCfgNode() = call.getFunction().(AttrNode).getObject()
+    result.asCfgNode() = call.getFunction().(Cfg::AttrNode).getObject()
   }
 
-  override ControlFlowNode getNode() { result = call }
+  override Cfg::ControlFlowNode getNode() { result = call }
 
   override Scope getScope() { result = call.getScope() }
 }
@@ -1625,7 +1635,7 @@ class SummaryCall extends DataFlowCall, TSummaryCall {
 
   override ArgumentNode getArgument(ArgumentPosition apos) { none() }
 
-  override ControlFlowNode getNode() { none() }
+  override Cfg::ControlFlowNode getNode() { none() }
 
   override string toString() { result = "[summary] call to " + receiver + " in " + c }
 
@@ -1767,12 +1777,12 @@ private class SummaryPostUpdateNode extends FlowSummaryNode, PostUpdateNodeImpl
  * This is used for tracking flow through captured variables.
  */
 class SynthCapturedVariablesArgumentNode extends Node, TSynthCapturedVariablesArgumentNode {
-  ControlFlowNode callable;
+  Cfg::ControlFlowNode callable;
 
   SynthCapturedVariablesArgumentNode() { this = TSynthCapturedVariablesArgumentNode(callable) }
 
-  /** Gets the `CallNode` corresponding to this captured variables argument node. */
-  CallNode getCallNode() { result.getFunction() = callable }
+  /** Gets the `Cfg::CallNode` corresponding to this captured variables argument node. */
+  Cfg::CallNode getCallNode() { result.getFunction() = callable }
 
   /** Gets the `CfgNode` that corresponds to this synthetic node. */
   CfgNode getUnderlyingNode() { result.asCfgNode() = callable }
@@ -1790,7 +1800,7 @@ class CapturedVariablesArgumentNodeAsArgumentNode extends ArgumentNode,
 {
   overlay[global]
   override predicate argumentOf(DataFlowCall call, ArgumentPosition pos) {
-    exists(CallNode callNode | callNode = this.getCallNode() |
+    exists(Cfg::CallNode callNode | callNode = this.getCallNode() |
       callNode = call.getNode() and
       exists(Function target | resolveCall(callNode, target, _) |
         target = any(VariableCapture::CapturedVariable v).getACapturingScope()
@@ -1804,7 +1814,7 @@ class CapturedVariablesArgumentNodeAsArgumentNode extends ArgumentNode,
 class SynthCapturedVariablesArgumentPostUpdateNode extends PostUpdateNodeImpl,
   TSynthCapturedVariablesArgumentPostUpdateNode
 {
-  ControlFlowNode callable;
+  Cfg::ControlFlowNode callable;
 
   SynthCapturedVariablesArgumentPostUpdateNode() {
     this = TSynthCapturedVariablesArgumentPostUpdateNode(callable)
@@ -1911,8 +1921,8 @@ abstract class ReturnNode extends Node {
 class ExtractedReturnNode extends ReturnNode, CfgNode {
   // See `TaintTrackingImplementation::returnFlowStep`
   ExtractedReturnNode() {
-    node = any(Return ret).getValue().getAFlowNode() or
-    node = any(Yield yield).getAFlowNode()
+    node.getNode() = any(Return ret).getValue() or
+    node.getNode() = any(Yield yield)
   }
 
   override ReturnKind getKind() { any() }
@@ -1930,7 +1940,7 @@ class ExtractedReturnNode extends ReturnNode, CfgNode {
 class YieldNodeInContextManagerFunction extends ReturnNode, CfgNode {
   YieldNodeInContextManagerFunction() {
     hasContextmanagerDecorator(node.getScope()) and
-    node = any(Yield yield).getValue().getAFlowNode()
+    node.getNode() = any(Yield yield).getValue()
   }
 
   override ReturnKind getKind() { any() }

python/ql/lib/semmle/python/dataflow/new/internal/DataFlowPrivate.qll

@@ -2,8 +2,9 @@ overlay[local?]
 module;
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import DataFlowPublic
-private import semmle.python.essa.SsaCompute
+private import semmle.python.dataflow.new.internal.SsaImpl as SsaImpl
 private import semmle.python.dataflow.new.internal.ImportResolution
 private import FlowSummaryImpl as FlowSummaryImpl
 private import semmle.python.frameworks.data.ModelsAsData
@@ -43,13 +44,23 @@ predicate isArgumentNode(ArgumentNode arg, DataFlowCall c, ArgumentPosition pos)
 // Nodes
 //--------
 overlay[local]
-predicate isExpressionNode(ControlFlowNode node) { node.getNode() instanceof Expr }
+predicate isExpressionNode(Cfg::ControlFlowNode node) {
+  node.getNode() instanceof Expr
+  or
+  // `Cfg::ForNode` wraps a `For` statement's iter position, but
+  // overrides `.getNode()` to return the `Py::For` statement (for
+  // legacy parity). The underlying AST is still an `Expr` (the iter
+  // expression); we want a dataflow node here so that for-loop
+  // content reads (`for y in l`) have a source expression node to
+  // read content from.
+  node instanceof Cfg::ForNode
+}
 
 // =============================================================================
 // SyntheticPreUpdateNode
 // =============================================================================
 class SyntheticPreUpdateNode extends Node, TSyntheticPreUpdateNode {
-  CallNode node;
+  Cfg::CallNode node;
 
   SyntheticPreUpdateNode() { this = TSyntheticPreUpdateNode(node) }
 
@@ -151,7 +162,7 @@ predicate synthStarArgsElementParameterNodeStoreStep(
  * been passed in a `**kwargs` argument.
  */
 class SynthDictSplatArgumentNode extends Node, TSynthDictSplatArgumentNode {
-  CallNode node;
+  Cfg::CallNode node;
 
   SynthDictSplatArgumentNode() { this = TSynthDictSplatArgumentNode(node) }
 
@@ -165,7 +176,7 @@ class SynthDictSplatArgumentNode extends Node, TSynthDictSplatArgumentNode {
 private predicate synthDictSplatArgumentNodeStoreStep(
   ArgumentNode nodeFrom, DictionaryElementContent c, SynthDictSplatArgumentNode nodeTo
 ) {
-  exists(string name, CallNode call, ArgumentPosition keywordPos |
+  exists(string name, Cfg::CallNode call, ArgumentPosition keywordPos |
     nodeTo = TSynthDictSplatArgumentNode(call) and
     getCallArg(call, _, _, nodeFrom, keywordPos) and
     keywordPos.isKeyword(name) and
@@ -185,8 +196,8 @@ private predicate synthDictSplatArgumentNodeStoreStep(
  */
 predicate yieldStoreStep(Node nodeFrom, Content c, Node nodeTo) {
   exists(Yield yield |
-    nodeTo.asCfgNode() = yield.getAFlowNode() and
-    nodeFrom.asCfgNode() = yield.getValue().getAFlowNode() and
+    nodeTo.asCfgNode().getNode() = yield and
+    nodeFrom.asCfgNode().getNode() = yield.getValue() and
     // TODO: Consider if this will also need to transfer dictionary content
     // once dictionary comprehensions are supported.
     c instanceof ListElementContent
@@ -289,7 +300,7 @@ abstract class PostUpdateNodeImpl extends Node {
  * Synthetic post-update nodes for synthetic nodes need to be listed one by one.
  */
 class SyntheticPostUpdateNode extends PostUpdateNodeImpl, TSyntheticPostUpdateNode {
-  ControlFlowNode node;
+  Cfg::ControlFlowNode node;
 
   SyntheticPostUpdateNode() { this = TSyntheticPostUpdateNode(node) }
 
@@ -333,16 +344,42 @@ module LocalFlow {
     //   `x = f(42)`
     //   nodeFrom is `f(42)`
     //   nodeTo is `x`
-    exists(AssignmentDefinition def |
+    //
+    // We use the CFG-level `DefinitionNode.getValue()` directly rather
+    // than going through SSA, because the new SSA library prunes write
+    // definitions that have no subsequent read in the same scope (e.g.
+    // a module-level `def f():` whose `f` is only read inside other
+    // functions). The CFG-level link is unconditional.
+    //
+    // The Name-target restriction mirrors legacy ESSA's
+    // `SsaDefinitions::assignment_definition`, which required
+    // `defn.(NameNode).defines(v)`. Subscript and attribute writes
+    // (`x[i] = 42`, `obj.attr = 42`) are intentionally excluded — their
+    // value flow is handled by the content-flow / `AttrWrite` machinery,
+    // not by a local-flow step *into* the Subscript/Attribute expression.
+    // Excluding them is essential for keeping augmented-assignment
+    // targets (`x[i] += 42`) classifiable as `LocalSourceNode` on the
+    // read side: the single canonical CFG node is both a load and a
+    // store, and any incoming local-flow step would disqualify it from
+    // being a local source.
+    exists(Cfg::DefinitionNode def |
       nodeFrom.(CfgNode).getNode() = def.getValue() and
-      nodeTo.(CfgNode).getNode() = def.getDefiningNode()
+      nodeTo.(CfgNode).getNode() = def and
+      def instanceof Cfg::NameNode and
+      // Parameter defaults are evaluated in the enclosing scope, while the
+      // parameter itself lives in the function's scope. The cross-scope
+      // edge is provided by `runtimeJumpStep` instead.
+      not exists(Py::Parameter param | def.getNode() = param.asName())
     )
     or
     // With definition
     //   `with f(42) as x:`
     //   nodeFrom is `f(42)`
     //   nodeTo is `x`
-    exists(With with, ControlFlowNode contextManager, WithDefinition withDef, ControlFlowNode var |
+    exists(
+      With with, Cfg::ControlFlowNode contextManager, SsaImpl::WithDefinition withDef,
+      Cfg::ControlFlowNode var
+    |
       var = withDef.getDefiningNode()
     |
       nodeFrom.(CfgNode).getNode() = contextManager and
@@ -361,13 +398,13 @@ module LocalFlow {
 
   predicate expressionFlowStep(Node nodeFrom, Node nodeTo) {
     // If expressions
-    nodeFrom.asCfgNode() = nodeTo.asCfgNode().(IfExprNode).getAnOperand()
+    nodeFrom.asCfgNode() = nodeTo.asCfgNode().(Cfg::IfExprNode).getAnOperand()
     or
     // Assignment expressions
-    nodeFrom.asCfgNode() = nodeTo.asCfgNode().(AssignmentExprNode).getValue()
+    nodeFrom.asCfgNode() = nodeTo.asCfgNode().(Cfg::AssignmentExprNode).getValue()
     or
     // boolean inline expressions such as `x or y` or `x and y`
-    nodeFrom.asCfgNode() = nodeTo.asCfgNode().(BoolExprNode).getAnOperand()
+    nodeFrom.asCfgNode() = nodeTo.asCfgNode().(Cfg::BoolExprNode).getAnOperand()
     or
     // Flow inside an unpacking assignment
     iterableUnpackingFlowStep(nodeFrom, nodeTo)
@@ -376,12 +413,28 @@ module LocalFlow {
     matchFlowStep(nodeFrom, nodeTo)
   }
 
-  predicate useToNextUse(NameNode nodeFrom, NameNode nodeTo) {
-    AdjacentUses::adjacentUseUse(nodeFrom, nodeTo)
+  predicate useToNextUse(Cfg::NameNode nodeFrom, Cfg::NameNode nodeTo) {
+    // The SSA-level adjacent-use predicate works on specific CFG variants
+    // (e.g. boolean-outcome `[true]`/`[false]` or emptiness `[empty]`/`[non-empty]`
+    // splits of the same AST node), but dataflow values are insensitive to
+    // those splits — there is at most one `CfgNode` per AST. Project both
+    // ends through `Cfg::isCanonicalAstNodeRepresentative` so all variants
+    // contribute their use-use edges to the canonical pair.
+    exists(Cfg::NameNode fromVariant, Cfg::NameNode toVariant |
+      SsaImpl::AdjacentUses::adjacentUseUse(fromVariant, toVariant) and
+      fromVariant.getNode() = nodeFrom.getNode() and
+      toVariant.getNode() = nodeTo.getNode() and
+      Cfg::isCanonicalAstNodeRepresentative(nodeFrom) and
+      Cfg::isCanonicalAstNodeRepresentative(nodeTo)
+    )
   }
 
-  predicate defToFirstUse(EssaVariable var, NameNode nodeTo) {
-    AdjacentUses::firstUse(var.getDefinition(), nodeTo)
+  predicate defToFirstUse(SsaImpl::EssaVariable var, Cfg::NameNode nodeTo) {
+    exists(Cfg::NameNode toVariant |
+      SsaImpl::AdjacentUses::firstUse(var.getDefinition(), toVariant) and
+      toVariant.getNode() = nodeTo.getNode() and
+      Cfg::isCanonicalAstNodeRepresentative(nodeTo)
+    )
   }
 
   predicate useUseFlowStep(Node nodeFrom, Node nodeTo) {
@@ -390,12 +443,14 @@ module LocalFlow {
     //   `x = f(y)`
     //   nodeFrom is `y` on first line
     //   nodeTo is `y` on second line
-    exists(EssaDefinition def |
-      nodeFrom.(CfgNode).getNode() = def.(EssaNodeDefinition).getDefiningNode()
+    exists(SsaImpl::EssaDefinition def, Cfg::NameNode toVariant |
+      nodeFrom.(CfgNode).getNode() = def.(SsaImpl::EssaNodeDefinition).getDefiningNode()
       or
       nodeFrom.(ScopeEntryDefinitionNode).getDefinition() = def
     |
-      AdjacentUses::firstUse(def, nodeTo.(CfgNode).getNode())
+      SsaImpl::AdjacentUses::firstUse(def, toVariant) and
+      toVariant.getNode() = nodeTo.(CfgNode).getNode().getNode() and
+      Cfg::isCanonicalAstNodeRepresentative(nodeTo.(CfgNode).getNode())
     )
     or
     // Next use after use
@@ -557,9 +612,9 @@ predicate runtimeJumpStep(Node nodeFrom, Node nodeTo) {
   // a parameter with a default value, since the parameter will be in the scope of the
   // function, while the default value itself will be in the scope that _defines_ the
   // function.
-  exists(ParameterDefinition param |
+  exists(SsaImpl::ParameterDefinition param |
     // note: we go to the _control-flow node_ of the parameter, and not the ESSA node of the parameter, since for type-tracking, the ESSA node is not a LocalSourceNode, so we would get in trouble.
-    nodeFrom.asCfgNode() = param.getDefault() and
+    nodeFrom.asCfgNode().getNode() = param.getParameter().(Parameter).getDefault() and
     nodeTo.asCfgNode() = param.getDefiningNode()
   )
   or
@@ -663,7 +718,7 @@ predicate neverSkipInPathGraph(Node n) {
   // ```
   // we would end up saying that the path MUST not skip the x in `y = x`, which is just
   // annoying and doesn't help the path explanation become clearer.
-  n.asCfgNode() = any(EssaNodeDefinition def).getDefiningNode()
+  n.asCfgNode() = any(SsaImpl::EssaNodeDefinition def).getDefiningNode()
 }
 
 /**
@@ -872,7 +927,7 @@ predicate listStoreStep(CfgNode nodeFrom, ListElementContent c, CfgNode nodeTo)
   //   nodeFrom is `42`, cfg node
   //   nodeTo is the list, `[..., 42, ...]`, cfg node
   //   c denotes element of list
-  nodeTo.getNode().(ListNode).getAnElement() = nodeFrom.getNode() and
+  nodeTo.getNode().(Cfg::ListNode).getAnElement() = nodeFrom.getNode() and
   not nodeTo.getNode() instanceof UnpackingAssignmentSequenceTarget and
   // Suppress unused variable warning
   c = c
@@ -885,7 +940,7 @@ predicate setStoreStep(CfgNode nodeFrom, SetElementContent c, CfgNode nodeTo) {
   //   nodeFrom is `42`, cfg node
   //   nodeTo is the set, `{..., 42, ...}`, cfg node
   //   c denotes element of list
-  nodeTo.getNode().(SetNode).getAnElement() = nodeFrom.getNode() and
+  nodeTo.getNode().(Cfg::SetNode).getAnElement() = nodeFrom.getNode() and
   // Suppress unused variable warning
   c = c
 }
@@ -898,7 +953,7 @@ predicate tupleStoreStep(CfgNode nodeFrom, TupleElementContent c, CfgNode nodeTo
   //   nodeTo is the tuple, `(..., 42, ...)`, cfg node
   //   c denotes element of tuple and index of nodeFrom
   exists(int n |
-    nodeTo.getNode().(TupleNode).getElement(n) = nodeFrom.getNode() and
+    nodeTo.getNode().(Cfg::TupleNode).getElement(n) = nodeFrom.getNode() and
     not nodeTo.getNode() instanceof UnpackingAssignmentSequenceTarget and
     c.getIndex() = n
   )
@@ -912,7 +967,7 @@ predicate dictStoreStep(CfgNode nodeFrom, DictionaryElementContent c, Node nodeT
   //   nodeTo is the dict, `{..., "key" = 42, ...}`, cfg node
   //   c denotes element of dictionary and the key `"key"`
   exists(KeyValuePair item |
-    item = nodeTo.asCfgNode().(DictNode).getNode().(Dict).getAnItem() and
+    item = nodeTo.asCfgNode().(Cfg::DictNode).getNode().(Dict).getAnItem() and
     nodeFrom.getNode().getNode() = item.getValue() and
     c.getKey() = item.getKey().(StringLiteral).getS()
   )
@@ -927,9 +982,9 @@ predicate dictStoreStep(CfgNode nodeFrom, DictionaryElementContent c, Node nodeT
 private predicate moreDictStoreSteps(CfgNode nodeFrom, DictionaryElementContent c, Node nodeTo) {
   // NOTE: It's important to add logic to the newtype definition of
   // DictionaryElementContent if you add new cases here.
-  exists(SubscriptNode subscript |
+  exists(Cfg::SubscriptNode subscript |
     nodeTo.(PostUpdateNode).getPreUpdateNode().asCfgNode() = subscript.getObject() and
-    nodeFrom.asCfgNode() = subscript.(DefinitionNode).getValue() and
+    nodeFrom.asCfgNode() = subscript.(Cfg::DefinitionNode).getValue() and
     c.getKey() = subscript.getIndex().getNode().(StringLiteral).getText()
   )
   or
@@ -942,8 +997,8 @@ private predicate moreDictStoreSteps(CfgNode nodeFrom, DictionaryElementContent
 }
 
 predicate dictClearStep(Node node, DictionaryElementContent c) {
-  exists(SubscriptNode subscript |
-    subscript instanceof DefinitionNode and
+  exists(Cfg::SubscriptNode subscript |
+    subscript instanceof Cfg::DefinitionNode and
     node.asCfgNode() = subscript.getObject() and
     c.getKey() = subscript.getIndex().getNode().(StringLiteral).getText()
   )
@@ -1018,7 +1073,7 @@ predicate subscriptReadStep(CfgNode nodeFrom, Content c, CfgNode nodeTo) {
   //   nodeFrom is `l`, cfg node
   //   nodeTo is `l[3]`, cfg node
   //   c is compatible with 3
-  nodeFrom.getNode() = nodeTo.getNode().(SubscriptNode).getObject() and
+  nodeFrom.getNode() = nodeTo.getNode().(Cfg::SubscriptNode).getObject() and
   (
     c instanceof ListElementContent
     or
@@ -1027,10 +1082,10 @@ predicate subscriptReadStep(CfgNode nodeFrom, Content c, CfgNode nodeTo) {
     c instanceof DictionaryElementAnyContent
     or
     c.(TupleElementContent).getIndex() =
-      nodeTo.getNode().(SubscriptNode).getIndex().getNode().(IntegerLiteral).getValue()
+      nodeTo.getNode().(Cfg::SubscriptNode).getIndex().getNode().(IntegerLiteral).getValue()
     or
     c.(DictionaryElementContent).getKey() =
-      nodeTo.getNode().(SubscriptNode).getIndex().getNode().(StringLiteral).getS()
+      nodeTo.getNode().(Cfg::SubscriptNode).getIndex().getNode().(StringLiteral).getS()
   )
 }
 

