PS: Make CFG construction compile again.

Author: MathiasVP

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

@@ -419,7 +419,10 @@ module ExprNodes {
 
   private class IndexExprWriteAccessChildMapping extends IndexExprChildMapping, IndexExprWriteAccess
   {
-    override predicate relevantChild(Ast child) { this.isExplicitWrite(child) }
+    override predicate relevantChild(Ast child) {
+      super.relevantChild(child) or
+      this.isExplicitWrite(child)
+    }
   }
 
   class IndexExprWriteAccessCfgNode extends IndexExprCfgNode {
@@ -443,7 +446,7 @@ module ExprNodes {
   }
 
   private class IndexExprReadAccessChildMapping extends IndexExprChildMapping, IndexExprReadAccess {
-    override predicate relevantChild(Ast child) { none() }
+    override predicate relevantChild(Ast child) { super.relevantChild(child) }
   }
 
   class IndexExprReadAccessCfgNode extends IndexExprCfgNode {
@@ -480,6 +483,8 @@ module ExprNodes {
     /** Gets the name that is used to select the callee. */
     string getName() { result = e.getName() }
 
+    predicate hasName(string name) { this.getName() = name }
+
     /** Gets the i'th positional argument to this call. */
     ExprCfgNode getPositionalArgument(int i) {
       e.hasCfgChild(e.getPositionalArgument(i), this, result)
@@ -558,7 +563,10 @@ module ExprNodes {
   private class MemberExprWriteAccessChildMapping extends MemberExprChildMapping,
     MemberExprWriteAccess
   {
-    override predicate relevantChild(Ast child) { this.isExplicitWrite(child) }
+    override predicate relevantChild(Ast child) {
+      super.relevantChild(child) or
+      this.isExplicitWrite(child)
+    }
   }
 
   class MemberExprWriteAccessCfgNode extends MemberExprCfgNode {
@@ -584,7 +592,7 @@ module ExprNodes {
   private class MemberExprReadAccessChildMapping extends MemberExprChildMapping,
     MemberExprReadAccess
   {
-    override predicate relevantChild(Ast child) { none() }
+    override predicate relevantChild(Ast child) { super.relevantChild(child) }
   }
 
   class MemberExprReadAccessCfgNode extends MemberExprCfgNode {
@@ -1322,9 +1330,7 @@ module StmtNodes {
   }
 
   class ConfigurationChildMapping extends NonExprChildMapping, Configuration {
-    override predicate relevantChild(Ast child) {
-      child = this.getName() or child = this.getBody()
-    }
+    override predicate relevantChild(Ast child) { child = this.getName() or child = this.getBody() }
   }
 
   class ConfigurationCfgNode extends StmtCfgNode {

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

@@ -6,7 +6,6 @@ private import SuccessorTypes
 private import internal.ControlFlowGraphImpl as CfgImpl
 private import internal.Splitting as Splitting
 private import internal.Completion
-private import internal.Scope
 
 /**
  * An AST node with an associated control-flow graph.
@@ -16,7 +15,16 @@ private import internal.Scope
  * Note that module declarations are not themselves CFG scopes, as they are part of
  * the CFG of the enclosing top-level or callable.
  */
-class CfgScope extends Scope instanceof CfgImpl::CfgScope { }
+class CfgScope extends Scope instanceof CfgImpl::CfgScope {
+  final CfgScope getOuterCfgScope() {
+    exists(Ast parent |
+      parent = this.getParent() and
+      result = CfgImpl::getCfgScope(parent)
+    )
+  }
+
+  Parameter getAParameter() { result = super.getAParameter() }
+}
 
 /**
  * A control flow node.

powershell/ql/lib/semmle/code/powershell/controlflow/internal/Completion.qll

@@ -22,9 +22,9 @@ private newtype TCompletion =
   TMatchingCompletion(Boolean b) or
   TEmptinessCompletion(Boolean isEmpty)
 
-private predicate commandThrows(Cmd c, boolean unconditional) {
-  c.getNamedArgument("ErrorAction").(StringConstExpr).getValue().getValue() = "Stop" and
-  if c.getCommandName() = "Write-Error" then unconditional = true else unconditional = false
+private predicate commandThrows(CallExpr c, boolean unconditional) {
+  c.getNamedArgument("ErrorAction").getValue().asString() = "Stop" and
+  if c.getName() = "Write-Error" then unconditional = true else unconditional = false
 }
 
 pragma[noinline]
@@ -127,7 +127,7 @@ private predicate mustHaveMatchingCompletion(Ast n) { inMatchingContext(n) }
  * that `n` evaluates to determines a true/false branch successor.
  */
 private predicate inBooleanContext(Ast n) {
-  n = any(IfStmt ifStmt).getACondition()
+  n = any(If ifStmt).getACondition()
   or
   n = any(WhileStmt whileStmt).getCondition()
   or
@@ -165,10 +165,7 @@ private predicate inBooleanContext(Ast n) {
     n = pipeline.getComponent(pipeline.getNumberOfComponents() - 1)
   )
   or
-  exists(CmdExpr cmdExpr |
-    inBooleanContext(cmdExpr) and
-    n = cmdExpr.getExpr()
-  )
+  n = any(ParenExpr parent | inBooleanContext(parent)).getExpr()
 }
 
 /**