Some improvements to core classes

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

@@ -7,7 +7,7 @@
 namespace System.Reactive
 {
     /// <summary>
-    /// Class to create an <see cref="IObservable{T}"/> instance from a delegate-based implementation of the Subscribe method.
+    /// Class to create an <see cref="IObservable{T}"/> instance from a delegate-based implementation of the <see cref="IObservable{T}.Subscribe(IObserver{T})"/> method.
     /// </summary>
     /// <typeparam name="T">The type of the elements in the sequence.</typeparam>
     public sealed class AnonymousObservable<T> : ObservableBase<T>
@@ -17,8 +17,8 @@ public sealed class AnonymousObservable<T> : ObservableBase<T>
         /// <summary>
         /// Creates an observable sequence object from the specified subscription function.
         /// </summary>
-        /// <param name="subscribe">Subscribe method implementation.</param>
-        /// <exception cref="ArgumentNullException"><paramref name="subscribe"/> is null.</exception>
+        /// <param name="subscribe"><see cref="IObservable{T}.Subscribe(IObserver{T})"/> method implementation.</param>
+        /// <exception cref="ArgumentNullException"><paramref name="subscribe"/> is <c>null</c>.</exception>
         public AnonymousObservable(Func<IObserver<T>, IDisposable> subscribe)
         {
             if (subscribe == null)

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

@@ -15,12 +15,12 @@ public sealed class AnonymousObserver<T> : ObserverBase<T>
         private readonly Action _onCompleted;
 
         /// <summary>
-        /// Creates an observer from the specified OnNext, OnError, and OnCompleted actions.
+        /// Creates an observer from the specified <see cref="IObserver{T}.OnNext(T)"/>, <see cref="IObserver{T}.OnError(Exception)"/>, and <see cref="IObserver{T}.OnCompleted()"/> actions.
         /// </summary>
-        /// <param name="onNext">Observer's OnNext action implementation.</param>
-        /// <param name="onError">Observer's OnError action implementation.</param>
-        /// <param name="onCompleted">Observer's OnCompleted action implementation.</param>
-        /// <exception cref="ArgumentNullException"><paramref name="onNext"/> or <paramref name="onError"/> or <paramref name="onCompleted"/> is null.</exception>
+        /// <param name="onNext">Observer's <see cref="IObserver{T}.OnNext(T)"/> action implementation.</param>
+        /// <param name="onError">Observer's <see cref="IObserver{T}.OnError(Exception)"/> action implementation.</param>
+        /// <param name="onCompleted">Observer's <see cref="IObserver{T}.OnCompleted()"/> action implementation.</param>
+        /// <exception cref="ArgumentNullException"><paramref name="onNext"/> or <paramref name="onError"/> or <paramref name="onCompleted"/> is <c>null</c>.</exception>
         public AnonymousObserver(Action<T> onNext, Action<Exception> onError, Action onCompleted)
         {
             if (onNext == null)
@@ -36,66 +36,54 @@ public AnonymousObserver(Action<T> onNext, Action<Exception> onError, Action onC
         }
 
         /// <summary>
-        /// Creates an observer from the specified OnNext action.
+        /// Creates an observer from the specified <see cref="IObserver{T}.OnNext(T)"/> action.
         /// </summary>
-        /// <param name="onNext">Observer's OnNext action implementation.</param>
-        /// <exception cref="ArgumentNullException"><paramref name="onNext"/> is null.</exception>
+        /// <param name="onNext">Observer's <see cref="IObserver{T}.OnNext(T)"/> action implementation.</param>
+        /// <exception cref="ArgumentNullException"><paramref name="onNext"/> is <c>null</c>.</exception>
         public AnonymousObserver(Action<T> onNext)
             : this(onNext, Stubs.Throw, Stubs.Nop)
         {
         }
 
         /// <summary>
-        /// Creates an observer from the specified OnNext and OnError actions.
+        /// Creates an observer from the specified <see cref="IObserver{T}.OnNext(T)"/> and <see cref="IObserver{T}.OnError(Exception)"/> actions.
         /// </summary>
-        /// <param name="onNext">Observer's OnNext action implementation.</param>
-        /// <param name="onError">Observer's OnError action implementation.</param>
-        /// <exception cref="ArgumentNullException"><paramref name="onNext"/> or <paramref name="onError"/> is null.</exception>
+        /// <param name="onNext">Observer's <see cref="IObserver{T}.OnNext(T)"/> action implementation.</param>
+        /// <param name="onError">Observer's <see cref="IObserver{T}.OnError(Exception)"/> action implementation.</param>
+        /// <exception cref="ArgumentNullException"><paramref name="onNext"/> or <paramref name="onError"/> is <c>null</c>.</exception>
         public AnonymousObserver(Action<T> onNext, Action<Exception> onError)
             : this(onNext, onError, Stubs.Nop)
         {
         }
 