python/ql/lib/semmle/python/dataflow/new/internal/DataFlowPublic.qll

@@ -5,11 +5,12 @@ overlay[local]
 module;
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import DataFlowPrivate
 import semmle.python.dataflow.new.TypeTracking
 import Attributes
 import LocalSources
-private import semmle.python.essa.SsaCompute
+private import semmle.python.dataflow.new.internal.SsaImpl as SsaImpl
 private import semmle.python.dataflow.new.internal.ImportStar
 private import semmle.python.frameworks.data.ModelsAsData
 private import FlowSummaryImpl as FlowSummaryImpl
@@ -27,16 +28,21 @@ private import semmle.python.frameworks.data.ModelsAsData
 overlay[local]
 newtype TNode =
   /** A node corresponding to a control flow node. */
-  TCfgNode(ControlFlowNode node) {
-    isExpressionNode(node)
-    or
-    node.getNode() instanceof Pattern
+  TCfgNode(Cfg::ControlFlowNode node) {
+    (
+      isExpressionNode(node)
+      or
+      node.getNode() instanceof Pattern
+    ) and
+    Cfg::isCanonicalAstNodeRepresentative(node)
   } or
   /**
    * A node corresponding to a scope entry definition. That is, the value of a variable
    * as it enters a scope.
    */
-  TScopeEntryDefinitionNode(ScopeEntryDefinition def) { not def.getScope() instanceof Module } or
+  TScopeEntryDefinitionNode(SsaImpl::ScopeEntryDefinition def) {
+    not def.getScope() instanceof Module
+  } or
   /**
    * A synthetic node representing the value of an object before a state change.
    *
@@ -47,36 +53,39 @@ newtype TNode =
   // NOTE: since we can't rely on the call graph, but we want to have synthetic
   // pre-update nodes for class calls, we end up getting synthetic pre-update nodes for
   // ALL calls :|
-  TSyntheticPreUpdateNode(CallNode call) or
+  TSyntheticPreUpdateNode(Cfg::CallNode call) { Cfg::isCanonicalAstNodeRepresentative(call) } or
   /**
    * A synthetic node representing the value of an object after a state change.
    * See QLDoc for `PostUpdateNode`.
    */
-  TSyntheticPostUpdateNode(ControlFlowNode node) {
-    exists(CallNode call |
-      node = call.getArg(_)
+  TSyntheticPostUpdateNode(Cfg::ControlFlowNode node) {
+    Cfg::isCanonicalAstNodeRepresentative(node) and
+    (
+      exists(Cfg::CallNode call |
+        node = call.getArg(_)
+        or
+        node = call.getArgByName(_)
+        or
+        // `self` argument when handling class instance calls (`__call__` special method))
+        node = call.getFunction()
+      )
       or
-      node = call.getArgByName(_)
+      node = any(Cfg::AttrNode a).getObject()
       or
-      // `self` argument when handling class instance calls (`__call__` special method))
-      node = call.getFunction()
+      node = any(Cfg::SubscriptNode s).getObject()
+      or
+      // self parameter when used implicitly in `super()`
+      exists(Class cls, Function func, SsaImpl::ParameterDefinition def |
+        func = cls.getAMethod() and
+        not isStaticmethod(func) and
+        // this matches what we do in ExtractedParameterNode
+        def.getDefiningNode() = node and
+        def.getParameter() = func.getArg(0)
+      )
+      or
+      // the iterable argument to the implicit comprehension function
+      node.getNode() = any(Comp c).getIterable()
     )
-    or
-    node = any(AttrNode a).getObject()
-    or
-    node = any(SubscriptNode s).getObject()
-    or
-    // self parameter when used implicitly in `super()`
-    exists(Class cls, Function func, ParameterDefinition def |
-      func = cls.getAMethod() and
-      not isStaticmethod(func) and
-      // this matches what we do in ExtractedParameterNode
-      def.getDefiningNode() = node and
-      def.getParameter() = func.getArg(0)
-    )
-    or
-    // the iterable argument to the implicit comprehension function
-    node.getNode() = any(Comp c).getIterable()
   } or
   /** A node representing a global (module-level) variable in a specific module. */
   TModuleVariableNode(Module m, GlobalVariable v) { v.getScope() = m } or
@@ -112,7 +121,9 @@ newtype TNode =
     exists(ParameterPosition ppos | ppos.isStarArgs(_) | exists(callable.getParameter(ppos)))
   } or
   /** A synthetic node to capture keyword arguments that are passed to a `**kwargs` parameter. */
-  TSynthDictSplatArgumentNode(CallNode call) { exists(call.getArgByName(_)) } or
+  TSynthDictSplatArgumentNode(Cfg::CallNode call) {
+    exists(call.getArgByName(_)) and Cfg::isCanonicalAstNodeRepresentative(call)
+  } or
   /** A synthetic node to allow flow to keyword parameters from a `**kwargs` argument. */
   TSynthDictSplatParameterNode(DataFlowCallable callable) {
     exists(ParameterPosition ppos | ppos.isKeyword(_) | exists(callable.getParameter(ppos)))
@@ -128,15 +139,17 @@ newtype TNode =
    * A synthetic node representing the values of the variables captured
    * by the callable being called.
    */
-  TSynthCapturedVariablesArgumentNode(ControlFlowNode callable) {
-    callable = any(CallNode c).getFunction()
+  TSynthCapturedVariablesArgumentNode(Cfg::ControlFlowNode callable) {
+    callable = any(Cfg::CallNode c).getFunction() and
+    Cfg::isCanonicalAstNodeRepresentative(callable)
   } or
   /**
    * A synthetic node representing the values of the variables captured
    * by the callable being called, after the output has been computed.
    */
-  TSynthCapturedVariablesArgumentPostUpdateNode(ControlFlowNode callable) {
-    callable = any(CallNode c).getFunction()
+  TSynthCapturedVariablesArgumentPostUpdateNode(Cfg::ControlFlowNode callable) {
+    callable = any(Cfg::CallNode c).getFunction() and
+    Cfg::isCanonicalAstNodeRepresentative(callable)
   } or
   /** A synthetic node representing the values of variables captured by a comprehension. */
   TSynthCompCapturedVariablesArgumentNode(Comp comp) {
@@ -194,7 +207,7 @@ class Node extends TNode {
   }
 
   /** Gets the control-flow node corresponding to this node, if any. */
-  ControlFlowNode asCfgNode() { none() }
+  Cfg::ControlFlowNode asCfgNode() { none() }
 
   /** Gets the expression corresponding to this node, if any. */
   Expr asExpr() { none() }
@@ -207,14 +220,14 @@ class Node extends TNode {
 
 /** A data-flow node corresponding to a control-flow node. */
 class CfgNode extends Node, TCfgNode {
-  ControlFlowNode node;
+  Cfg::ControlFlowNode node;
 
   CfgNode() { this = TCfgNode(node) }
 
-  /** Gets the `ControlFlowNode` represented by this data-flow node. */
-  ControlFlowNode getNode() { result = node }
+  /** Gets the `Cfg::ControlFlowNode` represented by this data-flow node. */
+  Cfg::ControlFlowNode getNode() { result = node }
 
-  override ControlFlowNode asCfgNode() { result = node }
+  override Cfg::ControlFlowNode asCfgNode() { result = node }
 
   /** Gets a textual representation of this element. */
   override string toString() { result = node.toString() }
@@ -224,9 +237,9 @@ class CfgNode extends Node, TCfgNode {
   override Location getLocation() { result = node.getLocation() }
 }
 
-/** A data-flow node corresponding to a `CallNode` in the control-flow graph. */
+/** A data-flow node corresponding to a `Cfg::CallNode` in the control-flow graph. */
 class CallCfgNode extends CfgNode, LocalSourceNode {
-  override CallNode node;
+  override Cfg::CallNode node;
 
   /**
    * Gets the data-flow node for the function component of the call corresponding to this data-flow
@@ -307,15 +320,15 @@ ExprNode exprNode(DataFlowExpr e) { result.getNode().getNode() = e }
  * as it enters a scope.
  */
 class ScopeEntryDefinitionNode extends Node, TScopeEntryDefinitionNode {
-  ScopeEntryDefinition def;
+  SsaImpl::ScopeEntryDefinition def;
 
   ScopeEntryDefinitionNode() { this = TScopeEntryDefinitionNode(def) }
 
-  /** Gets the `ScopeEntryDefinition` associated with this node. */
-  ScopeEntryDefinition getDefinition() { result = def }
+  /** Gets the `SsaImpl::ScopeEntryDefinition` associated with this node. */
+  SsaImpl::ScopeEntryDefinition getDefinition() { result = def }
 
   /** Gets the source variable represented by this node. */
-  SsaSourceVariable getVariable() { result = def.getSourceVariable() }
+  SsaImpl::SsaSourceVariable getVariable() { result = def.getSourceVariable() }
 
   override Location getLocation() { result = def.getLocation() }
 
@@ -337,7 +350,7 @@ class ParameterNode extends Node instanceof ParameterNodeImpl {
 /** A parameter node found in the source code (not in a summary). */
 class ExtractedParameterNode extends ParameterNodeImpl, CfgNode {
   //, LocalSourceNode {
-  ParameterDefinition def;
+  SsaImpl::ParameterDefinition def;
 
   ExtractedParameterNode() { node = def.getDefiningNode() }
 
@@ -368,10 +381,10 @@ Node getCallArgApproximation() {
   exists(Class c | result.asExpr() = c.getAMethod().getArg(0))
   or
   // the object part of an attribute expression (which might be a bound method)
-  result.asCfgNode() = any(AttrNode a).getObject()
+  result.asCfgNode() = any(Cfg::AttrNode a).getObject()
   or
   // the function part of any call
-  result.asCfgNode() = any(CallNode c).getFunction()
+  result.asCfgNode() = any(Cfg::CallNode c).getFunction()
 }
 
 /** Gets the extracted argument nodes that do not rely on `getCallArg`. */
@@ -380,7 +393,7 @@ private Node implicitArgumentNode() {
   normalCallArg(_, result, _)
   or
   // and self arguments
-  result.asCfgNode() = any(CallNode c).getFunction().(AttrNode).getObject()
+  result.asCfgNode() = any(Cfg::CallNode c).getFunction().(Cfg::AttrNode).getObject()
   or
   // for comprehensions, we allow the synthetic `iterable` argument
   result.asExpr() = any(Comp c).getIterable()
@@ -485,21 +498,24 @@ class ModuleVariableNode extends Node, TModuleVariableNode {
 
   /** Gets a node that reads this variable, excluding reads that happen through `from ... import *`. */
   Node getALocalRead() {
-    result.asCfgNode() = var.getALoad().getAFlowNode() and
+    result.asCfgNode().getNode() = var.getALoad() and
     not result.getScope() = mod
   }
 
-  /** Gets an `EssaNode` that corresponds to an assignment of this global variable. */
+  /** Gets a CFG node that corresponds to an assignment of this global variable. */
   Node getAWrite() {
-    any(EssaNodeDefinition def).definedBy(var, result.asCfgNode().(DefinitionNode))
+    exists(Cfg::NameNode n |
+      n.defines(var) and
+      result.asCfgNode() = n
+    )
   }
 
   /** Gets the possible values of the variable at the end of import time */
   CfgNode getADefiningWrite() {
-    exists(SsaVariable def |
-      def = any(SsaVariable ssa_var).getAnUltimateDefinition() and
-      def.getDefinition() = result.asCfgNode() and
-      def.getVariable() = var
+    exists(SsaImpl::EssaVariable def |
+      def = any(SsaImpl::EssaVariable ssa_var).getAnUltimateDefinition() and
+      def.getDefinition().(SsaImpl::EssaNodeDefinition).getDefiningNode() = result.asCfgNode() and
+      def.getSourceVariable().getVariable() = var
     )
   }
 
@@ -516,7 +532,7 @@ private ModuleVariableNode import_star_read(Node n) {
 overlay[global]
 pragma[nomagic]
 private predicate resolved_import_star_module(Module m, string name, Node n) {
-  exists(NameNode nn | nn = n.asCfgNode() |
+  exists(Cfg::NameNode nn | nn = n.asCfgNode() |
     ImportStar::importStarResolvesTo(pragma[only_bind_into](nn), m) and
     nn.getId() = name
   )
@@ -574,88 +590,110 @@ class StarPatternElementNode extends Node, TStarPatternElementNode {
 }
 
 /**
- * Gets a node that controls whether other nodes are evaluated.
+ * A node that participates in a conditional split: a CFG node whose
+ * evaluation outcome (true/false) is used to choose between two
+ * successor basic blocks. In the new shared CFG, such nodes appear in
+ * pairs of `isAfterTrue`/`isAfterFalse` annotated CFG nodes.
  *
- * In the base case, this is the last node of `conditionBlock`, and `flipped` is `false`.
- * This definition accounts for (short circuting) `and`- and `or`-expressions, as the structure
- * of basic blocks will reflect their semantics.
+ * Users typically obtain a `GuardNode` by casting from a more specific
+ * Cfg type: `g.(Cfg::CallNode)` for a call-based check, etc.
  *
- * However, in the program
- * ```python
- * if not is_safe(path):
- *   return
- * ```
- * the last node in the `ConditionBlock` is `not is_safe(path)`.
- *
- * We would like to consider also `is_safe(path)` a guard node, albeit with `flipped` being `true`.
- * Thus we recurse through `not`-expressions.
+ * This replaces the legacy (pre-shared-CFG) `GuardNode`/`flipped`
+ * machinery: the shared CFG carries outcome information structurally
+ * (via `isAfterTrue`/`isAfterFalse`), so no separate polarity field
+ * is required.
  */
-ControlFlowNode guardNode(ConditionBlock conditionBlock, boolean flipped) {
-  // Base case: the last node truly does determine which successor is chosen
-  result = conditionBlock.getLastNode() and
-  flipped = false
-  or
-  // Recursive cases:
-  // if a guard node is a `not`-expression,
-  // the operand is also a guard node, but with inverted polarity.
-  exists(UnaryExprNode notNode |
-    result = notNode.getOperand() and
-    notNode.getNode().getOp() instanceof Not
-  |
-    notNode = guardNode(conditionBlock, flipped.booleanNot())
-  )
-  or
-  // if a guard node is compared to a boolean literal,
-  // the other operand is also a guard node,
-  // but with polarity depending on the literal (and on the comparison).
-  exists(CompareNode cmpNode, Cmpop op, ControlFlowNode b, boolean should_flip |
-    (
-      cmpNode.operands(result, op, b) or
-      cmpNode.operands(b, op, result)
-    ) and
-    not result.getNode() instanceof BooleanLiteral and
-    (
-      // comparing to the boolean
-      (op instanceof Eq or op instanceof Is) and
-      // we should flip if the value compared against, here the value of `b`, is false
-      should_flip = b.getNode().(BooleanLiteral).booleanValue().booleanNot()
-      or
-      // comparing to the negation of the boolean
-      (op instanceof NotEq or op instanceof IsNot) and
-      // again, we should flip if the value compared against, here the value of `not b`, is false.
-      // That is, if the value of `b` is true.
-      should_flip = b.getNode().(BooleanLiteral).booleanValue()
+class GuardNode extends Cfg::ControlFlowNode {
+  GuardNode() {
+    // This is the canonical (post-order) version of an AST node, and
+    // some `[true]`/`[false]` variant of the same AST exists. We
+    // include the canonical node because users identify guards by
+    // their AST (`g.(Cfg::CallNode)` etc.), and the outcome-tagged
+    // variants are accessed by `outcomeOfGuard` below.
+    exists(Cfg::ControlFlowNode outcome |
+      outcome.getNode() = this.getNode() and
+      (outcome.isAfterTrue(_) or outcome.isAfterFalse(_))
     )
-  |
-    // we flip `flipped` according to `should_flip` via the formula `flipped xor should_flip`.
-    flipped in [true, false] and
-    cmpNode = guardNode(conditionBlock, flipped.booleanXor(should_flip))
-  )
+    or
+    // Or: this IS one of the outcome-tagged variants, supporting
+    // users who want to query the split point directly.
+    this.isAfterTrue(_)
+    or
+    this.isAfterFalse(_)
+  }
+
+  /** Holds if this guard controls block `b` upon evaluating to `branch`. */
+  predicate controlsBlock(Cfg::BasicBlock b, boolean branch) {
+    branch in [true, false] and
+    exists(Cfg::ControlFlowNode outcomeNode |
+      outcomeOfGuard(this, outcomeNode, branch) and
+      outcomeNode.getBasicBlock().dominates(b)
+    )
+  }
 }
 
 /**
- * A node that controls whether other nodes are evaluated.
+ * Holds if some execution that arrives at `outcomeNode` corresponds
+ * to `guard` having evaluated to `branch`.
  *
- * The field `flipped` allows us to match `GuardNode`s underneath
- * `not`-expressions and still choose the appropriate branch.
+ * For a direct guard `if g:`, the outcome node is `g` itself with
+ * `isAfterTrue`/`isAfterFalse`. For wrapped guards like `not g` or
+ * `g == True`, the outcome is on the wrapping expression with an
+ * appropriate polarity transform — we follow those wrappers up the
+ * AST to find the outermost expression that carries an actual
+ * `isAfterTrue`/`isAfterFalse` outcome.
  */
-class GuardNode extends ControlFlowNode {
-  ConditionBlock conditionBlock;
-  boolean flipped;
-
-  GuardNode() { this = guardNode(conditionBlock, flipped) }
-
-  /** Holds if this guard controls block `b` upon evaluating to `branch`. */
-  predicate controlsBlock(BasicBlock b, boolean branch) {
-    branch in [true, false] and
-    conditionBlock.controls(b, branch.booleanXor(flipped))
-  }
+private predicate outcomeOfGuard(
+  Cfg::ControlFlowNode guard, Cfg::ControlFlowNode outcomeNode, boolean branch
+) {
+  // Base case: the guard itself splits — the outcome node is the
+  // first node of an outcome BB, with matching outcome label.
+  // (The shared CFG also marks inner expressions with outcome flags
+  // for analysis purposes, but only "splitting" nodes — those that
+  // actually start an outcome BB — are valid guards on their own.)
+  outcomeNode.getNode() = guard.getNode() and
+  outcomeNode = outcomeNode.getBasicBlock().firstNode() and
+  (
+    outcomeNode.isAfterTrue(_) and branch = true
+    or
+    outcomeNode.isAfterFalse(_) and branch = false
+  )
+  or
+  // Recursive: `not guard` — same outcome split as `guard`, flipped.
+  exists(Cfg::UnaryExprNode notNode, boolean notBranch |
+    notNode.getOperand().getNode() = guard.getNode() and
+    notNode.getNode().getOp() instanceof Not and
+    outcomeOfGuard(notNode, outcomeNode, notBranch) and
+    branch = notBranch.booleanNot()
+  )
+  or
+  // Recursive: comparisons against a boolean literal.
+  exists(
+    Cfg::CompareNode cmpNode, Cmpop op, Cfg::ControlFlowNode otherOperand,
+    Cfg::ControlFlowNode guardOperand, boolean polarity, boolean cmpBranch
+  |
+    guardOperand.getNode() = guard.getNode() and
+    (
+      cmpNode.operands(guardOperand, op, otherOperand) or
+      cmpNode.operands(otherOperand, op, guardOperand)
+    ) and
+    not guard.getNode() instanceof BooleanLiteral and
+    (
+      (op instanceof Eq or op instanceof Is) and
+      polarity = otherOperand.getNode().(BooleanLiteral).booleanValue()
+      or
+      (op instanceof NotEq or op instanceof IsNot) and
+      polarity = otherOperand.getNode().(BooleanLiteral).booleanValue().booleanNot()
+    ) and
+    outcomeOfGuard(cmpNode, outcomeNode, cmpBranch) and
+    branch = cmpBranch.booleanXor(polarity.booleanNot())
+  )
 }
 
 /**
  * Holds if the guard `g` validates `node` upon evaluating to `branch`.
  */
-signature predicate guardChecksSig(GuardNode g, ControlFlowNode node, boolean branch);
+signature predicate guardChecksSig(GuardNode g, Cfg::ControlFlowNode node, boolean branch);
 
 /**
  * Provides a set of barrier nodes for a guard that validates a node.
@@ -670,7 +708,9 @@ module BarrierGuard<guardChecksSig/3 guardChecks> {
     result = ParameterizedBarrierGuard<Unit, extendedGuardChecks/4>::getABarrierNode(_)
   }
 
-  private predicate extendedGuardChecks(GuardNode g, ControlFlowNode node, boolean branch, Unit u) {
+  private predicate extendedGuardChecks(
+    GuardNode g, Cfg::ControlFlowNode node, boolean branch, Unit u
+  ) {
     guardChecks(g, node, branch) and
     u = u
   }
@@ -680,7 +720,7 @@ bindingset[this]
 private signature class ParamSig;
 
 private module WithParam<ParamSig P> {
-  signature predicate guardChecksSig(GuardNode g, ControlFlowNode node, boolean branch, P param);
+  signature predicate guardChecksSig(GuardNode g, Cfg::ControlFlowNode node, boolean branch, P param);
 }
 
