Attempting to remove registration for implicit types

src/Context/Pipeline/PipelineContext.cs

@@ -0,0 +1,22 @@
+using System;
+using System.Text.RegularExpressions;
+using Unity.Resolution;
+
+namespace Unity
+{
+    public struct PipelineContext
+    {
+        #region Public Properties
+
+        public bool    RunAsync;
+        public Type    Type;
+        public string? Name;
+        public Regex   Regex;
+        public object? Existing;
+        public bool    RunningAsync;
+        public ResolverOverride[] Overrides;
+        public UnityContainer.ContainerContext ContainerContext;
+
+        #endregion
+    }
+}

src/Pipeline/Abstracts/BuildPipelineAsync.cs

@@ -0,0 +1,6 @@
+using System.Threading.Tasks;
+
+namespace Unity
+{
+    public delegate ValueTask<object?> BuildPipelineAsync(ref PipelineContext context);
+}

src/Pipeline/Abstracts/MemberSelector.cs

@@ -1,10 +1,10 @@
 using System;
 using System.Collections.Generic;
 using System.Reflection;
-using Unity.Policy;
+using Unity.Registration;
 
 namespace Unity
 {
-    public delegate IEnumerable<object> MemberSelector<TMember>(Type type, IPolicySet set)
+    public delegate IEnumerable<object> MemberSelector<TMember>(Type type, IRegistration set)
         where TMember : MemberInfo;
 }

src/Pipeline/Abstracts/Pipeline.cs

@@ -12,7 +12,7 @@ namespace Unity
         #region Public Members
 
         public virtual IEnumerable<Expression> Build(UnityContainer container, IEnumerator<Pipeline> enumerator, 
-                                                      Type type, ImplicitRegistration registration) => throw new NotImplementedException();
+                                                      Type type, IRegistration registration) => throw new NotImplementedException();
 
         public virtual ResolveDelegate<BuilderContext>? Build(ref PipelineBuilder builder) => builder.Pipeline();
 

src/Pipeline/Builder/PipelineBuilder.cs

@@ -25,12 +25,13 @@ namespace Unity
 
         #endregion
 
-        
+
         #region Constructors
 
         public PipelineBuilder(ExplicitRegistration registration, UnityContainer container, IEnumerable<Pipeline> pipelines)
         {
             Type = registration.Type ?? typeof(object);
+            Name = registration.Name;
             Registration = registration;
             ContainerContext = container.Context;
 
@@ -38,9 +39,24 @@ namespace Unity
             _enumerator = pipelines.GetEnumerator();
         }
 
+        public PipelineBuilder(ref PipelineContext context)
+        {
+            Seed = null;
+            Type = context.Type;
+            Name = context.Name;
+            Registration = null;
+            ContainerContext = context.ContainerContext;
+
+            _enumerator = context.ContainerContext
+                                 .TypePipelineCache
+                                 .AsEnumerable<Pipeline>()
+                                 .GetEnumerator();
+        }
+
         public PipelineBuilder(ref BuilderContext context)
         {
             Type = context.Type;
+            Name = context.Name;
             Registration = context.Registration;
             ContainerContext = context.ContainerContext;
 
@@ -55,13 +71,13 @@ namespace Unity
 
         public Type Type;
 
-        public string? Name => Registration.Name;
+        public string? Name { get; }
 
         public ResolveDelegate<BuilderContext>? Seed { get; private set; }
 
         public readonly ContainerContext ContainerContext;
 
-        public readonly IRegistration Registration;
+        public readonly IRegistration? Registration;
 
         #endregion
 
@@ -88,7 +104,9 @@ namespace Unity
 
         public PipelineDelegate PipelineDelegate()
         {
-            return Registration.LifetimeManager switch
+            var manager = Registration?.LifetimeManager;
+
+            return manager switch
             {
                 null                        => TransientLifetime(),
                 TransientLifetimeManager  _ => TransientLifetime(),

src/Pipeline/Constructor/ConstructorDiagnostic.cs

@@ -9,7 +9,6 @@ using Unity.Builder;
 using Unity.Exceptions;
 using Unity.Injection;
 using Unity.Lifetime;
-using Unity.Policy;
 using Unity.Registration;
 using Unity.Resolution;
 
@@ -76,12 +75,12 @@ namespace Unity
 
         #region Selection
 
-        public override IEnumerable<object> Select(Type type, IPolicySet registration)
+        public override IEnumerable<object> Select(Type type, IRegistration registration)
         {
             var members = new List<InjectionMember>();
 
