diff --git a/Src/IronPython.Modules/_collections.cs b/Src/IronPython.Modules/_collections.cs
index f0f838ba4..77067c319 100644
--- a/Src/IronPython.Modules/_collections.cs
+++ b/Src/IronPython.Modules/_collections.cs
@@ -551,20 +551,13 @@ public void __delitem__(CodeContext/*!*/ context, object index) {
                 }
             }
 
-            public PythonTuple __reduce__() {
-                lock (_lockObj) {
-                    object[] items = new object[_itemCnt];
-                    int curItem = 0;
-                    WalkDeque(delegate(int curIndex) {
-                        items[curItem++] = _data[curIndex];
-                        return true;
-                    });
-
-                    return PythonTuple.MakeTuple(
-                        DynamicHelpers.GetPythonType(this),
-                        PythonTuple.MakeTuple(PythonList.FromArrayNoCopy(items))
-                    );
-                }
+            public PythonTuple __reduce__(CodeContext context) {
+                return PythonTuple.MakeTuple(
+                    DynamicHelpers.GetPythonType(this),
+                    _maxLen == -1 ? PythonTuple.EMPTY : PythonTuple.MakeTuple(PythonTuple.EMPTY, maxlen),
+                    GetType() == typeof(deque) ? null : PythonOps.GetBoundAttr(context, this, "__dict__"),
+                    PythonOps.GetEnumeratorObject(context, this)
+                );
             }
 
             public int __len__() {
diff --git a/Src/IronPython.Modules/_socket.cs b/Src/IronPython.Modules/_socket.cs
index 9587d6864..52bedab8c 100644
--- a/Src/IronPython.Modules/_socket.cs
+++ b/Src/IronPython.Modules/_socket.cs
@@ -136,14 +136,27 @@ public void __init__(CodeContext/*!*/ context, int family = DefaultAddressFamily
                     throw MakeException(context, new SocketException((int)SocketError.ProtocolNotSupported));
                 }
 
-                Socket? socket;
+                Socket? socket = null;
                 if (fileno is socket sock) {
                     socket = sock._socket;
                     _hostName = sock._hostName;
                     // we now own the lifetime of the socket
                     GC.SuppressFinalize(sock);
-                } else if (fileno != null && (socket = HandleToSocket((long)fileno)) != null) {
-                    // nothing to do here
+                } else if (fileno != null) {
+                    if (!PythonOps.TryToIndex(fileno, out object? handleObj)) {
+                        throw PythonOps.TypeErrorForUnIndexableObject(fileno);
+                    }
+                    long handle = Converter.ConvertToInt64(handleObj);
+                    // Windows reserves only INVALID_SOCKET (~0) as an invalid handle
+                    if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? handle == -1 : handle < 0) {
+                        throw PythonOps.ValueError("negative file descriptor");
+                    }
+                    socket = HandleToSocket(handle);
+                    if (socket is null) {
+                        throw PythonOps.OSError(RuntimeInformation.IsOSPlatform(OSPlatform.Windows)
+                            ? PythonErrorNumber.WSAENOTSOCK : PythonErrorNumber.EBADF,
+                            "Bad file descriptor");
+                    }
                 } else {
                     try {
                         socket = new Socket(addressFamily, socketType, protocolType);
@@ -413,7 +426,7 @@ public Bytes recv(int bufsize, int flags = 0) {
                     try {
                         bytesRead = _socket.Receive(buffer, bufsize, (SocketFlags)flags);
                     } catch (Exception e) {
-                        throw MakeRecvException(e, SocketError.NotConnected);
+                        throw MakeException(_context, e);
                     }
 
                     var bytes = new byte[bytesRead];
@@ -449,7 +462,7 @@ public int recv_into([NotNone] IBufferProtocol buffer, int nbytes = 0, int flags
                     try {
                         bytesRead = _socket.Receive(byteBuffer, nbytes, (SocketFlags)flags);
                     } catch (Exception e) {
-                        throw MakeRecvException(e, SocketError.NotConnected);
+                        throw MakeException(_context, e);
                     }
 
                     byteBuffer.AsSpan(0, bytesRead).CopyTo(span);
@@ -486,7 +499,7 @@ public PythonTuple recvfrom(int bufsize, int flags = 0) {
                     try {
                         bytesRead = _socket.ReceiveFrom(buffer, bufsize, (SocketFlags)flags, ref remoteEP);
                     } catch (Exception e) {
-                        throw MakeRecvException(e, SocketError.InvalidArgument);
+                        throw MakeException(_context, e);
                     }
 
