PS: Lift automatic variables to the cfg and dataflow layers.

Author: MathiasVP

powershell/ql/lib/semmle/code/powershell/controlflow/CfgNodes.qll

@@ -1061,6 +1061,20 @@ module ExprNodes {
 
     ExprCfgNode getAnOperand() { e.hasCfgChild(e.getAnOperand(), this, result) }
   }
+
+  private class AutomaticVariableChildMapping extends ExprChildMapping, AutomaticVariable {
+    override predicate relevantChild(Ast child) { none() }
+  }
+
+  class AutomaticVariableCfgNode extends ExprCfgNode {
+    override string getAPrimaryQlClass() { result = "AutomaticVariableCfgNode" }
+
+    override AutomaticVariableChildMapping e;
+
+    override AutomaticVariable getExpr() { result = e }
+
+    string getName() { result = e.getName() }
+  }
 }
 
 module StmtNodes {

powershell/ql/lib/semmle/code/powershell/dataflow/internal/DataFlowPublic.qll

@@ -555,3 +555,12 @@ class QualifiedTypeNameNode extends TypeNameNode {
 
   final override CfgNodes::ExprNodes::QualifiedTypeNameExprCfgNode getExprNode() { result = n }
 }
+
+/** A use of an automatic variable, viewed as a node in a data flow graph. */
+class AutomaticVariableNode extends ExprNode {
+  override CfgNodes::ExprNodes::AutomaticVariableCfgNode n;
+
+  final override CfgNodes::ExprNodes::AutomaticVariableCfgNode getExprNode() { result = n }
+
+  string getName() { result = n.getName() }
+}