             // Select Injected Members
-            foreach (var injectionMember in ((ImplicitRegistration)registration).InjectionMembers ?? EmptyCollection)
+            foreach (var injectionMember in registration.InjectionMembers ?? EmptyCollection)
             {
                 if (injectionMember is InjectionMember<ConstructorInfo, object[]>)
                 {

src/Pipeline/Constructor/ConstructorExpression.cs

@@ -4,7 +4,6 @@ using System.Linq;
 using System.Linq.Expressions;
 using System.Reflection;
 using Unity.Builder;
-using Unity.Exceptions;
 using Unity.Lifetime;
 using Unity.Registration;
 
@@ -37,7 +36,7 @@ namespace Unity
         #region PipelineBuilder
 
         public override IEnumerable<Expression> Build(UnityContainer container, IEnumerator<Pipeline> enumerator,
-                                                      Type type, ImplicitRegistration registration)
+                                                      Type type, IRegistration registration)
         {
             //// Select ConstructorInfo
             //var selector = GetOrDefault(registration);

src/Pipeline/Constructor/ConstructorResolution.cs

@@ -39,8 +39,8 @@ namespace Unity
             }
 
             // Select ConstructorInfo
-            var selector = GetOrDefault((IPolicySet)builder.Registration);
-            var selection = selector.Invoke(builder.Type, (IPolicySet)builder.Registration)
+            var selector = GetOrDefault(builder.Registration);
+            var selection = selector.Invoke(builder.Type, builder.Registration)
                                     .FirstOrDefault();
 
             // Select constructor for the Type

src/Pipeline/Constructor/ConstructorSelection.cs

@@ -5,7 +5,6 @@ using System.Linq;
 using System.Reflection;
 using Unity.Exceptions;
 using Unity.Injection;
-using Unity.Policy;
 using Unity.Registration;
 
 namespace Unity
@@ -13,10 +12,10 @@ namespace Unity
     public partial class ConstructorPipeline
     {
 
-        public override IEnumerable<object> Select(Type type, IPolicySet registration)
+        public override IEnumerable<object> Select(Type type, IRegistration registration)
         {
             // Select Injected Members
-            foreach (var injectionMember in ((ImplicitRegistration)registration).InjectionMembers ?? EmptyCollection)
+            foreach (var injectionMember in registration.InjectionMembers ?? EmptyCollection)
             {
                 if (injectionMember is InjectionMember<ConstructorInfo, object[]>)
                 {

src/Pipeline/Factory/FactoryPipeline.cs

@@ -16,7 +16,7 @@ namespace Unity
         #region PipelineBuilder
 
         public override IEnumerable<Expression> Build(UnityContainer container, IEnumerator<Pipeline> enumerator, 
-                                                      Type type, ImplicitRegistration registration)
+                                                      Type type, IRegistration registration)
         {
             yield break;
         }

src/Pipeline/Fields/FieldDiagnostic.cs

@@ -3,11 +3,10 @@ using System.Collections.Generic;
 using System.Linq.Expressions;
 using System.Reflection;
 using Unity.Builder;
+using Unity.Exceptions;
 using Unity.Injection;
-using Unity.Policy;
 using Unity.Registration;
 using Unity.Resolution;
-using Unity.Exceptions;
 
 namespace Unity
 {
@@ -25,12 +24,12 @@ namespace Unity
 
         #region Overrides
 
-        public override IEnumerable<object> Select(Type type, IPolicySet registration)
+        public override IEnumerable<object> Select(Type type, IRegistration registration)
         {
             HashSet<object> memberSet = new HashSet<object>();
 
             // Select Injected Members
-            foreach (var injectionMember in ((ImplicitRegistration)registration).InjectionMembers ?? EmptyCollection)
+            foreach (var injectionMember in registration.InjectionMembers ?? EmptyCollection)
             {
                 if (injectionMember is InjectionMember<FieldInfo, object> && memberSet.Add(injectionMember))
                     yield return injectionMember;

src/Pipeline/Member/MemberExpression.cs

@@ -12,7 +12,7 @@ namespace Unity
         #region PipelineBuilder
 
         public override IEnumerable<Expression> Build(UnityContainer container, IEnumerator<Pipeline> enumerator,
-                                                      Type type, ImplicitRegistration registration)
+                                                      Type type, IRegistration registration)
         {
             yield break;
         }