 /**
@@ -693,10 +733,10 @@ module ParameterizedBarrierGuard<ParamSig P, WithParam<P>::guardChecksSig/4 guar
   /** Gets a node that is safely guarded by the given guard check with parameter `param`. */
   overlay[global]
   ExprNode getABarrierNode(P param) {
-    exists(GuardNode g, EssaDefinition def, ControlFlowNode node, boolean branch |
-      AdjacentUses::useOfDef(def, node) and
+    exists(GuardNode g, SsaImpl::EssaDefinition def, Cfg::ControlFlowNode node, boolean branch |
+      SsaImpl::AdjacentUses::useOfDef(def, node) and
       guardChecks(g, node, branch, param) and
-      AdjacentUses::useOfDef(def, result.asCfgNode()) and
+      SsaImpl::AdjacentUses::useOfDef(def, result.asCfgNode()) and
       g.controlsBlock(result.asCfgNode().getBasicBlock(), branch)
     )
   }
@@ -712,7 +752,7 @@ module ExternalBarrierGuard {
   private import semmle.python.ApiGraphs
 
   overlay[global]
-  private predicate guardCheck(GuardNode g, ControlFlowNode node, boolean branch, string kind) {
+  private predicate guardCheck(GuardNode g, Cfg::ControlFlowNode node, boolean branch, string kind) {
     exists(API::CallNode call, API::Node parameter |
       parameter = call.getAParameter() and
       parameter = ModelOutput::getABarrierGuardNode(kind, branch)
@@ -748,10 +788,10 @@ newtype TContent =
   TSetElementContent() or
   /** An element of a tuple at a specific index. */
   TTupleElementContent(int index) {
-    exists(any(TupleNode tn).getElement(index))
+    exists(any(Cfg::TupleNode tn).getElement(index))
     or
     // Arguments can overflow and end up in the starred parameter tuple.
-    exists(any(CallNode cn).getArg(index))
+    exists(any(Cfg::CallNode cn).getArg(index))
     or
     // since flow summaries might use tuples, we ensure that we at least have valid
     // TTupleElementContent for the 0..7 (7 was picked to match `small_tuple` in
@@ -768,10 +808,14 @@ newtype TContent =
     or
     // d["key"] = ...
     key =
-      any(SubscriptNode sub | sub.isStore() | sub.getIndex().getNode().(StringLiteral).getText())
+      any(Cfg::SubscriptNode sub |
+        sub.isStore()
+      |
+        sub.getIndex().getNode().(StringLiteral).getText()
+      )
     or
     // d.setdefault("key", ...)
-    exists(CallNode call | call.getFunction().(AttrNode).getName() = "setdefault" |
+    exists(Cfg::CallNode call | call.getFunction().(Cfg::AttrNode).getName() = "setdefault" |
       key = call.getArg(0).getNode().(StringLiteral).getText()
     )
   } or

python/ql/lib/semmle/python/dataflow/new/internal/ImportResolution.qll

@@ -5,11 +5,24 @@
  */
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
+private import semmle.python.dataflow.new.internal.SsaImpl as SsaImpl
 private import semmle.python.dataflow.new.DataFlow
 private import semmle.python.dataflow.new.internal.ImportStar
 private import semmle.python.dataflow.new.TypeTracking
 private import semmle.python.dataflow.new.internal.DataFlowPrivate
-private import semmle.python.essa.SsaDefinitions
+
+/**
+ * Holds if the name of `var` refers to a submodule of a package and `init` is
+ * the `__init__` module of that package. Locally inlined replacement for the
+ * legacy `SsaSource::init_module_submodule_defn` so that this module has no
+ * direct dependency on `semmle.python.essa.SsaDefinitions`.
+ */
+private predicate initModuleSubmoduleDefn(GlobalVariable var, Module init) {
+  init.isPackageInit() and
+  exists(init.getPackage().getSubModule(var.getId())) and
+  var.getScope() = init
+}
 
 /**
  * Python modules and the way imports are resolved are... complicated. Here's a crash course in how
@@ -69,13 +82,19 @@ module ImportResolution {
    * Holds if there is an ESSA step from `defFrom` to `defTo`, which should be allowed
    * for import resolution.
    */
-  private predicate allowedEssaImportStep(EssaDefinition defFrom, EssaDefinition defTo) {
+  private predicate allowedEssaImportStep(
+    SsaImpl::EssaDefinition defFrom, SsaImpl::EssaDefinition defTo
+  ) {
     // to handle definitions guarded by if-then-else
-    defFrom = defTo.(PhiFunction).getAnInput()
+    defFrom = defTo.(SsaImpl::PhiFunction).getAnInput()
     or
-    // refined variable
-    // example: https://github.com/nvbn/thefuck/blob/ceeaeab94b5df5a4fe9d94d61e4f6b0bbea96378/thefuck/utils.py#L25-L45
-    defFrom = defTo.(EssaNodeRefinement).getInput().getDefinition()
+    // to handle uncertain writes such as `from X import *`, which create an
+    // uncertain SSA definition for every name in the importing scope. The
+    // immediately preceding definition is still potentially the value of the
+    // module export.
+    SsaImpl::Ssa::uncertainWriteDefinitionInput(defTo, defFrom)
+    // Note: legacy ESSA refinement-step (e.g. for `foo.bar = X`) is
+    // not modelled in the new SSA beyond the cases handled above.
   }
 
   /**
@@ -92,30 +111,32 @@ module ImportResolution {
     // Definitions made inside `m` itself
     //
     // for code such as `foo = ...; foo.bar = ...` there will be TWO
-    // EssaDefinition/EssaVariable. One for `foo = ...` (AssignmentDefinition) and one
+    // SsaImpl::EssaDefinition/SsaImpl::EssaVariable. One for `foo = ...` (SsaImpl::AssignmentDefinition) and one
     // for `foo.bar = ...`. The one for `foo.bar = ...` (EssaNodeRefinement). The
     // EssaNodeRefinement is the one that will reach the end of the module (normal
     // exit).
     //
     // However, we cannot just use the EssaNodeRefinement as the `val`, because the
     // normal data-flow depends on use-use flow, and use-use flow targets CFG nodes not
-    // EssaNodes. So we need to go back from the EssaDefinition/EssaVariable that
+    // EssaNodes. So we need to go back from the SsaImpl::EssaDefinition/SsaImpl::EssaVariable that
     // reaches the end of the module, to the first definition of the variable, and then
     // track forwards using use-use flow to find a suitable CFG node that has flow into
     // it from use-use flow.
-    exists(EssaVariable lastUseVar, EssaVariable firstDef |
+    exists(SsaImpl::EssaVariable lastUseVar, SsaImpl::EssaVariable firstDef |
       lastUseVar.getName() = name and
       // we ignore special variable $ introduced by our analysis (not used for anything)
       // we ignore special variable * introduced by `from <pkg> import *` -- TODO: understand why we even have this?
       not name in ["$", "*"] and
-      lastUseVar.getAUse() = m.getANormalExit() and
+      exists(Cfg::ControlFlowNode exit |
+        exit.isNormalExit() and exit.getScope() = m and lastUseVar.getAUse() = exit
+      ) and
       allowedEssaImportStep*(firstDef, lastUseVar) and
       not allowedEssaImportStep(_, firstDef)
     |
       not LocalFlow::defToFirstUse(firstDef, _) and
-      val.asCfgNode() = firstDef.getDefinition().(EssaNodeDefinition).getDefiningNode()
+      val.asCfgNode() = firstDef.getDefinition().(SsaImpl::EssaNodeDefinition).getDefiningNode()
       or
-      exists(ControlFlowNode mid, ControlFlowNode end |
+      exists(Cfg::ControlFlowNode mid, Cfg::ControlFlowNode end |
         LocalFlow::defToFirstUse(firstDef, mid) and
         LocalFlow::useToNextUse*(mid, end) and
         not LocalFlow::useToNextUse(end, _) and
@@ -143,9 +164,9 @@ module ImportResolution {
    * handles simple cases where we can statically tell that this is the case.
    */
   private predicate all_mentions_name(Module m, string name) {
-    exists(DefinitionNode def, SequenceNode n |
+    exists(Cfg::DefinitionNode def, Cfg::SequenceNode n |
       def.getValue() = n and
-      def.(NameNode).getId() = "__all__" and
+      def.(Cfg::NameNode).getId() = "__all__" and
       def.getScope() = m and
       any(StringLiteral s | s.getText() = name) = n.getAnElement().getNode()
     )
@@ -158,18 +179,20 @@ module ImportResolution {
    */
   private predicate no_or_complicated_all(Module m) {
     // No mention of `__all__` in the module
-    not exists(DefinitionNode def | def.getScope() = m and def.(NameNode).getId() = "__all__")
+    not exists(Cfg::DefinitionNode def |
+      def.getScope() = m and def.(Cfg::NameNode).getId() = "__all__"
+    )
     or
     // `__all__` is set to a non-sequence value
-    exists(DefinitionNode def |
-      def.(NameNode).getId() = "__all__" and
+    exists(Cfg::DefinitionNode def |
+      def.(Cfg::NameNode).getId() = "__all__" and
       def.getScope() = m and
-      not def.getValue() instanceof SequenceNode
+      not def.getValue() instanceof Cfg::SequenceNode
     )
     or
     // `__all__` is used in some way that doesn't involve storing a value in it. This usually means
     // it is being mutated through `append` or `extend`, which we don't handle.
-    exists(NameNode n | n.getId() = "__all__" and n.getScope() = m and n.isLoad())
+    exists(Cfg::NameNode n | n.getId() = "__all__" and n.getScope() = m and n.isLoad())
   }
 
   private predicate potential_module_export(Module m, string name) {
@@ -177,7 +200,7 @@ module ImportResolution {
     or
     no_or_complicated_all(m) and
     (
-      exists(NameNode n | n.getId() = name and n.getScope() = m and name.charAt(0) != "_")
+      exists(Cfg::NameNode n | n.getId() = name and n.getScope() = m and name.charAt(0) != "_")
       or
       exists(Alias a | a.getAsname().(Name).getId() = name and a.getValue().getScope() = m)
     )
@@ -207,12 +230,12 @@ module ImportResolution {
 
   /** Gets a module that may have been added to `sys.modules`. */
   private Module sys_modules_module_with_name(string name) {
-    exists(ControlFlowNode n, DataFlow::Node mod |
-      exists(SubscriptNode sub |
+    exists(Cfg::ControlFlowNode n, DataFlow::Node mod |
+      exists(Cfg::SubscriptNode sub |
         sub.getObject() = sys_modules_reference().asCfgNode() and
         sub.getIndex() = n and
         n.getNode().(StringLiteral).getText() = name and
-        sub.(DefinitionNode).getValue() = mod.asCfgNode() and
+        sub.(Cfg::DefinitionNode).getValue() = mod.asCfgNode() and
         mod = getModuleReference(result)
       )
     )
@@ -324,11 +347,11 @@ module ImportResolution {
     // name as a submodule, we always consider that this attribute _could_ be a
     // reference to the submodule, even if we don't know that the submodule has been
     // imported yet.
-    exists(string submodule, Module package, EssaVariable var |
+    exists(string submodule, Module package, SsaImpl::EssaVariable var |
       submodule = var.getName() and
-      SsaSource::init_module_submodule_defn(var.getSourceVariable(), package.getEntryNode()) and
+      initModuleSubmoduleDefn(var.getSourceVariable().getVariable(), package) and
       m = getModuleFromName(package.getPackageName() + "." + submodule) and
-      result.asCfgNode() = var.getDefinition().(EssaNodeDefinition).getDefiningNode()
+      result.asCfgNode() = var.getDefinition().(SsaImpl::EssaNodeDefinition).getDefiningNode()
     )
   }
 

python/ql/lib/semmle/python/dataflow/new/internal/ImportStar.qll

@@ -3,6 +3,7 @@ overlay[local]
 module;
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import semmle.python.dataflow.new.internal.Builtins
 private import semmle.python.dataflow.new.internal.ImportResolution
 private import semmle.python.dataflow.new.DataFlow
@@ -15,7 +16,7 @@ module ImportStar {
    */
   overlay[local]
   cached
-  predicate namePossiblyDefinedInImportStar(NameNode n, string name, Scope s) {
+  predicate namePossiblyDefinedInImportStar(Cfg::NameNode n, string name, Scope s) {
     n.isLoad() and
     name = n.getId() and
     s = n.getScope().getEnclosingScope*() and
@@ -52,7 +53,7 @@ module ImportStar {
   /** Holds if a global variable called `name` is assigned a value in the module `m`. */
   cached
   predicate globalNameDefinedInModule(string name, Module m) {
-    exists(NameNode n |
+    exists(Cfg::NameNode n |
       not exists(LocalVariable v | n.defines(v)) and
       n.isStore() and
       name = n.getId() and
@@ -66,7 +67,7 @@ module ImportStar {
    */
   overlay[global]
   cached
-  predicate importStarResolvesTo(NameNode n, Module m) {
+  predicate importStarResolvesTo(Cfg::NameNode n, Module m) {
     m = getStarImported+(n.getEnclosingModule()) and
     globalNameDefinedInModule(n.getId(), m) and
     not isDefinedLocally(n.getNode())
@@ -99,7 +100,7 @@ module ImportStar {
    */
   overlay[local]
   cached
-  ControlFlowNode potentialImportStarBase(Scope s) {
-    result = any(ImportStarNode n | n.getScope() = s).getModule()
+  Cfg::ControlFlowNode potentialImportStarBase(Scope s) {
+    result = any(Cfg::ImportStarNode n | n.getScope() = s).getModule()
   }
 }

python/ql/lib/semmle/python/dataflow/new/internal/IterableUnpacking.qll

@@ -170,6 +170,8 @@ overlay[local]
 module;
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
+private import semmle.python.dataflow.new.internal.SsaImpl as SsaImpl
 private import DataFlowPublic
 
 /**
@@ -178,7 +180,7 @@ private import DataFlowPublic
  * This class abstracts away the differing representations of comprehensions and
  * for statements.
  */
-class ForTarget extends ControlFlowNode {
+class ForTarget extends Cfg::ControlFlowNode {
   Expr source;
 
   ForTarget() {
@@ -198,7 +200,7 @@ class ForTarget extends ControlFlowNode {
 }
 
 /** The LHS of an assignment, it also records the assigned value. */
-class AssignmentTarget extends ControlFlowNode {
+class AssignmentTarget extends Cfg::ControlFlowNode {
   Expr value;
 
   AssignmentTarget() {
@@ -209,7 +211,7 @@ class AssignmentTarget extends ControlFlowNode {
 }
 
 /** A direct (or top-level) target of an unpacking assignment. */
-class UnpackingAssignmentDirectTarget extends ControlFlowNode instanceof SequenceNode {
+class UnpackingAssignmentDirectTarget extends Cfg::ControlFlowNode instanceof Cfg::SequenceNode {
   Expr value;
 
   UnpackingAssignmentDirectTarget() {
@@ -222,7 +224,7 @@ class UnpackingAssignmentDirectTarget extends ControlFlowNode instanceof Sequenc
 }
 
 /** A (possibly recursive) target of an unpacking assignment. */
-class UnpackingAssignmentTarget extends ControlFlowNode {
+class UnpackingAssignmentTarget extends Cfg::ControlFlowNode {
   UnpackingAssignmentTarget() {
     this instanceof UnpackingAssignmentDirectTarget
     or
@@ -231,10 +233,11 @@ class UnpackingAssignmentTarget extends ControlFlowNode {
 }
 
 /** A (possibly recursive) target of an unpacking assignment which is also a sequence. */
-class UnpackingAssignmentSequenceTarget extends UnpackingAssignmentTarget instanceof SequenceNode {
-  ControlFlowNode getElement(int i) { result = super.getElement(i) }
+class UnpackingAssignmentSequenceTarget extends UnpackingAssignmentTarget instanceof Cfg::SequenceNode
+{
+  Cfg::ControlFlowNode getElement(int i) { result = super.getElement(i) }
 
-  ControlFlowNode getAnElement() { result = this.getElement(_) }
+  Cfg::ControlFlowNode getAnElement() { result = this.getElement(_) }
 }
 
 /**
@@ -255,7 +258,7 @@ predicate iterableUnpackingAssignmentFlowStep(Node nodeFrom, Node nodeTo) {
 predicate iterableUnpackingForReadStep(CfgNode nodeFrom, Content c, Node nodeTo) {
   exists(ForTarget target |
     nodeFrom.getNode().getNode() = target.getSource() and
-    target instanceof SequenceNode and
+    target instanceof Cfg::SequenceNode and
     nodeTo = TIterableSequenceNode(target)
   ) and
   (
@@ -323,11 +326,11 @@ predicate iterableUnpackingConvertingStoreStep(Node nodeFrom, Content c, Node no
  */
 predicate iterableUnpackingElementReadStep(Node nodeFrom, Content c, Node nodeTo) {
   exists(
-    UnpackingAssignmentSequenceTarget target, int index, ControlFlowNode element, int starIndex
+    UnpackingAssignmentSequenceTarget target, int index, Cfg::ControlFlowNode element, int starIndex
   |
-    target.getElement(starIndex) instanceof StarredNode
+    target.getElement(starIndex) instanceof Cfg::StarredNode
     or
-    not exists(target.getAnElement().(StarredNode)) and
+    not exists(target.getAnElement().(Cfg::StarredNode)) and
     starIndex = -1
   |
     nodeFrom.(CfgNode).getNode() = target and
@@ -342,18 +345,18 @@ predicate iterableUnpackingElementReadStep(Node nodeFrom, Content c, Node nodeTo
         else c.(TupleElementContent).getIndex() >= index - 1
     ) and
     (
-      if element instanceof SequenceNode
+      if element instanceof Cfg::SequenceNode
       then
         // Step 5b
         nodeTo = TIterableSequenceNode(element)
       else
-        if element instanceof StarredNode
+        if element instanceof Cfg::StarredNode
         then
           // Step 5c
           nodeTo = TIterableElementNode(element)
         else
           // Step 5a
-          exists(MultiAssignmentDefinition mad | element = mad.getDefiningNode() |
+          exists(SsaImpl::MultiAssignmentDefinition mad | element = mad.getDefiningNode() |
             nodeTo.(CfgNode).getNode() = element
           )
     )
@@ -366,7 +369,7 @@ predicate iterableUnpackingElementReadStep(Node nodeFrom, Content c, Node nodeTo
  * content type `ListElementContent`.
  */
 predicate iterableUnpackingStarredElementStoreStep(Node nodeFrom, Content c, Node nodeTo) {
-  exists(ControlFlowNode starred, MultiAssignmentDefinition mad |
+  exists(Cfg::ControlFlowNode starred, SsaImpl::MultiAssignmentDefinition mad |
     starred.getNode() instanceof Starred and
     starred = mad.getDefiningNode()
   |

python/ql/lib/semmle/python/dataflow/new/internal/LocalSources.qll

@@ -9,6 +9,7 @@ overlay[local]
 module;
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 import DataFlowPublic
 private import DataFlowPrivate
 private import semmle.python.internal.CachedStages
@@ -314,7 +315,7 @@ private module Cached {
    */
   cached
   predicate subscript(LocalSourceNode node, CfgNode subscript, CfgNode index) {
-    exists(CfgNode seq, SubscriptNode subscriptNode | subscriptNode = subscript.getNode() |
+    exists(CfgNode seq, Cfg::SubscriptNode subscriptNode | subscriptNode = subscript.getNode() |
       node.flowsTo(seq) and
       seq.getNode() = subscriptNode.getObject() and
       index.getNode() = subscriptNode.getIndex()

python/ql/lib/semmle/python/dataflow/new/internal/MatchUnpacking.qll

@@ -91,9 +91,7 @@ predicate matchAsFlowStep(Node nodeFrom, Node nodeTo) {
     or
     // the interior pattern flows to the alias
     nodeFrom.(CfgNode).getNode().getNode() = subject.getPattern() and
-    exists(PatternAliasDefinition pad | pad.getDefiningNode().getNode() = alias |
-      nodeTo.(CfgNode).getNode() = pad.getDefiningNode()
-    )
+    nodeTo.(CfgNode).getNode().getNode() = alias
   )
 }
 