         /// <summary>
-        /// Creates an observer from the specified OnNext and OnCompleted actions.
+        /// Creates an observer from the specified <see cref="IObserver{T}.OnNext(T)"/> and <see cref="IObserver{T}.OnCompleted()"/> actions.
         /// </summary>
-        /// <param name="onNext">Observer's OnNext action implementation.</param>
-        /// <param name="onCompleted">Observer's OnCompleted action implementation.</param>
-        /// <exception cref="ArgumentNullException"><paramref name="onNext"/> or <paramref name="onCompleted"/> is null.</exception>
+        /// <param name="onNext">Observer's <see cref="IObserver{T}.OnNext(T)"/> action implementation.</param>
+        /// <param name="onCompleted">Observer's <see cref="IObserver{T}.OnCompleted()"/> action implementation.</param>
+        /// <exception cref="ArgumentNullException"><paramref name="onNext"/> or <paramref name="onCompleted"/> is <c>null</c>.</exception>
         public AnonymousObserver(Action<T> onNext, Action onCompleted)
             : this(onNext, Stubs.Throw, onCompleted)
         {
         }
 
         /// <summary>
-        /// Calls the onNext action.
+        /// Calls the action implementing <see cref="IObserver{T}.OnNext(T)"/>.
         /// </summary>
         /// <param name="value">Next element in the sequence.</param>
-        protected override void OnNextCore(T value)
-        {
-            _onNext(value);
-        }
+        protected override void OnNextCore(T value) => _onNext(value);
 
         /// <summary>
-        /// Calls the onError action.
+        /// Calls the action implementing <see cref="IObserver{T}.OnError(Exception)"/>.
         /// </summary>
         /// <param name="error">The error that has occurred.</param>
-        protected override void OnErrorCore(Exception error)
-        {
-            _onError(error);
-        }
+        protected override void OnErrorCore(Exception error) => _onError(error);
 
         /// <summary>
-        /// Calls the onCompleted action.
+        /// Calls the action implementing <see cref="IObserver{T}.OnCompleted()"/>.
         /// </summary>
-        protected override void OnCompletedCore()
-        {
-            _onCompleted();
-        }
+        protected override void OnCompletedCore() => _onCompleted();
 
-        internal IObserver<T> MakeSafe(IDisposable disposable)
-        {
-            return new AnonymousSafeObserver<T>(_onNext, _onError, _onCompleted, disposable);
-        }
+        internal IObserver<T> MakeSafe(IDisposable disposable) => new AnonymousSafeObserver<T>(_onNext, _onError, _onCompleted, disposable);
     }
 }

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

@@ -18,7 +18,7 @@ namespace System.Reactive
     /// that accept delegates for the On* handlers. By doing the fusion, we make the call stack depth shorter which
     /// helps debugging and some performance.
     /// </summary>
-    class AnonymousSafeObserver<T> : IObserver<T>
+    internal sealed class AnonymousSafeObserver<T> : IObserver<T>
     {
         private readonly Action<T> _onNext;
         private readonly Action<Exception> _onError;

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

@@ -7,8 +7,8 @@ namespace System.Reactive.PlatformServices
     /// <summary>
     /// Provides access to the platform enlightenments used by other Rx libraries to improve system performance and
     /// runtime efficiency. While Rx can run without platform enlightenments loaded, it's recommended to deploy the
-    /// System.Reactive.PlatformServices assembly with your application and call <see cref="EnlightenmentProvider.
-    /// EnsureLoaded"/> during application startup to ensure enlightenments are properly loaded.
+    /// System.Reactive.PlatformServices assembly with your application and call <see cref="EnsureLoaded"/> during
+    /// application startup to ensure enlightenments are properly loaded.
     /// </summary>
     public static class EnlightenmentProvider
     {

