Prevent diagnostics on .NET SDK 8.0.100 (#2049)

Address collection expression diagnostics

In most cases, we now just use the new (C# 12.0) collection expression syntax. However, we've disabled IDE0305 because it makes suggestions that aren't an obvious improvement. It wants to rewrite use of ToArray() to be a collection expression. E.g. something.ToArray() would become [.. something]. Perhaps that will seem natural once we've all got used to spreads in collection expressions, but to me (idg10) today that looks odd.

Add comment explaining why we've disable IDE0290

Make UWP test runner use the same warning settings as everything else, except for CS0618, which a large number of tests appear to depend on.

Author: idg10

Rx.NET/Source/Directory.build.props

@@ -61,7 +61,7 @@
     <EnableNETAnalyzers>true</EnableNETAnalyzers>
 
     <!--
-    Disable diagnostics:
+    Disabled diagnostics:
     CA1001 - types holding disposable fields should implement IDisposable. See next item.
     CA2213 - IDisposable types should Dispose any IDisposable fields. This rule finds over 600
                 examples! These are all in subtle multithreaded or async code. Some of them appear
@@ -74,9 +74,21 @@
 
     IDE0056 - Use of index/range syntax - relevant types not available on all targets, so we can't
     IDE0057     do this.
+
+    IDE0290 - Primary ctors. This diagnostic suggests them in a lot of places where we don't want
+                them. E.g., in most types with multiple constructors I find I prefer not to have
+                a primary ctor. Since this is all or nothing, we turn it off.
+    IDE0305 - Suggests Collection expressions in place of .ToArray. E.g, wants to change this:
+                  _readyList.ToArray()
+              to this:
+                  [.. readyList]
+              This won't improve performance as far as we know (sometimes a reason for using that
+              syntax), and it's not obviously an improvement in readability.
+
+    CA1510 - use ArgumentNullException.ThrowIf (not available on all targets)
+    CA1513 - use ObjectDisposedException.ThrowIf (not available on all targets)
     -->
-    <!-- Get diagnostics back to the level that the .NET 5.0 SDK had for now. Fix these properly before release. -->
-    <NoWarn>$(NoWarn);CA1001;CA2213;IDE0056;IDE0057</NoWarn>
+    <NoWarn>$(NoWarn);CA1001;CA2213;CA1510;CA1513;IDE0056;IDE0057;IDE0290;IDE0305</NoWarn>
   </PropertyGroup>
 
   <ItemGroup>

Rx.NET/Source/src/Microsoft.Reactive.Testing/ColdObservable.cs

@@ -13,7 +13,7 @@ internal class ColdObservable<T> : ITestableObservable<T>
     {
         private readonly TestScheduler _scheduler;
         private readonly Recorded<Notification<T>>[] _messages;
-        private readonly List<Subscription> _subscriptions = new();
+        private readonly List<Subscription> _subscriptions = [];
 
         public ColdObservable(TestScheduler scheduler, params Recorded<Notification<T>>[] messages)
         {

Rx.NET/Source/src/Microsoft.Reactive.Testing/HotObservable.cs

@@ -12,8 +12,8 @@ namespace Microsoft.Reactive.Testing
     internal class HotObservable<T> : ITestableObservable<T>
     {
         private readonly TestScheduler _scheduler;
-        private readonly List<IObserver<T>> _observers = new();
-        private readonly List<Subscription> _subscriptions = new();
+        private readonly List<IObserver<T>> _observers = [];
+        private readonly List<Subscription> _subscriptions = [];
         private readonly Recorded<Notification<T>>[] _messages;
 
         public HotObservable(TestScheduler scheduler, params Recorded<Notification<T>>[] messages)

