From 719f29d56cf1c84d35ca508dc9ab500aef418222 Mon Sep 17 00:00:00 2001
From: Eric Arndt <erarndt@microsoft.com>
Date: Mon, 11 Dec 2023 16:02:44 -0800
Subject: [PATCH] Avoid creating the capture class for calls to WithExtension

---
 .../RestoreCommand/Utility/BuildAssetsUtils.cs   | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/NuGet.Core/NuGet.Commands/RestoreCommand/Utility/BuildAssetsUtils.cs b/src/NuGet.Core/NuGet.Commands/RestoreCommand/Utility/BuildAssetsUtils.cs
index 9de48fec63a..7b597c90937 100644
--- a/src/NuGet.Core/NuGet.Commands/RestoreCommand/Utility/BuildAssetsUtils.cs
+++ b/src/NuGet.Core/NuGet.Commands/RestoreCommand/Utility/BuildAssetsUtils.cs
@@ -722,12 +722,24 @@ private static bool Exists(this Lazy<LocalPackageSourceInfo> package)
 
         private static IEnumerable<LockFileItem> WithExtension(this IList<LockFileItem> items, string extension)
         {
-            if (items == null)
+            if (items == null || items.Count == 0)
             {
                 return Enumerable.Empty<LockFileItem>();
             }
 
-            return items.Where(c => extension.Equals(Path.GetExtension(c.Path), StringComparison.OrdinalIgnoreCase));
+            return FilterExtensions(items, extension);
+
+            static IEnumerable<LockFileItem> FilterExtensions(IList<LockFileItem> items, string extension)
+            {
+                for (int i = 0; i < items.Count; ++i)
+                {
+                    var item = items[i];
+                    if (extension.Equals(Path.GetExtension(item.Path), StringComparison.OrdinalIgnoreCase))
+                    {
+                        yield return item;
+                    }
+                }
+            }
         }
 
         private static string GetMatchingFrameworkStrings(PackageSpec spec, NuGetFramework framework)