PS: Port changes from github#20132 to PowerShell.

Author: MathiasVP

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

@@ -185,7 +185,8 @@ private module Cached {
     cached // nothing is actually cached
     module BarrierGuard<guardChecksSig/3 guardChecks> {
       private predicate guardChecksAdjTypes(
-        DataFlowIntegrationInput::Guard g, DataFlowIntegrationInput::Expr e, boolean branch
+        DataFlowIntegrationInput::Guard g, DataFlowIntegrationInput::Expr e,
+        DataFlowIntegrationInput::GuardValue branch
       ) {
         guardChecks(g, e.asExprCfgNode(), branch)
       }
@@ -283,6 +284,8 @@ class ParameterExt extends TParameterExt {
 }
 
 private module DataFlowIntegrationInput implements Impl::DataFlowIntegrationInputSig {
+  private import codeql.util.Boolean
+
   private newtype TExpr =
     TExprCfgNode(Cfg::CfgNodes::ExprCfgNode e) or
     TFinalEnvVarRead(Scope scope, EnvVariable v) {
@@ -330,21 +333,27 @@ private module DataFlowIntegrationInput implements Impl::DataFlowIntegrationInpu
     any(ParameterExt p).isInitializedBy(def) or def.(Ssa::WriteDefinition).assigns(_)
   }
 
+  class GuardValue = Boolean;
+
   class Guard extends Cfg::CfgNodes::AstCfgNode {
     /**
      * Holds if the control flow branching from `bb1` is dependent on this guard,
      * and that the edge from `bb1` to `bb2` corresponds to the evaluation of this
      * guard to `branch`.
      */
-    predicate controlsBranchEdge(SsaInput::BasicBlock bb1, SsaInput::BasicBlock bb2, boolean branch) {
-      this.hasBranchEdge(bb1, bb2, branch)
+    predicate valueControlsBranchEdge(
+      SsaInput::BasicBlock bb1, SsaInput::BasicBlock bb2, GuardValue branch
+    ) {
+      this.hasValueBranchEdge(bb1, bb2, branch)
     }
 
     /**
      * Holds if the evaluation of this guard to `branch` corresponds to the edge
      * from `bb1` to `bb2`.
      */
-    predicate hasBranchEdge(SsaInput::BasicBlock bb1, SsaInput::BasicBlock bb2, boolean branch) {
+    predicate hasValueBranchEdge(
+      SsaInput::BasicBlock bb1, SsaInput::BasicBlock bb2, GuardValue branch
+    ) {
       exists(Cfg::SuccessorTypes::ConditionalSuccessor s |
         this.getBasicBlock() = bb1 and
         bb2 = bb1.getASuccessor(s) and
@@ -354,7 +363,7 @@ private module DataFlowIntegrationInput implements Impl::DataFlowIntegrationInpu
   }
 
   /** Holds if the guard `guard` controls block `bb` upon evaluating to `branch`. */
-  predicate guardDirectlyControlsBlock(Guard guard, SsaInput::BasicBlock bb, boolean branch) {
+  predicate guardDirectlyControlsBlock(Guard guard, SsaInput::BasicBlock bb, GuardValue branch) {
     none()
   }
 }