Rx.NET/Source/src/Microsoft.Reactive.Testing/MockObserver.cs

@@ -11,12 +11,11 @@ namespace Microsoft.Reactive.Testing
     internal class MockObserver<T> : ITestableObserver<T>
     {
         private readonly TestScheduler _scheduler;
-        private readonly List<Recorded<Notification<T>>> _messages;
+        private readonly List<Recorded<Notification<T>>> _messages = [];
 
         public MockObserver(TestScheduler scheduler)
         {
             _scheduler = scheduler ?? throw new ArgumentNullException(nameof(scheduler));
-            _messages = new List<Recorded<Notification<T>>>();
         }
 
         public void OnNext(T value)

Rx.NET/Source/src/System.Reactive/Concurrency/LocalScheduler.TimerQueue.cs

@@ -55,7 +55,7 @@ public partial class LocalScheduler
         /// Set of disposable handles to all of the current short term work Schedule calls,
         /// allowing those to be cancelled upon a system clock change.
         /// </summary>
-        private readonly HashSet<IDisposable> _shortTermWork = new();
+        private readonly HashSet<IDisposable> _shortTermWork = [];
 
         /// <summary>
         /// Threshold where an item is considered to be short term work or gets moved from

Rx.NET/Source/src/System.Reactive/Concurrency/Scheduler.Recursive.cs

@@ -175,12 +175,11 @@ private abstract class InvokeRecBaseState : IDisposable
         {
             protected readonly IScheduler Scheduler;
 
-            protected readonly CompositeDisposable Group;
+            protected readonly CompositeDisposable Group = [];
 
             protected InvokeRecBaseState(IScheduler scheduler)
             {
                 Scheduler = scheduler;
-                Group = new CompositeDisposable();
             }
 
             public void Dispose()

Rx.NET/Source/src/System.Reactive/Concurrency/Scheduler.Services.cs

@@ -10,12 +10,13 @@ namespace System.Reactive.Concurrency
     //
     public static partial class Scheduler
     {
-        internal static Type[] Optimizations = {
+        internal static Type[] Optimizations =
+        [
             typeof(ISchedulerLongRunning),
             typeof(IStopwatchProvider),
             typeof(ISchedulerPeriodic)
             /* update this list if new interface-based optimizations are added */
-        };
+        ];
 
         /// <summary>
         /// Returns the <see cref="ISchedulerLongRunning"/> implementation of the specified scheduler, or <c>null</c> if no such implementation is available.

Rx.NET/Source/src/System.Reactive/Concurrency/SchedulerWrapper.cs

@@ -9,12 +9,16 @@ namespace System.Reactive.Concurrency
     internal abstract class SchedulerWrapper : IScheduler, IServiceProvider
     {
         protected readonly IScheduler _scheduler;
-        private readonly ConditionalWeakTable<IScheduler, IScheduler> _cache;
+        private readonly ConditionalWeakTable<IScheduler, IScheduler> _cache =
+#if NET472_OR_GREATER || NETSTANDARD2_0_OR_GREATER
+            new();
+#else
+            [];
+#endif
 
         protected SchedulerWrapper(IScheduler scheduler)
         {
             _scheduler = scheduler;
-            _cache = new ConditionalWeakTable<IScheduler, IScheduler>();
         }
 
         protected SchedulerWrapper(IScheduler scheduler, ConditionalWeakTable<IScheduler, IScheduler> cache)

Rx.NET/Source/src/System.Reactive/Diagnostics/CodeAnalysis/NullableAttributes.cs

@@ -96,7 +96,7 @@ internal sealed class MemberNotNullAttribute : Attribute
         /// The field or property member that is promised to be not-null.
         /// </param>
 #pragma warning disable CA1019 // Define accessors for attribute arguments - this needs to be identical to the real type
-        public MemberNotNullAttribute(string member) => Members = new[] { member };
+        public MemberNotNullAttribute(string member) => Members = [member];
 #pragma warning restore CA1019
 