                     var bytes = new byte[bytesRead];
@@ -519,7 +532,7 @@ public PythonTuple recvfrom_into([NotNone] IBufferProtocol buffer, int nbytes =
                     try {
                         bytesRead = _socket.ReceiveFrom(byteBuffer, nbytes, (SocketFlags)flags, ref remoteEP);
                     } catch (Exception e) {
-                        throw MakeRecvException(e, SocketError.InvalidArgument);
+                        throw MakeException(_context, e);
                     }
 
                     byteBuffer.AsSpan(0, bytesRead).CopyTo(span);
@@ -551,18 +564,6 @@ private static int byteBufferSize(string funcName, int nbytes, int bufLength, in
                 }
             }
 
-            private Exception MakeRecvException(Exception e, SocketError errorCode = SocketError.InvalidArgument) {
-                if (e is ObjectDisposedException) return MakeException(_context, e);
-
-                // on the socket recv throw a special socket error code when SendTimeout is zero
-                if (_socket.SendTimeout == 0) {
-                    var s = new SocketException((int)errorCode);
-                    return PythonExceptions.CreateThrowable(error, s.ErrorCode, s.Message);
-                } else {
-                    return MakeException(_context, e);
-                }
-            }
-
             [Documentation("send(string[, flags]) -> bytes_sent\n\n"
                 + "Send data to the remote socket. The socket must be connected to a remote\n"
                 + "socket (by calling either connect() or accept(). Returns the number of bytes\n"
@@ -1787,7 +1788,7 @@ internal static Exception MakeException(CodeContext/*!*/ context, Exception exce
                 }
             } else if (exception is ObjectDisposedException) {
                 return PythonExceptions.CreateThrowable(error, PythonErrorNumber.EBADF, "Socket is closed");
-            } else if (exception is InvalidOperationException) {
+            } else if (exception is InvalidOperationException or ArgumentException) {
                 return MakeException(context, new SocketException((int)SocketError.InvalidArgument));
             } else {
                 return exception;
diff --git a/Src/IronPython.Modules/array.cs b/Src/IronPython.Modules/array.cs
index 578ec8d2f..2bee03a5f 100644
--- a/Src/IronPython.Modules/array.cs
+++ b/Src/IronPython.Modules/array.cs
@@ -196,11 +196,7 @@ public array InPlaceMultiply(int value) {
                 if (value <= 0) {
                     _data.Clear();
                 } else {
-                    var myData = __copy__();
-
-                    for (int i = 0; i < (value - 1); i++) {
-                        ExtendArray(myData);
-                    }
+                    _data.InPlaceMultiply(value);
                 }
                 return this;
             }
diff --git a/Src/IronPython.Modules/time.cs b/Src/IronPython.Modules/time.cs
index f3aa4c69a..806efd26c 100644
--- a/Src/IronPython.Modules/time.cs
+++ b/Src/IronPython.Modules/time.cs
@@ -340,10 +340,12 @@ private static List<FormatInfo> PythonFormatToCLIFormat(string format) {
             List<FormatInfo> newFormat = new List<FormatInfo>();
 
             for (int i = 0; i < format.Length; i++) {
-                if (format[i] == '%') {
+                var ch = format[i];
+                if (ch == '%') {
                     if (i + 1 == format.Length) throw PythonOps.ValueError("Invalid format string");
 
                     switch (format[++i]) {
+                        case '\0': throw PythonOps.ValueError("embedded null character");
                         case 'a': newFormat.Add(new FormatInfo("ddd")); break;
                         case 'A': newFormat.Add(new FormatInfo("dddd")); break;
                         case 'b': newFormat.Add(new FormatInfo("MMM")); break;
@@ -379,10 +381,11 @@ private static List<FormatInfo> PythonFormatToCLIFormat(string format) {
                             throw PythonOps.ValueError("Invalid format string");
                     }
                 } else {
+                    if (ch == '\0') throw PythonOps.ValueError("embedded null character");
                     if (newFormat.Count == 0 || newFormat[newFormat.Count - 1].Type != FormatInfoType.UserText)
-                        newFormat.Add(new FormatInfo(FormatInfoType.UserText, format[i].ToString()));
+                        newFormat.Add(new FormatInfo(FormatInfoType.UserText, ch.ToString()));
                     else
-                        newFormat[newFormat.Count - 1].Text += format[i];
+                        newFormat[newFormat.Count - 1].Text += ch;
                 }
             }
 