src/Pipeline/Member/MemberPipeline.cs

@@ -125,7 +125,7 @@ namespace Unity
         /// <param name="type"></param>
         /// <param name="registration"></param>
         /// <returns></returns>
-        public IEnumerable<Expression> GetExpressions(Type type, ImplicitRegistration registration)
+        public IEnumerable<Expression> GetExpressions(Type type, IRegistration registration)
         {
             var selector = GetOrDefault(registration);
             var members = selector(type, registration);

src/Pipeline/Member/MemberSelection.cs

@@ -2,19 +2,18 @@
 using System.Collections.Generic;
 using System.Reflection;
 using Unity.Injection;
-using Unity.Policy;
 using Unity.Registration;
 
 namespace Unity
 {
     public abstract partial class MemberPipeline<TMemberInfo, TData>
     {
-        public virtual IEnumerable<object> Select(Type type, IPolicySet registration)
+        public virtual IEnumerable<object> Select(Type type, IRegistration registration)
         {
             HashSet<object> memberSet = new HashSet<object>();
 
             // Select Injected Members
-            foreach (var injectionMember in ((ImplicitRegistration)registration).InjectionMembers ?? EmptyCollection)
+            foreach (var injectionMember in registration.InjectionMembers ?? EmptyCollection)
             {
                 if (injectionMember is InjectionMember<TMemberInfo, TData> && memberSet.Add(injectionMember))
                     yield return injectionMember;

src/Pipeline/Methods/MethodDiagnostic.cs

@@ -6,7 +6,6 @@ using System.Reflection;
 using Unity.Builder;
 using Unity.Exceptions;
 using Unity.Injection;
-using Unity.Policy;
 using Unity.Registration;
 using Unity.Resolution;
 
@@ -27,12 +26,12 @@ namespace Unity
 
         #region Overrides
 
-        public override IEnumerable<object> Select(Type type, IPolicySet registration)
+        public override IEnumerable<object> Select(Type type, IRegistration registration)
         {
             HashSet<object> memberSet = new HashSet<object>();
 
             // Select Injected Members
-            foreach (var injectionMember in ((ImplicitRegistration)registration).InjectionMembers ?? EmptyCollection)
+            foreach (var injectionMember in registration.InjectionMembers ?? EmptyCollection)
             {
                 if (injectionMember is InjectionMember<MethodInfo, object[]> && memberSet.Add(injectionMember))
                     yield return injectionMember;

src/Pipeline/Methods/MethodSelection.cs

@@ -2,7 +2,6 @@
 using System.Collections.Generic;
 using System.Reflection;
 using Unity.Injection;
-using Unity.Policy;
 using Unity.Registration;
 
 namespace Unity
@@ -10,12 +9,12 @@ namespace Unity
     public partial class MethodPipeline
     {
 
-        public override IEnumerable<object> Select(Type type, IPolicySet registration)
+        public override IEnumerable<object> Select(Type type, IRegistration registration)
         {
             HashSet<object> memberSet = new HashSet<object>();
 
             // Select Injected Members
-            foreach (var injectionMember in ((ImplicitRegistration)registration).InjectionMembers ?? EmptyCollection)
+            foreach (var injectionMember in registration.InjectionMembers ?? EmptyCollection)
             {
                 if (injectionMember is InjectionMember<MethodInfo, object[]> && memberSet.Add(injectionMember))
                     yield return injectionMember;

src/Pipeline/Properties/PropertyDiagnostic.cs

@@ -5,7 +5,6 @@ using System.Reflection;
 using Unity.Builder;
 using Unity.Exceptions;
 using Unity.Injection;
-using Unity.Policy;
 using Unity.Registration;
 using Unity.Resolution;
 
@@ -26,12 +25,12 @@ namespace Unity
 
         #region Overrides
 
-        public override IEnumerable<object> Select(Type type, IPolicySet registration)
+        public override IEnumerable<object> Select(Type type, IRegistration registration)
         {
             HashSet<object> memberSet = new HashSet<object>();
 
