Do not compare Span<T> with null

src/coreclr/System.Private.CoreLib/src/Internal/Runtime/InteropServices/ComActivator.cs

@@ -203,7 +203,6 @@ private static void ClassRegistrationScenarioForType(ComActivationContext cxt, b
                     // Finally validate signature
                     ReadOnlySpan<ParameterInfo> methParams = method.GetParametersAsSpan();
                     if (method.ReturnType != typeof(void)
-                        || methParams == null
                         || methParams.Length != 1
                         || (methParams[0].ParameterType != typeof(string) && methParams[0].ParameterType != typeof(Type)))
                     {

src/coreclr/System.Private.CoreLib/src/System/Reflection/Emit/DynamicILGenerator.cs

@@ -417,7 +417,7 @@ private int GetMemberRefToken(MethodInfo methodInfo, Type[]? optionalParameterTy
                 throw new ArgumentException(SR.Argument_MustBeRuntimeMethodInfo, nameof(methodInfo));
 
             ReadOnlySpan<ParameterInfo> paramInfo = methodInfo.GetParametersAsSpan();
-            if (paramInfo != null && paramInfo.Length != 0)
+            if (paramInfo.Length != 0)
             {
                 parameterTypes = new Type[paramInfo.Length];
                 requiredCustomModifiers = new Type[parameterTypes.Length][];

src/coreclr/nativeaot/System.Private.CoreLib/src/System/Reflection/Runtime/MethodInfos/CustomMethodInvoker.cs

@@ -36,7 +36,7 @@ public CustomMethodInvoker(Type thisType, Type[] parameterTypes, InvokerOptions
             if (!(thisObject == null && 0 != (_options & InvokerOptions.AllowNullThis)))
                 ValidateThis(thisObject, _thisType.TypeHandle);
 
-            int argCount = (arguments != null) ? arguments.Length : 0;
+            int argCount = arguments.Length;
             if (argCount != _parameterTypes.Length)
                 throw new TargetParameterCountException();
 

src/libraries/Common/src/Interop/OSX/System.Security.Cryptography.Native.Apple/Interop.SecKeyRef.macOS.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Diagnostics;
+using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using System.Security.Cryptography;
 using System.Security.Cryptography.Apple;
@@ -36,7 +37,7 @@ private static partial int AppleCryptoNative_SecKeyImportEphemeral(
 
         internal static SafeSecKeyRefHandle ImportEphemeralKey(ReadOnlySpan<byte> keyBlob, bool hasPrivateKey)
         {
-            Debug.Assert(keyBlob != null);
+            Debug.Assert(!Unsafe.IsNullRef(ref MemoryMarshal.GetReference(keyBlob)));
 
             SafeSecKeyRefHandle keyHandle;
             int osStatus;

src/libraries/Common/src/System/Net/Http/aspnetcore/Http2/Hpack/Huffman.cs

@@ -677,7 +677,7 @@ public static int Decode(ReadOnlySpan<byte> src, ref byte[] dstArray)
             // see comments in GenerateDecodingLookupTree() describing decoding table
 
             Span<byte> dst = dstArray;
-            Debug.Assert(dst != null && dst.Length > 0);
+            Debug.Assert(dst.Length > 0);
 
             ushort[] decodingTree = s_decodingTree;
 

src/libraries/Common/src/System/Number.Parsing.Common.cs

@@ -336,7 +336,7 @@ internal enum ParsingStatus
         private static unsafe TChar* MatchChars<TChar>(TChar* p, TChar* pEnd, ReadOnlySpan<TChar> value)
             where TChar : unmanaged, IUtfChar<TChar>
         {
-            Debug.Assert((p != null) && (pEnd != null) && (p <= pEnd) && (value != null));
+            Debug.Assert((p != null) && (pEnd != null) && (p <= pEnd));
 
             fixed (TChar* stringPointer = &MemoryMarshal.GetReference(value))
             {

src/libraries/System.IO.FileSystem.Watcher/src/System/IO/FileSystemWatcher.Linux.cs