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

@@ -58,9 +58,9 @@ public EventPattern(TSender sender, TEventArgs e)
         /// <returns><c>true</c> if both <see cref="EventPattern{TSender, TEventArgs}"/> objects represent the same event; otherwise, <c>false</c>.</returns>
         public bool Equals(EventPattern<TSender, TEventArgs> other)
         {
-            if (object.ReferenceEquals(null, other))
+            if (ReferenceEquals(null, other))
                 return false;
-            if (object.ReferenceEquals(this, other))
+            if (ReferenceEquals(this, other))
                 return true;
 
             return EqualityComparer<TSender>.Default.Equals(Sender, other.Sender) && EqualityComparer<TEventArgs>.Default.Equals(EventArgs, other.EventArgs);
@@ -71,10 +71,7 @@ public bool Equals(EventPattern<TSender, TEventArgs> other)
         /// </summary>
         /// <param name="obj">The System.Object to compare with the current <see cref="EventPattern{TSender, TEventArgs}"/>.</param>
         /// <returns><c>true</c> if the specified System.Object is equal to the current <see cref="EventPattern{TSender, TEventArgs}"/>; otherwise, <c>false</c>.</returns>
-        public override bool Equals(object obj)
-        {
-            return Equals(obj as EventPattern<TSender, TEventArgs>);
-        }
+        public override bool Equals(object obj) => Equals(obj as EventPattern<TSender, TEventArgs>);
 
         /// <summary>
         /// Returns the hash code for the current <see cref="EventPattern{TSender, TEventArgs}"/> instance.
@@ -93,20 +90,14 @@ public override int GetHashCode()
         /// <param name="first">The first <see cref="EventPattern{TSender, TEventArgs}"/> to compare, or <c>null</c>.</param>
         /// <param name="second">The second <see cref="EventPattern{TSender, TEventArgs}"/> to compare, or <c>null</c>.</param>
         /// <returns><c>true</c> if both <see cref="EventPattern{TSender, TEventArgs}"/> objects represent the same event; otherwise, <c>false</c>.</returns>
-        public static bool operator ==(EventPattern<TSender, TEventArgs> first, EventPattern<TSender, TEventArgs> second)
-        {
-            return object.Equals(first, second);
-        }
+        public static bool operator ==(EventPattern<TSender, TEventArgs> first, EventPattern<TSender, TEventArgs> second) => Equals(first, second);
 
         /// <summary>
         /// Determines whether two specified <see cref="EventPattern{TSender, TEventArgs}"/> objects represent a different event.
         /// </summary>
         /// <param name="first">The first <see cref="EventPattern{TSender, TEventArgs}"/> to compare, or <c>null</c>.</param>
         /// <param name="second">The second <see cref="EventPattern{TSender, TEventArgs}"/> to compare, or <c>null</c>.</param>
         /// <returns><c>true</c> if both <see cref="EventPattern{TSender, TEventArgs}"/> objects don't represent the same event; otherwise, <c>false</c>.</returns>
-        public static bool operator !=(EventPattern<TSender, TEventArgs> first, EventPattern<TSender, TEventArgs> second)
-        {
-            return !object.Equals(first, second);
-        }
+        public static bool operator !=(EventPattern<TSender, TEventArgs> first, EventPattern<TSender, TEventArgs> second) => !Equals(first, second);
     }
 }

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

@@ -4,7 +4,7 @@
 
 namespace System.Reactive
 {
-    class EventPatternSource<TEventArgs> : EventPatternSourceBase<object, TEventArgs>, IEventPatternSource<TEventArgs>
+    internal sealed class EventPatternSource<TEventArgs> : EventPatternSourceBase<object, TEventArgs>, IEventPatternSource<TEventArgs>
     {
         public EventPatternSource(IObservable<EventPattern<object, TEventArgs>> source, Action<Action<object, TEventArgs>, /*object,*/ EventPattern<object, TEventArgs>> invokeHandler)
             : base(source, invokeHandler)

