Delete some dead code (#68333)

Author: stephentoub

src/libraries/Microsoft.CSharp/src/Microsoft/CSharp/RuntimeBinder/Semantics/WithType.cs

@@ -171,14 +171,6 @@ public PropWithType(SymWithType swt)
         }
     }
 
-    internal sealed class EventWithType : SymWithType
-    {
-        public EventWithType(EventSymbol @event, AggregateType ats)
-        {
-            Set(@event, ats);
-        }
-    }
-
     internal sealed class FieldWithType : SymWithType
     {
         public FieldWithType(FieldSymbol field, AggregateType ats)

src/libraries/System.Data.Common/src/System/Data/Filter/FilterException.cs

@@ -52,10 +52,8 @@ public SyntaxErrorException(string? s) : base(s) { }
         public SyntaxErrorException(string? message, Exception? innerException) : base(message, innerException) { }
     }
 
-    internal sealed class ExprException
+    internal static class ExprException
     {
-        private ExprException() { /* prevent utility class from being insantiated*/ }
-
         private static OverflowException _Overflow(string error)
         {
             OverflowException e = new OverflowException(error);

src/libraries/System.Data.Common/src/System/Data/Filter/Operators.cs

@@ -3,10 +3,8 @@
 
 namespace System.Data
 {
-    internal sealed class Operators
+    internal static class Operators
     {
-        private Operators() { /* prevent utility class from being insantiated*/ }
-
         internal const int Noop = 0;
 
         /* Unary operations */

src/libraries/System.Data.Common/src/System/Data/XmlKeywords.cs

@@ -3,10 +3,8 @@
 
 namespace System.Data
 {
-    internal sealed class Keywords
+    internal static class Keywords
     {
-        private Keywords() { /* prevent utility class from being insantiated*/ }
-
         // Keywords for DataSet Namespace
         internal const string DFF = "diffgr";
         internal const string DFFNS = "urn:schemas-microsoft-com:xml-diffgram-v1";

src/libraries/System.Data.Odbc/src/System/Data/Odbc/OdbcEnvironment.cs

@@ -5,13 +5,11 @@
 
 namespace System.Data.Odbc
 {
-    internal sealed class OdbcEnvironment
+    internal static class OdbcEnvironment
     {
         private static object? s_globalEnvironmentHandle;
         private static readonly object s_globalEnvironmentHandleLock = new object();
 
-        private OdbcEnvironment() { }  // default const.
-
         internal static OdbcEnvironmentHandle GetGlobalEnvironmentHandle()
         {
             OdbcEnvironmentHandle? globalEnvironmentHandle = s_globalEnvironmentHandle as OdbcEnvironmentHandle;

src/libraries/System.Net.Security/src/System/Net/NTAuthentication.cs

@@ -88,34 +88,6 @@ internal bool IsNTLM
             }
         }
 
-        private sealed class InitializeCallbackContext
-        {
-            internal InitializeCallbackContext(NTAuthentication thisPtr, bool isServer, string package, NetworkCredential credential, string spn, ContextFlagsPal requestedContextFlags, ChannelBinding channelBinding)
-            {
-                ThisPtr = thisPtr;
-                IsServer = isServer;
-                Package = package;
-                Credential = credential;
-                Spn = spn;
-                RequestedContextFlags = requestedContextFlags;
-                ChannelBinding = channelBinding;
-            }
-
-            internal readonly NTAuthentication ThisPtr;
-            internal readonly bool IsServer;
-            internal readonly string Package;
-            internal readonly NetworkCredential Credential;
-            internal readonly string Spn;
-            internal readonly ContextFlagsPal RequestedContextFlags;
-            internal readonly ChannelBinding ChannelBinding;
-        }
-
-        private static void InitializeCallback(object state)
-        {
-            InitializeCallbackContext context = (InitializeCallbackContext)state;
-            context.ThisPtr.Initialize(context.IsServer, context.Package, context.Credential, context.Spn, context.RequestedContextFlags, context.ChannelBinding);
-        }
-
         internal int Encrypt(ReadOnlySpan<byte> buffer, [NotNull] ref byte[]? output, uint sequenceNumber)
         {
             return NegotiateStreamPal.Encrypt(

src/libraries/System.Net.Sockets/src/System/Net/Sockets/Socket.Tasks.cs

@@ -884,21 +884,6 @@ private void DisposeCachedTaskSocketAsyncEventArgs()
             Interlocked.Exchange(ref _singleBufferSendEventArgs, null)?.Dispose();
         }
 
-        /// <summary>A TaskCompletionSource that carries an extra field of strongly-typed state.</summary>
-        private sealed class StateTaskCompletionSource<TField1, TResult> : TaskCompletionSource<TResult>
-        {
-            internal TField1 _field1 = default!; // always set on construction
-            public StateTaskCompletionSource(object baseState) : base(baseState) { }
-        }
-
-        /// <summary>A TaskCompletionSource that carries several extra fields of strongly-typed state.</summary>
-        private sealed class StateTaskCompletionSource<TField1, TField2, TResult> : TaskCompletionSource<TResult>
-        {
-            internal TField1 _field1 = default!; // always set on construction
-            internal TField2 _field2 = default!; // always set on construction
-            public StateTaskCompletionSource(object baseState) : base(baseState) { }
-        }
-
         /// <summary>A SocketAsyncEventArgs with an associated async method builder.</summary>
         private sealed class TaskSocketAsyncEventArgs<TResult> : SocketAsyncEventArgs
         {

src/libraries/System.Private.Xml/src/System.Private.Xml.csproj

@@ -702,7 +702,6 @@
     <Compile Include="System\Xml\Xsl\XsltOld\CopyNamespacesAction.cs" />
     <Compile Include="System\Xml\Xsl\XsltOld\CopyNodeSetAction.cs" />
     <Compile Include="System\Xml\Xsl\XsltOld\CopyOfAction.cs" />
-    <Compile Include="System\Xml\Xsl\XsltOld\DbgCompiler.cs" />
     <Compile Include="System\Xml\Xsl\XsltOld\DocumentScope.cs" />
     <Compile Include="System\Xml\Xsl\XsltOld\ElementAction.cs" />
     <Compile Include="System\Xml\Xsl\XsltOld\EndEvent.cs" />

src/libraries/System.Private.Xml/src/System/Xml/Xsl/XsltOld/ApplyTemplatesAction.cs

@@ -63,14 +63,7 @@ internal override bool CompileAttribute(Compiler compiler)
             else if (Ref.Equal(name, compiler.Atoms.Mode))
             {
                 Debug.Assert(_mode == null);
-                if (compiler.AllowBuiltInMode && value == "*")
-                {
-                    _mode = Compiler.BuiltInMode;
-                }
-                else
-                {
-                    _mode = compiler.CreateXPathQName(value);
-                }
+                _mode = compiler.CreateXPathQName(value);
             }
             else
             {

src/libraries/System.Private.Xml/src/System/Xml/Xsl/XsltOld/Compiler.cs

@@ -91,7 +91,6 @@ internal class Compiler
         private int _rtfCount;
 
         // Used to load Built In templates
-        public bool AllowBuiltInMode;
         public static XmlQualifiedName BuiltInMode = new XmlQualifiedName("*", string.Empty);
 
         internal KeywordsTable Atoms