Remove some stale nullable suppressions / TODOs (#37978)

src/libraries/System.Drawing.Common/src/System/Drawing/ClientUtils.cs

@@ -112,8 +112,7 @@ public override bool Equals(object? obj)
                 {
                     if (InnerList[i] != other.InnerList[i])
                     {
-                        // TODO-NULLABLE: https://github.com/dotnet/roslyn/issues/34644
-                        if (InnerList[i] == null || !InnerList[i]!.Equals(other.InnerList[i]))
+                        if (InnerList[i] == null || !InnerList[i]!.Equals(other.InnerList[i])) // TODO-NULLABLE: https://github.com/dotnet/roslyn/issues/34644
                         {
                             return false;
                         }

src/libraries/System.Drawing.Common/src/System/Drawing/Printing/PrintingServices.Unix.cs

@@ -664,12 +664,10 @@ internal static void GetPrintDialogInfo(string printer, ref string port, ref str
                 NameValueCollection options = LoadPrinterOptions(cups_dests.options, cups_dests.num_options);
 
                 if (options["printer-state"] != null)
-                    // TODO-NULLABLE dotnet/roslyn#34644
-                    state = int.Parse(options["printer-state"]!);
+                    state = int.Parse(options["printer-state"]!); // TODO-NULLABLE dotnet/roslyn#34644
 
                 if (options["printer-comment"] != null)
-                    // TODO-NULLABLE dotnet/roslyn#34644
-                    comment = options["printer-state"]!;
+                    comment = options["printer-state"]!; // TODO-NULLABLE dotnet/roslyn#34644
 
                 switch (state)
                 {

src/libraries/System.Linq.Parallel/src/System/Linq/Parallel/Helpers.cs

@@ -68,7 +68,7 @@ public bool Remove(TElement value)
             int last = -1;
             for (int i = _buckets[bucket] - 1; i >= 0; last = i, i = _slots[i].next)
             {
-                if (_slots[i].hashCode == hashCode && _comparer.Equals(_slots[i].value!, value)) // TODO-NULLABLE: https://github.com/dotnet/csharplang/issues/2872
+                if (_slots[i].hashCode == hashCode && _comparer.Equals(_slots[i].value, value))
                 {
                     if (last < 0)
                     {
@@ -92,7 +92,7 @@ private bool Find(TElement value, bool add)
             int hashCode = InternalGetHashCode(value);
             for (int i = _buckets[hashCode % _buckets.Length] - 1; i >= 0; i = _slots[i].next)
             {
-                if (_slots[i].hashCode == hashCode && _comparer.Equals(_slots[i].value!, value)) return true; // TODO-NULLABLE: https://github.com/dotnet/csharplang/issues/2872
+                if (_slots[i].hashCode == hashCode && _comparer.Equals(_slots[i].value, value)) return true;
             }
             if (add)
             {

src/libraries/System.Linq.Parallel/src/System/Linq/Parallel/Merging/AsynchronousChannelMergeEnumerator.cs

@@ -33,7 +33,7 @@ internal sealed class AsynchronousChannelMergeEnumerator<T> : MergeEnumerator<T>
         private IntValueEvent? _consumerEvent; // The consumer event.
         private readonly bool[] _done;       // Tracks which channels are done.
         private int _channelIndex;  // The next channel from which we'll dequeue.
-        [MaybeNull, AllowNull] private T _currentElement = default;  // The remembered element from the previous MoveNext. TODO-NULLABLE: https://github.com/dotnet/roslyn/issues/37511
+        [MaybeNull, AllowNull] private T _currentElement = default;  // The remembered element from the previous MoveNext.
 