@@ -720,9 +720,9 @@ private bool ProcessEvent(NotifyEvent nextEvent, ref ReadOnlySpan<char> previous
 
                         break;
                     case Interop.Sys.NotifyEvents.IN_MOVED_TO:
-                        if (previousEventName != null)
+                        if (!previousEventName.IsEmpty)
                         {
-                            // If the previous name from IN_MOVED_FROM is non-null, then this is a rename.
+                            // If the previous name from IN_MOVED_FROM is non-empty, then this is a rename.
                             watcher.NotifyRenameEventArgs(WatcherChangeTypes.Renamed, expandedName, previousEventName);
                         }
                         else

src/libraries/System.IO.Packaging/src/System/IO/Packaging/ContentType.cs

@@ -351,8 +351,6 @@ private void ParseParameterAndValue(ReadOnlySpan<char> parameterAndValue)
         /// <returns></returns>
         private static int GetLengthOfParameterValue(ReadOnlySpan<char> s, int startIndex)
         {
-            Debug.Assert(s != null);
-
             int length;
 
             //if the parameter value does not start with a '"' then,

src/libraries/System.Net.Primitives/src/System/Net/IPAddress.cs

@@ -142,7 +142,6 @@ public IPAddress(ReadOnlySpan<byte> address, long scopeid)
 
         internal IPAddress(ReadOnlySpan<ushort> numbers, uint scopeid)
         {
-            Debug.Assert(numbers != null);
             Debug.Assert(numbers.Length == NumberOfLabels);
 
             _numbers = numbers.ToArray();

src/libraries/System.Net.Primitives/src/System/Net/IPAddressParser.cs

@@ -67,7 +67,6 @@ private static unsafe bool TryParseIpv4(ReadOnlySpan<char> ipSpan, out long addr
 
         private static unsafe bool TryParseIPv6(ReadOnlySpan<char> ipSpan, Span<ushort> numbers, int numbersLength, out uint scope)
         {
-            Debug.Assert(numbers != null);
             Debug.Assert(numbersLength >= IPAddressParserStatics.IPv6AddressShorts);
 
             int end = ipSpan.Length;

src/libraries/System.Net.Sockets/src/System/Net/Sockets/SocketPal.Unix.cs

@@ -528,7 +528,6 @@ private static unsafe int SysReceiveMessageFrom(
             out SocketFlags receivedFlags, out IPPacketInformation ipPacketInformation, out Interop.Error errno)
         {
             Debug.Assert(socket.IsSocket);
-            Debug.Assert(socketAddress != null, "Expected non-null socketAddress");
 
             int buffersCount = buffers.Count;
             bool allocOnStack = buffersCount <= IovStackThreshold;
@@ -810,7 +809,6 @@ public static unsafe bool TryCompleteReceiveFrom(SafeSocketHandle socket, Span<b
                 {
                     Debug.Assert(flags == SocketFlags.None);
                     Debug.Assert(buffers == null);
-                    Debug.Assert(socketAddress == null);
 
                     receivedFlags = default;
                     received = SysRead(socket, buffer, out errno);
@@ -956,7 +954,7 @@ public static bool TryCompleteSendTo(SafeSocketHandle socket, ReadOnlySpan<byte>
                     {
                         sent = buffers != null ?
                             SysSend(socket, flags, buffers, ref bufferIndex, ref offset, socketAddress, out errno) :
-                            socketAddress == null ? SysSend(socket, flags, buffer, ref offset, ref count, out errno) :
+                            socketAddress.IsEmpty ? SysSend(socket, flags, buffer, ref offset, ref count, out errno) :
                                                     SysSend(socket, flags, buffer, ref offset, ref count, socketAddress, out errno);
                     }
                 }

