diff --git a/src/Workspaces/SharedUtilitiesAndExtensions/Compiler/Core/Utilities/ICollectionExtensions.cs b/src/Dependencies/Collections/Extensions/ICollectionExtensions.cs
similarity index 73%
rename from src/Workspaces/SharedUtilitiesAndExtensions/Compiler/Core/Utilities/ICollectionExtensions.cs
rename to src/Dependencies/Collections/Extensions/ICollectionExtensions.cs
index f864393c6a3cb..0f88c8c6faeba 100644
--- a/src/Workspaces/SharedUtilitiesAndExtensions/Compiler/Core/Utilities/ICollectionExtensions.cs
+++ b/src/Dependencies/Collections/Extensions/ICollectionExtensions.cs
@@ -7,17 +7,35 @@
 using System.Collections.Immutable;
 using Microsoft.CodeAnalysis.PooledObjects;
 
-namespace Roslyn.Utilities;
+namespace Microsoft.CodeAnalysis;
 
 internal static class ICollectionExtensions
 {
-    public static void AddRange<T>(this ICollection<T> collection, IEnumerable<T>? values)
+    public static void RemoveRange<T>(this ICollection<T> collection, IEnumerable<T>? items)
     {
-        if (collection == null)
+        if (items != null)
         {
-            throw new ArgumentNullException(nameof(collection));
+            foreach (var item in items)
+            {
+                collection.Remove(item);
+            }
         }
+    }
+
+    public static void AddIfNotNull<T>(this ICollection<T> collection, T? value) where T : struct
+    {
+        if (value != null)
+            collection.Add(value.Value);
+    }
+
+    public static void AddIfNotNull<T>(this ICollection<T> collection, T? value) where T : class
+    {
+        if (value != null)
+            collection.Add(value);
+    }
 
+    public static void AddRange<T>(this ICollection<T> collection, IEnumerable<T>? values)
+    {
         if (values != null)
         {
             foreach (var item in values)
@@ -29,9 +47,6 @@ public static void AddRange<T>(this ICollection<T> collection, IEnumerable<T>? v
 
     public static void AddRange<T>(this ICollection<T> collection, ArrayBuilder<T>? values)
     {
-        if (collection == null)
-            throw new ArgumentNullException(nameof(collection));
-
         if (values != null)
         {
             foreach (var item in values)
@@ -41,9 +56,6 @@ public static void AddRange<T>(this ICollection<T> collection, ArrayBuilder<T>?
 
     public static void AddRange<T>(this ICollection<T> collection, HashSet<T>? values)
     {
-        if (collection == null)
-            throw new ArgumentNullException(nameof(collection));
-
         if (values != null)
         {
             foreach (var item in values)
@@ -53,9 +65,6 @@ public static void AddRange<T>(this ICollection<T> collection, HashSet<T>? value
 
     public static void AddRange<TKey, TValue>(this ICollection<TKey> collection, Dictionary<TKey, TValue>.KeyCollection? keyCollection) where TKey : notnull
     {
-        if (collection == null)
-            throw new ArgumentNullException(nameof(collection));
-
         if (keyCollection != null)
         {
             foreach (var key in keyCollection)
@@ -65,11 +74,6 @@ public static void AddRange<TKey, TValue>(this ICollection<TKey> collection, Dic
 
     public static void AddRange<T>(this ICollection<T> collection, ImmutableArray<T> values)
     {
-        if (collection == null)
-        {
-            throw new ArgumentNullException(nameof(collection));
-        }
-
         if (!values.IsDefault)
         {
             foreach (var item in values)
diff --git a/src/Dependencies/Collections/Extensions/EnumerableExtensions.cs b/src/Dependencies/Collections/Extensions/IEnumerableExtensions.cs
similarity index 98%
rename from src/Dependencies/Collections/Extensions/EnumerableExtensions.cs
rename to src/Dependencies/Collections/Extensions/IEnumerableExtensions.cs
index 9d9617032ba09..058e1e54e38e7 100644
--- a/src/Dependencies/Collections/Extensions/EnumerableExtensions.cs
+++ b/src/Dependencies/Collections/Extensions/IEnumerableExtensions.cs
@@ -347,6 +347,19 @@ public static IEnumerable<T> WhereNotNull<T>(this IEnumerable<T?> source)
             return source.Where((Func<T?, bool>)s_notNullTest)!;
         }
 