         //-----------------------------------------------------------------------------------
         // Allocates a new enumerator over a set of one-to-one channels.
@@ -99,7 +99,7 @@ public override bool MoveNext()
             }
 
             // Else try the fast path.
-            if (!_done[index] && _channels[index].TryDequeue(ref _currentElement!)) // TODO-NULLABLE: https://github.com/dotnet/csharplang/issues/2872
+            if (!_done[index] && _channels[index].TryDequeue(ref _currentElement))
             {
                 _channelIndex = (index + 1) % _channels.Length;
                 return true;
@@ -127,7 +127,7 @@ private bool MoveNextSlowPath()
                 AsynchronousChannel<T> current = _channels[currChannelIndex];
 
                 bool isDone = _done[currChannelIndex];
-                if (!isDone && current.TryDequeue(ref _currentElement!)) // TODO-NULLABLE: https://github.com/dotnet/csharplang/issues/2872
+                if (!isDone && current.TryDequeue(ref _currentElement))
                 {
                     // The channel has an item to be processed. We already remembered the current
                     // element (Dequeue stores it as an out-parameter), so we just return true
@@ -147,7 +147,7 @@ private bool MoveNextSlowPath()
                         // we still need to continue processing them.
                         if (!current.IsChunkBufferEmpty)
                         {
-                            bool dequeueResult = current.TryDequeue(ref _currentElement!); // TODO-NULLABLE: https://github.com/dotnet/csharplang/issues/2872
+                            bool dequeueResult = current.TryDequeue(ref _currentElement);
                             Debug.Assert(dequeueResult, "channel isn't empty, yet the dequeue failed, hmm");
                             return true;
                         }
@@ -192,7 +192,7 @@ private bool MoveNextSlowPath()
                             for (int i = 0; i < _channels.Length; i++)
                             {
                                 bool channelIsDone = false;
-                                if (!_done[i] && _channels[i].TryDequeue(ref _currentElement!, ref channelIsDone)) // TODO-NULLABLE: https://github.com/dotnet/csharplang/issues/2872
+                                if (!_done[i] && _channels[i].TryDequeue(ref _currentElement, ref channelIsDone))
                                 {
                                     // The channel has received an item since the last time we checked.
                                     // Just return and let the consumer process the element returned.

src/libraries/System.Memory/src/System/Buffers/ReadOnlySequence.cs

@@ -121,7 +121,7 @@ public ReadOnlySequence(T[] array)
             _startObject = array;
             _endObject = array;
             _startInteger = ReadOnlySequence.ArrayToSequenceStart(0);
-            _endInteger = ReadOnlySequence.ArrayToSequenceEnd(array!.Length); // TODO-NULLABLE: Remove ! when [DoesNotReturn] respected
+            _endInteger = ReadOnlySequence.ArrayToSequenceEnd(array.Length);
         }
 
         /// <summary>
@@ -146,9 +146,7 @@ public ReadOnlySequence(T[] array, int start, int length)
         /// </summary>
         public ReadOnlySequence(ReadOnlyMemory<T> memory)
         {
-#pragma warning disable CS8631 // TODO-NULLABLE: ILLink rewriter removing some necessary metadata (https://github.com/dotnet/corefx/pull/38983#issuecomment-506757237)
             if (MemoryMarshal.TryGetMemoryManager(memory, out MemoryManager<T>? manager, out int index, out int length))
-#pragma warning restore CS8631
             {
                 _startObject = manager;
                 _endObject = manager;

src/libraries/System.Memory/src/System/ThrowHelper.cs

@@ -2,8 +2,9 @@
 // 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.Runtime.CompilerServices;
 using System.Buffers;
+using System.Diagnostics.CodeAnalysis;
+using System.Runtime.CompilerServices;
 
 namespace System
 {
@@ -24,37 +25,45 @@ namespace System
 
     internal static class ThrowHelper
     {
+        [DoesNotReturn]
         internal static void ThrowArgumentNullException(ExceptionArgument argument) { throw CreateArgumentNullException(argument); }
         [MethodImpl(MethodImplOptions.NoInlining)]
         private static Exception CreateArgumentNullException(ExceptionArgument argument) { return new ArgumentNullException(argument.ToString()); }
 
+        [DoesNotReturn]
         internal static void ThrowArgumentOutOfRangeException(ExceptionArgument argument) { throw CreateArgumentOutOfRangeException(argument); }
         [MethodImpl(MethodImplOptions.NoInlining)]
         private static Exception CreateArgumentOutOfRangeException(ExceptionArgument argument) { return new ArgumentOutOfRangeException(argument.ToString()); }
 