         /// <summary>Initializes the attribute with the list of field and property members.</summary>
@@ -125,7 +125,7 @@ public MemberNotNullWhenAttribute(bool returnValue, string member)
 #pragma warning restore CA1019
         {
             ReturnValue = returnValue;
-            Members = new[] { member };
+            Members = [member];
         }
 
         /// <summary>Initializes the attribute with the specified return value condition and list of field and property members.</summary>

Rx.NET/Source/src/System.Reactive/Disposables/CompositeDisposable.cs

@@ -29,7 +29,7 @@ public sealed class CompositeDisposable : ICollection<IDisposable>, ICancelable
         /// </summary>
         public CompositeDisposable()
         {
-            _disposables = new List<IDisposable?>();
+            _disposables = [];
         }
 
         /// <summary>
@@ -387,7 +387,7 @@ public IEnumerator<IDisposable> GetEnumerator()
         /// method to avoid allocation on disposed or empty composites.
         /// </summary>
         private static readonly CompositeEnumerator EmptyEnumerator =
-            new(Array.Empty<IDisposable?>());
+            new([]);
 
         /// <summary>
         /// An enumerator for an array of disposables.

Rx.NET/Source/src/System.Reactive/Disposables/SingleAssignmentDisposableValue.cs

@@ -50,10 +50,10 @@ public void Dispose()
         }
 
         /// <inheritdoc/>
-        public override bool Equals(object? obj) => false;
+        public override readonly bool Equals(object? obj) => false;
 
         /// <inheritdoc/>
-        public override int GetHashCode() => 0;
+        public override readonly int GetHashCode() => 0;
 
 #pragma warning disable IDE0060 // (Remove unused parameter.) Required part of public API
         public static bool operator ==(SingleAssignmentDisposableValue left, SingleAssignmentDisposableValue right) => false;

Rx.NET/Source/src/System.Reactive/EventPattern.cs

@@ -17,9 +17,7 @@ public class EventPattern<TEventArgs> : EventPattern<object, TEventArgs>
         /// </summary>
         /// <param name="sender">The sender object that raised the event.</param>
         /// <param name="e">The event data that was generated by the event.</param>
-#pragma warning disable CA2109 // (Consider making non-public.) This has long been part of the public API so we couldn't change this even if we wanted to.
         public EventPattern(object? sender, TEventArgs e)
-#pragma warning restore CA2109
             : base(sender, e)
         {
         }

Rx.NET/Source/src/System.Reactive/EventPatternSourceBase.cs

@@ -76,7 +76,7 @@ public void SetResource(IDisposable resource)
         }
 
         private readonly IObservable<EventPattern<TSender, TEventArgs>> _source;
-        private readonly Dictionary<Delegate, Stack<IDisposable>> _subscriptions;
+        private readonly Dictionary<Delegate, Stack<IDisposable>> _subscriptions = [];
         private readonly Action<Action<TSender?, TEventArgs>, /*object,*/ EventPattern<TSender, TEventArgs>> _invokeHandler;
 
         /// <summary>
@@ -89,7 +89,6 @@ protected EventPatternSourceBase(IObservable<EventPattern<TSender, TEventArgs>>
         {
             _source = source ?? throw new ArgumentNullException(nameof(source));
             _invokeHandler = invokeHandler ?? throw new ArgumentNullException(nameof(invokeHandler));
-            _subscriptions = new Dictionary<Delegate, Stack<IDisposable>>();
         }
 
         /// <summary>

Rx.NET/Source/src/System.Reactive/EventSource.cs

@@ -9,14 +9,13 @@ namespace System.Reactive
     internal sealed class EventSource<T> : IEventSource<T>
     {
         private readonly IObservable<T> _source;
-        private readonly Dictionary<Delegate, Stack<IDisposable>> _subscriptions;
+        private readonly Dictionary<Delegate, Stack<IDisposable>> _subscriptions = [];
         private readonly Action<Action<T>, /*object,*/ T> _invokeHandler;
 
         public EventSource(IObservable<T> source, Action<Action<T>, /*object,*/ T> invokeHandler)
         {
             _source = source;
             _invokeHandler = invokeHandler;
-            _subscriptions = new Dictionary<Delegate, Stack<IDisposable>>();
         }
 
         public event Action<T> OnNext

Rx.NET/Source/src/System.Reactive/Internal/ImmutableList.cs

@@ -10,7 +10,7 @@ internal sealed class ImmutableList<T>
 
         private readonly T[] _data;
 