+        public static ImmutableArray<T> WhereAsArray<T, TArg>(this IEnumerable<T> values, Func<T, TArg, bool> predicate, TArg arg)
+        {
+            var result = ArrayBuilder<T>.GetInstance();
+
+            foreach (var value in values)
+            {
+                if (predicate(value, arg))
+                    result.Add(value);
+            }
+
+            return result.ToImmutableAndFree();
+        }
+
         public static T[] AsArray<T>(this IEnumerable<T> source)
             => source as T[] ?? source.ToArray();
 
diff --git a/src/Dependencies/Collections/Extensions/ImmutableArrayExtensions.cs b/src/Dependencies/Collections/Extensions/ImmutableArrayExtensions.cs
index 3cab1a5c85c9f..a57b085a28477 100644
--- a/src/Dependencies/Collections/Extensions/ImmutableArrayExtensions.cs
+++ b/src/Dependencies/Collections/Extensions/ImmutableArrayExtensions.cs
@@ -6,7 +6,6 @@
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Diagnostics;
-using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
diff --git a/src/Dependencies/Collections/Microsoft.CodeAnalysis.Collections.projitems b/src/Dependencies/Collections/Microsoft.CodeAnalysis.Collections.projitems
index e4388508a4636..3155af37e00c9 100644
--- a/src/Dependencies/Collections/Microsoft.CodeAnalysis.Collections.projitems
+++ b/src/Dependencies/Collections/Microsoft.CodeAnalysis.Collections.projitems
@@ -66,8 +66,9 @@
     <Compile Include="$(MSBuildThisFileDirectory)OneOrMany.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)TemporaryArray`1.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)TemporaryArrayExtensions.cs" />
-    <Compile Include="$(MSBuildThisFileDirectory)Extensions\EnumerableExtensions.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Extensions\IEnumerableExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Extensions\ImmutableArrayExtensions.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Extensions\ICollectionExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Specialized\SpecializedCollections.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Specialized\SpecializedCollections.Empty.Collection.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Specialized\SpecializedCollections.Empty.cs" />
diff --git a/src/Features/Core/Portable/CodeFixes/Suppression/AbstractSuppressionBatchFixAllProvider.cs b/src/Features/Core/Portable/CodeFixes/Suppression/AbstractSuppressionBatchFixAllProvider.cs
index e36fe24b17ec0..330bd176ee8f1 100644
--- a/src/Features/Core/Portable/CodeFixes/Suppression/AbstractSuppressionBatchFixAllProvider.cs
+++ b/src/Features/Core/Portable/CodeFixes/Suppression/AbstractSuppressionBatchFixAllProvider.cs
@@ -89,7 +89,7 @@ internal abstract class AbstractSuppressionBatchFixAllProvider : FixAllProvider
             // Determine the set of documents to actually fix.  We can also use this to update the progress bar with
             // the amount of remaining work to perform.  We'll update the progress bar as we compute each fix in
             // AddDocumentFixesAsync.
-            var source = documentsAndDiagnosticsToFixMap.WhereAsArray(static (kvp, _) => !kvp.Value.IsDefaultOrEmpty, state: false);
+            var source = documentsAndDiagnosticsToFixMap.WhereAsArray(static (kvp, _) => !kvp.Value.IsDefaultOrEmpty, arg: false);
             progressTracker.AddItems(source.Length);
 
             return await ProducerConsumer<(Diagnostic diagnostic, CodeAction action)>.RunParallelAsync(
diff --git a/src/Features/ExternalAccess/Copilot/Internal/Analyzer/AbstractCopilotCodeAnalysisService.cs b/src/Features/ExternalAccess/Copilot/Internal/Analyzer/AbstractCopilotCodeAnalysisService.cs
index 48af70a1e8696..ae44dadd08e08 100644
--- a/src/Features/ExternalAccess/Copilot/Internal/Analyzer/AbstractCopilotCodeAnalysisService.cs
+++ b/src/Features/ExternalAccess/Copilot/Internal/Analyzer/AbstractCopilotCodeAnalysisService.cs
@@ -16,6 +16,7 @@
 using Microsoft.CodeAnalysis.QuickInfo;
 using Microsoft.CodeAnalysis.Shared.Extensions;
 using Microsoft.CodeAnalysis.Text;
+using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.ExternalAccess.Copilot.Internal.Analyzer;
 