@@ -124,11 +122,9 @@ predicate matchLiteralFlowStep(Node nodeFrom, Node nodeTo) {
  * syntax (toplevel): `case var:`
  */
 predicate matchCaptureFlowStep(Node nodeFrom, Node nodeTo) {
-  exists(MatchCapturePattern capture, Name var | capture.getVariable() = var |
+  exists(MatchCapturePattern capture |
     nodeFrom.(CfgNode).getNode().getNode() = capture and
-    exists(PatternCaptureDefinition pcd | pcd.getDefiningNode().getNode() = var |
-      nodeTo.(CfgNode).getNode() = pcd.getDefiningNode()
-    )
+    nodeTo.(CfgNode).getNode().getNode() = capture.getVariable()
   )
 }
 

python/ql/lib/semmle/python/dataflow/new/internal/SsaImpl.qll

@@ -0,0 +1,547 @@
+/**
+ * Provides the Python SSA implementation built on the new (shared) CFG.
+ *
+ * Mirrors the Java SSA adapter at
+ * `java/ql/lib/semmle/code/java/dataflow/internal/SsaImpl.qll`:
+ * an `InputSig` is defined in terms of positional `(BasicBlock, int)`
+ * variable references, and the shared
+ * `codeql.ssa.Ssa::Make<Location, Cfg, Input>` module is then
+ * instantiated.
+ *
+ * `SourceVariable` is the AST-level `Py::Variable`. Variable references
+ * are looked up via the CFG facade's `NameNode.defines`/`uses`/`deletes`
+ * predicates, which themselves are one-line bridges to AST-level
+ * `Name.defines`/`uses`/`deletes`.
+ *
+ * Implicit-entry definitions are inserted for:
+ *   - non-local / global / builtin variables that are read in the scope
+ *     but never assigned (no enclosing CFG node defines them),
+ *   - captured variables (variables defined in an enclosing scope that
+ *     are read inside the scope), and
+ *   - parameters, but only if the corresponding parameter name is *not*
+ *     itself a CFG node. With the C#-style parameter wiring already
+ *     installed in `AstNodeImpl.qll`, parameter names *are* CFG nodes,
+ *     so the regular `variableWrite` path handles them — no `i = -1`
+ *     entry is needed for ordinary parameters.
+ */
+overlay[local?]
+module;
+
+private import python as Py
+private import semmle.python.controlflow.internal.AstNodeImpl as CfgImpl
+private import semmle.python.controlflow.internal.Cfg as Cfg
+private import codeql.ssa.Ssa as SsaImplCommon
+private import codeql.controlflow.BasicBlock as BB
+
+/**
+ * Adapts the Python `Cfg` facade to the shared SSA library's `CfgSig`.
+ * All members are inherited from `Cfg::ControlFlowNode` and
+ * `Cfg::BasicBlock`.
+ */
+private module CfgForSsa implements BB::CfgSig<Py::Location> {
+  class ControlFlowNode = CfgImpl::ControlFlowNode;
+
+  class BasicBlock = CfgImpl::BasicBlock;
+
+  class EntryBasicBlock = CfgImpl::Cfg::EntryBasicBlock;
+
+  predicate dominatingEdge = CfgImpl::Cfg::dominatingEdge/2;
+}
+
+/**
+ * A source variable for SSA, wrapping a Python AST `Variable`.
+ *
+ * We only track variables that are read at least once in their scope —
+ * tracking write-only variables would be unnecessary work — *except*
+ * for module-scope globals, where the "read" can be external (e.g.
+ * `import mymodule; mymodule.x`). Such globals are tracked
+ * unconditionally so that import-resolution can find their defining
+ * write.
+ */
+private newtype TSsaSourceVariable =
+  TPyVar(Py::Variable v) {
+    // Has a use somewhere — read-relevant for SSA.
+    exists(Cfg::NameNode n | n.uses(v))
+    or
+    // Or has a deletion (treated as a write that destroys the value).
+    exists(Cfg::NameNode n | n.deletes(v))
+    or
+    // Or is a module-scope global written in this module — must be
+    // tracked even if never read locally, because importers may read
+    // it as an attribute on the module object.
+    v.getScope() instanceof Py::Module and
+    exists(Cfg::NameNode n | n.defines(v))
+    or
+    // Or is a parameter — parameters must always have a
+    // `ParameterDefinition` for dataflow argument-routing to work,
+    // even if the parameter is never read in its scope. Mirrors
+    // legacy ESSA's `ParameterDefinition` (which fired for every
+    // parameter binding regardless of liveness).
+    exists(Py::Parameter p | p.asName() = v.getAStore())
+  }
+
+/**
+ * A source variable for SSA, wrapping a Python AST `Variable`.
+ */
+class SsaSourceVariable extends TSsaSourceVariable {
+  /** Gets the underlying Python AST variable. */
+  Py::Variable getVariable() { this = TPyVar(result) }
+
+  /** Gets the (textual) name of this variable. */
+  string getName() { result = this.getVariable().getId() }
+
+  /** Gets a textual representation of this source variable. */
+  string toString() { result = this.getVariable().toString() }
+
+  /** Gets the location of this source variable. */
+  Py::Location getLocation() { result = this.getVariable().getScope().getLocation() }
+
+  /** Gets the scope in which this variable lives. */
+  Py::Scope getScope() { result = this.getVariable().getScope() }
+
+  /**
+   * Gets a use of this variable as it appears in the source — a `NameNode`
+   * that loads or deletes the variable. Mirrors legacy
+   * `SsaSourceVariable.getASourceUse()`.
+   */
+  Cfg::ControlFlowNode getASourceUse() {
+    exists(Cfg::NameNode n | result = n |
+      n.uses(this.getVariable()) or n.deletes(this.getVariable())
+    )
+  }
+
+  /**
+   * Gets an implicit use of this variable. The new SSA does not have
+   * implicit-use refinements, but we keep this for API parity — every
+   * normal-exit of the variable's scope counts as a sink, ensuring
+   * variables stay live to scope exit for taint-tracking.
+   */
+  Cfg::ControlFlowNode getAnImplicitUse() {
+    result.isNormalExit() and result.getScope() = this.getScope()
+  }
+
+  /**
+   * Gets a use of this variable — either an explicit source use or an
+   * implicit use at scope exit. Mirrors legacy `SsaSourceVariable.getAUse()`.
+   */
+  Cfg::ControlFlowNode getAUse() {
+    result = this.getASourceUse() or result = this.getAnImplicitUse()
+  }
+}
+
+/**
+ * Holds if `v` is a non-local read in scope `s`, in the sense that `s`
+ * uses `v` but does not write it within `s`. This includes globals,
+ * builtins, and variables captured from an enclosing function scope.
+ *
+ * The `Py::Variable` `v` lives in some defining scope (the module for
+ * globals, an outer function for closures, etc.); the reading scope
+ * `s` is the scope where the use of `v` occurs.
+ */
+private predicate nonLocalReadIn(Py::Variable v, Py::Scope s) {
+  exists(Cfg::NameNode n |
+    n.uses(v) and
+    n.getScope() = s and
+    not exists(Cfg::NameNode def | def.defines(v) and def.getScope() = s)
+  ) and
+  // Match legacy ESSA: only create entry defs for variables that have
+  // at least one defining store somewhere — otherwise the entry def
+  // represents "nothing reaches here", which is the default anyway and
+  // introduces no useful flow. (Legacy's `ModuleVariable` required a
+  // store; this is the closure-aware generalisation.)
+  exists(Cfg::NameNode store | store.defines(v))
+}
+
+/**
+ * Holds if `bb` is the entry basic block of a scope where `v` should
+ * have an implicit entry definition. This covers:
+ *   - non-local / global / builtin variables read in `s`, and
+ *   - captured variables (defined in an enclosing scope but read in `s`).
+ *
+ * Each reading scope gets its own entry def, so a closure variable can
+ * have multiple entry defs across all functions/methods that read it.
+ *
+ * Parameters are *not* included: their bound `Name` is itself a CFG
+ * node (per the C#-style parameter wiring), so `variableWrite` fires at
+ * the parameter's natural CFG index.
+ */
+private predicate hasEntryDefIn(SsaSourceVariable v, CfgImpl::BasicBlock bb) {
+  exists(Py::Scope s |
+    nonLocalReadIn(v.getVariable(), s) and
+    bb = entryBlock(s)
+  )
+}
+
+/**
+ * Gets the entry basic block of scope `s`, where implicit entry
+ * definitions are placed (at synthetic index `-1`).
+ */
+private CfgImpl::BasicBlock entryBlock(Py::Scope s) {
+  exists(CfgImpl::ControlFlowNode entry |
+    entry instanceof CfgImpl::ControlFlow::EntryNode and
+    entry.getEnclosingCallable().asScope() = s and
+    result = entry.getBasicBlock()
+  )
+}
+
+/**
+ * The SSA `InputSig` for Python. References are positional
+ * `(BasicBlock, int)` pairs into the new CFG.
+ */
+private module SsaImplInput implements SsaImplCommon::InputSig<Py::Location, CfgImpl::BasicBlock> {
+  class SourceVariable = SsaSourceVariable;
+
+  predicate variableWrite(CfgImpl::BasicBlock bb, int i, SourceVariable v, boolean certain) {
+    // Explicit binding at a CFG node — includes assignments,
+    // parameter Names (wired in via the C# pattern), exception-handler
+    // `as`-bindings, import aliases, and match-pattern captures.
+    exists(Cfg::NameNode n |
+      bb.getNode(i) = n and
+      n.defines(v.getVariable()) and
+      certain = true
+    )
+    or
+    // `del x` — removes the binding. Modelled as a certain write that
+    // makes any subsequent read invalid.
+    exists(Cfg::NameNode n |
+      bb.getNode(i) = n and
+      n.deletes(v.getVariable()) and
+      certain = true
+    )
+    or
+    // Implicit entry definition for non-local / captured / global /
+    // builtin variables read in some scope. Each reading scope's entry
+    // block gets one such write, allowing closures: e.g. when `x` is a
+    // parameter of an outer function and read inside a nested
+    // function, both scopes get entry defs for `x`.
+    hasEntryDefIn(v, bb) and
+    i = -1 and
+    certain = true
+    or
+    // `from X import *` — possibly rebinds every name in the importing
+    // scope. Modelled as an uncertain write at the import-star's CFG
+    // position for every variable that lives in (or is referenced
+    // from) the same scope as the import-star. Mirrors legacy ESSA's
+    // `ImportStarRefinement` (see `essa/SsaDefinitions.qll`'s
+    // `import_star_refinement` predicate). The write is uncertain so
+    // that prior definitions of the variable remain available — the
+    // shared-SSA `SsaUncertainWrite` merges the new value with the
+    // immediately preceding definition.
+    exists(Cfg::ImportStarNode imp |
+      bb.getNode(i) = imp and
+      certain = false and
+      (
+        v.getVariable().getScope() = imp.getScope()
+        or
+        // Variable is defined in some other scope but referenced in
+        // the same scope as the import-star (matches legacy clause 2:
+        // `other.uses(v) and def.getScope() = other.getScope()`).
+        exists(Cfg::NameNode other |
+          other.uses(v.getVariable()) and
+          imp.getScope() = other.getScope()
+        )
+      )
+    )
+  }
+
+  predicate variableRead(CfgImpl::BasicBlock bb, int i, SourceVariable v, boolean certain) {
+    // Explicit source use — a `Name` load or a `del x` of the variable.
+    exists(Cfg::NameNode n |
+      bb.getNode(i) = n and
+      n.uses(v.getVariable()) and
+      certain = true
+    )
+    or
+    // Synthetic use at the normal exit of the variable's defining scope.
+    // This keeps every variable live to scope exit so that callers (e.g.
+    // `module_export` in ImportResolution.qll, or taint-tracking pass-through
+    // through unread locals) can ask "which definition reaches end of
+    // scope?". Mirrors legacy ESSA's `SsaSourceVariable.getAUse()` which
+    // included `getScope().getANormalExit()`.
+    exists(Cfg::ControlFlowNode exit |
+      exit.isNormalExit() and
+      exit.getScope() = v.getVariable().getScope() and
+      bb.getNode(i) = exit and
+      certain = true
+    )
+  }
+}
+
+/**
+ * The shared SSA instantiation for Python.
+ *
+ * Members:
+ *   - `Definition` — the union of explicit, uncertain, and phi definitions
+ *   - `WriteDefinition`, `UncertainWriteDefinition`, `PhiNode`
+ *   - the standard SSA predicates (`getAUse`, `getAnUltimateDefinition`, ...).
+ */
+module Ssa = SsaImplCommon::Make<Py::Location, CfgForSsa, SsaImplInput>;
+
+final class Definition = Ssa::Definition;
+
+final class WriteDefinition = Ssa::WriteDefinition;
+
+final class UncertainWriteDefinition = Ssa::UncertainWriteDefinition;
+
+final class PhiNode = Ssa::PhiNode;
+
+// ===========================================================================
+// ESSA-shaped adapter layer
+//
+// The dataflow library (`python/ql/lib/semmle/python/dataflow/new/`) and
+// related modules (`ApiGraphs.qll`, etc.) consume the legacy ESSA API
+// (`EssaVariable`, `EssaDefinition`, `AssignmentDefinition`,
+// `ScopeEntryDefinition`, `ParameterDefinition`, `WithDefinition`,
+// `PhiFunction`, plus the `AdjacentUses` module). To migrate them off
+// the legacy CFG, we expose the same API surface on top of the
+// shared SSA built above.
+//
+// This adapter is intentionally narrow: it covers only the predicates
+// that new dataflow consumes. The richer legacy ESSA — refinement
+// nodes, attribute refinements, edge refinements — stays available
+// via `semmle.python.essa.Essa` for points-to / legacy code.
+// ===========================================================================
+/**
+ * Gets the CFG node at which a write definition's binding takes place.
+ *
+ * For ordinary writes (assignment, deletion, parameter) this is the
+ * canonical CFG node of the bound Name. For implicit entry definitions
+ * (synthesised at position `-1` of a scope's entry BB) this is the
+ * scope's entry node.
+ */
+private Cfg::ControlFlowNode writeDefNode(Ssa::WriteDefinition def) {
+  exists(CfgImpl::BasicBlock bb, int i | def.definesAt(_, bb, i) |
+    i >= 0 and result = bb.getNode(i)
+    or
+    i = -1 and result = bb.getNode(0)
+  )
+}
+
+/**
+ * A write definition whose binding has a corresponding CFG node — i.e.
+ * everything that's not a phi node. Mirrors legacy ESSA's
+ * `EssaNodeDefinition`.
+ */
+class EssaNodeDefinition extends Ssa::WriteDefinition {
+  /** Gets the CFG node where this definition's binding takes place. */
+  Cfg::ControlFlowNode getDefiningNode() { result = writeDefNode(this) }
+
+  /** Gets the variable defined here (legacy name). */
+  SsaSourceVariable getVariable() { result = this.getSourceVariable() }
+
+  /** Gets the enclosing scope. */
+  Py::Scope getScope() {
+    exists(Cfg::ControlFlowNode n | n = this.getDefiningNode() | result = n.getScope())
+  }
+
+  /**
+   * Holds if this definition defines source variable `v` at CFG node
+   * `defNode`. Flatter form of `getSourceVariable()` +
+   * `getDefiningNode()`, matching legacy ESSA's `definedBy`.
+   */
+  predicate definedBy(SsaSourceVariable v, Cfg::ControlFlowNode defNode) {
+    v = this.getSourceVariable() and defNode = this.getDefiningNode()
+  }
+}
+
+/**
+ * An assignment definition: any binding where the value being assigned
+ * is statically known via `Cfg::DefinitionNode.getValue()`. Includes
+ * plain assignments, walrus, annotated assignments, augmented
+ * assignments, import aliases (`import x` / `from m import x [as y]`),
+ * `with ... as x`, and for-target bindings (where `getValue()` returns
+ * the iter expression's CFG node). Excludes parameter bindings —
+ * those are modelled by `ParameterDefinition`.
+ */
+class AssignmentDefinition extends EssaNodeDefinition {
+  AssignmentDefinition() {
+    exists(Cfg::NameNode n | n = this.getDefiningNode() |
+      exists(n.(Cfg::DefinitionNode).getValue()) and
+      not n.(Cfg::ControlFlowNode).isParameter()
+    )
+  }
+
+  /** Gets the CFG node for the value being assigned, if statically known. */
+  Cfg::ControlFlowNode getValue() {
+    result = this.getDefiningNode().(Cfg::DefinitionNode).getValue()
+  }
+}
+
+/**
+ * A parameter definition — the binding of a parameter name in a
+ * function's scope.
+ */
+class ParameterDefinition extends EssaNodeDefinition {
+  ParameterDefinition() { this.getDefiningNode().isParameter() }
+
+  /** Gets the AST `Parameter` (a `Py::Name` in param context). */
+  Py::Name getParameter() { result = this.getDefiningNode().getNode() }
+}
+
+/**
+ * A definition introduced by a `with ... as x:` clause.
+ */
+class WithDefinition extends EssaNodeDefinition {
+  WithDefinition() {
+    exists(Cfg::NameNode n, Py::With w |
+      n = this.getDefiningNode() and
+      w.getOptionalVars() = n.getNode()
+    )
+  }
+}
+
+/**
+ * An assignment where the LHS is a tuple/list and the RHS is unpacked:
+ * `a, b = (1, 2)` or `a, *rest = xs`. The SSA def lives at the inner
+ * `Name` CFG node, but for IterableUnpacking integration we expose
+ * the enclosing `StarredNode` as the `getDefiningNode()` for `*rest`
+ * patterns — mirroring legacy ESSA's `multi_assignment_definition`,
+ * which placed the def at the StarredNode CFG node.
+ */
+class MultiAssignmentDefinition extends EssaNodeDefinition {
+  MultiAssignmentDefinition() {
+    exists(Cfg::NameNode n | n = super.getDefiningNode() |
+      exists(Py::Assign a, Py::Expr lhs |
+        a.getATarget() = lhs and
+        (lhs instanceof Py::Tuple or lhs instanceof Py::List) and
+        lhs.getASubExpression+() = n.getNode()
+      )
+      or
+      // For-loop with tuple/list target: `for a, b in xs:` —
+      // tuple-unpacking semantics applies to the for-target.
+      exists(Py::For f, Py::Expr lhs |
+        f.getTarget() = lhs and
+        (lhs instanceof Py::Tuple or lhs instanceof Py::List) and
+        lhs.getASubExpression+() = n.getNode()
+      )
+    )
+  }
+
+  override Cfg::ControlFlowNode getDefiningNode() {
+    // Default: the underlying `Name` CFG node (where the SSA def lives).
+    not exists(Cfg::StarredNode s |
+      s.getNode().(Py::Starred).getValue() = super.getDefiningNode().getNode()
+    ) and
+    result = super.getDefiningNode()
+    or
+    // Exception: for `*rest`, expose the enclosing `Starred` CFG node
+    // so that `IterableUnpacking::iterableUnpackingStarredElementStoreStep`
+    // can attach the rest-list to it.
+    exists(Cfg::StarredNode s |
+      s.getNode().(Py::Starred).getValue() = super.getDefiningNode().getNode()
+    |
+      result = s
+    )
+  }
+}
+
+/**
+ * An implicit entry definition for a non-local / captured / global /
+ * builtin variable read in a scope but not defined there.
+ *
+ * Inherits from `EssaNodeDefinition` and exposes the scope's entry node
+ * as its defining node (matching legacy ESSA semantics).
+ */
+class ScopeEntryDefinition extends EssaNodeDefinition {
+  ScopeEntryDefinition() {
+    exists(CfgImpl::BasicBlock bb |
+      this.definesAt(_, bb, -1) and
+      bb instanceof CfgImpl::Cfg::EntryBasicBlock
+    )
+  }
+
+  /** Gets the enclosing scope (the scope whose entry block this def is in). */
+  override Py::Scope getScope() {
+    exists(CfgImpl::BasicBlock bb |
+      this.definesAt(_, bb, -1) and
+      result = bb.getNode(0).(Cfg::ControlFlowNode).getScope()
+    )
+  }
+}
+
+/** A phi node (alias matching legacy naming). */
+class PhiFunction extends PhiNode {
+  /**
+   * Gets an input to this phi function (a definition that flows into
+   * the phi from one of its predecessor blocks). Mirrors legacy
+   * ESSA's `PhiFunction.getAnInput()`.
+   */
+  Ssa::Definition getAnInput() { Ssa::phiHasInputFromBlock(this, result, _) }
+}
+
+/** Base class for all ESSA definitions (legacy-shaped). */
+class EssaDefinition = Ssa::Definition;
+
+/**
+ * An adapter representing a single SSA-defined "variable" — wrapping
+ * one `Ssa::Definition`. Mirrors legacy `EssaVariable` API.
+ */
+class EssaVariable extends Ssa::Definition {
+  /** Gets the underlying SSA definition (legacy name). */
+  Ssa::Definition getDefinition() { result = this }
+
+  /**
+   * Gets a CFG node where this definition is used. Includes regular
+   * `Name` reads as well as the synthetic scope-exit "use" registered
+   * via `SsaImplInput::variableRead` — mirrors legacy ESSA's
+   * `EssaVariable.getAUse()` which inherited the synthetic exit-use
+   * from `SsaSourceVariable`.
+   */
+  Cfg::ControlFlowNode getAUse() {
+    exists(CfgImpl::BasicBlock bb, int i |
+      Ssa::ssaDefReachesRead(this.getSourceVariable(), this, bb, i) and
+      bb.getNode(i) = result
+    )
+  }
+
+  /** Gets the (textual) name of the underlying variable. */
+  string getName() { result = this.getSourceVariable().getVariable().getId() }
+
+  /** Gets the scope in which this variable lives. */
+  Py::Scope getScope() { result = this.getSourceVariable().getVariable().getScope() }
+
+  /** Gets an ultimate non-phi ancestor of this definition. */
+  EssaVariable getAnUltimateDefinition() {
+    if this instanceof PhiNode
+    then
+      exists(Ssa::Definition input |
+        Ssa::phiHasInputFromBlock(this, input, _) and
+        result = input.(EssaVariable).getAnUltimateDefinition()
+      )
+    else result = this
+  }
+}
+
+/**
+ * Adjacent use-use and def-use relations exposed by the shared SSA
+ * library. Provides the same interface as legacy
+ * `semmle.python.essa.SsaCompute::AdjacentUses`.
+ */
+module AdjacentUses {
+  /** Holds if `nodeFrom` and `nodeTo` are adjacent uses of the same SSA variable. */
+  predicate adjacentUseUse(Cfg::NameNode nodeFrom, Cfg::NameNode nodeTo) {
+    exists(SsaSourceVariable v, CfgImpl::BasicBlock bb1, int i1, CfgImpl::BasicBlock bb2, int i2 |
+      Ssa::adjacentUseUse(bb1, i1, bb2, i2, v, _) and
+      nodeFrom = bb1.getNode(i1) and
+      nodeTo = bb2.getNode(i2)
+    )
+  }
+
+  /** Holds if `use` is a first use of definition `def`. */
+  predicate firstUse(Ssa::Definition def, Cfg::NameNode use) {
+    exists(CfgImpl::BasicBlock bb, int i |
+      Ssa::firstUse(def, bb, i, _) and
+      use = bb.getNode(i)
+    )
+  }
+
+  /**
+   * Holds if `use` is any reachable use of definition `def`. Combines
+   * `firstUse` with transitive use-use adjacency.
+   */
+  predicate useOfDef(Ssa::Definition def, Cfg::NameNode use) {
+    firstUse(def, use)
+    or
+    exists(Cfg::NameNode mid | useOfDef(def, mid) and adjacentUseUse(mid, use))
+  }
+}

python/ql/lib/semmle/python/dataflow/new/internal/TaintTrackingPrivate.qll

@@ -1,4 +1,6 @@
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
+private import semmle.python.dataflow.new.internal.SsaImpl as SsaImpl
 private import semmle.python.dataflow.new.DataFlow
 private import semmle.python.dataflow.new.internal.DataFlowPrivate as DataFlowPrivate
 private import FlowSummaryImpl as FlowSummaryImpl
@@ -75,7 +77,7 @@ import Cached
  * and isn't a big problem in practice.
  */
 predicate concatStep(DataFlow::CfgNode nodeFrom, DataFlow::CfgNode nodeTo) {
-  exists(BinaryExprNode add | add = nodeTo.getNode() |
+  exists(Cfg::BinaryExprNode add | add = nodeTo.getNode() |
     add.getOp() instanceof Add and add.getAnOperand() = nodeFrom.getNode()
   )
 }
@@ -84,7 +86,7 @@ predicate concatStep(DataFlow::CfgNode nodeFrom, DataFlow::CfgNode nodeTo) {
  * Holds if taint can flow from `nodeFrom` to `nodeTo` with a step related to subscripting.
  */
 predicate subscriptStep(DataFlow::CfgNode nodeFrom, DataFlow::CfgNode nodeTo) {
-  nodeTo.getNode().(SubscriptNode).getObject() = nodeFrom.getNode()
+  nodeTo.getNode().(Cfg::SubscriptNode).getObject() = nodeFrom.getNode()
 }
 