             // Select Injected Members
-            foreach (var injectionMember in ((ImplicitRegistration)registration).InjectionMembers ?? EmptyCollection)
+            foreach (var injectionMember in registration.InjectionMembers ?? EmptyCollection)
             {
                 if (injectionMember is InjectionMember<PropertyInfo, object> && memberSet.Add(injectionMember))
                     yield return injectionMember;

src/Storage/Pipelines.cs

@@ -0,0 +1,135 @@
+using System;
+using System.Diagnostics;
+using System.Security;
+using Unity.Policy;
+using Unity.Registration;
+
+namespace Unity.Storage
+{
+    [SecuritySafeCritical]
+    public class Pipelines
+    {
+        #region Fields
+
+        private readonly int _prime;
+        public readonly int[] Buckets;
+        public readonly Entry[] Entries;
+        public int Count;
+
+        #endregion
+
+
+        #region Constructors
+
+
+        public Pipelines()
+        {
+            var size = Primes[0];
+
+            Buckets = new int[size];
+            Entries = new Entry[size];
+            Count = 0;
+
+#if !NET40
+            unsafe
+            {
+                fixed (int* bucketsPtr = Buckets)
+                {
+                    int* ptr = bucketsPtr;
+                    var end = bucketsPtr + Buckets.Length;
+                    while (ptr < end) *ptr++ = -1;
+                }
+            }
+#else
+            for(int i = 0; i < Buckets.Length; i++)
+                Buckets[i] = -1;
+#endif
+        }
+
+        public Pipelines(int prime)
+        {
+            if (prime < 0 || prime >= Primes.Length) throw new ArgumentException("Capacity Overflow");
+
+            _prime = prime;
+
+            var size = Primes[_prime];
+            Buckets = new int[size];
+            Entries = new Entry[size];
+
+#if !NET40
+            unsafe
+            {
+                fixed (int* bucketsPtr = Buckets)
+                {
+                    int* ptr = bucketsPtr;
+                    var end = bucketsPtr + Buckets.Length;
+                    while (ptr < end) *ptr++ = -1;
+                }
+            }
+#else
+            for(int i = 0; i < Buckets.Length; i++)
+                Buckets[i] = -1;
+#endif
+        }
+
+        public Pipelines(Pipelines Pipelines)
+            : this(Pipelines._prime + 1)
+        {
+            Array.Copy(Pipelines.Entries, 0, Entries, 0, Pipelines.Count);
+            for (var i = 0; i < Pipelines.Count; i++)
+            {
+                var hashCode = Entries[i].Key.HashCode;
+                if (hashCode < 0) continue;
+
+                var bucket = hashCode % Buckets.Length;
+                Entries[i].Next = Buckets[bucket];
+                Buckets[bucket] = i;
+            }
+            Count = Pipelines.Count;
+        }
+
+        public Pipelines(BuildPipelineAsync value)
+            : this(0)
+        {
+            ref var entry = ref Entries[0];
+            entry.Next = -1;
+            entry.Pipeline = value;
+
+            Buckets[0] = 0;
+            Count++;
+        }
+
+        #endregion
+
+
+        #region Public Members
+
+        public bool RequireToGrow => (Entries.Length - Count) < 100 &&
+                                     (float)Count / Entries.Length > 0.72f;
+        #endregion
+
+
+        #region Entry Type
+
+        public struct Entry
+        {
+            public HashKey Key;
+            public int Next;
+            public BuildPipelineAsync Pipeline;
+        }
+
+        #endregion
+
+
+        #region Prime Numbers
+
+        public static readonly int[] Primes = {
+            37, 71, 107, 131, 163, 197, 239, 293, 353, 431, 521, 631, 761, 919, 1103, 1327, 1597,
+            1931, 2333, 2801, 3371, 4049, 4861, 5839, 7013, 8419, 10103, 12143, 14591, 17519, 21023,
+            25229, 30293, 36353, 43627, 52361, 62851, 75431, 90523, 108631, 130363, 156437, 187751,
+            225307, 270371, 324449, 389357, 467237, 560689, 672827, 807403, 968897, 1162687, 1395263,
+            1674319, 2009191, 2411033, 2893249, 3471899, 4166287, 4999559, 5999471, 7199369};
+
+        #endregion
+    }
+}

src/UnityContainer.IUnityContainerAsync.cs

@@ -192,27 +192,33 @@ namespace Unity
         ValueTask<object?> IUnityContainerAsync.ResolveAsync(Type type, string? name, params ResolverOverride[] overrides)
         {
             // Setup Context
-            var registration = GetRegistration(type ?? throw new ArgumentNullException(nameof(type)), name);
+            var pipeline = GetPipeline(type ?? throw new ArgumentNullException(nameof(type)), name);
 