diff --git a/Src/IronPython.Modules/winreg.cs b/Src/IronPython.Modules/winreg.cs
index 5b80836d2..fa885bae0 100644
--- a/Src/IronPython.Modules/winreg.cs
+++ b/Src/IronPython.Modules/winreg.cs
@@ -4,9 +4,8 @@
 
 #if FEATURE_REGISTRY
 
-using Microsoft.Win32;
-using Microsoft.Win32.SafeHandles;
 using System;
+using System.Buffers.Binary;
 using System.Collections.Concurrent;
 using System.ComponentModel;
 using System.Diagnostics;
@@ -22,6 +21,9 @@
 using IronPython.Runtime.Exceptions;
 using IronPython.Runtime.Types;
 
+using Microsoft.Win32;
+using Microsoft.Win32.SafeHandles;
+
 [assembly: PythonModule("winreg", typeof(IronPython.Modules.PythonWinReg), PlatformsAttribute.PlatformFamily.Windows)]
 namespace IronPython.Modules {
     [SupportedOSPlatform("windows")]
@@ -70,6 +72,7 @@ public static class PythonWinReg {
         public const int REG_FULL_RESOURCE_DESCRIPTOR = 0X9;
         public const int REG_RESOURCE_REQUIREMENTS_LIST = 0XA;
         public const int REG_QWORD = 0xB;
+        public const int REG_QWORD_LITTLE_ENDIAN = 0XB;
 
         public const int REG_NOTIFY_CHANGE_NAME = 0X1;
         public const int REG_NOTIFY_CHANGE_ATTRIBUTES = 0X2;
@@ -346,19 +349,22 @@ private static void QueryValueExImpl(SafeRegistryHandle handle, string valueName
                     break;
                 case REG_EXPAND_SZ:
                 case REG_SZ:
-                    if (length >= 2 && data[length - 1] == 0 && data[length - 2] == 0) {
-                        value = ExtractString(data, 0, (int)length - 2);
-                    } else {
-                        value = ExtractString(data, 0, (int)length);
-                    }
+                    var span = MemoryMarshal.Cast<byte, char>(data.AsSpan());
+                    var len = span.IndexOf((char)0);
+                    if (len != -1) span = span.Slice(0, len);
+                    value = span.ToString();
                     break;
                 case REG_DWORD:
-                    if (BitConverter.IsLittleEndian) {
-                        value = (uint)((data[3] << 24) | (data[2] << 16) | (data[1] << 8) | data[0]);
-                    } else {
-                        value = (uint)((data[0] << 24) | (data[1] << 16) | (data[2] << 8) | data[3]);
-                    }
+                    var dval = BitConverter.ToUInt32(data, 0);
+                    if (!BitConverter.IsLittleEndian) dval = BinaryPrimitives.ReverseEndianness(dval);
+                    value = dval > int.MaxValue ? (BigInteger)dval : unchecked((int)dval);
                     break;
+                case REG_QWORD:
+                    var qval = BitConverter.ToUInt64(data, 0);
+                    if (!BitConverter.IsLittleEndian) qval = BinaryPrimitives.ReverseEndianness(qval);
+                    value = (BigInteger)qval;
+                    break;
+
                 default:
                     value = null;
                     break;
diff --git a/Src/IronPython.Modules/winsound.cs b/Src/IronPython.Modules/winsound.cs
index 56cb0cfc8..045b99124 100644
--- a/Src/IronPython.Modules/winsound.cs
+++ b/Src/IronPython.Modules/winsound.cs
@@ -120,20 +120,20 @@ public static void PlaySound(CodeContext/*!*/ context, [NotNone] IBufferProtocol
 This parameter must be in the range 37 through 32,767.
 The duration argument specifies the number of milliseconds.
 ")]
-        public static void Beep(CodeContext/*!*/ context, int freq, int dur) {
-            if (freq < 37 || freq > 32767) {
+        public static void Beep(CodeContext/*!*/ context, int frequency, int duration) {
+            if (frequency < 37 || frequency > 32767) {
                 throw PythonOps.ValueError("frequency must be in 37 thru 32767");
             }
 