+        [DoesNotReturn]
         internal static void ThrowInvalidOperationException() { throw CreateInvalidOperationException(); }
         [MethodImpl(MethodImplOptions.NoInlining)]
         private static Exception CreateInvalidOperationException() { return new InvalidOperationException(); }
 
+        [DoesNotReturn]
         internal static void ThrowInvalidOperationException_EndPositionNotReached() { throw CreateInvalidOperationException_EndPositionNotReached(); }
         [MethodImpl(MethodImplOptions.NoInlining)]
         private static Exception CreateInvalidOperationException_EndPositionNotReached() { return new InvalidOperationException(SR.EndPositionNotReached); }
 
+        [DoesNotReturn]
         internal static void ThrowArgumentOutOfRangeException_PositionOutOfRange() { throw CreateArgumentOutOfRangeException_PositionOutOfRange(); }
         [MethodImpl(MethodImplOptions.NoInlining)]
         private static Exception CreateArgumentOutOfRangeException_PositionOutOfRange() { return new ArgumentOutOfRangeException("position"); }
 
+        [DoesNotReturn]
         internal static void ThrowArgumentOutOfRangeException_OffsetOutOfRange() { throw CreateArgumentOutOfRangeException_OffsetOutOfRange(); }
         [MethodImpl(MethodImplOptions.NoInlining)]
         private static Exception CreateArgumentOutOfRangeException_OffsetOutOfRange() { return new ArgumentOutOfRangeException(nameof(ExceptionArgument.offset)); }
 
+        [DoesNotReturn]
         internal static void ThrowObjectDisposedException_ArrayMemoryPoolBuffer() { throw CreateObjectDisposedException_ArrayMemoryPoolBuffer(); }
         [MethodImpl(MethodImplOptions.NoInlining)]
         private static Exception CreateObjectDisposedException_ArrayMemoryPoolBuffer() { return new ObjectDisposedException("ArrayMemoryPoolBuffer"); }
 
         //
         // ReadOnlySequence .ctor validation Throws coalesced to enable inlining of the .ctor
         //
+        [DoesNotReturn]
         public static void ThrowArgumentValidationException<T>(ReadOnlySequenceSegment<T>? startSegment, int startIndex, ReadOnlySequenceSegment<T>? endSegment)
             => throw CreateArgumentValidationException(startSegment, startIndex, endSegment);
 
@@ -72,6 +81,7 @@ private static Exception CreateArgumentValidationException<T>(ReadOnlySequenceSe
                 return CreateArgumentOutOfRangeException(ExceptionArgument.endIndex);
         }
 
+        [DoesNotReturn]
         public static void ThrowArgumentValidationException(Array? array, int start)
             => throw CreateArgumentValidationException(array, start);
 
@@ -88,6 +98,7 @@ private static Exception CreateArgumentValidationException(Array? array, int sta
         //
         // ReadOnlySequence Slice validation Throws coalesced to enable inlining of the Slice
         //
+        [DoesNotReturn]
         public static void ThrowStartOrEndArgumentValidationException(long start)
             => throw CreateStartOrEndArgumentValidationException(start);
 