@@ -167,7 +168,7 @@ public async Task<ImmutableArray<Diagnostic>> GetCachedDocumentDiagnosticsAsync(
 
     protected virtual Task<ImmutableArray<Diagnostic>> GetDiagnosticsIntersectWithSpanAsync(Document document, IReadOnlyList<Diagnostic> diagnostics, TextSpan span, CancellationToken cancellationToken)
     {
-        return Task.FromResult(diagnostics.WhereAsArray((diagnostic, _) => diagnostic.Location.SourceSpan.IntersectsWith(span), state: (object?)null));
+        return Task.FromResult(diagnostics.WhereAsArray(static (diagnostic, span) => diagnostic.Location.SourceSpan.IntersectsWith(span), span));
     }
 
     public async Task StartRefinementSessionAsync(Document oldDocument, Document newDocument, Diagnostic? primaryDiagnostic, CancellationToken cancellationToken)
diff --git a/src/LanguageServer/Microsoft.CodeAnalysis.LanguageServer/Testing/TestRunner.TestRunHandler.cs b/src/LanguageServer/Microsoft.CodeAnalysis.LanguageServer/Testing/TestRunner.TestRunHandler.cs
index ff23961901e3b..2cc948741a56a 100644
--- a/src/LanguageServer/Microsoft.CodeAnalysis.LanguageServer/Testing/TestRunner.TestRunHandler.cs
+++ b/src/LanguageServer/Microsoft.CodeAnalysis.LanguageServer/Testing/TestRunner.TestRunHandler.cs
@@ -12,6 +12,7 @@
 using Microsoft.VisualStudio.TestPlatform.ObjectModel;
 using Microsoft.VisualStudio.TestPlatform.ObjectModel.Client;
 using Microsoft.VisualStudio.TestPlatform.ObjectModel.Logging;
+using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.LanguageServer.Testing;
 
diff --git a/src/Workspaces/Core/Portable/FindSymbols/FindReferences/Finders/ConstructorSymbolReferenceFinder.cs b/src/Workspaces/Core/Portable/FindSymbols/FindReferences/Finders/ConstructorSymbolReferenceFinder.cs
index 01ea7e24cdb94..46be6a928a41d 100644
--- a/src/Workspaces/Core/Portable/FindSymbols/FindReferences/Finders/ConstructorSymbolReferenceFinder.cs
+++ b/src/Workspaces/Core/Portable/FindSymbols/FindReferences/Finders/ConstructorSymbolReferenceFinder.cs
@@ -10,6 +10,7 @@
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.LanguageService;
 using Microsoft.CodeAnalysis.Shared.Extensions;
+using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.FindSymbols.Finders;
 
diff --git a/src/Workspaces/Core/Portable/FindSymbols/FindReferences/Finders/ExplicitConversionSymbolReferenceFinder.cs b/src/Workspaces/Core/Portable/FindSymbols/FindReferences/Finders/ExplicitConversionSymbolReferenceFinder.cs
index 379f2f543d2bd..647a4cb6565e2 100644
--- a/src/Workspaces/Core/Portable/FindSymbols/FindReferences/Finders/ExplicitConversionSymbolReferenceFinder.cs
+++ b/src/Workspaces/Core/Portable/FindSymbols/FindReferences/Finders/ExplicitConversionSymbolReferenceFinder.cs
@@ -10,6 +10,7 @@
 using Microsoft.CodeAnalysis.LanguageService;
 using Microsoft.CodeAnalysis.PooledObjects;
 using Microsoft.CodeAnalysis.Shared.Extensions;
+using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.FindSymbols.Finders;
 
diff --git a/src/Workspaces/Core/Portable/FindSymbols/FindReferences/Finders/NamedTypeSymbolReferenceFinder.cs b/src/Workspaces/Core/Portable/FindSymbols/FindReferences/Finders/NamedTypeSymbolReferenceFinder.cs
index 7e50775f7fc1a..e94f628cce45d 100644
--- a/src/Workspaces/Core/Portable/FindSymbols/FindReferences/Finders/NamedTypeSymbolReferenceFinder.cs
+++ b/src/Workspaces/Core/Portable/FindSymbols/FindReferences/Finders/NamedTypeSymbolReferenceFinder.cs
@@ -11,6 +11,7 @@
 using Microsoft.CodeAnalysis.LanguageService;
 using Microsoft.CodeAnalysis.PooledObjects;
 using Microsoft.CodeAnalysis.Shared.Extensions;
+using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.FindSymbols.Finders;
 
diff --git a/src/Workspaces/Core/Portable/FindSymbols/FindReferences/Finders/NamespaceSymbolReferenceFinder.cs b/src/Workspaces/Core/Portable/FindSymbols/FindReferences/Finders/NamespaceSymbolReferenceFinder.cs
index a37a5aa784526..e64b29bd4b776 100644
--- a/src/Workspaces/Core/Portable/FindSymbols/FindReferences/Finders/NamespaceSymbolReferenceFinder.cs
+++ b/src/Workspaces/Core/Portable/FindSymbols/FindReferences/Finders/NamespaceSymbolReferenceFinder.cs
@@ -9,7 +9,7 @@
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.LanguageService;
 using Microsoft.CodeAnalysis.PooledObjects;
-using Microsoft.CodeAnalysis.Shared.Extensions;
+using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.FindSymbols.Finders;
 