-            bool ok = Beep(freq, dur);
+            bool ok = Beep(frequency, duration);
             if (!ok) {
                 throw PythonOps.RuntimeError("Failed to beep");
             }
         }
 
         [Documentation("MessageBeep(x) - call Windows MessageBeep(x). x defaults to MB_OK.")]
-        public static void MessageBeep(CodeContext/*!*/ context, int x=MB_OK) {
-            MessageBeep(x);
+        public static void MessageBeep(CodeContext/*!*/ context, int type=MB_OK) {
+            MessageBeep(type);
         }
 
         #endregion
diff --git a/Src/IronPython/Lib/iptest/ipunittest.py b/Src/IronPython/Lib/iptest/ipunittest.py
index ca990a35a..91c4cddb9 100644
--- a/Src/IronPython/Lib/iptest/ipunittest.py
+++ b/Src/IronPython/Lib/iptest/ipunittest.py
@@ -206,24 +206,25 @@ def _flatten_suite(suite):
 
 def generate_suite(tests, failing_tests, skip_tests=[]):
     all_tests = _flatten_suite(tests)
+    test_indices = {t: i for i, t in enumerate(all_tests)}
     unknown_tests = []
 
     for t in skip_tests:
         try:
-            all_tests.remove(t)
+            all_tests[test_indices.pop(t)] = None
         except ValueError:
             unknown_tests.append(t)
 
     for t in failing_tests:
         try:
-            all_tests[all_tests.index(t)] = unittest.expectedFailure(t)
-        except:
+            all_tests[test_indices.pop(t)] = unittest.expectedFailure(t)
+        except ValueError:
             unknown_tests.append(t)
 
     if unknown_tests:
         raise ValueError("Unknown tests:\n - {}".format('\n - '.join(str(t) for t in unknown_tests)))
 
-    return unittest.TestSuite(all_tests)
+    return unittest.TestSuite(t for t in all_tests if t is not None)
 
 # class testpath:
 #     # find the ironpython root directory
diff --git a/Src/IronPython/Modules/Builtin.cs b/Src/IronPython/Modules/Builtin.cs
index 6d21a52f1..3131022e7 100644
--- a/Src/IronPython/Modules/Builtin.cs
+++ b/Src/IronPython/Modules/Builtin.cs
@@ -135,7 +135,7 @@ public static string bin(object? number) {
 
         public static PythonType bytes => TypeCache.Bytes;
 
-        public static PythonType bytearray => DynamicHelpers.GetPythonTypeFromType(typeof(ByteArray));
+        public static PythonType bytearray => TypeCache.ByteArray;
 
         [Documentation("callable(object) -> bool\n\nReturn whether the object is callable (i.e., some kind of function).")]
         public static bool callable(CodeContext/*!*/ context, object? o) {
diff --git a/Src/IronPython/Runtime/ArrayData.cs b/Src/IronPython/Runtime/ArrayData.cs
index c8f2b60ca..4b12de25e 100644
--- a/Src/IronPython/Runtime/ArrayData.cs
+++ b/Src/IronPython/Runtime/ArrayData.cs
@@ -27,6 +27,7 @@ internal interface ArrayData : IList {
         void InsertRange(int index, int count, ArrayData value);
         void RemoveSlice(Slice slice);
         ArrayData Multiply(int count);
+        void InPlaceMultiply(int count);
         new bool Remove(object? item);
         void Reverse();
         Span<byte> AsByteSpan();
diff --git a/Src/IronPython/Runtime/ByteArray.cs b/Src/IronPython/Runtime/ByteArray.cs
index ef3f6a2a0..38e54bb6a 100644
--- a/Src/IronPython/Runtime/ByteArray.cs
+++ b/Src/IronPython/Runtime/ByteArray.cs
@@ -9,16 +9,16 @@
 using System.Collections.Generic;
 using System.Numerics;
 using System.Runtime.CompilerServices;
-using System.Runtime.InteropServices;
 using System.Text;
 
-using Microsoft.Scripting.Runtime;
-using Microsoft.Scripting.Utils;
-
 using IronPython.Runtime.Exceptions;
 using IronPython.Runtime.Operations;
 using IronPython.Runtime.Types;
 
