diff --git a/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/DependencyManager.cs b/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/DependencyManager.cs
index 44925dc1d68..13f8cc4e2a5 100644
--- a/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/DependencyManager.cs
+++ b/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/DependencyManager.cs
@@ -157,7 +157,7 @@ namespace Semmle.Extraction.CSharp.DependencyFetching
             return frameworkLocations;
         }
 
-        private void RestoreNugetPackages(List<FileInfo> allNonBinaryFiles, List<string> allProjects, List<string> allSolutions, HashSet<string> dllPaths)
+        private void RestoreNugetPackages(List<FileInfo> allNonBinaryFiles, IEnumerable<string> allProjects, IEnumerable<string> allSolutions, HashSet<string> dllPaths)
         {
             try
             {
@@ -719,7 +719,7 @@ namespace Semmle.Extraction.CSharp.DependencyFetching
         /// Returns a list of projects that are up to date with respect to restore.
         /// </summary>
         /// <param name="solutions">A list of paths to solution files.</param>
-        private IEnumerable<string> RestoreSolutions(List<string> solutions, out IEnumerable<string> assets)
+        private IEnumerable<string> RestoreSolutions(IEnumerable<string> solutions, out IEnumerable<string> assets)
         {
             var successCount = 0;
             var assetFiles = new List<string>();
@@ -841,21 +841,13 @@ namespace Semmle.Extraction.CSharp.DependencyFetching
                     if (!res.Success)
                     {
                         logger.LogInfo($"Failed to restore nuget package {package}");
-                    }
-                    else
-                    {
-                        lock (sync)
-                        {
-                            successCount++;
-                        }
+                        return;
                     }
                 }
-                else
+
+                lock (sync)
                 {
-                    lock (sync)
-                    {
-                        successCount++;
-                    }
+                    successCount++;
                 }
             });
 
diff --git a/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/NugetPackages.cs b/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/NugetPackages.cs
index 89970a221a1..db0f20bc8cb 100644
--- a/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/NugetPackages.cs
+++ b/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/NugetPackages.cs
@@ -107,7 +107,7 @@ namespace Semmle.Extraction.CSharp.DependencyFetching
         /// Restore all files in a specified package.
         /// </summary>
         /// <param name="package">The package file.</param>
-        private bool RestoreNugetPackage(string package)
+        private bool TryRestoreNugetPackage(string package)
         {
             logger.LogInfo($"Restoring file {package}...");
 
@@ -157,17 +157,7 @@ namespace Semmle.Extraction.CSharp.DependencyFetching
         /// </summary>
         public int InstallPackages()
         {
-            var success = 0;
-            foreach (var package in packageFiles)
-            {
-                var result = RestoreNugetPackage(package.FullName);
-                if (result)
-                {
-                    success++;
-                }
-            }
-
-            return success;
+            return packageFiles.Count(package => TryRestoreNugetPackage(package.FullName));
         }
     }
 }
diff --git a/csharp/extractor/Semmle.Extraction.CSharp.Standalone/Extractor.cs b/csharp/extractor/Semmle.Extraction.CSharp.Standalone/Extractor.cs
index 829591818d5..115a8d418b6 100644
--- a/csharp/extractor/Semmle.Extraction.CSharp.Standalone/Extractor.cs
+++ b/csharp/extractor/Semmle.Extraction.CSharp.Standalone/Extractor.cs
@@ -5,6 +5,7 @@ using System.Diagnostics;
 using System.Linq;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
+using Semmle.Extraction.CSharp.DependencyFetching;
 using Semmle.Util;
 using Semmle.Util.Logging;
 