src/libraries/System.Private.Xml/src/System/Xml/Core/XmlSubtreeReader.cs

@@ -260,7 +260,6 @@ public override int AttributeCount
             {
                 if (name == _nsAttributes![i].name)
                 {
-                    // TODO-NULLABLE: https://github.com/dotnet/roslyn/issues/34644
                     return _nsAttributes[i].value;
                 }
             }
@@ -284,7 +283,6 @@ public override int AttributeCount
             {
                 if (name == _nsAttributes![i].localName && namespaceURI == _xmlnsUri)
                 {
-                    // TODO-NULLABLE: https://github.com/dotnet/roslyn/issues/34644
                     return _nsAttributes[i].value;
                 }
             }
@@ -1353,12 +1351,12 @@ private void RemoveNamespace(string prefix, string localName)
             for (int i = 0; i < _nsAttrCount; i++)
             {
                 if (Ref.Equal(prefix, _nsAttributes![i].prefix) &&
-                     Ref.Equal(localName, _nsAttributes![i].localName)) // TODO-NULLABLE: https://github.com/dotnet/roslyn/issues/34644
+                    Ref.Equal(localName, _nsAttributes[i].localName))
                 {
                     if (i < _nsAttrCount - 1)
                     {
                         // swap
-                        NodeData tmpNodeData = _nsAttributes![i]; // TODO-NULLABLE: https://github.com/dotnet/roslyn/issues/34644
+                        NodeData tmpNodeData = _nsAttributes[i];
                         _nsAttributes[i] = _nsAttributes[_nsAttrCount - 1];
                         _nsAttributes[_nsAttrCount - 1] = tmpNodeData;
                     }

src/libraries/System.Runtime/tests/System/NullableMetadataTests.cs

@@ -62,7 +62,7 @@ public static void NullableAttributesOnPublicApiOnly(Type type)
             {
                 // When using BindingFlags.NonPublic protected members are included and those are expected
                 // to have Nullable attributes.
-                if (internalMember.IsProtected() || internalMember is PropertyInfo) // TODO-NULLABLE: validate properties (https://github.com/dotnet/roslyn/issues/37161)
+                if (internalMember.IsProtected() || internalMember is PropertyInfo)
                     continue;
 
                 Assert.Empty(internalMember.CustomAttributes.GetNullableAttributes());

src/libraries/System.Threading.Channels/src/System/Threading/Channels/SingleConsumerUnboundedChannel.cs

@@ -32,13 +32,11 @@ internal sealed class SingleConsumerUnboundedChannel<T> : Channel<T>, IDebugEnum
         /// <summary>non-null if the channel has been marked as complete for writing.</summary>
         private volatile Exception? _doneWriting;
 
-#pragma warning disable CA1823 // TODO-NULLABLE: https://github.com/dotnet/roslyn/issues/38195
         /// <summary>An <see cref="AsyncOperation{T}"/> if there's a blocked reader.</summary>
         private AsyncOperation<T>? _blockedReader;
 
         /// <summary>A waiting reader (e.g. WaitForReadAsync) if there is one.</summary>
         private AsyncOperation<bool>? _waitingReader;
-#pragma warning restore CA1823
 
         /// <summary>Initialize the channel.</summary>
         /// <param name="runContinuationsAsynchronously">Whether to force continuations to be executed asynchronously.</param>

src/libraries/System.Threading.Tasks.Dataflow/src/Blocks/BatchBlock.cs

@@ -127,9 +127,7 @@ public IDisposable LinkTo(ITargetBlock<T[]> target, DataflowLinkOptions linkOpti
         }
 
         /// <include file='XmlDocs/CommonXmlDocComments.xml' path='CommonXmlDocComments/Sources/Member[@name="TryReceive"]/*' />
-#pragma warning disable CS8614 // TODO-NULLABLE: https://github.com/dotnet/roslyn/issues/42470
         public bool TryReceive(Predicate<T[]>? filter, [NotNullWhen(true)] out T[]? item)
-#pragma warning restore CS8614
         {
             return _source.TryReceive(filter, out item);
         }

src/libraries/System.Threading.Tasks.Dataflow/src/Blocks/BatchedJoinBlock.cs

@@ -132,9 +132,7 @@ public IDisposable LinkTo(ITargetBlock<Tuple<IList<T1>, IList<T2>>> target, Data
         }
 
         /// <include file='XmlDocs/CommonXmlDocComments.xml' path='CommonXmlDocComments/Sources/Member[@name="TryReceive"]/*' />
-#pragma warning disable CS8614 // TODO-NULLABLE: https://github.com/dotnet/roslyn/issues/42470
         public bool TryReceive(Predicate<Tuple<IList<T1>, IList<T2>>>? filter, [NotNullWhen(true)] out Tuple<IList<T1>, IList<T2>>? item)
-#pragma warning restore CS8614
         {
             return _source.TryReceive(filter, out item);
         }
@@ -396,9 +394,7 @@ public IDisposable LinkTo(ITargetBlock<Tuple<IList<T1>, IList<T2>, IList<T3>>> t
         }
 