+using Microsoft.Scripting;
+using Microsoft.Scripting.Runtime;
+using Microsoft.Scripting.Utils;
+
 namespace IronPython.Runtime {
     /// <summary>
     /// bytearray(string, encoding[, errors]) -> bytearray
@@ -56,6 +56,12 @@ internal ByteArray(IEnumerable<byte> bytes) {
             _bytes = new ArrayData<byte>(bytes);
         }
 
+        [StaticExtensionMethod]
+        public static object __new__(CodeContext context, [NotNone] PythonType cls, [ParamDictionary, NotNone] IDictionary<object, object> dict, [NotNone] params object[] args) {
+            if (cls == TypeCache.ByteArray) return new ByteArray();
+            return cls.CreateInstance(context);
+        }
+
         public void __init__() {
             lock (this) {
                 _bytes.Clear();
@@ -74,7 +80,7 @@ public void __init__(int source) {
         }
 
         public void __init__([NotNone] IBufferProtocol source) {
-            if (Converter.TryConvertToIndex(source, out int size, throwNonInt: false)) {
+            if (Converter.TryConvertToIndex(source, out int size, throwTypeError: false)) {
                 __init__(size);
             } else {
                 lock (this) {
@@ -86,7 +92,7 @@ public void __init__([NotNone] IBufferProtocol source) {
         }
 
         public void __init__(CodeContext context, object? source) {
-            if (Converter.TryConvertToIndex(source, out int size, throwNonInt: false)) {
+            if (Converter.TryConvertToIndex(source, out int size, throwTypeError: false)) {
                 __init__(size);
             } else if (source is IEnumerable<byte> en) {
                 lock (this) {
@@ -466,8 +472,13 @@ public int find(BigInteger @byte, object? start, object? end) {
             }
         }
 
-        public static ByteArray fromhex([NotNone] string @string) {
-            return new ByteArray(IListOfByteOps.FromHex(@string));
+        [ClassMethod]
+        public static object fromhex(CodeContext context, [NotNone] PythonType cls, [NotNone] string @string) {
+            var hex = IListOfByteOps.FromHex(@string);
+            if (cls == TypeCache.ByteArray) {
+                return new ByteArray(hex);
+            }
+            return PythonTypeOps.CallParams(context, cls, new Bytes(hex));
         }
 
         public string hex() => Bytes.ToHex(_bytes.AsByteSpan()); // new in CPython 3.5
diff --git a/Src/IronPython/Runtime/Bytes.cs b/Src/IronPython/Runtime/Bytes.cs
index 1f4c3d1d0..e6d5ac5d3 100644
--- a/Src/IronPython/Runtime/Bytes.cs
+++ b/Src/IronPython/Runtime/Bytes.cs
@@ -61,7 +61,7 @@ public static object __new__(CodeContext context, [NotNone] PythonType cls, [Not
                     return source;
                 } else if (TryInvokeBytesOperator(context, source, out Bytes? res)) {
                     return res;
-                } else if (Converter.TryConvertToIndex(source, out int size, throwNonInt: false)) {
+                } else if (Converter.TryConvertToIndex(source, out int size, throwTypeError: false)) {
                     if (size < 0) throw PythonOps.ValueError("negative count");
                     return new Bytes(new byte[size]);
                 } else {
@@ -79,7 +79,7 @@ public static object __new__(CodeContext context, [NotNone] PythonType cls, obje
                     return @object;
                 } else if (TryInvokeBytesOperator(context, @object, out Bytes? res)) {
                     return res;
-                } else if (Converter.TryConvertToIndex(@object, out int size, throwNonInt: false)) {
+                } else if (Converter.TryConvertToIndex(@object, out int size, throwTypeError: false)) {
                     if (size < 0) throw PythonOps.ValueError("negative count");
                     return new Bytes(new byte[size]);
                 } else {
@@ -367,8 +367,13 @@ public int find(BigInteger @byte, object? start, object? end) {
         }
 