@@ -12,7 +13,6 @@ namespace Semmle.Extraction.CSharp.Standalone
 {
     public static class Extractor
     {
-
         private static IEnumerable<Action> GetResolvedReferencesStandalone(IEnumerable<string> referencePaths, BlockingCollection<MetadataReference> references)
         {
             return referencePaths.Select<string, Action>(path => () =>
@@ -138,10 +138,9 @@ namespace Semmle.Extraction.CSharp.Standalone
 
             using var logger = new ConsoleLogger(options.Verbosity, logThreadId: true);
             logger.Log(Severity.Info, "Extracting C# in buildless mode");
-            using var a = new Analysis(logger, options);
-            var sourceFileCount = a.Extraction.Sources.Count;
+            using var dependencyManager = new DependencyManager(options.SrcDir, options.Dependencies, logger);
 
-            if (sourceFileCount == 0)
+            if (!dependencyManager.AllSourceFiles.Any())
             {
                 logger.Log(Severity.Error, "No source files found");
                 return ExitCode.Errors;
@@ -152,7 +151,7 @@ namespace Semmle.Extraction.CSharp.Standalone
             logger.Log(Severity.Info, "");
             logger.Log(Severity.Info, "Extracting...");
             ExtractStandalone(
-                new ExtractionInput(a.Extraction.Sources, a.References, a.CompilationInfos),
+                new ExtractionInput(dependencyManager.AllSourceFiles, dependencyManager.ReferenceFiles, dependencyManager.CompilationInfos),
                 new ExtractionProgress(logger),
                 fileLogger,
                 options);
diff --git a/csharp/extractor/Semmle.Extraction.CSharp.Standalone/Program.cs b/csharp/extractor/Semmle.Extraction.CSharp.Standalone/Program.cs
index 8437896c807..fc13b774f4f 100644
--- a/csharp/extractor/Semmle.Extraction.CSharp.Standalone/Program.cs
+++ b/csharp/extractor/Semmle.Extraction.CSharp.Standalone/Program.cs
@@ -5,51 +5,6 @@ using Semmle.Extraction.CSharp.DependencyFetching;
 
 namespace Semmle.Extraction.CSharp.Standalone
 {
-    /// <summary>
-    ///     One independent run of the extractor.
-    /// </summary>
-    internal class Extraction
-    {
-        public Extraction(string directory)
-        {
-            Directory = directory;
-        }
-
-        public string Directory { get; }
-        public List<string> Sources { get; } = new List<string>();
-    };
-
-    /// <summary>
-    ///     Searches for source/references and creates separate extractions.
-    /// </summary>
-    internal sealed class Analysis : IDisposable
-    {
-        public Analysis(ILogger logger, Options options)
-        {
-            dependencyManager = new DependencyManager(options.SrcDir, options.Dependencies, logger);
-            References = dependencyManager.ReferenceFiles;
-            Extraction = new Extraction(options.SrcDir);
-            Extraction.Sources.AddRange(dependencyManager.AllSourceFiles);
-            CompilationInfos = dependencyManager.CompilationInfos;
-        }
-
-        public IEnumerable<string> References { get; }
-
-        /// <summary>
-        /// The extraction configuration.
-        /// </summary>
-        public Extraction Extraction { get; }
-
-        public IEnumerable<(string, string)> CompilationInfos { get; }
-
-        private readonly DependencyManager dependencyManager;
-
-        public void Dispose()
-        {
-            dependencyManager.Dispose();
-        }
-    };
-
     public class Program
     {
         public static int Main(string[] args)
diff --git a/csharp/extractor/Semmle.Extraction.CSharp/Extractor/Analyser.cs b/csharp/extractor/Semmle.Extraction.CSharp/Extractor/Analyser.cs
index 51a63cef5f5..c3ed0217559 100644
--- a/csharp/extractor/Semmle.Extraction.CSharp/Extractor/Analyser.cs
+++ b/csharp/extractor/Semmle.Extraction.CSharp/Extractor/Analyser.cs
@@ -21,7 +21,7 @@ namespace Semmle.Extraction.CSharp
         protected CSharpCompilation? compilation;
         protected CommonOptions? options;
         private protected Entities.Compilation? compilationEntity;
-        private TrapWriter? compilationTrapFile;
+        private IDisposable? compilationTrapFile;
 
         private readonly object progressMutex = new object();