 /**
@@ -100,15 +102,15 @@ predicate stringManipulation(DataFlow::CfgNode nodeFrom, DataFlow::CfgNode nodeT
     (
       call = API::builtin(["str", "bytes", "unicode"]).getACall()
       or
-      call.getFunction().asCfgNode().(NameNode).getId() in ["str", "bytes", "unicode"]
+      call.getFunction().asCfgNode().(Cfg::NameNode).getId() in ["str", "bytes", "unicode"]
     ) and
     nodeFrom in [call.getArg(0), call.getArgByName("object")]
   )
   or
   // String methods. Note that this doesn't recognize `meth = "foo".upper; meth()`
-  exists(CallNode call, string method_name, ControlFlowNode object |
+  exists(Cfg::CallNode call, string method_name, Cfg::ControlFlowNode object |
     call = nodeTo.getNode() and
-    object = call.getFunction().(AttrNode).getObject(method_name)
+    object = call.getFunction().(Cfg::AttrNode).getObject(method_name)
   |
     nodeFrom.getNode() = object and
     method_name in [
@@ -139,7 +141,7 @@ predicate stringManipulation(DataFlow::CfgNode nodeFrom, DataFlow::CfgNode nodeT
   )
   or
   // % formatting
-  exists(BinaryExprNode fmt | fmt = nodeTo.getNode() |
+  exists(Cfg::BinaryExprNode fmt | fmt = nodeTo.getNode() |
     fmt.getOp() instanceof Mod and
     (
       fmt.getLeft() = nodeFrom.getNode()
@@ -149,7 +151,7 @@ predicate stringManipulation(DataFlow::CfgNode nodeFrom, DataFlow::CfgNode nodeT
   )
   or
   // string multiplication -- `"foo" * 10`
-  exists(BinaryExprNode mult | mult = nodeTo.getNode() |
+  exists(Cfg::BinaryExprNode mult | mult = nodeTo.getNode() |
     mult.getOp() instanceof Mult and
     mult.getLeft() = nodeFrom.getNode()
   )
@@ -207,8 +209,8 @@ predicate awaitStep(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {
  * the variable `f` is tainted if the result of `open("foo")` is tainted.
  */
 predicate asyncWithStep(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {
-  exists(With with, ControlFlowNode contextManager, ControlFlowNode var |
-    var = any(WithDefinition wd).getDefiningNode()
+  exists(With with, Cfg::ControlFlowNode contextManager, Cfg::ControlFlowNode var |
+    var = any(SsaImpl::WithDefinition wd).getDefiningNode()
   |
     nodeFrom.(DataFlow::CfgNode).getNode() = contextManager and
     nodeTo.(DataFlow::CfgNode).getNode() = var and

python/ql/lib/semmle/python/dataflow/new/internal/TypeTrackingImpl.qll

@@ -2,6 +2,8 @@ import codeql.util.Unit
 import codeql.typetracking.TypeTracking as Shared
 import codeql.typetracking.internal.TypeTrackingImpl as SharedImpl
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
+private import semmle.python.dataflow.new.internal.SsaImpl as SsaImpl
 private import semmle.python.internal.CachedStages
 private import semmle.python.dataflow.new.internal.DataFlowPublic as DataFlowPublic
 private import semmle.python.dataflow.new.internal.DataFlowPrivate as DataFlowPrivate
@@ -94,8 +96,10 @@ private module SummaryTypeTrackerInput implements SummaryTypeTracker::Input {
   Node returnOf(Node callable, SummaryComponent return) {
     return = FlowSummaryImpl::Private::SummaryComponent::return() and
     // `result` should be the return value of a callable expression (lambda or function) referenced by `callable`
-    result.asCfgNode() =
-      callable.getALocalSource().asExpr().(CallableExpr).getInnerScope().getAReturnValueFlowNode()
+    exists(Return ret |
+      ret.getScope() = callable.getALocalSource().asExpr().(CallableExpr).getInnerScope() and
+      result.asCfgNode().getNode() = ret.getValue()
+    )
   }
 
   // Relating callables to nodes
@@ -160,7 +164,7 @@ module TypeTrackingInput implements Shared::TypeTrackingInput<Location> {
     // ignore the flow steps from the synthetic sequence node to the real sequence node,
     // since we only support one level of content in type-trackers, and the nested
     // structure requires two levels at least to be useful.
-    not exists(SequenceNode outer |
+    not exists(Cfg::SequenceNode outer |
       outer.getAnElement() = nodeTo.asCfgNode() and
       IterableUnpacking::iterableUnpackingTupleFlowStep(nodeFrom, nodeTo)
     )
@@ -259,7 +263,7 @@ module TypeTrackingInput implements Shared::TypeTrackingInput<Location> {
     // Since we only support one level of content in type-trackers we don't actually
     // support `(aa, ab), (ba, bb) = ...`. Therefore we exclude the read-step from `(aa,
     // ab)` to `aa` (since it is not needed).
-    not exists(SequenceNode outer |
+    not exists(Cfg::SequenceNode outer |
       outer.getAnElement() = nodeFrom.asCfgNode() and
       IterableUnpacking::iterableUnpackingTupleFlowStep(_, nodeFrom)
     ) and
@@ -269,7 +273,7 @@ module TypeTrackingInput implements Shared::TypeTrackingInput<Location> {
       IterableUnpacking::iterableUnpackingForReadStep(_, _, seq) and
       IterableUnpacking::iterableUnpackingConvertingReadStep(seq, _, elem) and
       IterableUnpacking::iterableUnpackingConvertingStoreStep(elem, _, nodeFrom) and
-      nodeFrom.asCfgNode() instanceof SequenceNode
+      nodeFrom.asCfgNode() instanceof Cfg::SequenceNode
     )
     or
     TypeTrackerSummaryFlow::basicLoadStep(nodeFrom, nodeTo, content)
@@ -306,13 +310,15 @@ module TypeTrackingInput implements Shared::TypeTrackingInput<Location> {
     //
     // nodeFrom is `expr`
     // nodeTo is entry node for `f`
-    exists(ScopeEntryDefinition e, SsaSourceVariable var, DefinitionNode def |
+    exists(
+      SsaImpl::ScopeEntryDefinition e, SsaImpl::SsaSourceVariable var, Cfg::DefinitionNode def
+    |
       e.getSourceVariable() = var and
-      var.hasDefiningNode(def)
+      def.getNode() = var.getVariable().getAStore()
     |
       nodeTo.(DataFlowPublic::ScopeEntryDefinitionNode).getDefinition() = e and
       nodeFrom.asCfgNode() = def and
-      var.getScope().getScope*() = nodeFrom.getScope()
+      var.getVariable().getScope().getScope*() = nodeFrom.getScope()
     )
   }
 

python/ql/lib/semmle/python/dataflow/new/internal/VariableCapture.qll

@@ -3,6 +3,9 @@ overlay[local]
 module;
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
+private import semmle.python.controlflow.internal.AstNodeImpl as CfgImpl
+private import semmle.python.dataflow.new.internal.SsaImpl as SsaImpl
 private import DataFlowPublic
 private import semmle.python.dataflow.new.internal.DataFlowPrivate
 private import codeql.dataflow.VariableCapture as Shared
@@ -14,10 +17,10 @@ private import codeql.dataflow.VariableCapture as Shared
 // The first is the main implementation, the second is a performance motivated restriction.
 // The restriction is to clear any `CapturedVariableContent` before writing a new one
 // to avoid long access paths (see the link for a nice explanation).
-private module CaptureInput implements Shared::InputSig<Location, Cfg::BasicBlock> {
+private module CaptureInput implements Shared::InputSig<Location, CfgImpl::BasicBlock> {
   private import python as PY
 
-  additional class ExprCfgNode extends ControlFlowNode {
+  additional class ExprCfgNode extends Cfg::ControlFlowNode {
     ExprCfgNode() { isExpressionNode(this) }
   }
 
@@ -25,7 +28,9 @@ private module CaptureInput implements Shared::InputSig<Location, Cfg::BasicBloc
     predicate isConstructor() { none() }
   }
 
-  Callable basicBlockGetEnclosingCallable(Cfg::BasicBlock bb) { result = bb.getScope() }
+  Callable basicBlockGetEnclosingCallable(CfgImpl::BasicBlock bb) {
+    result = bb.getEnclosingCallable().asScope()
+  }
 
   class CapturedVariable extends LocalVariable {
     Function f;
@@ -51,27 +56,29 @@ private module CaptureInput implements Shared::InputSig<Location, Cfg::BasicBloc
   class CapturedParameter extends CapturedVariable {
     CapturedParameter() { this.isParameter() }
 
-    ControlFlowNode getCfgNode() { result.getNode().(Parameter) = this.getAnAccess() }
+    Cfg::ControlFlowNode getCfgNode() { result.getNode().(Parameter) = this.getAnAccess() }
   }
 
   class Expr extends ExprCfgNode {
-    predicate hasCfgNode(Cfg::BasicBlock bb, int i) { this = bb.getNode(i) }
+    predicate hasCfgNode(CfgImpl::BasicBlock bb, int i) { this = bb.getNode(i) }
   }
 
-  class VariableWrite extends ControlFlowNode {
+  class VariableWrite extends Cfg::ControlFlowNode {
     CapturedVariable v;
 
-    VariableWrite() { this = v.getAStore().getAFlowNode().(DefinitionNode).getValue() }
+    VariableWrite() {
+      exists(Cfg::DefinitionNode d | d.getNode() = v.getAStore() | this = d.getValue())
+    }
 
     CapturedVariable getVariable() { result = v }
 
-    predicate hasCfgNode(Cfg::BasicBlock bb, int i) { this = bb.getNode(i) }
+    predicate hasCfgNode(CfgImpl::BasicBlock bb, int i) { this = bb.getNode(i) }
   }
 
   class VariableRead extends Expr {
     CapturedVariable v;
 
-    VariableRead() { this = v.getALoad().getAFlowNode() }
+    VariableRead() { this.getNode() = v.getALoad() }
 
     CapturedVariable getVariable() { result = v }
   }
@@ -80,9 +87,14 @@ private module CaptureInput implements Shared::InputSig<Location, Cfg::BasicBloc
     // TODO: Other languages have an extra case here looking like
     //   simpleAstFlowStep(nodeFrom, nodeTo)
     // we should investigate the potential benefit of adding that.
-    exists(SsaVariable def |
+    exists(SsaImpl::EssaVariable def |
       def.getAUse() = nodeTo and
-      def.getAnUltimateDefinition().getDefinition().(DefinitionNode).getValue() = nodeFrom
+      def.getAnUltimateDefinition()
+          .getDefinition()
+          .(SsaImpl::EssaNodeDefinition)
+          .getDefiningNode()
+          .(Cfg::DefinitionNode)
+          .getValue() = nodeFrom
     )
   }
 
@@ -107,7 +119,7 @@ class CapturedVariable = CaptureInput::CapturedVariable;
 
 class ClosureExpr = CaptureInput::ClosureExpr;
 
-module Flow = Shared::Flow<Location, Cfg, CaptureInput>;
+module Flow = Shared::Flow<Location, Cfg::CfgSigImpl, CaptureInput>;
 
 private Flow::ClosureNode asClosureNode(Node n) {
   result = n.(SynthCaptureNode).getSynthesizedCaptureNode()

python/ql/lib/semmle/python/dataflow/old/Implementation.qll

@@ -448,8 +448,7 @@ class TaintTrackingImplementation extends string instanceof TaintTracking::Confi
       context = TNoParam() and
       src = TTaintTrackingNode_(retval, TNoParam(), path, kind, this) and
       node.asCfgNode() = call and
-      retval.asCfgNode() =
-        any(Return ret | ret.getScope() = pyfunc.getScope()).getValue().getAFlowNode()
+      retval.asCfgNode().getNode() = any(Return ret | ret.getScope() = pyfunc.getScope()).getValue()
     ) and
     edgeLabel = "return"
   }
@@ -471,8 +470,7 @@ class TaintTrackingImplementation extends string instanceof TaintTracking::Confi
       this.callContexts(call, src, pyfunc, context, callee) and
       retnode = TTaintTrackingNode_(retval, callee, path, kind, this) and
       node.asCfgNode() = call and
-      retval.asCfgNode() =
-        any(Return ret | ret.getScope() = pyfunc.getScope()).getValue().getAFlowNode()
+      retval.asCfgNode().getNode() = any(Return ret | ret.getScope() = pyfunc.getScope()).getValue()
     ) and
     edgeLabel = "call"
   }
@@ -716,8 +714,10 @@ private class EssaTaintTracking extends string instanceof TaintTracking::Configu
       src = TTaintTrackingNode_(srcnode, context, path, srckind, this) and
       path.noAttribute()
     |
-      assign.getValue().getAFlowNode() = srcnode.asCfgNode() and
-      depth = iterable_unpacking_descent(assign.getATarget().getAFlowNode(), defn.getDefiningNode()) and
+      srcnode.asCfgNode().getNode() = assign.getValue() and
+      exists(SequenceNode left_parent | left_parent.getNode() = assign.getATarget() |
+        depth = iterable_unpacking_descent(left_parent, defn.getDefiningNode())
+      ) and
       kind = taint_at_depth(srckind, depth)
     )
   }
@@ -964,7 +964,7 @@ private TaintKind taint_at_depth(SequenceKind parent_kind, int depth) {
  * - with `left_defn` = `*y`, `left_parent` = `((x, *y), ...)`, result = 1
  */
 int iterable_unpacking_descent(SequenceNode left_parent, ControlFlowNode left_defn) {
-  exists(Assign a | a.getATarget().getASubExpression*().getAFlowNode() = left_parent) and
+  exists(Assign a | left_parent.getNode() = a.getATarget().getASubExpression*()) and
   left_parent.getAnElement() = left_defn and
   // Handle `a, *b = some_iterable`
   if left_defn instanceof StarredNode then result = 0 else result = 1

python/ql/lib/semmle/python/essa/SsaDefinitions.qll

@@ -56,7 +56,7 @@ module SsaSource {
   predicate with_definition(Variable v, ControlFlowNode defn) {
     exists(With with, Name var |
       with.getOptionalVars() = var and
-      var.getAFlowNode() = defn
+      defn.getNode() = var
     |
       var = v.getAStore()
     )
@@ -67,7 +67,7 @@ module SsaSource {
   predicate pattern_capture_definition(Variable v, ControlFlowNode defn) {
     exists(MatchCapturePattern capture, Name var |
       capture.getVariable() = var and
-      var.getAFlowNode() = defn
+      defn.getNode() = var
     |
       var = v.getAStore()
     )
@@ -78,7 +78,7 @@ module SsaSource {
   predicate pattern_alias_definition(Variable v, ControlFlowNode defn) {
     exists(MatchAsPattern pattern, Name var |
       pattern.getAlias() = var and
-      var.getAFlowNode() = defn
+      defn.getNode() = var
     |
       var = v.getAStore()
     )

python/ql/lib/semmle/python/frameworks/Bottle.qll

@@ -4,6 +4,7 @@
  */
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import semmle.python.Concepts
 private import semmle.python.ApiGraphs
 private import semmle.python.dataflow.new.RemoteFlowSources
@@ -59,7 +60,7 @@ module Bottle {
 
         override Parameter getARoutedParameter() { none() }
 
-        override Function getARequestHandler() { result.getADecorator().getAFlowNode() = node }
+        override Function getARequestHandler() { node.getNode() = result.getADecorator() }
       }
     }
 
@@ -73,7 +74,10 @@ module Bottle {
       /** A response returned by a view callable. */
       class BottleReturnResponse extends Http::Server::HttpResponse::Range {
         BottleReturnResponse() {
-          this.asCfgNode() = any(View::ViewCallable vc).getAReturnValueFlowNode()
+          exists(Return ret |
+            ret.getScope() = any(View::ViewCallable vc) and
+            this.asCfgNode().getNode() = ret.getValue()
+          )
         }
 
         override DataFlow::Node getBody() { result = this }
@@ -154,9 +158,9 @@ module Bottle {
         DataFlow::Node value;
 
         HeaderWriteSubscript() {
-          exists(SubscriptNode subscript |
+          exists(Cfg::SubscriptNode subscript |
             this.asCfgNode() = subscript and
-            value.asCfgNode() = subscript.(DefinitionNode).getValue() and
+            value.asCfgNode() = subscript.(Cfg::DefinitionNode).getValue() and
             name.asCfgNode() = subscript.getIndex() and
             subscript.getObject() = headers().asSource().asCfgNode()
           )

python/ql/lib/semmle/python/frameworks/Django.qll

@@ -4,6 +4,7 @@
  */
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import semmle.python.dataflow.new.DataFlow
 private import semmle.python.dataflow.new.RemoteFlowSources
 private import semmle.python.dataflow.new.TaintTracking
@@ -1305,7 +1306,7 @@ module PrivateDjango {
                   dict.(DataFlow::MethodCallNode).calls(files, "dict")
                 )
               |
-                this.asCfgNode().(SubscriptNode).getObject() = dict.asCfgNode()
+                this.asCfgNode().(Cfg::SubscriptNode).getObject() = dict.asCfgNode()
                 or
                 this.(DataFlow::MethodCallNode).calls(dict, "get")
               )
@@ -1314,7 +1315,7 @@ module PrivateDjango {
               exists(DataFlow::AttrRead files, DataFlow::MethodCallNode getlistCall |
                 files.accesses(instance(), "FILES") and
                 getlistCall.calls(files, "getlist") and
-                this.asCfgNode().(SubscriptNode).getObject() = getlistCall.asCfgNode()
+                this.asCfgNode().(Cfg::SubscriptNode).getObject() = getlistCall.asCfgNode()
               )
             }
           }
@@ -2216,7 +2217,7 @@ module PrivateDjango {
           DataFlow::Node value;
 
           DjangoResponseCookieSubscriptWrite() {
-            exists(SubscriptNode subscript, DataFlow::AttrRead cookieLookup |
+            exists(Cfg::SubscriptNode subscript, DataFlow::AttrRead cookieLookup |
               // To give `this` a value, we need to choose between either LHS or RHS,
               // and just go with the LHS
               this.asCfgNode() = subscript
@@ -2228,7 +2229,7 @@ module PrivateDjango {
               |
                 cookieLookup.flowsTo(subscriptObj)
               ) and
-              value.asCfgNode() = subscript.(DefinitionNode).getValue() and
+              value.asCfgNode() = subscript.(Cfg::DefinitionNode).getValue() and
               index.asCfgNode() = subscript.getIndex()
             )
           }
@@ -2249,7 +2250,7 @@ module PrivateDjango {
           DataFlow::Node value;
 
           DjangoResponseHeaderSubscriptWrite() {
-            exists(SubscriptNode subscript, DataFlow::AttrRead headerLookup |
+            exists(Cfg::SubscriptNode subscript, DataFlow::AttrRead headerLookup |
               // To give `this` a value, we need to choose between either LHS or RHS,
               // and just go with the LHS
               this.asCfgNode() = subscript
@@ -2261,7 +2262,7 @@ module PrivateDjango {
               |
                 headerLookup.flowsTo(subscriptObj)
               ) and
-              value.asCfgNode() = subscript.(DefinitionNode).getValue() and
+              value.asCfgNode() = subscript.(Cfg::DefinitionNode).getValue() and
               index.asCfgNode() = subscript.getIndex()
             )
           }
@@ -2284,14 +2285,14 @@ module PrivateDjango {
           DataFlow::Node value;
 