         [ClassMethod]
-        public static object fromhex(CodeContext context, [NotNone] PythonType cls, [NotNone] string @string)
-            => __new__(context, cls, IListOfByteOps.FromHex(@string));
+        public static object fromhex(CodeContext context, [NotNone] PythonType cls, [NotNone] string @string) {
+            var hex = IListOfByteOps.FromHex(@string);
+            if (cls == TypeCache.Bytes) {
+                return new Bytes(hex);
+            }
+            return PythonTypeOps.CallParams(context, cls, new Bytes(hex));
+        }
 
         public string hex() => ToHex(_bytes.AsSpan()); // new in CPython 3.5
 
@@ -1190,6 +1195,13 @@ public bool __eq__(CodeContext context, [NotNone] string value) {
 
         public bool __eq__(CodeContext context, [NotNone] Extensible<string> value) => __eq__(context, value.Value);
 
+        public bool __eq__(CodeContext context, [NotNone] int value) {
+            if (context.LanguageContext.PythonOptions.BytesWarning != Microsoft.Scripting.Severity.Ignore) {
+                PythonOps.Warn(context, PythonExceptions.BytesWarning, "Comparison between bytes and int");
+            }
+            return false;
+        }
+
         [return: MaybeNotImplemented]
         public NotImplementedType __eq__(CodeContext context, object? value) => NotImplementedType.Value;
 
@@ -1199,6 +1211,8 @@ public bool __eq__(CodeContext context, [NotNone] string value) {
 
         public bool __ne__(CodeContext context, [NotNone] Extensible<string> value) => !__eq__(context, value);
 
+        public bool __ne__(CodeContext context, [NotNone] int value) => !__eq__(context, value);
+
         [return: MaybeNotImplemented]
         public NotImplementedType __ne__(CodeContext context, object? value) => NotImplementedType.Value;
 
diff --git a/Src/IronPython/Runtime/Converter.cs b/Src/IronPython/Runtime/Converter.cs
index e8e860457..9dc49999e 100644
--- a/Src/IronPython/Runtime/Converter.cs
+++ b/Src/IronPython/Runtime/Converter.cs
@@ -335,28 +335,34 @@ public static IEnumerable ConvertToIEnumerable(object o) {
         /// If throwOverflowError is true then BigInteger's outside the normal range of integers will
         /// result in an OverflowError.
         ///
-        /// When throwNonInt is true, a TypeError will be thrown if __index__ returned a non-int.
+        /// When throwTypeError is true, a TypeError will be thrown if __index__ throw a TypeError or
+        /// returned a non-int.
         /// </summary>
-        internal static bool TryConvertToIndex(object? value, out int index, bool throwOverflowError = true, bool throwNonInt = true) {
+        internal static bool TryConvertToIndex(object? value, out int index, bool throwOverflowError = true, bool throwTypeError = true) {
             if (TryGetInt(value, out index, throwOverflowError, value)) {
                 return true;
             }
 
-            if (PythonTypeOps.TryInvokeUnaryOperator(DefaultContext.Default, value, "__index__", out object indexObj)) {
-                if (TryGetInt(indexObj, out index, throwOverflowError, value)) {
-                    return true;
-                }
+            if (throwTypeError) {
+                if (PythonTypeOps.TryInvokeUnaryOperator(DefaultContext.Default, value, "__index__", out object indexObj)) {
+                    if (TryGetInt(indexObj, out index, throwOverflowError, value)) {
+                        return true;
+                    }
 
-                if (throwNonInt) {
                     throw PythonOps.TypeError("__index__ returned non-int (type {0})", PythonOps.GetPythonTypeName(indexObj));
                 }
+            } else {
+                try {
+                    return PythonTypeOps.TryInvokeUnaryOperator(DefaultContext.Default, value, "__index__", out object indexObj) &&
+                        TryGetInt(indexObj, out index, throwOverflowError, value);
+                } catch (Exceptions.TypeErrorException) { }
             }
 
             return false;
         }
 
         public static int ConvertToIndex(object? value, bool throwOverflowError = false) {
-            if (TryConvertToIndex(value, out int index, throwOverflowError: throwOverflowError, throwNonInt: true))
+            if (TryConvertToIndex(value, out int index, throwOverflowError: throwOverflowError))
                 return index;
 
             throw PythonOps.TypeError("expected integer value, got {0}", PythonOps.GetPythonTypeName(value));
diff --git a/Src/IronPython/Runtime/DictionaryOps.cs b/Src/IronPython/Runtime/DictionaryOps.cs
index cf5f3cd0d..dec342ce0 100644
--- a/Src/IronPython/Runtime/DictionaryOps.cs
+++ b/Src/IronPython/Runtime/DictionaryOps.cs
@@ -51,7 +51,12 @@ public static class DictionaryOps {
                         buf.Append(PythonOps.Repr(context, kv.Key));
                     buf.Append(": ");
 
