Use FindDescendentReferences in DirectiveRemovalOptimizationPass

There's no need to use a custom visitor when there's a perfectly good helper that does the job.

Author: DustinCampbell

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/DirectiveRemovalOptimizationPass.cs

@@ -1,9 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-#nullable disable
-
-using System.Collections.Generic;
 using Microsoft.AspNetCore.Razor.Language.Intermediate;
 
 namespace Microsoft.AspNetCore.Razor.Language;
@@ -14,25 +11,12 @@ internal class DirectiveRemovalOptimizationPass : IntermediateNodePassBase, IRaz
 
     protected override void ExecuteCore(RazorCodeDocument codeDocument, DocumentIntermediateNode documentNode)
     {
-        var visitor = new Visitor();
-        visitor.VisitDocument(documentNode);
-
-        foreach (var nodeReference in visitor.DirectiveNodes)
+        foreach (var nodeReference in documentNode.FindDescendantReferences<DirectiveIntermediateNode>())
         {
             // Lift the diagnostics in the directive node up to the document node.
             documentNode.AddDiagnosticsFromNode(nodeReference.Node);
 
             nodeReference.Remove();
         }
     }
-
-    private class Visitor : IntermediateNodeWalker
-    {
-        public IList<IntermediateNodeReference> DirectiveNodes { get; } = new List<IntermediateNodeReference>();
-
-        public override void VisitDirective(DirectiveIntermediateNode node)
-        {
-            DirectiveNodes.Add(new IntermediateNodeReference(Parent, node));
-        }
-    }
 }