             // Check if pipeline exists
-            if (null == registration.Pipeline && !(registration.LifetimeManager is PerThreadLifetimeManager))
+            if (null == pipeline)
             {
                 // Start a new Task to create and execute pipeline
                 var task = Task.Factory.StartNew(() =>
                 {
-                    var context = new BuilderContext
+                    Debug.Assert(null != _root);
+                    Debug.Assert(null != _root._pipelines);
+
+                    // Get pipeline builder
+                    pipeline = _root._pipelines.Entries[0].Pipeline;
+
+                    var context = new PipelineContext
                     {
                         Type = type,
-                        IsAsync = true,
+                        Name = name,
+                        RunningAsync = true,
                         Overrides = overrides,
-                        Registration = registration,
                         ContainerContext = Context,
                     };
 
                     try
                     {
                         // Execute pipeline
-                        return context.Pipeline(ref context).Result;
+                        return pipeline(ref context).Result;
                     }
                     catch (Exception ex)
                     when (ex is InvalidRegistrationException || 
@@ -227,21 +233,19 @@ namespace Unity
                 return new ValueTask<object?>(task);
             }
 
-            // Existing pipeline
-            var context = new BuilderContext
+            // Execute pipeline
+            var context = new PipelineContext
             {
-                Async = true,
-
                 Type = type,
+                Name = name,
+                RunAsync = true,
                 Overrides = overrides,
-                Registration = registration,
                 ContainerContext = Context,
             };
 
             try
             {
-                // Execute pipeline
-                return context.Pipeline(ref context);
+                return pipeline(ref context);
             }
             catch (Exception ex)
             when (ex is InvalidRegistrationException || 

src/UnityContainer.Implementation.cs

@@ -12,7 +12,6 @@ using Unity.Events;
 using Unity.Exceptions;
 using Unity.Extension;
 using Unity.Lifetime;
-using Unity.Policy;
 using Unity.Registration;
 using Unity.Resolution;
 using Unity.Storage;
@@ -41,6 +40,7 @@ namespace Unity
         // Essentials
         private Metadata? _metadata;
         private Registry? _registry;
+        private Pipelines? _pipelines;
         private readonly UnityContainer _root;
         private readonly UnityContainer? _parent;
 
@@ -72,8 +72,8 @@ namespace Unity
         private UnityContainer(UnityContainer parent)
         {
             // Validate input
-            Debug.Assert(null != parent, nameof(parent));
-            Debug.Assert(null != parent._root, nameof(parent._root));
+            Debug.Assert(null != parent);
+            Debug.Assert(null != parent._root);
 
             // Register with parent
             _parent = parent;

src/UnityContainer.Pipeline.cs

@@ -0,0 +1,51 @@
+using System;
+using System.Diagnostics;
+using System.Security;
+using System.Threading.Tasks;
+using Unity.Builder;
+using Unity.Storage;
+
+namespace Unity
+{
+    public partial class UnityContainer
+    {
+        private BuildPipelineAsync? GetPipeline(Type type, string? name)
+        {
+            var key = new HashKey(type, name);
+
+            // Iterate through containers hierarchy
+            for (UnityContainer? container = this; null != container; container = container._parent)
+            {
+                // Skip to the parent if no pipelines
+                if (null == container._pipelines) continue;
+
+                var registry = container._pipelines;
+
+                // Check for exact match
+                for (var i = registry.Buckets[key.HashCode % registry.Buckets.Length]; i >= 0; i = registry.Entries[i].Next)
+                {
+                    ref var candidate = ref registry.Entries[i];
+                    if (candidate.Key != key) continue;
+
+                    // Found it
+                    return candidate.Pipeline;
+                }
+            }
+
+            return null;
+        }
+
+
+        #region Root Build Pipeline
+
+        [SecuritySafeCritical]
+        public ValueTask<object?> DefaultBuildPipeline(ref PipelineContext context)
+        {
+            var builder = new PipelineBuilder(ref PipelineContext context);
+
+            throw new NotImplementedException();
+        }
+
+        #endregion
+    }
+}

src/UnityContainer.Public.cs

@@ -67,8 +67,9 @@ namespace Unity
             };
 