-                    buf.Append(PythonOps.Repr(context, kv.Value));
+                    try {
+                        PythonOps.FunctionPushFrame(context.LanguageContext);
+                        buf.Append(PythonOps.Repr(context, kv.Value));
+                    } finally {
+                        PythonOps.FunctionPopFrame();
+                    }
                 }
                 buf.Append("}");
                 return buf.ToString();
@@ -94,12 +99,12 @@ public static object pop(PythonDictionary self, object key, object defaultValue)
             }
         }
 
-        public static PythonTuple popitem(IDictionary<object, object> self) {
-            IEnumerator<KeyValuePair<object, object>> ie = self.GetEnumerator();
+        public static PythonTuple popitem(PythonDictionary self) {
+            using IEnumerator<KeyValuePair<object, object>> ie = self.GetEnumerator();
             if (ie.MoveNext()) {
                 object key = ie.Current.Key;
                 object val = ie.Current.Value;
-                self.Remove(key);
+                self.RemoveDirect(key);
                 return PythonTuple.MakeTuple(key, val);
             }
             throw PythonOps.KeyError("dictionary is empty");
diff --git a/Src/IronPython/Runtime/Exceptions/PythonExceptions.cs b/Src/IronPython/Runtime/Exceptions/PythonExceptions.cs
index 8ff54a605..55e97d29b 100644
--- a/Src/IronPython/Runtime/Exceptions/PythonExceptions.cs
+++ b/Src/IronPython/Runtime/Exceptions/PythonExceptions.cs
@@ -881,7 +881,7 @@ internal static void RemoveTraceBack(this Exception e) {
 
             string sourceLine = PythonContext.GetSourceLine(e);
             string fileName = e.GetSymbolDocumentName();
-            object column = (e.Column == 0 || e.Data[PythonContext._syntaxErrorNoCaret] != null) ? null : (object)e.Column;
+            int column = e.Data[PythonContext._syntaxErrorNoCaret] is not null ? 0 : e.Column;
 
             se.args = PythonTuple.MakeTuple(e.Message, PythonTuple.MakeTuple(fileName, e.Line, column, sourceLine));
 
diff --git a/Src/IronPython/Runtime/PythonDictionary.cs b/Src/IronPython/Runtime/PythonDictionary.cs
index c5bda3617..5fd1cff15 100644
--- a/Src/IronPython/Runtime/PythonDictionary.cs
+++ b/Src/IronPython/Runtime/PythonDictionary.cs
@@ -1053,34 +1053,22 @@ void ICollection.CopyTo(Array array, int index) {
         #region ICodeFormattable Members
 
         public string __repr__(CodeContext context) {
-            List<object> infinite = PythonOps.GetAndCheckInfinite(this);
-            if (infinite == null) {
-                return "...";
-            }
-
-            int index = infinite.Count;
-            infinite.Add(this);
-            try {
-                StringBuilder res = new StringBuilder(20);
-                res.Append("dict_values([");
-                string comma = "";
-                foreach (object value in this) {
-                    res.Append(comma);
-                    comma = ", ";
-                    try {
-                        PythonOps.FunctionPushFrame(context.LanguageContext);
-                        res.Append(PythonOps.Repr(context, value));
-                    } finally {
-                        PythonOps.FunctionPopFrame();
-                    }
+            StringBuilder res = new StringBuilder(20);
+            res.Append("dict_values([");
+            string comma = "";
+            foreach (object value in this) {
+                res.Append(comma);
+                comma = ", ";
+                try {
+                    PythonOps.FunctionPushFrame(context.LanguageContext);
+                    res.Append(PythonOps.Repr(context, value));
+                } finally {
+                    PythonOps.FunctionPopFrame();
                 }
-                res.Append("])");
-
-                return res.ToString();
-            } finally {
-                Debug.Assert(index == infinite.Count - 1);
-                infinite.RemoveAt(index);
             }
+            res.Append("])");
+
+            return res.ToString();
         }
 