src/libraries/System.Private.CoreLib/src/System/Globalization/TimeSpanFormat.cs

@@ -268,12 +268,11 @@ internal static unsafe bool TryFormatStandard<TChar>(TimeSpan value, StandardFor
                 // Write fraction and separator, if necessary
                 if (fractionDigits != 0)
                 {
-                    Debug.Assert(format == StandardFormat.C || decimalSeparator != null);
                     if (format == StandardFormat.C)
                     {
                         *p++ = TChar.CastFrom('.');
                     }
-                    else if (decimalSeparator!.Length == 1)
+                    else if (decimalSeparator.Length == 1)
                     {
                         *p++ = decimalSeparator[0];
                     }

src/libraries/System.Private.CoreLib/src/System/Number.Formatting.cs

@@ -3498,7 +3498,6 @@ private static unsafe void FormatFixed<TChar>(
             {
                 if (groupDigits != null)
                 {
-                    Debug.Assert(sGroup != null, "Must be null when groupDigits != null");
                     int groupSizeIndex = 0;                             // Index into the groupDigits array.
                     int bufferSize = digPos;                            // The length of the result buffer string.
                     int groupSize = 0;                                  // The current group size.
@@ -3583,7 +3582,6 @@ private static unsafe void FormatFixed<TChar>(
 
             if (nMaxDigits > 0)
             {
-                Debug.Assert(sDecimal != null);
                 vlb.Append(sDecimal);
                 if ((digPos < 0) && (nMaxDigits > 0))
                 {

src/libraries/System.Security.Cryptography/src/System/Security/Cryptography/HashProviderCng.cs

@@ -39,7 +39,7 @@ internal HashProviderCng(string hashAlgId, ReadOnlySpan<byte> key, bool isHmac)
             // So keep hHash trapped in this scope to prevent (mis-)use of it.
             {
                 SafeBCryptHashHandle hHash;
-                NTSTATUS ntStatus = Interop.BCrypt.BCryptCreateHash(_hAlgorithm, out hHash, IntPtr.Zero, 0, key, key == null ? 0 : key.Length, BCryptCreateHashFlags.BCRYPT_HASH_REUSABLE_FLAG);
+                NTSTATUS ntStatus = Interop.BCrypt.BCryptCreateHash(_hAlgorithm, out hHash, IntPtr.Zero, 0, key, key.Length, BCryptCreateHashFlags.BCRYPT_HASH_REUSABLE_FLAG);
                 if (ntStatus == NTSTATUS.STATUS_INVALID_PARAMETER)
                 {
                     hHash.Dispose();

src/libraries/System.Security.Cryptography/src/System/Security/Cryptography/X509Certificates/CertificateRequest.cs

@@ -812,7 +812,7 @@ public X509Certificate2 Create(
 
             if (notAfter < notBefore)
                 throw new ArgumentException(SR.Cryptography_CertReq_DatesReversed);
-            if (serialNumber == null || serialNumber.Length < 1)
+            if (serialNumber.Length < 1)
                 throw new ArgumentException(SR.Arg_EmptyOrNullArray, nameof(serialNumber));
 
             byte[] signatureAlgorithm = generator.GetSignatureAlgorithmIdentifier(HashAlgorithm);

src/libraries/System.Security.Cryptography/src/System/Security/Cryptography/X509Certificates/X500NameEncoder.cs

@@ -444,7 +444,6 @@ private static List<byte[]> ParseDistinguishedName(
                 // then some whitespace.
                 case ParseState.MaybeEndQuote:
                 case ParseState.SeekComma:
-                    Debug.Assert(tagOid != null);
                     Debug.Assert(valueStart != -1);
                     Debug.Assert(valueEnd != -1);
 

src/libraries/System.Text.Json/src/System/Text/Json/Document/JsonDocument.Parse.cs

@@ -165,8 +165,6 @@ internal static JsonDocument ParseValue(Stream utf8Json, JsonDocumentOptions opt
 
         internal static JsonDocument ParseValue(ReadOnlySpan<byte> utf8Json, JsonDocumentOptions options)
         {
-            Debug.Assert(utf8Json != null);
-
             byte[] owned = new byte[utf8Json.Length];
             utf8Json.CopyTo(owned);