           DjangoResponseSubscriptWrite() {
-            exists(SubscriptNode subscript |
+            exists(Cfg::SubscriptNode subscript |
               // To give `this` a value, we need to choose between either LHS or RHS,
               // and just go with the LHS
               this.asCfgNode() = subscript
             |
               subscript.getObject() =
                 DjangoImpl::DjangoHttp::Response::HttpResponse::instance().asCfgNode() and
-              value.asCfgNode() = subscript.(DefinitionNode).getValue() and
+              value.asCfgNode() = subscript.(Cfg::DefinitionNode).getValue() and
               index.asCfgNode() = subscript.getIndex()
             )
           }
@@ -2426,7 +2427,7 @@ module PrivateDjango {
     /** Gets a reference to the result of calling the `as_view` classmethod of this class. */
     private DataFlow::TypeTrackingNode asViewResult(DataFlow::TypeTracker t) {
       t.start() and
-      result.asCfgNode().(CallNode).getFunction() = this.asViewRef().asCfgNode()
+      result.asCfgNode().(Cfg::CallNode).getFunction() = this.asViewRef().asCfgNode()
       or
       exists(DataFlow::TypeTracker t2 | result = this.asViewResult(t2).track(t2, t))
     }
@@ -2872,7 +2873,10 @@ module PrivateDjango {
     DataFlow::CfgNode
   {
     DjangoRedirectViewGetRedirectUrlReturn() {
-      node = any(GetRedirectUrlFunction f).getAReturnValueFlowNode()
+      exists(Return ret |
+        ret.getScope() = any(GetRedirectUrlFunction f) and
+        node.getNode() = ret.getValue()
+      )
     }
 
     override DataFlow::Node getRedirectLocation() { result = this }

python/ql/lib/semmle/python/frameworks/FastApi.qll

@@ -4,6 +4,7 @@
  */
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import semmle.python.dataflow.new.DataFlow
 private import semmle.python.dataflow.new.RemoteFlowSources
 private import semmle.python.dataflow.new.TaintTracking
@@ -129,7 +130,7 @@ module FastApi {
       result in [this.getArg(0), this.getArgByName("path")]
     }
 
-    override Function getARequestHandler() { result.getADecorator().getAFlowNode() = node }
+    override Function getARequestHandler() { node.getNode() = result.getADecorator() }
 
     override string getFramework() { result = "FastAPI" }
 
@@ -309,7 +310,10 @@ module FastApi {
       FastApiRouteSetup routeSetup;
 
       FastApiRequestHandlerReturn() {
-        node = routeSetup.getARequestHandler().getAReturnValueFlowNode()
+        exists(Return ret |
+          ret.getScope() = routeSetup.getARequestHandler() and
+          node.getNode() = ret.getValue()
+        )
       }
 
       override DataFlow::Node getBody() { result = this }
@@ -438,7 +442,7 @@ module FastApi {
       DataFlow::Node value;
 
       HeaderSubscriptWrite() {
-        exists(SubscriptNode subscript, DataFlow::AttrRead headerLookup |
+        exists(Cfg::SubscriptNode subscript, DataFlow::AttrRead headerLookup |
           // To give `this` a value, we need to choose between either LHS or RHS,
           // and just go with the LHS
           this.asCfgNode() = subscript
@@ -447,7 +451,7 @@ module FastApi {
           exists(DataFlow::Node subscriptObj | subscriptObj.asCfgNode() = subscript.getObject() |
             headerLookup.flowsTo(subscriptObj)
           ) and
-          value.asCfgNode() = subscript.(DefinitionNode).getValue() and
+          value.asCfgNode() = subscript.(Cfg::DefinitionNode).getValue() and
           index.asCfgNode() = subscript.getIndex()
         )
       }

python/ql/lib/semmle/python/frameworks/Flask.qll

@@ -371,7 +371,7 @@ module Flask {
       result in [this.getArg(0), this.getArgByName("rule")]
     }
 
-    override Function getARequestHandler() { result.getADecorator().getAFlowNode() = node }
+    override Function getARequestHandler() { node.getNode() = result.getADecorator() }
   }
 
   /**
@@ -536,7 +536,7 @@ module Flask {
     FlaskRouteHandlerReturn() {
       exists(Function routeHandler |
         routeHandler = any(FlaskRouteSetup rs).getARequestHandler() and
-        node = routeHandler.getAReturnValueFlowNode() and
+        exists(Return ret | ret.getScope() = routeHandler and node.getNode() = ret.getValue()) and
         not this instanceof Flask::Response::InstanceSource
       )
     }

python/ql/lib/semmle/python/frameworks/FlaskAdmin.qll

@@ -38,7 +38,7 @@ private module FlaskAdmin {
       result in [this.getArg(0), this.getArgByName("url")]
     }
 
-    override Function getARequestHandler() { result.getADecorator().getAFlowNode() = node }
+    override Function getARequestHandler() { node.getNode() = result.getADecorator() }
   }
 
   /**
@@ -71,7 +71,7 @@ private module FlaskAdmin {
 
     override Function getARequestHandler() {
       exists(Flask::FlaskViewClass cls |
-        cls.getADecorator().getAFlowNode() = node and
+        node.getNode() = cls.getADecorator() and
         result = cls.getARequestHandler()
       )
     }

python/ql/lib/semmle/python/frameworks/Gradio.qll

@@ -4,6 +4,7 @@
  */
 
 import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 import semmle.python.dataflow.new.RemoteFlowSources
 import semmle.python.dataflow.new.TaintTracking
 import semmle.python.ApiGraphs
@@ -51,9 +52,9 @@ module Gradio {
         // limit only to lists of parameters given to `inputs`.
         (
           (
-            call.getKeywordParameter("inputs").asSink().asCfgNode() instanceof ListNode
+            call.getKeywordParameter("inputs").asSink().asCfgNode() instanceof Cfg::ListNode
             or
-            call.getParameter(1).asSink().asCfgNode() instanceof ListNode
+            call.getParameter(1).asSink().asCfgNode() instanceof Cfg::ListNode
           ) and
           (
             this = call.getKeywordParameter("inputs").getASubscript().getAValueReachingSink()
@@ -75,8 +76,8 @@ module Gradio {
       exists(GradioInput call |
         this = call.getParameter(0, "fn").getParameter(_).asSource() and
         // exclude lists of parameters given to `inputs`
-        not call.getKeywordParameter("inputs").asSink().asCfgNode() instanceof ListNode and
-        not call.getParameter(1).asSink().asCfgNode() instanceof ListNode
+        not call.getKeywordParameter("inputs").asSink().asCfgNode() instanceof Cfg::ListNode and
+        not call.getParameter(1).asSink().asCfgNode() instanceof Cfg::ListNode
       )
     }
 
@@ -105,16 +106,16 @@ module Gradio {
         // handle cases where there are multiple arguments passed as a list to `inputs`
         (
           (
-            node.getKeywordParameter("inputs").asSink().asCfgNode() instanceof ListNode
+            node.getKeywordParameter("inputs").asSink().asCfgNode() instanceof Cfg::ListNode
             or
-            node.getParameter(1).asSink().asCfgNode() instanceof ListNode
+            node.getParameter(1).asSink().asCfgNode() instanceof Cfg::ListNode
           ) and
           exists(int i | nodeTo = node.getParameter(0, "fn").getParameter(i).asSource() |
             nodeFrom.asCfgNode() =
-              node.getKeywordParameter("inputs").asSink().asCfgNode().(ListNode).getElement(i)
+              node.getKeywordParameter("inputs").asSink().asCfgNode().(Cfg::ListNode).getElement(i)
             or
             nodeFrom.asCfgNode() =
-              node.getParameter(1).asSink().asCfgNode().(ListNode).getElement(i)
+              node.getParameter(1).asSink().asCfgNode().(Cfg::ListNode).getElement(i)
           )
         )
       )

python/ql/lib/semmle/python/frameworks/MarkupSafe.qll

@@ -4,6 +4,7 @@
  */
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import semmle.python.dataflow.new.DataFlow
 private import semmle.python.dataflow.new.TaintTracking
 private import semmle.python.Concepts
@@ -46,7 +47,7 @@ module MarkupSafeModel {
 
     /** A direct instantiation of `markupsafe.Markup`. */
     private class ClassInstantiation extends InstanceSource, DataFlow::CallCfgNode {
-      override CallNode node;
+      override Cfg::CallNode node;
 
       ClassInstantiation() { this = classRef().getACall() }
     }
@@ -64,7 +65,7 @@ module MarkupSafeModel {
 
     /** A string concatenation with a `markupsafe.Markup` involved. */
     class StringConcat extends Markup::InstanceSource, DataFlow::CfgNode {
-      override BinaryExprNode node;
+      override Cfg::BinaryExprNode node;
 
       StringConcat() {
         node.getOp() instanceof Add and
@@ -79,7 +80,7 @@ module MarkupSafeModel {
 
     /** A %-style string format with `markupsafe.Markup` as the format string. */
     class PercentStringFormat extends Markup::InstanceSource, DataFlow::CfgNode {
-      override BinaryExprNode node;
+      override Cfg::BinaryExprNode node;
 
       PercentStringFormat() {
         node.getOp() instanceof Mod and

python/ql/lib/semmle/python/frameworks/Pycurl.qll

@@ -7,6 +7,7 @@
  */
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import semmle.python.Concepts
 private import semmle.python.ApiGraphs
 private import semmle.python.frameworks.data.ModelsAsData
@@ -56,7 +57,7 @@ module Pycurl {
     {
       OutgoingRequestCall() {
         this = setopt().getACall() and
-        this.getArg(0).asCfgNode().(AttrNode).getName() = "URL"
+        this.getArg(0).asCfgNode().(Cfg::AttrNode).getName() = "URL"
       }
 
       override DataFlow::Node getAUrlPart() {
@@ -81,7 +82,7 @@ module Pycurl {
     private class CurlSslCall extends Http::Client::Request::Range instanceof DataFlow::CallCfgNode {
       CurlSslCall() {
         this = setopt().getACall() and
-        this.getArg(0).asCfgNode().(AttrNode).getName() = ["SSL_VERIFYPEER", "SSL_VERIFYHOST"]
+        this.getArg(0).asCfgNode().(Cfg::AttrNode).getName() = ["SSL_VERIFYPEER", "SSL_VERIFYHOST"]
       }
 
       override DataFlow::Node getAUrlPart() { none() }

python/ql/lib/semmle/python/frameworks/Pydantic.qll

@@ -7,6 +7,7 @@
  */
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import semmle.python.dataflow.new.DataFlow
 private import semmle.python.dataflow.new.TaintTracking
 private import semmle.python.Concepts
@@ -93,7 +94,7 @@ module Pydantic {
       // be a Pydantic model. So `model[0]` will be an overapproximation, but should not
       // really cause problems (since we don't expect real code to contain such accesses)
       nodeFrom = instance() and
-      nodeTo.asCfgNode().(SubscriptNode).getObject() = nodeFrom.asCfgNode()
+      nodeTo.asCfgNode().(Cfg::SubscriptNode).getObject() = nodeFrom.asCfgNode()
     }
 
     /**

python/ql/lib/semmle/python/frameworks/Pyramid.qll

@@ -166,7 +166,10 @@ module Pyramid {
     /** A response returned by a view callable. */
     private class PyramidReturnResponse extends Http::Server::HttpResponse::Range {
       PyramidReturnResponse() {
-        this.asCfgNode() = any(View::ViewCallable vc).getAReturnValueFlowNode() and
+        exists(Return ret |
+          ret.getScope() = any(View::ViewCallable vc) and
+          this.asCfgNode().getNode() = ret.getValue()
+        ) and
         not this = instance()
       }
 

python/ql/lib/semmle/python/frameworks/Stdlib.qll

@@ -6,6 +6,7 @@ overlay[local?]
 module;
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import semmle.python.dataflow.new.DataFlow
 private import semmle.python.dataflow.new.TaintTracking
 private import semmle.python.dataflow.new.RemoteFlowSources
@@ -1246,7 +1247,7 @@ module StdlibPrivate {
   /** An additional taint step for calls to `os.path.join` */
   private class OsPathJoinCallAdditionalTaintStep extends TaintTracking::AdditionalTaintStep {
     override predicate step(DataFlow::Node nodeFrom, DataFlow::Node nodeTo) {
-      exists(CallNode call |
+      exists(Cfg::CallNode call |
         nodeTo.asCfgNode() = call and
         call = OS::OsPath::join().getACall().asCfgNode() and
         call.getAnArg() = nodeFrom.asCfgNode()
@@ -1317,13 +1318,13 @@ module StdlibPrivate {
           // run, so if we're able to, we only mark the first element as the command
           // (and not the arguments to the command).
           //
-          result.asCfgNode() = arg_args.asCfgNode().(SequenceNode).getElement(0)
+          result.asCfgNode() = arg_args.asCfgNode().(Cfg::SequenceNode).getElement(0)
           or
           // Either the "args" argument is not a sequence (which is valid) or we where
           // just not able to figure it out. Simply mark the "args" argument as the
           // command.
           //
-          not arg_args.asCfgNode() instanceof SequenceNode and
+          not arg_args.asCfgNode() instanceof Cfg::SequenceNode and
           result = arg_args
         )
       )
@@ -1542,7 +1543,7 @@ module StdlibPrivate {
    * See https://docs.python.org/3/library/functions.html#eval
    */
   private class BuiltinsEvalCall extends CodeExecution::Range, DataFlow::CallCfgNode {
-    override CallNode node;
+    override Cfg::CallNode node;
 
     BuiltinsEvalCall() { this = API::builtin("eval").getACall() }
 
@@ -1923,7 +1924,7 @@ module StdlibPrivate {
           nodeFrom = instance().getAValueReachableFromSource() and
           nodeTo = [getvalueRef(), getfirstRef(), getlistRef()].getAValueReachableFromSource()
           or
-          nodeFrom.asCfgNode() = nodeTo.asCfgNode().(CallNode).getFunction() and
+          nodeFrom.asCfgNode() = nodeTo.asCfgNode().(Cfg::CallNode).getFunction() and
           (
             nodeFrom = getvalueRef().getAValueReachableFromSource() and
             nodeTo = getvalueResult().asSource()
@@ -1939,7 +1940,7 @@ module StdlibPrivate {
           nodeFrom in [
               instance().getAValueReachableFromSource(), fieldList().getAValueReachableFromSource()
             ] and
-          nodeTo.asCfgNode().(SubscriptNode).getObject() = nodeFrom.asCfgNode()
+          nodeTo.asCfgNode().(Cfg::SubscriptNode).getObject() = nodeFrom.asCfgNode()
           or
           // Attributes on Field
           nodeFrom = field().getAValueReachableFromSource() and
@@ -2254,8 +2255,9 @@ module StdlibPrivate {
       DataFlow::CfgNode
     {
       WsgirefSimpleServerApplicationReturn() {
-        exists(WsgirefSimpleServerApplication requestHandler |
-          node = requestHandler.getAReturnValueFlowNode()
+        exists(Return ret |
+          ret.getScope() = any(WsgirefSimpleServerApplication requestHandler) and
+          node.getNode() = ret.getValue()
         )
       }
 
@@ -2337,9 +2339,9 @@ module StdlibPrivate {
         DataFlow::Node value;
 
         HeaderWriteSubscript() {
-          exists(SubscriptNode subscript |
+          exists(Cfg::SubscriptNode subscript |
             this.asCfgNode() = subscript and
-            value.asCfgNode() = subscript.(DefinitionNode).getValue() and
+            value.asCfgNode() = subscript.(Cfg::DefinitionNode).getValue() and
             name.asCfgNode() = subscript.getIndex() and
             subscript.getObject() = instance().asCfgNode()
           )
@@ -2681,7 +2683,7 @@ module StdlibPrivate {
     or
     // Data injection
     //   Special handling of the `/` operator
-    exists(BinaryExprNode slash, DataFlow::Node pathOperand, DataFlow::TypeTracker t2 |
+    exists(Cfg::BinaryExprNode slash, DataFlow::Node pathOperand, DataFlow::TypeTracker t2 |
       slash.getOp() instanceof Div and
       pathOperand.asCfgNode() = slash.getAnOperand() and
       pathlibPath(t2).flowsTo(pathOperand) and
@@ -2806,7 +2808,7 @@ module StdlibPrivate {
       pathlibPath().flowsTo(nodeTo) and
       (
         // Special handling of the `/` operator
-        exists(BinaryExprNode slash, DataFlow::Node pathOperand |
+        exists(Cfg::BinaryExprNode slash, DataFlow::Node pathOperand |
           slash.getOp() instanceof Div and
           pathOperand.asCfgNode() = slash.getAnOperand() and
           pathlibPath().flowsTo(pathOperand)
@@ -4605,9 +4607,9 @@ module StdlibPrivate {
     }
 
     override predicate propagatesFlow(string input, string output, boolean preservesValue) {
-      exists(CallNode c, string name, ControlFlowNode n, DataFlow::AttributeContent ac |
-        c.getFunction().(NameNode).getId() = "replace" or
-        c.getFunction().(AttrNode).getName() = "replace"
+      exists(Cfg::CallNode c, string name, Cfg::ControlFlowNode n, DataFlow::AttributeContent ac |
+        c.getFunction().(Cfg::NameNode).getId() = "replace" or
+        c.getFunction().(Cfg::AttrNode).getName() = "replace"
       |
         n = c.getArgByName(name) and
         ac.getAttribute() = name and
@@ -5151,10 +5153,10 @@ module StdlibPrivate {
  * See https://docs.python.org/3.9/library/stdtypes.html#str.startswith
  */
 private class StartswithCall extends Path::SafeAccessCheck::Range {
-  StartswithCall() { this.(CallNode).getFunction().(AttrNode).getName() = "startswith" }
+  StartswithCall() { this.(Cfg::CallNode).getFunction().(Cfg::AttrNode).getName() = "startswith" }
 
-  override predicate checks(ControlFlowNode node, boolean branch) {
-    node = this.(CallNode).getFunction().(AttrNode).getObject() and
+  override predicate checks(Cfg::ControlFlowNode node, boolean branch) {
+    node = this.(Cfg::CallNode).getFunction().(Cfg::AttrNode).getObject() and
     branch = true
   }
 }

python/ql/lib/semmle/python/frameworks/Stdlib/Urllib.qll

@@ -8,6 +8,7 @@
  */
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import semmle.python.Concepts
 private import semmle.python.ApiGraphs
 private import semmle.python.security.dataflow.UrlRedirectCustomizations
@@ -91,7 +92,7 @@ private module Urllib {
      * A read of the `netloc` attribute of a parsed URL as returned by `urllib.parse.urlparse`,
      * which is being checked in a way that is relevant for URL redirection vulnerabilities.
      */
-    private predicate netlocCheck(DataFlow::GuardNode g, ControlFlowNode node, boolean branch) {
+    private predicate netlocCheck(DataFlow::GuardNode g, Cfg::ControlFlowNode node, boolean branch) {
       exists(DataFlow::CallCfgNode urlParseCall, DataFlow::AttrRead netlocRead |
         urlParseCall = getUrlParseCall() and
         netlocRead = urlParseCall.getAnAttributeRead("netloc") and

python/ql/lib/semmle/python/frameworks/Tornado.qll

@@ -4,6 +4,7 @@
  */
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import semmle.python.dataflow.new.DataFlow
 private import semmle.python.dataflow.new.RemoteFlowSources
 private import semmle.python.dataflow.new.TaintTracking
@@ -72,9 +73,9 @@ module Tornado {
       DataFlow::Node value;
 
       TornadoHeaderSubscriptWrite() {
-        exists(SubscriptNode subscript |
+        exists(Cfg::SubscriptNode subscript |
           subscript.getObject() = instance().asCfgNode() and
-          value.asCfgNode() = subscript.(DefinitionNode).getValue() and
+          value.asCfgNode() = subscript.(Cfg::DefinitionNode).getValue() and
           index.asCfgNode() = subscript.getIndex() and
           this.asCfgNode() = subscript
         )
@@ -422,7 +423,7 @@ module Tornado {
             // be able to do something more structured for providing modeling of the members
             // of a container-object.
             exists(DataFlow::AttrRead files | files.accesses(instance(), "cookies") |
-              this.asCfgNode().(SubscriptNode).getObject() = files.asCfgNode()
+              this.asCfgNode().(Cfg::SubscriptNode).getObject() = files.asCfgNode()
               or
               this.(DataFlow::MethodCallNode).calls(files, "get")
             )
@@ -479,20 +480,20 @@ module Tornado {
   // routing
   // ---------------------------------------------------------------------------
   /** Gets a sequence that defines a number of route rules */
-  SequenceNode routeSetupRuleList() {
-    exists(CallNode call |
+  Cfg::SequenceNode routeSetupRuleList() {
+    exists(Cfg::CallNode call |
       call = any(TornadoModule::Web::Application::ClassInstantiation c).asCfgNode()
     |
       result in [call.getArg(0), call.getArgByName("handlers")]
     )
     or
-    exists(CallNode call |
+    exists(Cfg::CallNode call |
       call.getFunction() = TornadoModule::Web::Application::add_handlers().asCfgNode()
     |
       result in [call.getArg(1), call.getArgByName("host_handlers")]
     )
     or
-    result = routeSetupRuleList().getElement(_).(TupleNode).getElement(1)
+    result = routeSetupRuleList().getElement(_).(Cfg::TupleNode).getElement(1)
   }
 
   /** A tornado route setup. */
@@ -515,12 +516,12 @@ module Tornado {
 
   /** A route setup using a tuple. */
   private class TornadoTupleRouteSetup extends TornadoRouteSetup, DataFlow::CfgNode {
-    override TupleNode node;
+    override Cfg::TupleNode node;
 
     TornadoTupleRouteSetup() {
       node = routeSetupRuleList().getElement(_) and
       count(node.getElement(_)) = 2 and
-      not node.getElement(1) instanceof SequenceNode
+      not node.getElement(1) instanceof Cfg::SequenceNode
     }
 
     override DataFlow::Node getUrlPatternArg() { result.asCfgNode() = node.getElement(0) }

python/ql/lib/semmle/python/frameworks/Twisted.qll

@@ -182,7 +182,10 @@ private module Twisted {
     DataFlow::CfgNode
   {
     TwistedResourceRenderMethodReturn() {
-      this.asCfgNode() = any(TwistedResourceRenderMethod meth).getAReturnValueFlowNode()
+      exists(Return ret |
+        ret.getScope() = any(TwistedResourceRenderMethod meth) and
+        this.asCfgNode().getNode() = ret.getValue()
+      )
     }
 
     override DataFlow::Node getBody() { result = this }

python/ql/lib/semmle/python/frameworks/Werkzeug.qll

@@ -6,6 +6,7 @@
  */
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import semmle.python.dataflow.new.DataFlow
 private import semmle.python.dataflow.new.TaintTracking
 private import semmle.python.ApiGraphs
@@ -221,9 +222,9 @@ module Werkzeug {
       DataFlow::Node value;
 