             // Create Registry
-            _metadata = new Metadata();
-            _registry = new Registry(Defaults);
+            _metadata  = new Metadata();
+            _registry  = new Registry(Defaults);
+            _pipelines = new Pipelines(DefaultBuildPipeline);
             _registry.Set(typeof(IUnityContainer),      null, container);
             _registry.Set(typeof(IUnityContainerAsync), null, container);
 

src/UnityContainer.Registration.cs

@@ -43,7 +43,7 @@ namespace Unity
 
         #region Getting Registration During Resolution
 
-        internal ImplicitRegistration GetRegistration(Type type, string? name)
+        internal IRegistration GetRegistration(Type type, string? name)
         {
 #if NETSTANDARD1_0 || NETCOREAPP1_0
             var info = type.GetTypeInfo();
@@ -53,7 +53,7 @@ namespace Unity
 #endif
         }
 
-        private ImplicitRegistration GetSimpleRegistration(Type type, string? name)
+        private IRegistration GetSimpleRegistration(Type type, string? name)
         {
             var key = new HashKey(type, name);
 
@@ -73,10 +73,10 @@ namespace Unity
                     if (candidate.Key != key) continue;
 
                     // Found a registration
-                    if (!(candidate.Policies is ImplicitRegistration))
+                    if (!(candidate.Policies is IRegistration))
                         candidate.Policies = container.CreateRegistration(type, name, candidate.Policies);
 
-                    return (ImplicitRegistration)candidate.Policies;
+                    return (IRegistration)candidate.Policies;
                 }
             }
 
@@ -87,9 +87,9 @@ namespace Unity
 
 
 #if NETSTANDARD1_0 || NETCOREAPP1_0
-        private ImplicitRegistration GetGenericRegistration(Type type, string? name, TypeInfo info)
+        private IRegistration GetGenericRegistration(Type type, string? name, TypeInfo info)
 #else
-        private ImplicitRegistration GetGenericRegistration(Type type, string? name)
+        private IRegistration GetGenericRegistration(Type type, string? name)
 #endif
         {
             bool initGenerics = true;
@@ -116,10 +116,10 @@ namespace Unity
                     if (candidate.Key != keyExact) continue;
 
                     // Found a registration
-                    if (!(candidate.Policies is ImplicitRegistration))
+                    if (!(candidate.Policies is IRegistration))
                         candidate.Policies = container.CreateRegistration(type, name, candidate.Policies);
 
-                    return (ImplicitRegistration)candidate.Policies;
+                    return (IRegistration)candidate.Policies;
                 }
 
                 // Generic registrations
@@ -296,7 +296,7 @@ namespace Unity
             throw new NotImplementedException();
         }
 
-        private ImplicitRegistration GetOrAdd(ref HashKey key, Type type, string? name, IPolicySet? factory = null)
+        private IRegistration GetOrAdd(ref HashKey key, Type type, string? name, IPolicySet? factory = null)
         {
             Debug.Assert(null != _registry);
 
@@ -315,10 +315,10 @@ namespace Unity
                         continue;
                     }
 
-                    if (!(candidate.Policies is ImplicitRegistration))
+                    if (!(candidate.Policies is IRegistration))
                         candidate.Policies = CreateRegistration(type, name, candidate.Policies);
 
-                    return (ImplicitRegistration)candidate.Policies;
+                    return (IRegistration)candidate.Policies;
                 }
 
                 // Expand if required
@@ -330,7 +330,6 @@ namespace Unity
 
                 // Add registration
                 var registration = CreateRegistration(type, name, factory);
-                registration.AddRef();
                 ref var entry = ref _registry.Entries[_registry.Count];
                 entry.Key = key;
                 entry.Type = type;
@@ -338,7 +337,7 @@ namespace Unity
                 entry.Policies = registration;
                 _registry.Buckets[targetBucket] = _registry.Count++;
 
-                return (ImplicitRegistration)entry.Policies;
+                return (IRegistration)entry.Policies;
             }
         }
 
@@ -347,7 +346,7 @@ namespace Unity
 
         #region Creating Implicit Registration
 
-        private ImplicitRegistration CreateRegistration(Type type, string? name, IPolicySet? set)
+        private IRegistration CreateRegistration(Type type, string? name, IPolicySet? set)
         {
             var registration = set is ImplicitRegistration factory 
                              ? new ImplicitRegistration(this, name, factory)

src/UnityContainer.Resolution.cs

@@ -8,7 +8,6 @@ using Unity.Exceptions;
 using Unity.Registration;
 using Unity.Resolution;
 using Unity.Storage;
-using Unity.Utility;
 
 namespace Unity
 {