         #endregion
@@ -1784,34 +1772,22 @@ public override bool Equals(object obj) {
         #region ICodeFormattable Members
 
         public string __repr__(CodeContext context) {
-            List<object> infinite = PythonOps.GetAndCheckInfinite(this);
-            if (infinite == null) {
-                return "...";
-            }
-
-            int index = infinite.Count;
-            infinite.Add(this);
-            try {
-                StringBuilder res = new StringBuilder(20);
-                res.Append("dict_items([");
-                string comma = "";
-                foreach (object item in this) {
-                    res.Append(comma);
-                    comma = ", ";
-                    try {
-                        PythonOps.FunctionPushFrame(context.LanguageContext);
-                        res.Append(PythonOps.Repr(context, item));
-                    } finally {
-                        PythonOps.FunctionPopFrame();
-                    }
+            StringBuilder res = new StringBuilder(20);
+            res.Append("dict_items([");
+            string comma = "";
+            foreach (object item in this) {
+                res.Append(comma);
+                comma = ", ";
+                try {
+                    PythonOps.FunctionPushFrame(context.LanguageContext);
+                    res.Append(PythonOps.Repr(context, item));
+                } finally {
+                    PythonOps.FunctionPopFrame();
                 }
-                res.Append("])");
-
-                return res.ToString();
-            } finally {
-                Debug.Assert(index == infinite.Count - 1);
-                infinite.RemoveAt(index);
             }
+            res.Append("])");
+
+            return res.ToString();
         }
 
         #endregion
diff --git a/Src/IronPython/Runtime/PythonList.cs b/Src/IronPython/Runtime/PythonList.cs
index a2a2b5e33..286d55010 100644
--- a/Src/IronPython/Runtime/PythonList.cs
+++ b/Src/IronPython/Runtime/PythonList.cs
@@ -772,7 +772,10 @@ public void extend([NotNone] PythonTuple/*!*/ seq) {
 
         public void extend(CodeContext context, object? seq) {
             if (PythonOps.TryInvokeLengthHint(context, seq, out int len)) {
-                EnsureSize(len);
+                // CPython proceeds without resizing if the length overflows
+                if (int.MaxValue - len >= Count) {
+                    EnsureSize(Count + len);
+                }
             }
 
             ExtendNoLengthCheck(context, seq);
diff --git a/Src/IronPython/Runtime/PythonRange.cs b/Src/IronPython/Runtime/PythonRange.cs
index 750791250..d5cde273d 100644
--- a/Src/IronPython/Runtime/PythonRange.cs
+++ b/Src/IronPython/Runtime/PythonRange.cs
@@ -83,9 +83,9 @@ public PythonTuple __reduce__() {
             );
         }
 
-        public int __len__() {
-            return (int)_length;
-        }
+        public int __len__() => (int)_length;
+
+        public bool __bool__() => _length != 0;
 
         public object this[int index] => this[(BigInteger)index];
 
diff --git a/Tests/test_codecs_stdlib.py b/Tests/test_codecs_stdlib.py
index ed66ccdd1..061dc11b9 100644
--- a/Tests/test_codecs_stdlib.py
+++ b/Tests/test_codecs_stdlib.py
@@ -35,8 +35,6 @@ def load_tests(loader, standard_tests, pattern):
             test.test_codecs.SurrogateEscapeTest('test_charmap'), # .NET iso-8859-3 decodes b'\xa5' to 'uf7f5' rather than undefined
             test.test_codecs.TransformCodecTest('test_custom_hex_error_is_wrapped'), # "^decoding with 'hex_codec' codec failed" does not match "Odd-length string"
             test.test_codecs.TransformCodecTest('test_custom_zlib_error_is_wrapped'), # "^decoding with 'zlib_codec' codec failed" does not match "Error -3 while decompressing data: incorrect header check"
-            test.test_codecs.TransformCodecTest('test_read'), # TypeError: expected str, got bytes
-            test.test_codecs.TransformCodecTest('test_readline'), # Exception: BZ_DATA_ERROR
             test.test_codecs.UTF7Test('test_errors'), # AssertionError: UnicodeDecodeError not raised by utf_7_decode
             test.test_codecs.UTF7Test('test_lone_surrogates'), # UnicodeEncodeError: 'utf_8' codec can't encode character '\ud801' in position 503: Unable to translate Unicode character \uD801 at index 503 to specified code page.
         ]