       HeaderWriteSubscript() {
-        exists(SubscriptNode subscript |
+        exists(Cfg::SubscriptNode subscript |
           this.asCfgNode() = subscript and
-          value.asCfgNode() = subscript.(DefinitionNode).getValue() and
+          value.asCfgNode() = subscript.(Cfg::DefinitionNode).getValue() and
           name.asCfgNode() = subscript.getIndex() and
           subscript.getObject() = instance().asCfgNode()
         )

python/ql/lib/semmle/python/frameworks/Yaml.qll

@@ -8,6 +8,7 @@
  */
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import semmle.python.dataflow.new.DataFlow
 private import semmle.python.Concepts
 private import semmle.python.ApiGraphs
@@ -28,7 +29,7 @@ private module Yaml {
    * See https://pyyaml.org/wiki/PyYAMLDocumentation (you will have to scroll down).
    */
   private class YamlLoadCall extends Decoding::Range, DataFlow::CallCfgNode {
-    override CallNode node;
+    override Cfg::CallNode node;
     string func_name;
 
     YamlLoadCall() {

python/ql/lib/semmle/python/frameworks/Yarl.qll

@@ -4,6 +4,7 @@
  */
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import semmle.python.dataflow.new.DataFlow
 private import semmle.python.dataflow.new.TaintTracking
 private import semmle.python.Concepts
@@ -111,7 +112,7 @@ module Yarl {
     }
 
     private predicate yarlUrlIsAbsoluteCall(
-      DataFlow::GuardNode g, ControlFlowNode node, boolean branch
+      DataFlow::GuardNode g, Cfg::ControlFlowNode node, boolean branch
     ) {
       exists(ClassInstantiation instance, DataFlow::MethodCallNode call |
         call.calls(instance, "is_absolute") and

python/ql/lib/semmle/python/frameworks/internal/SubclassFinder.qll

@@ -11,6 +11,7 @@ private import semmle.python.dataflow.new.internal.ImportResolution
 private import semmle.python.ApiGraphs
 private import semmle.python.filters.Tests
 private import semmle.python.Module
+private import semmle.python.controlflow.internal.Cfg as Cfg
 
 // very much inspired by the draft at https://github.com/github/codeql/pull/5632
 module NotExposed {
@@ -206,7 +207,7 @@ module NotExposed {
     string relevantName, Location loc
   ) {
     loc = mod.getLocation() and
-    exists(API::Node relevantClass, ControlFlowNode value |
+    exists(API::Node relevantClass, Cfg::ControlFlowNode value |
       relevantClass = newOrExistingModeling(spec).getASubclass*() and
       ImportResolution::module_export(mod, relevantName, def) and
       value = relevantClass.getAValueReachableFromSource().asCfgNode() and

python/ql/lib/semmle/python/internal/CachedStages.qll

@@ -77,7 +77,7 @@ module Stages {
       or
       exists(any(AstExtended::AstNode n).getParentNode())
       or
-      exists(any(AstExtended::AstNode n).getAFlowNode())
+      exists(PyFlow::ControlFlowNode cfg, AstExtended::AstNode n | cfg.getNode() = n)
       or
       exists(any(PyFlow::BasicBlock b).getImmediateDominator())
       or

python/ql/lib/semmle/python/objects/Callables.qll

@@ -56,8 +56,9 @@ abstract class CallableObjectInternal extends ObjectInternal {
 /** A Python function. */
 class PythonFunctionObjectInternal extends CallableObjectInternal, TPythonFunctionObject {
   override Function getScope() {
-    exists(CallableExpr expr |
-      this = TPythonFunctionObject(expr.getAFlowNode()) and
+    exists(CallableExpr expr, ControlFlowNode exprCfg |
+      exprCfg.getNode() = expr and
+      this = TPythonFunctionObject(exprCfg) and
       result = expr.getInnerScope()
     )
   }
@@ -80,11 +81,12 @@ class PythonFunctionObjectInternal extends CallableObjectInternal, TPythonFuncti
 
   pragma[nomagic]
   override predicate callResult(PointsToContext callee, ObjectInternal obj, CfgOrigin origin) {
-    exists(Function func, ControlFlowNode rval, ControlFlowNode forigin |
+    exists(Function func, Return ret, ControlFlowNode rval, ControlFlowNode forigin |
       func = this.getScope() and
       callee.appliesToScope(func)
     |
-      rval = func.getAReturnValueFlowNode() and
+      ret.getScope() = func and
+      rval.getNode() = ret.getValue() and
       PointsToInternal::pointsTo(rval, callee, obj, forigin) and
       origin = CfgOrigin::fromCfgNode(forigin)
     )
@@ -160,10 +162,11 @@ class PythonFunctionObjectInternal extends CallableObjectInternal, TPythonFuncti
 }
 
 private BasicBlock blockReturningNone(Function func) {
-  exists(Return ret |
+  exists(Return ret, ControlFlowNode ret_ |
     not exists(ret.getValue()) and
     ret.getScope() = func and
-    result = ret.getAFlowNode().getBasicBlock()
+    ret_.getNode() = ret and
+    result = ret_.getBasicBlock()
   )
 }
 

python/ql/lib/semmle/python/objects/Classes.qll

@@ -113,8 +113,9 @@ abstract class ClassObjectInternal extends ObjectInternal {
 class PythonClassObjectInternal extends ClassObjectInternal, TPythonClassObject {
   /** Gets the scope for this Python class */
   Class getScope() {
-    exists(ClassExpr expr |
-      this = TPythonClassObject(expr.getAFlowNode()) and
+    exists(ClassExpr expr, ControlFlowNode exprCfg |
+      exprCfg.getNode() = expr and
+      this = TPythonClassObject(exprCfg) and
       result = expr.getInnerScope()
     )
   }

python/ql/lib/semmle/python/objects/ObjectAPI.qll

@@ -745,7 +745,12 @@ class PythonFunctionValue extends FunctionValue {
   override int maxParameters() { result = this.getScope().getMaxPositionalArguments() }
 
   /** Gets a control flow node corresponding to a return statement in this function */
-  ControlFlowNode getAReturnedNode() { result = this.getScope().getAReturnValueFlowNode() }
+  ControlFlowNode getAReturnedNode() {
+    exists(Return ret |
+      ret.getScope() = this.getScope() and
+      result.getNode() = ret.getValue()
+    )
+  }
 
   override ClassValue getARaisedType() { scope_raises(result, this.getScope()) }
 

python/ql/lib/semmle/python/objects/TObject.qll

@@ -387,7 +387,7 @@ private PythonClassObjectInternal abcMetaClassObject() {
 private predicate neither_class_nor_static_method(Function f) {
   not exists(f.getADecorator())
   or
-  exists(ControlFlowNode deco | deco = f.getADecorator().getAFlowNode() |
+  exists(ControlFlowNode deco | deco.getNode() = f.getADecorator() |
     exists(ObjectInternal o | PointsToInternal::pointsTo(deco, _, o, _) |
       o != ObjectInternal::staticMethod() and
       o != ObjectInternal::classMethod()

python/ql/lib/semmle/python/pointsto/PointsTo.qll

@@ -711,7 +711,7 @@ private module InterModulePointsTo {
     ControlFlowNode f, PointsToContext context, ObjectInternal value, ControlFlowNode origin
   ) {
     exists(string name, ImportExpr i |
-      i.getAFlowNode() = f and
+      f.getNode() = i and
       i.getImportedModuleName() = name and
       PointsToInternal::module_imported_as(value, name) and
       origin = f and
@@ -2118,8 +2118,9 @@ module Types {
     result.getBuiltin() = cls.getBuiltin().getBaseClass() and n = 0
     or
     exists(Class pycls | pycls = cls.(PythonClassObjectInternal).getScope() |
-      exists(ObjectInternal base |
-        PointsToInternal::pointsTo(pycls.getBase(n).getAFlowNode(), _, base, _)
+      exists(ObjectInternal base, ControlFlowNode baseNode |
+        baseNode.getNode() = pycls.getBase(n) and
+        PointsToInternal::pointsTo(baseNode, _, base, _)
       |
         result = base and base != ObjectInternal::unknown()
         or
@@ -2223,7 +2224,10 @@ module Types {
   }
 
   private ControlFlowNode decorator_call_callee(PythonClassObjectInternal cls) {
-    result = cls.getScope().getADecorator().getAFlowNode().(CallNode).getFunction()
+    exists(CallNode deco |
+      deco.getNode() = cls.getScope().getADecorator() and
+      result = deco.getFunction()
+    )
   }
 
   private boolean has_six_add_metaclass(PythonClassObjectInternal cls) {
@@ -2262,7 +2266,7 @@ module Types {
   }
 
   private EssaVariable metaclass_var(Class cls) {
-    result.getASourceUse() = cls.getMetaClass().getAFlowNode()
+    result.getASourceUse().getNode() = cls.getMetaClass()
     or
     major_version() = 2 and
     not exists(cls.getMetaClass()) and

python/ql/lib/semmle/python/regexp/internal/ParseRegExp.qll

@@ -3,6 +3,7 @@
  */
 
 import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import semmle.python.dataflow.new.DataFlow
 private import semmle.python.Concepts as Concepts
 private import semmle.python.regex
@@ -78,7 +79,7 @@ private module FindRegexMode {
     t.start() and
     exists(API::Node flag | flag_name = canonical_name(flag) and result = flag.asSource())
     or
-    exists(BinaryExprNode binop, DataFlow::Node operand |
+    exists(Cfg::BinaryExprNode binop, DataFlow::Node operand |
       operand.getALocalSource() = re_flag_tracker(flag_name, t.continue()) and
       operand.asCfgNode() = binop.getAnOperand() and
       (binop.getOp() instanceof BitOr or binop.getOp() instanceof Add) and

python/ql/lib/semmle/python/security/dataflow/ExceptionInfo.qll

@@ -3,6 +3,7 @@
 import python
 import semmle.python.dataflow.new.DataFlow
 private import semmle.python.ApiGraphs
+private import semmle.python.controlflow.internal.Cfg as Cfg
 
 /**
  * INTERNAL: Do not use.
@@ -29,7 +30,7 @@ private class TracebackFunctionCall extends ExceptionInfo, DataFlow::CallCfgNode
 private class CaughtException extends ExceptionInfo {
   CaughtException() {
     this.asExpr() = any(ExceptStmt s).getName() and
-    this.asCfgNode() = any(EssaNodeDefinition def).getDefiningNode()
+    this.asCfgNode().(Cfg::NameNode).defines(_)
   }
 }
 

python/ql/lib/semmle/python/security/dataflow/ServerSideRequestForgeryCustomizations.qll

@@ -11,6 +11,7 @@ private import semmle.python.dataflow.new.RemoteFlowSources
 private import semmle.python.dataflow.new.BarrierGuards
 private import semmle.python.ApiGraphs
 private import semmle.python.frameworks.data.internal.ApiGraphModels
+private import semmle.python.controlflow.internal.Cfg as Cfg
 
 /**
  * Provides default sources, sinks and sanitizers for detecting
@@ -95,7 +96,7 @@ module ServerSideRequestForgery {
   class StringConstructionAsFullUrlControlSanitizer extends FullUrlControlSanitizer {
     StringConstructionAsFullUrlControlSanitizer() {
       // string concat
-      exists(BinaryExprNode add |
+      exists(Cfg::BinaryExprNode add |
         add.getOp() instanceof Add and
         add.getRight() = this.asCfgNode() and
         not add.getLeft().getNode().(StringLiteral).getText().toLowerCase() in [
@@ -104,7 +105,7 @@ module ServerSideRequestForgery {
       )
       or
       // % formatting
-      exists(BinaryExprNode fmt |
+      exists(Cfg::BinaryExprNode fmt |
         fmt.getOp() instanceof Mod and
         fmt.getRight() = this.asCfgNode() and
         // detecting %-formatting is not super easy, so we simplify it to only handle
@@ -155,7 +156,9 @@ module ServerSideRequestForgery {
     }
   }
 
-  private predicate stringRestriction(DataFlow::GuardNode g, ControlFlowNode node, boolean branch) {
+  private predicate stringRestriction(
+    DataFlow::GuardNode g, Cfg::ControlFlowNode node, boolean branch
+  ) {
     exists(DataFlow::MethodCallNode call, DataFlow::Node strNode |
       call.asCfgNode() = g and strNode.asCfgNode() = node
     |

python/ql/lib/semmle/python/security/dataflow/TarSlipCustomizations.qll

@@ -9,6 +9,7 @@ private import semmle.python.dataflow.new.DataFlow
 private import semmle.python.Concepts
 private import semmle.python.dataflow.new.BarrierGuards
 private import semmle.python.ApiGraphs
+private import semmle.python.controlflow.internal.Cfg as Cfg
 
 /**
  * Provides default sources, sinks and sanitizers for detecting
@@ -139,8 +140,8 @@ module TarSlip {
    * where `<check_path>` is any function matching `"%path"`.
    * `info` is assumed to be a `TarInfo` instance.
    */
-  predicate tarFileInfoSanitizer(DataFlow::GuardNode g, ControlFlowNode tarInfo, boolean branch) {
-    exists(CallNode call, AttrNode attr |
+  predicate tarFileInfoSanitizer(DataFlow::GuardNode g, Cfg::ControlFlowNode tarInfo, boolean branch) {
+    exists(Cfg::CallNode call, Cfg::AttrNode attr |
       g = call and
       // We must test the name of the tar info object.
       attr = call.getAnArg() and
@@ -148,9 +149,9 @@ module TarSlip {
       attr.getObject() = tarInfo
     |
       // The assumption that any test that matches %path is a sanitizer might be too broad.
-      call.getAChild*().(AttrNode).getName().matches("%path")
+      call.getAChild*().(Cfg::AttrNode).getName().matches("%path")
       or
-      call.getAChild*().(NameNode).getId().matches("%path")
+      call.getAChild*().(Cfg::NameNode).getId().matches("%path")
     ) and
     branch = false
   }

python/ql/lib/semmle/python/security/dataflow/UrlRedirectCustomizations.qll

@@ -5,6 +5,7 @@
  */
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import semmle.python.dataflow.new.DataFlow
 private import semmle.python.Concepts
 private import semmle.python.ApiGraphs
@@ -111,7 +112,7 @@ module UrlRedirect {
       // Url redirection is a problem only if the user controls the prefix of the URL.
       // TODO: This is a copy of the taint-sanitizer from the old points-to query, which doesn't
       // cover formatting.
-      exists(BinaryExprNode string_concat | string_concat.getOp() instanceof Add |
+      exists(Cfg::BinaryExprNode string_concat | string_concat.getOp() instanceof Add |
         string_concat.getRight() = this.asCfgNode()
       )
     }

python/ql/lib/semmle/python/types/ClassObject.qll

@@ -181,7 +181,7 @@ class ClassObject extends Object {
     )
   }
 
-  ControlFlowNode declaredMetaClass() { result = this.getPyClass().getMetaClass().getAFlowNode() }
+  ControlFlowNode declaredMetaClass() { result.getNode() = this.getPyClass().getMetaClass() }
 
   /** Has type inference failed to compute the full class hierarchy for this class for the reason given. */
   predicate failedInference(string reason) { Types::failedInference(this.theClass(), reason) }
@@ -195,8 +195,9 @@ class ClassObject extends Object {
    * It is guaranteed that getProbableSingletonInstance() returns at most one Object for each ClassObject.
    */
   Object getProbableSingletonInstance() {
-    exists(ControlFlowNodeWithPointsTo use, Expr origin |
-      use.refersTo(result, this, origin.getAFlowNode())
+    exists(ControlFlowNodeWithPointsTo use, Expr origin, ControlFlowNode origin_ |
+      origin_.getNode() = origin and
+      use.refersTo(result, this, origin_)
     |
       this.hasStaticallyUniqueInstance() and
       /* Ensure that original expression will be executed only one. */

python/ql/lib/semmle/python/types/Exceptions.qll

@@ -427,7 +427,7 @@ class ExceptFlowNodeWithPointsTo extends ExceptFlowNode {
 }
 
 private ControlFlowNodeWithPointsTo element_from_tuple_objectapi(Object tuple) {
-  exists(Tuple t | t = tuple.getOrigin() and result = t.getAnElt().getAFlowNode())
+  exists(Tuple t | t = tuple.getOrigin() and result.getNode() = t.getAnElt())
 }
 
 /**

python/ql/lib/semmle/python/types/Extensions.qll

@@ -36,8 +36,8 @@ class RangeIterationVariableFact extends PointsToExtension {
   RangeIterationVariableFact() {
     exists(For f, ControlFlowNode iterable |
       iterable.getBasicBlock().dominates(this.(ControlFlowNode).getBasicBlock()) and
-      f.getIter().getAFlowNode() = iterable and
-      f.getTarget().getAFlowNode() = this and
+      iterable.getNode() = f.getIter() and
+      this.(ControlFlowNode).getNode() = f.getTarget() and
       exists(ObjectInternal range |
         PointsTo::pointsTo(iterable, _, range, _) and
         range.getClass() = ObjectInternal::builtin("range")

python/ql/lib/semmle/python/types/FunctionObject.qll

@@ -137,7 +137,10 @@ class PyFunctionObject extends FunctionObject {
 
   /** Gets a control flow node corresponding to the value of a return statement */
   ControlFlowNodeWithPointsTo getAReturnedNode() {
-    result = this.getFunction().getAReturnValueFlowNode()
+    exists(Return ret |
+      ret.getScope() = this.getFunction() and
+      result.getNode() = ret.getValue()
+    )
   }
 
   override string descriptiveString() {
@@ -170,7 +173,7 @@ class PyFunctionObject extends FunctionObject {
   predicate unconditionallyReturnsParameter(int n) {
     exists(SsaVariable pvar |
       exists(Parameter p | p = this.getFunction().getArg(n) |
-        p.asName().getAFlowNode() = pvar.getDefinition()
+        pvar.getDefinition().getNode() = p.asName()
       ) and
       exists(NameNode rval |
         rval = pvar.getAUse() and

python/ql/lib/semmle/python/types/Object.qll

@@ -337,7 +337,7 @@ class TupleObject extends SequenceObject {
     or
     this instanceof TupleNode
     or
-    exists(Function func | func.getVararg().getAFlowNode() = this)
+    exists(Function func | this.(ControlFlowNode).getNode() = func.getVararg())
   }
 }
 