diff --git a/src/Workspaces/Core/Portable/FindSymbols/FindReferences/Finders/OperatorSymbolReferenceFinder.cs b/src/Workspaces/Core/Portable/FindSymbols/FindReferences/Finders/OperatorSymbolReferenceFinder.cs
index 3284a0a82ca4d..869ff256c1691 100644
--- a/src/Workspaces/Core/Portable/FindSymbols/FindReferences/Finders/OperatorSymbolReferenceFinder.cs
+++ b/src/Workspaces/Core/Portable/FindSymbols/FindReferences/Finders/OperatorSymbolReferenceFinder.cs
@@ -9,6 +9,7 @@
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.LanguageService;
 using Microsoft.CodeAnalysis.Shared.Extensions;
+using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.FindSymbols.Finders;
 
diff --git a/src/Workspaces/SharedUtilitiesAndExtensions/Compiler/Core/CompilerExtensions.projitems b/src/Workspaces/SharedUtilitiesAndExtensions/Compiler/Core/CompilerExtensions.projitems
index 513c2c6c07907..f8c115b73eff7 100644
--- a/src/Workspaces/SharedUtilitiesAndExtensions/Compiler/Core/CompilerExtensions.projitems
+++ b/src/Workspaces/SharedUtilitiesAndExtensions/Compiler/Core/CompilerExtensions.projitems
@@ -482,7 +482,6 @@
     <Compile Include="$(MSBuildThisFileDirectory)Utilities\EditDistance.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Utilities\IBidirectionalMap.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Utilities\ICacheEntry.cs" />
-    <Compile Include="$(MSBuildThisFileDirectory)Utilities\ICollectionExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Utilities\IDictionaryExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Utilities\IGroupingExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Utilities\IntegerUtilities.cs" />
@@ -544,7 +543,6 @@
     <Compile Include="$(MSBuildThisFileDirectory)Extensions\ControlFlowGraphExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Extensions\ControlFlowRegionExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Extensions\IAssemblySymbolExtensions.cs" />
-    <Compile Include="$(MSBuildThisFileDirectory)Extensions\ICollectionExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Extensions\ICompilationExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Extensions\IMethodSymbolExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Extensions\INamedTypeSymbolExtensions.cs" />
diff --git a/src/Workspaces/SharedUtilitiesAndExtensions/Compiler/Core/Extensions/ICollectionExtensions.cs b/src/Workspaces/SharedUtilitiesAndExtensions/Compiler/Core/Extensions/ICollectionExtensions.cs
deleted file mode 100644
index b0d57c834df5b..0000000000000
--- a/src/Workspaces/SharedUtilitiesAndExtensions/Compiler/Core/Extensions/ICollectionExtensions.cs
+++ /dev/null
@@ -1,54 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-using System;
-using System.Collections.Generic;
-using System.Collections.Immutable;
-using Microsoft.CodeAnalysis.PooledObjects;
-
-namespace Microsoft.CodeAnalysis.Shared.Extensions;
-
-internal static class ICollectionExtensions
-{
-    public static ImmutableArray<T> WhereAsArray<T, TState>(this IEnumerable<T> values, Func<T, TState, bool> predicate, TState state)
-    {
-        using var _ = ArrayBuilder<T>.GetInstance(out var result);
-
-        foreach (var value in values)
-        {
-            if (predicate(value, state))
-                result.Add(value);
-        }
-
-        return result.ToImmutableAndClear();
-    }
-
-    public static void RemoveRange<T>(this ICollection<T> collection, IEnumerable<T>? items)
-    {
-        if (collection == null)
-        {
-            throw new ArgumentNullException(nameof(collection));
-        }
-
-        if (items != null)
-        {
-            foreach (var item in items)
-            {
-                collection.Remove(item);
-            }
-        }
-    }
-
-    public static void AddIfNotNull<T>(this ICollection<T> collection, T? value) where T : struct
-    {
-        if (value != null)
-            collection.Add(value.Value);
-    }
-
-    public static void AddIfNotNull<T>(this ICollection<T> collection, T? value) where T : class
-    {
-        if (value != null)
-            collection.Add(value);
-    }
-}