-        private ImmutableList() => _data = Array.Empty<T>();
+        private ImmutableList() => _data = [];
 
         public ImmutableList(T[] data) => _data = data;
 

Rx.NET/Source/src/System.Reactive/Internal/Lookup.cs

@@ -23,7 +23,7 @@ public void Add(K key, E element)
         {
             if (!_dictionary.TryGetValue(key, out var list))
             {
-                _dictionary[key] = list = new List<E>();
+                _dictionary[key] = list = [];
             }
 
             list.Add(element);

Rx.NET/Source/src/System.Reactive/Internal/SystemClock.cs

@@ -21,7 +21,7 @@ public static class SystemClock
     {
         private static readonly Lazy<ISystemClock> ServiceSystemClock = new(InitializeSystemClock);
         private static readonly Lazy<INotifySystemClockChanged> ServiceSystemClockChanged = new(InitializeSystemClockChanged);
-        internal static readonly HashSet<WeakReference<LocalScheduler>> SystemClockChanged = new();
+        internal static readonly HashSet<WeakReference<LocalScheduler>> SystemClockChanged = [];
         private static IDisposable? _systemClockChangedHandlerCollector;
 
         private static int _refCount;
@@ -123,7 +123,7 @@ private static void CollectHandlers()
                 {
                     if (!handler.TryGetTarget(out _))
                     {
-                        remove ??= new HashSet<WeakReference<LocalScheduler>>();
+                        remove ??= [];
 
                         remove.Add(handler);
                     }

Rx.NET/Source/src/System.Reactive/Joins/ActivePlan.cs

@@ -8,7 +8,7 @@ namespace System.Reactive.Joins
 {
     internal abstract class ActivePlan
     {
-        private readonly Dictionary<IJoinObserver, IJoinObserver> _joinObservers = new();
+        private readonly Dictionary<IJoinObserver, IJoinObserver> _joinObservers = [];
 
         protected readonly Action _onCompleted;
 

Rx.NET/Source/src/System.Reactive/Joins/JoinObserver.cs

@@ -19,7 +19,7 @@ internal sealed class JoinObserver<T> : ObserverBase<Notification<T>>, IJoinObse
         private object? _gate;
         private readonly IObservable<T> _source;
         private readonly Action<Exception> _onError;
-        private readonly List<ActivePlan> _activePlans;
+        private readonly List<ActivePlan> _activePlans = [];
         private SingleAssignmentDisposableValue _subscription;
         private bool _isDisposed;
 
@@ -28,7 +28,6 @@ public JoinObserver(IObservable<T> source, Action<Exception> onError)
             _source = source;
             _onError = onError;
             Queue = new Queue<Notification<T>>();
-            _activePlans = new List<ActivePlan>();
         }
 
         public Queue<Notification<T>> Queue { get; }

Rx.NET/Source/src/System.Reactive/Linq/Observable/Buffer.cs

@@ -436,7 +436,7 @@ public TimeHopping(IObservable<TSource> source, TimeSpan timeSpan, IScheduler sc
             internal sealed class _ : Sink<TSource, IList<TSource>>
             {
                 private readonly object _gate = new();
-                private List<TSource> _list = new();
+                private List<TSource> _list = [];
 
                 public _(IObserver<IList<TSource>> observer)
                     : base(observer)
@@ -465,7 +465,7 @@ private void Tick()
                     lock (_gate)
                     {
                         ForwardOnNext(_list);
-                        _list = new List<TSource>();
+                        _list = [];
                     }
                 }
 