@@ -352,7 +352,9 @@ module TupleObject {
 }
 
 class NonEmptyTupleObject extends TupleObject {
-  NonEmptyTupleObject() { exists(Function func | func.getVararg().getAFlowNode() = this) }
+  NonEmptyTupleObject() {
+    exists(Function func | this.(ControlFlowNode).getNode() = func.getVararg())
+  }
 
   override boolean booleanValue() { result = true }
 }

python/ql/lib/utils/test/dataflow/MaximalFlowTest.qll

@@ -1,4 +1,5 @@
 import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 import semmle.python.dataflow.new.DataFlow
 private import semmle.python.dataflow.new.internal.DataFlowPrivate
 import FlowTest
@@ -23,7 +24,7 @@ import MakeTest<MakeTestSig<MaximalFlowTest>>
 module MaximalFlowsConfig implements DataFlow::ConfigSig {
   predicate isSource(DataFlow::Node node) {
     exists(node.getLocation().getFile().getRelativePath()) and
-    not node.asCfgNode() instanceof CallNode and
+    not node.asCfgNode() instanceof Cfg::CallNode and
     not node.asCfgNode().getNode() instanceof Return and
     not node instanceof DataFlow::ParameterNode and
     not node instanceof DataFlow::PostUpdateNode and
@@ -34,9 +35,9 @@ module MaximalFlowsConfig implements DataFlow::ConfigSig {
 
   predicate isSink(DataFlow::Node node) {
     exists(node.getLocation().getFile().getRelativePath()) and
-    not any(CallNode c).getArg(_) = node.asCfgNode() and
+    not any(Cfg::CallNode c).getArg(_) = node.asCfgNode() and
     not isArgumentNode(node, _, _) and
-    not node.asCfgNode().(NameNode).getId().matches("SINK%") and
+    not node.asCfgNode().(Cfg::NameNode).getId().matches("SINK%") and
     not DataFlow::localFlowStep(node, _)
   }
 }

python/ql/lib/utils/test/dataflow/NormalDataflowTest.qll

@@ -1,4 +1,5 @@
 import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 import utils.test.dataflow.FlowTest
 import utils.test.dataflow.testConfig
 private import semmle.python.dataflow.new.internal.PrintNode
@@ -19,7 +20,7 @@ query predicate missingAnnotationOnSink(Location location, string error, string
     TestConfig::isSink(sink) and
     // note: we only care about `SINK` and not `SINK_F`, so we have to reconstruct manually.
     exists(DataFlow::CallCfgNode call |
-      call.getFunction().asCfgNode().(NameNode).getId() = "SINK" and
+      call.getFunction().asCfgNode().(Cfg::NameNode).getId() = "SINK" and
       (sink = call.getArg(_) or sink = call.getArgByName(_))
     ) and
     location = sink.getLocation() and

python/ql/lib/utils/test/dataflow/NormalTaintTrackingTest.qll

@@ -1,4 +1,5 @@
 import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 import utils.test.dataflow.FlowTest
 import utils.test.dataflow.testTaintConfig
 private import semmle.python.dataflow.new.internal.PrintNode
@@ -18,7 +19,7 @@ query predicate missingAnnotationOnSink(Location location, string error, string
   exists(DataFlow::Node sink |
     exists(DataFlow::CallCfgNode call |
       // note: we only care about `SINK` and not `SINK_F`, so we have to reconstruct manually.
-      call.getFunction().asCfgNode().(NameNode).getId() = "SINK" and
+      call.getFunction().asCfgNode().(Cfg::NameNode).getId() = "SINK" and
       (sink = call.getArg(_) or sink = call.getArgByName(_))
     ) and
     location = sink.getLocation() and

python/ql/lib/utils/test/dataflow/RoutingTest.qll

@@ -1,4 +1,5 @@
 import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 import semmle.python.dataflow.new.DataFlow
 import utils.test.InlineExpectationsTest
 private import semmle.python.dataflow.new.internal.PrintNode
@@ -49,7 +50,7 @@ private string fromValue(DataFlow::Node fromNode) {
 
 pragma[inline]
 private string fromFunc(DataFlow::ArgumentNode fromNode) {
-  result = fromNode.getCall().getNode().(CallNode).getFunction().getNode().(Name).getId()
+  result = fromNode.getCall().getNode().(Cfg::CallNode).getFunction().getNode().(Name).getId()
 }
 
 pragma[inline]

python/ql/lib/utils/test/dataflow/UnresolvedCalls.qll

@@ -1,15 +1,17 @@
 import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 private import semmle.python.dataflow.new.internal.PrintNode
 private import semmle.python.dataflow.new.internal.DataFlowPrivate as DataFlowPrivate
 private import semmle.python.ApiGraphs
 import utils.test.InlineExpectationsTest
 
 signature module UnresolvedCallExpectationsSig {
-  predicate unresolvedCall(CallNode call);
+  predicate unresolvedCall(Cfg::CallNode call);
 }
 
 module DefaultUnresolvedCallExpectations implements UnresolvedCallExpectationsSig {
-  predicate unresolvedCall(CallNode call) {
+  predicate unresolvedCall(Cfg::CallNode call) {
+    Cfg::isCanonicalAstNodeRepresentative(call) and
     not exists(DataFlowPrivate::DataFlowCall dfc |
       exists(dfc.getCallable()) and dfc.getNode() = call
     ) and
@@ -24,7 +26,7 @@ module MakeUnresolvedCallExpectations<UnresolvedCallExpectationsSig Impl> {
 
     predicate hasActualResult(Location location, string element, string tag, string value) {
       exists(location.getFile().getRelativePath()) and
-      exists(CallNode call | Impl::unresolvedCall(call) |
+      exists(Cfg::CallNode call | Impl::unresolvedCall(call) |
         location = call.getLocation() and
         tag = "unresolved_call" and
         value = prettyExpr(call.getNode()) and

python/ql/lib/utils/test/dataflow/testConfig.qll

@@ -21,11 +21,12 @@
  */
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 import semmle.python.dataflow.new.DataFlow
 
 module TestConfig implements DataFlow::ConfigSig {
   predicate isSource(DataFlow::Node node) {
-    node.(DataFlow::CfgNode).getNode().(NameNode).getId() = "SOURCE"
+    node.(DataFlow::CfgNode).getNode().(Cfg::NameNode).getId() = "SOURCE"
     or
     node.(DataFlow::CfgNode).getNode().getNode().(StringLiteral).getS() = "source"
     or
@@ -37,7 +38,7 @@ module TestConfig implements DataFlow::ConfigSig {
 
   predicate isSink(DataFlow::Node node) {
     exists(DataFlow::CallCfgNode call |
-      call.getFunction().asCfgNode().(NameNode).getId() in ["SINK", "SINK_F"] and
+      call.getFunction().asCfgNode().(Cfg::NameNode).getId() in ["SINK", "SINK_F"] and
       (node = call.getArg(_) or node = call.getArgByName(_)) and
       not node = call.getArgByName("not_present_at_runtime")
     )

python/ql/lib/utils/test/dataflow/testTaintConfig.qll

@@ -21,12 +21,13 @@
  */
 
 private import python
+private import semmle.python.controlflow.internal.Cfg as Cfg
 import semmle.python.dataflow.new.DataFlow
 import semmle.python.dataflow.new.TaintTracking
 
 module TestConfig implements DataFlow::ConfigSig {
   predicate isSource(DataFlow::Node node) {
-    node.(DataFlow::CfgNode).getNode().(NameNode).getId() = "SOURCE"
+    node.(DataFlow::CfgNode).getNode().(Cfg::NameNode).getId() = "SOURCE"
     or
     node.(DataFlow::CfgNode).getNode().getNode().(StringLiteral).getS() = "source"
     or
@@ -37,8 +38,8 @@ module TestConfig implements DataFlow::ConfigSig {
   }
 
   predicate isSink(DataFlow::Node node) {
-    exists(CallNode call |
-      call.getFunction().(NameNode).getId() in ["SINK", "SINK_F"] and
+    exists(Cfg::CallNode call |
+      call.getFunction().(Cfg::NameNode).getId() in ["SINK", "SINK_F"] and
       node.(DataFlow::CfgNode).getNode() = call.getAnArg()
     )
   }

python/ql/src/Classes/ClassAttributes.qll

@@ -48,9 +48,11 @@ class CheckClass extends ClassObject {
         self_dict = sub.getObject()
         or
         /* Indirect assignment via temporary variable */
-        exists(SsaVariable v |
-          v.getAUse() = sub.getObject().getAFlowNode() and
-          v.getDefinition().(DefinitionNode).getValue() = self_dict.getAFlowNode()
+        exists(SsaVariable v, ControlFlowNode subObjCfg, ControlFlowNode selfDictCfg |
+          subObjCfg.getNode() = sub.getObject() and selfDictCfg.getNode() = self_dict
+        |
+          v.getAUse() = subObjCfg and
+          v.getDefinition().(DefinitionNode).getValue() = selfDictCfg
         )
       ) and
       a.getATarget() = sub and
@@ -62,9 +64,10 @@ class CheckClass extends ClassObject {
 
   pragma[nomagic]
   private predicate monkeyPatched(string name) {
-    exists(Attribute a |
+    exists(Attribute a, ControlFlowNode objCfg |
+      objCfg.getNode() = a.getObject() and
       a.getCtx() instanceof Store and
-      PointsTo::points_to(a.getObject().getAFlowNode(), _, this, _, _) and
+      PointsTo::points_to(objCfg, _, this, _, _) and
       a.getName() = name
     )
   }
@@ -84,9 +87,9 @@ class CheckClass extends ClassObject {
   }
 
   predicate interestingUndefined(SelfAttributeRead a) {
-    exists(string name | name = a.getName() |
+    exists(string name, ControlFlowNode aCfg | name = a.getName() and aCfg.getNode() = a |
       this.interestingContext(a, name) and
-      not this.definedInBlock(a.getAFlowNode().getBasicBlock(), name)
+      not this.definedInBlock(aCfg.getBasicBlock(), name)
     )
   }
 
@@ -109,8 +112,9 @@ class CheckClass extends ClassObject {
 
   pragma[nomagic]
   private predicate definitionInBlock(BasicBlock b, string name) {
-    exists(SelfAttributeStore sa |
-      sa.getAFlowNode().getBasicBlock() = b and
+    exists(SelfAttributeStore sa, ControlFlowNode saCfg |
+      saCfg.getNode() = sa and
+      saCfg.getBasicBlock() = b and
       sa.getName() = name and
       sa.getClass() = this.getPyClass()
     )

python/ql/src/Exceptions/CatchingBaseException.ql

@@ -15,7 +15,9 @@
 import python
 import semmle.python.ApiGraphs
 
-predicate doesnt_reraise(ExceptStmt ex) { ex.getAFlowNode().getBasicBlock().reachesExit() }
+predicate doesnt_reraise(ExceptStmt ex) {
+  exists(ControlFlowNode exCfg | exCfg.getNode() = ex | exCfg.getBasicBlock().reachesExit())
+}
 
 predicate catches_base_exception(ExceptStmt ex) {
   ex.getType() = API::builtin("BaseException").getAValueReachableFromSource().asExpr()

python/ql/src/Exceptions/UnguardedNextInGenerator.ql

@@ -12,6 +12,8 @@
 
 import python
 private import semmle.python.ApiGraphs
+private import semmle.python.controlflow.internal.Cfg as Cfg
+private import semmle.python.Flow as Flow
 
 API::Node iter() { result = API::builtin("iter") }
 
@@ -19,17 +21,17 @@ API::Node next() { result = API::builtin("next") }
 
 API::Node stopIteration() { result = API::builtin("StopIteration") }
 
-predicate call_to_iter(CallNode call, EssaVariable sequence) {
-  call = iter().getACall().asCfgNode() and
+predicate call_to_iter(Flow::CallNode call, EssaVariable sequence) {
+  call.getNode() = iter().getACall().asCfgNode().(Cfg::CallNode).getNode() and
   call.getArg(0) = sequence.getAUse()
 }
 
-predicate call_to_next(CallNode call, ControlFlowNode iter) {
-  call = next().getACall().asCfgNode() and
+predicate call_to_next(Flow::CallNode call, Flow::ControlFlowNode iter) {
+  call.getNode() = next().getACall().asCfgNode().(Cfg::CallNode).getNode() and
   call.getArg(0) = iter
 }
 
-predicate call_to_next_has_default(CallNode call) {
+predicate call_to_next_has_default(Flow::CallNode call) {
   exists(call.getArg(1)) or exists(call.getArgByName("default"))
 }
 
@@ -49,14 +51,14 @@ predicate iter_not_exhausted(EssaVariable iterator) {
   )
 }
 
-predicate stop_iteration_handled(CallNode call) {
+predicate stop_iteration_handled(Flow::CallNode call) {
   exists(Try t |
     t.containsInScope(call.getNode()) and
     t.getAHandler().getType() = stopIteration().getAValueReachableFromSource().asExpr()
   )
 }
 
-from CallNode call
+from Flow::CallNode call
 where
   call_to_next(call, _) and
   not call_to_next_has_default(call) and

python/ql/src/Expressions/CallArgs.qll

@@ -116,7 +116,7 @@ FunctionValue get_function_or_initializer(Value func_or_cls) {
 predicate illegally_named_parameter_objectapi(Call call, Object func, string name) {
   not func.isC() and
   name = call.getANamedArgumentName() and
-  call.getAFlowNode() = get_a_call_objectapi(func) and
+  exists(ControlFlowNode callCfg | callCfg.getNode() = call | callCfg = get_a_call_objectapi(func)) and
   not get_function_or_initializer_objectapi(func).isLegalArgumentName(name)
 }
 
@@ -124,7 +124,7 @@ predicate illegally_named_parameter_objectapi(Call call, Object func, string nam
 predicate illegally_named_parameter(Call call, Value func, string name) {
   not func.isBuiltin() and
   name = call.getANamedArgumentName() and
-  call.getAFlowNode() = get_a_call(func) and
+  exists(ControlFlowNode callCfg | callCfg.getNode() = call | callCfg = get_a_call(func)) and
   not get_function_or_initializer(func).isLegalArgumentName(name)
 }
 
@@ -146,7 +146,9 @@ predicate too_few_args_objectapi(Call call, Object callable, int limit) {
     call = func.getAMethodCall().getNode() and limit = func.minParameters() - 1
     or
     callable instanceof ClassObject and
-    call.getAFlowNode() = get_a_call_objectapi(callable) and
+    exists(ControlFlowNode callCfg | callCfg.getNode() = call |
+      callCfg = get_a_call_objectapi(callable)
+    ) and
     limit = func.minParameters() - 1
   )
 }
@@ -172,7 +174,7 @@ predicate too_few_args(Call call, Value callable, int limit) {
     call = func.getAMethodCall().getNode() and limit = func.minParameters() - 1
     or
     callable instanceof ClassValue and
-    call.getAFlowNode() = get_a_call(callable) and
+    exists(ControlFlowNode callCfg | callCfg.getNode() = call | callCfg = get_a_call(callable)) and
     limit = func.minParameters() - 1
   )
 }
@@ -191,7 +193,9 @@ predicate too_many_args_objectapi(Call call, Object callable, int limit) {
     call = func.getAMethodCall().getNode() and limit = func.maxParameters() - 1
     or
     callable instanceof ClassObject and
-    call.getAFlowNode() = get_a_call_objectapi(callable) and
+    exists(ControlFlowNode callCfg | callCfg.getNode() = call |
+      callCfg = get_a_call_objectapi(callable)
+    ) and
     limit = func.maxParameters() - 1
   ) and
   positional_arg_count_for_call_objectapi(call, callable) > limit
@@ -211,7 +215,7 @@ predicate too_many_args(Call call, Value callable, int limit) {
     call = func.getAMethodCall().getNode() and limit = func.maxParameters() - 1
     or
     callable instanceof ClassValue and
-    call.getAFlowNode() = get_a_call(callable) and
+    exists(ControlFlowNode callCfg | callCfg.getNode() = call | callCfg = get_a_call(callable)) and
     limit = func.maxParameters() - 1
   ) and
   positional_arg_count_for_call(call, callable) > limit

python/ql/src/Expressions/DuplicateKeyInDictionaryLiteral.ql

@@ -36,11 +36,15 @@ where
   exists(string s | dict_key(d, k1, s) and dict_key(d, k2, s) and k1 != k2) and
   (
     exists(BasicBlock b, int i1, int i2 |
-      k1.getAFlowNode() = b.getNode(i1) and
-      k2.getAFlowNode() = b.getNode(i2) and
+      b.getNode(i1).getNode() = k1 and
+      b.getNode(i2).getNode() = k2 and
       i1 < i2
     )
     or
-    k1.getAFlowNode().getBasicBlock().strictlyDominates(k2.getAFlowNode().getBasicBlock())
+    exists(ControlFlowNode k1Cfg, ControlFlowNode k2Cfg |
+      k1Cfg.getNode() = k1 and k2Cfg.getNode() = k2
+    |
+      k1Cfg.getBasicBlock().strictlyDominates(k2Cfg.getBasicBlock())
+    )
   )
 select k1, "Dictionary key " + repr(k1) + " is subsequently $@.", k2, "overwritten"

python/ql/src/Expressions/Formatting/AdvancedFormatting.qll

@@ -98,16 +98,18 @@ private predicate brace_pair(PossibleAdvancedFormatString fmt, int start, int en
 }
 
 private predicate advanced_format_call(Call format_expr, PossibleAdvancedFormatString fmt, int args) {
-  exists(CallNode call | call = format_expr.getAFlowNode() |
+  exists(CallNode call, ControlFlowNode fmtCfg |
+    call.getNode() = format_expr and fmtCfg.getNode() = fmt
+  |
     call.getFunction().(ControlFlowNodeWithPointsTo).pointsTo(Value::named("format")) and
-    call.getArg(0).(ControlFlowNodeWithPointsTo).pointsTo(_, fmt.getAFlowNode()) and
+    call.getArg(0).(ControlFlowNodeWithPointsTo).pointsTo(_, fmtCfg) and
     args = count(format_expr.getAnArg()) - 1
     or
     call.getFunction()
         .(AttrNode)
         .getObject("format")
         .(ControlFlowNodeWithPointsTo)
-        .pointsTo(_, fmt.getAFlowNode()) and
+        .pointsTo(_, fmtCfg) and
     args = count(format_expr.getAnArg())
   )
 }

python/ql/src/Expressions/IncorrectComparisonUsingIs.ql

@@ -15,7 +15,7 @@ import python
 
 /** Holds if the comparison `comp` uses `is` or `is not` (represented as `op`) to compare its `left` and `right` arguments. */
 predicate comparison_using_is(Compare comp, ControlFlowNode left, Cmpop op, ControlFlowNode right) {
-  exists(CompareNode fcomp | fcomp = comp.getAFlowNode() |
+  exists(CompareNode fcomp | fcomp.getNode() = comp |
     fcomp.operands(left, op, right) and
     (op instanceof Is or op instanceof IsNot)
   )

python/ql/src/Expressions/IsComparisons.qll

@@ -5,7 +5,7 @@ private import LegacyPointsTo
 
 /** Holds if the comparison `comp` uses `is` or `is not` (represented as `op`) to compare its `left` and `right` arguments. */
 predicate comparison_using_is(Compare comp, ControlFlowNode left, Cmpop op, ControlFlowNode right) {
-  exists(CompareNode fcomp | fcomp = comp.getAFlowNode() |
+  exists(CompareNode fcomp | fcomp.getNode() = comp |
     fcomp.operands(left, op, right) and
     (op instanceof Is or op instanceof IsNot)
   )

python/ql/src/Expressions/TruncatedDivision.ql

@@ -19,7 +19,7 @@ where
   // Only relevant for Python 2, as all later versions implement true division
   major_version() = 2 and
   exists(BinaryExprNode bin, Value lval, Value rval |
-    bin = div.getAFlowNode() and
+    bin.getNode() = div and
     bin.getNode().getOp() instanceof Div and
     bin.getLeft().(ControlFlowNodeWithPointsTo).pointsTo(lval, left) and
     lval.getClass() = ClassValue::int_() and

python/ql/src/Expressions/UseofApply.ql

@@ -11,8 +11,9 @@
 
 import python
 private import semmle.python.ApiGraphs
+private import semmle.python.controlflow.internal.Cfg as Cfg
 
-from CallNode call
+from Cfg::CallNode call
 where
   major_version() = 2 and
   call = API::builtin("apply").getACall().asCfgNode()

python/ql/src/Functions/ExplicitReturnInInit.ql

@@ -19,7 +19,9 @@ where
   exists(Function init | init.isInitMethod() and r.getScope() = init) and
   r.getValue() = rv and
   not rv.pointsTo(Value::none_()) and
-  not exists(FunctionValue f | f.getACall() = rv.getAFlowNode() | f.neverReturns()) and
+  not exists(FunctionValue f, ControlFlowNode rvCfg | rvCfg.getNode() = rv |
+    f.getACall() = rvCfg and f.neverReturns()
+  ) and
   // to avoid double reporting, don't trigger if returning result from other __init__ function
   not exists(Attribute meth | meth = rv.(Call).getFunc() | meth.getName() = "__init__")
 select r, "Explicit return in __init__ method."

python/ql/src/Functions/ReturnValueIgnored.ql

@@ -69,7 +69,12 @@ where
   returns_meaningful_value(callee) and
   not wrapped_in_try_except(call) and
   exists(int unused |
-    unused = count(ExprStmt e | e.getValue().getAFlowNode() = callee.getACall()) and
+    unused =
+      count(ExprStmt e |
+        exists(ControlFlowNode eValCfg | eValCfg.getNode() = e.getValue() |
+          eValCfg = callee.getACall()
+        )
+      ) and
     total = count(callee.getACall())
   |
     percentage_used = (100.0 * (total - unused) / total).floor()

python/ql/src/Functions/SignatureOverriddenMethod.ql

@@ -15,6 +15,7 @@
 import python
 import semmle.python.dataflow.new.DataFlow
 import semmle.python.dataflow.new.internal.DataFlowDispatch
+private import semmle.python.controlflow.internal.Cfg as Cfg
 import codeql.util.Option
 
 /** Holds if `base` is overridden by `sub` */
@@ -143,7 +144,7 @@ predicate ignore(Function f) {
 
 /** Gets a function that `call` may resolve to. */
 Function resolveCall(Call call) {
-  exists(DataFlowCall dfc | call = dfc.getNode().(CallNode).getNode() |
+  exists(DataFlowCall dfc | call = dfc.getNode().(Cfg::CallNode).getNode() |
     result = viableCallable(dfc).(DataFlowFunction).getScope()
   )
 }

python/ql/src/Resources/FileNotAlwaysClosedQuery.qll

@@ -3,6 +3,7 @@
 import python
 import semmle.python.dataflow.new.internal.DataFlowDispatch
 import semmle.python.ApiGraphs
+private import semmle.python.controlflow.internal.Cfg as Cfg
 
 /** A CFG node where a file is opened. */
 abstract class FileOpenSource extends DataFlow::CfgNode { }
@@ -64,12 +65,14 @@ abstract class FileClose extends DataFlow::CfgNode {
   }
 }
 
-private predicate bbSuccessor(BasicBlock src, BasicBlock sink) { sink = src.getASuccessor() }
+private predicate bbSuccessor(Cfg::BasicBlock src, Cfg::BasicBlock sink) {
+  sink = src.getASuccessor()
+}
 
-private predicate bbReachableStrict(BasicBlock src, BasicBlock sink) =
+private predicate bbReachableStrict(Cfg::BasicBlock src, Cfg::BasicBlock sink) =
   fastTC(bbSuccessor/2)(src, sink)
 
-private predicate bbReachableRefl(BasicBlock src, BasicBlock sink) {
+private predicate bbReachableRefl(Cfg::BasicBlock src, Cfg::BasicBlock sink) {
   bbReachableStrict(src, sink) or src = sink
 }