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

@@ -24,7 +24,7 @@ public abstract class EventPatternSourceBase<TSender, TEventArgs>
         /// </summary>
         /// <param name="source">Source sequence to expose as an event.</param>
         /// <param name="invokeHandler">Delegate used to invoke the event for each element of the sequence.</param>
-        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="invokeHandler"/> is null.</exception>
+        /// <exception cref="ArgumentNullException"><paramref name="source"/> or <paramref name="invokeHandler"/> is <c>null</c>.</exception>
         protected EventPatternSourceBase(IObservable<EventPattern<TSender, TEventArgs>> source, Action<Action<TSender, TEventArgs>, /*object,*/ EventPattern<TSender, TEventArgs>> invokeHandler)
         {
             if (source == null)
@@ -40,9 +40,9 @@ protected EventPatternSourceBase(IObservable<EventPattern<TSender, TEventArgs>>
         /// <summary>
         /// Adds the specified event handler, causing a subscription to the underlying source.
         /// </summary>
-        /// <param name="handler">Event handler to add. The same delegate should be passed to the Remove operation in order to remove the event handler.</param>
+        /// <param name="handler">Event handler to add. The same delegate should be passed to the <see cref="Remove(Delegate)"/> operation in order to remove the event handler.</param>
         /// <param name="invoke">Invocation delegate to raise the event in the derived class.</param>
-        /// <exception cref="ArgumentNullException"><paramref name="handler"/> or <paramref name="invoke"/> is null.</exception>
+        /// <exception cref="ArgumentNullException"><paramref name="handler"/> or <paramref name="invoke"/> is <c>null</c>.</exception>
         protected void Add(Delegate handler, Action<TSender, TEventArgs> invoke)
         {
             if (handler == null)
@@ -59,9 +59,13 @@ protected void Add(Delegate handler, Action<TSender, TEventArgs> invoke)
                 lock (gate)
                 {
                     if (isAdded)
+                    {
                         Remove(handler);
+                    }
                     else
+                    {
                         isDone = true;
+                    }
                 }
             });
 
@@ -90,17 +94,19 @@ private void Add(Delegate handler, IDisposable disposable)
             {
                 var l = new Stack<IDisposable>();
                 if (!_subscriptions.TryGetValue(handler, out l))
+                {
                     _subscriptions[handler] = l = new Stack<IDisposable>();
+                }
 
                 l.Push(disposable);
             }
         }
 
         /// <summary>
-        /// Removes the specified event handler, causing a disposal of the corresponding subscription to the underlying source that was created during the Add operation.
+        /// Removes the specified event handler, causing a disposal of the corresponding subscription to the underlying source that was created during the <see cref="Add(Delegate, Action{TSender, TEventArgs})"/> operation.
         /// </summary>
-        /// <param name="handler">Event handler to remove. This should be the same delegate as one that was passed to the Add operation.</param>
-        /// <exception cref="ArgumentNullException"><paramref name="handler"/> is null.</exception>
+        /// <param name="handler">Event handler to remove. This should be the same delegate as one that was passed to the <see cref="Add(Delegate, Action{TSender, TEventArgs})"/> operation.</param>
+        /// <exception cref="ArgumentNullException"><paramref name="handler"/> is <c>null</c>.</exception>
         protected void Remove(Delegate handler)
         {
             if (handler == null)
@@ -114,13 +120,15 @@ protected void Remove(Delegate handler)
                 if (_subscriptions.TryGetValue(handler, out l))
                 {
                     d = l.Pop();
+
                     if (l.Count == 0)
+                    {
                         _subscriptions.Remove(handler);
+                    }
                 }
             }
 
-            if (d != null)
-                d.Dispose();
+            d?.Dispose();
         }
     }
 }

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

@@ -6,7 +6,7 @@
 
 namespace System.Reactive
 {
-    class EventSource<T> : IEventSource<T>
+    internal sealed class EventSource<T> : IEventSource<T>
     {
         private readonly IObservable<T> _source;
         private readonly Dictionary<Delegate, Stack<IDisposable>> _subscriptions;
@@ -32,9 +32,13 @@ public event Action<T> OnNext
                     lock (gate)
                     {
                         if (isAdded)
+                        {
                             Remove(value);
+                        }
                         else
+                        {
                             isDone = true;
+                        }
                     }
                 });
 
@@ -69,7 +73,9 @@ private void Add(Delegate handler, IDisposable disposable)
             {
                 var l = new Stack<IDisposable>();
                 if (!_subscriptions.TryGetValue(handler, out l))
+                {
                     _subscriptions[handler] = l = new Stack<IDisposable>();
+                }
 
                 l.Push(disposable);
             }
@@ -85,13 +91,15 @@ private void Remove(Delegate handler)
                 if (_subscriptions.TryGetValue(handler, out l))
                 {
                     d = l.Pop();
+
                     if (l.Count == 0)
+                    {
                         _subscriptions.Remove(handler);
+                    }
                 }
             }
 
-            if (d != null)
-                d.Dispose();
+            d?.Dispose();
         }
     }
 }

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

@@ -12,4 +12,4 @@ internal sealed class ExcludeFromCodeCoverageAttribute : Attribute
     }
 }
 
-#endif
+#endif