@@ -521,7 +521,7 @@ internal sealed class _ : Sink<TSource, IList<TSource>>
             {
                 private readonly Ferry _parent;
                 private readonly object _gate = new();
-                private List<TSource> _s = new();
+                private List<TSource> _s = [];
 
                 public _(Ferry parent, IObserver<IList<TSource>> observer)
                     : base(observer)
@@ -574,7 +574,7 @@ private void Tick(int id)
                         var newId = ++_windowId;
 
                         var res = _s;
-                        _s = new List<TSource>();
+                        _s = [];
                         ForwardOnNext(res);
 
                         CreateTimer(newId);
@@ -598,7 +598,7 @@ public override void OnNext(TSource value)
                             newId = ++_windowId;
 
                             var res = _s;
-                            _s = new List<TSource>();
+                            _s = [];
                             ForwardOnNext(res);
                         }
 
@@ -653,7 +653,7 @@ internal sealed class _ : Sink<TSource, IList<TSource>>
                 private readonly AsyncLock _bufferGate = new();
                 private readonly Func<IObservable<TBufferClosing>> _bufferClosingSelector;
 
-                private List<TSource> _buffer = new();
+                private List<TSource> _buffer = [];
                 private SerialDisposableValue _bufferClosingSerialDisposable;
 
                 public _(Selector parent, IObserver<IList<TSource>> observer)
@@ -706,7 +706,7 @@ private void CloseBuffer(IDisposable closingSubscription)
                     lock (_gate)
                     {
                         var res = _buffer;
-                        _buffer = new List<TSource>();
+                        _buffer = [];
                         ForwardOnNext(res);
                     }
 
@@ -785,7 +785,7 @@ internal sealed class _ : Sink<TSource, IList<TSource>>
             {
                 private readonly object _gate = new();
 
-                private List<TSource> _buffer = new();
+                private List<TSource> _buffer = [];
                 private SingleAssignmentDisposableValue _boundariesDisposable;
 
                 public _(IObserver<IList<TSource>> observer)
@@ -823,7 +823,7 @@ public void OnNext(TBufferClosing value)
                         lock (_parent._gate)
                         {
                             var res = _parent._buffer;
-                            _parent._buffer = new List<TSource>();
+                            _parent._buffer = [];
                             _parent.ForwardOnNext(res);
                         }
                     }

Rx.NET/Source/src/System.Reactive/Linq/Observable/Delay.cs

@@ -597,7 +597,7 @@ protected Base(IObservable<TSource> source)
 
             internal abstract class _ : IdentitySink<TSource>
             {
-                private readonly CompositeDisposable _delays = new();
+                private readonly CompositeDisposable _delays = [];
                 private readonly object _gate = new();
 
                 private readonly Func<TSource, IObservable<TDelay>> _delaySelector;

Rx.NET/Source/src/System.Reactive/Linq/Observable/FromEventPattern.cs

@@ -142,7 +142,7 @@ private Action AddHandlerCore(Delegate handler)
             private Action AddHandlerCoreWinRT(Delegate handler)
             {
                 var token = _addMethod.Invoke(_target, new object[] { handler });
-                return () => _removeMethod.Invoke(_target, new[] { token });
+                return () => _removeMethod.Invoke(_target, [token]);
             }
         }
     }

Rx.NET/Source/src/System.Reactive/Linq/Observable/GroupByUntil.cs

@@ -35,7 +35,7 @@ internal sealed class _ : Sink<TSource, IGroupedObservable<TKey, TElement>>
         {
             private readonly object _gate = new();
             private readonly object _nullGate = new();
-            private readonly CompositeDisposable _groupDisposable = new();
+            private readonly CompositeDisposable _groupDisposable = [];
             private readonly RefCountDisposable _refCountDisposable;
             private readonly Map<TKey, ISubject<TElement>> _map;