         /// <include file='XmlDocs/CommonXmlDocComments.xml' path='CommonXmlDocComments/Sources/Member[@name="TryReceive"]/*' />
-#pragma warning disable CS8614 // TODO-NULLABLE: https://github.com/dotnet/roslyn/issues/42470
         public bool TryReceive(Predicate<Tuple<IList<T1>, IList<T2>, IList<T3>>>? filter, [NotNullWhen(true)] out Tuple<IList<T1>, IList<T2>, IList<T3>>? item)
-#pragma warning restore CS8614
         {
             return _source.TryReceive(filter, out item);
         }

src/libraries/System.Threading.Tasks.Dataflow/src/Blocks/JoinBlock.cs

@@ -117,9 +117,7 @@ public IDisposable LinkTo(ITargetBlock<Tuple<T1, T2>> target, DataflowLinkOption
         }
 
         /// <include file='XmlDocs/CommonXmlDocComments.xml' path='CommonXmlDocComments/Sources/Member[@name="TryReceive"]/*' />
-#pragma warning disable CS8614 // TODO-NULLABLE: https://github.com/dotnet/roslyn/issues/42470
         public bool TryReceive(Predicate<Tuple<T1, T2>>? filter, [NotNullWhen(true)] out Tuple<T1, T2>? item)
-#pragma warning restore CS8614
         {
             return _source.TryReceive(filter, out item);
         }
@@ -166,9 +164,7 @@ void IDataflowBlock.Fault(Exception exception)
         public ITargetBlock<T2> Target2 { get { return _target2; } }
 
         /// <include file='XmlDocs/CommonXmlDocComments.xml' path='CommonXmlDocComments/Sources/Member[@name="ConsumeMessage"]/*' />
-#pragma warning disable CS8616 // TODO-NULLABLE: https://github.com/dotnet/roslyn/issues/42470
         Tuple<T1, T2>? ISourceBlock<Tuple<T1, T2>>.ConsumeMessage(DataflowMessageHeader messageHeader, ITargetBlock<Tuple<T1, T2>> target, out bool messageConsumed)
-#pragma warning restore CS8616
         {
             return _source.ConsumeMessage(messageHeader, target, out messageConsumed);
         }
@@ -349,9 +345,7 @@ public IDisposable LinkTo(ITargetBlock<Tuple<T1, T2, T3>> target, DataflowLinkOp
         }
 
         /// <include file='XmlDocs/CommonXmlDocComments.xml' path='CommonXmlDocComments/Sources/Member[@name="TryReceive"]/*' />
-#pragma warning disable CS8614 // TODO-NULLABLE: https://github.com/dotnet/roslyn/issues/42470
         public bool TryReceive(Predicate<Tuple<T1, T2, T3>>? filter, [NotNullWhen(true)] out Tuple<T1, T2, T3>? item)
-#pragma warning restore CS8614
         {
             return _source.TryReceive(filter, out item);
         }
@@ -403,9 +397,7 @@ void IDataflowBlock.Fault(Exception exception)
         public ITargetBlock<T3> Target3 { get { return _target3; } }
 
         /// <include file='XmlDocs/CommonXmlDocComments.xml' path='CommonXmlDocComments/Sources/Member[@name="ConsumeMessage"]/*' />
-#pragma warning disable CS8616 // TODO-NULLABLE: https://github.com/dotnet/roslyn/issues/42470
         Tuple<T1, T2, T3>? ISourceBlock<Tuple<T1, T2, T3>>.ConsumeMessage(DataflowMessageHeader messageHeader, ITargetBlock<Tuple<T1, T2, T3>> target, out bool messageConsumed)
-#pragma warning restore CS8616
         {
             return _source.ConsumeMessage(messageHeader, target, out messageConsumed);
         }