Update remaining ArgumentNullException to use extension method

.editorconfig

@@ -509,6 +509,8 @@ dotnet_diagnostic.RCS1190.severity=error
 dotnet_diagnostic.RCS1195.severity=error
 dotnet_diagnostic.RCS1214.severity=error
 
+dotnet_diagnostic.IDE1006.severity=none
+
 # C++ Files
 [*.{cpp,h,in}]
 curly_bracket_next_line = true

src/DynamicData/Cache/PageResponse.cs

@@ -42,7 +42,7 @@ public override bool Equals(object? obj)
             return false;
         }
 
-        if (!(obj is IPageResponse pageResponse))
+        if (obj is not IPageResponse pageResponse)
         {
             return false;
         }

src/DynamicData/Cache/PagedChangeSet.cs

@@ -12,7 +12,7 @@ internal sealed class PagedChangeSet<TObject, TKey> : ChangeSet<TObject, TKey>,
     where TObject : notnull
     where TKey : notnull
 {
-    public static readonly new IPagedChangeSet<TObject, TKey> Empty = new PagedChangeSet<TObject, TKey>();
+    public static new readonly IPagedChangeSet<TObject, TKey> Empty = new PagedChangeSet<TObject, TKey>();
 
     public PagedChangeSet(IKeyValueCollection<TObject, TKey> sortedItems, IEnumerable<Change<TObject, TKey>> updates, IPageResponse response)
         : base(updates)

src/DynamicData/Cache/SortedChangeSet.cs

@@ -11,7 +11,7 @@ internal class SortedChangeSet<TObject, TKey> : ChangeSet<TObject, TKey>, ISorte
     where TObject : notnull
     where TKey : notnull
 {
-    public static readonly new ISortedChangeSet<TObject, TKey> Empty = new SortedChangeSet<TObject, TKey>();
+    public static new readonly ISortedChangeSet<TObject, TKey> Empty = new SortedChangeSet<TObject, TKey>();
 
     public SortedChangeSet(IKeyValueCollection<TObject, TKey> sortedItems, IEnumerable<Change<TObject, TKey>> updates)
         : base(updates) => SortedItems = sortedItems;

src/DynamicData/Cache/SourceCacheEx.cs

@@ -23,13 +23,5 @@ public static class SourceCacheEx
     public static IObservable<IChangeSet<TDestination, TKey>> Cast<TSource, TKey, TDestination>(this IObservableCache<TSource, TKey> source, Func<TSource, TDestination> converter)
         where TSource : notnull
         where TKey : notnull
-        where TDestination : notnull
-    {
-        if (source is null)
-        {
-            throw new ArgumentNullException(nameof(source));
-        }
-
-        return source.Connect().Cast(converter);
-    }
+        where TDestination : notnull => source is null ? throw new ArgumentNullException(nameof(source)) : source.Connect().Cast(converter);
 }

src/DynamicData/Cache/VirtualChangeSet.cs

@@ -11,7 +11,7 @@ internal sealed class VirtualChangeSet<TObject, TKey> : ChangeSet<TObject, TKey>
     where TObject : notnull
     where TKey : notnull
 {
-    public static readonly new IVirtualChangeSet<TObject, TKey> Empty = new VirtualChangeSet<TObject, TKey>();
+    public static new readonly IVirtualChangeSet<TObject, TKey> Empty = new VirtualChangeSet<TObject, TKey>();
 
     public VirtualChangeSet(IEnumerable<Change<TObject, TKey>> items, IKeyValueCollection<TObject, TKey> sortedItems, IVirtualResponse response)
         : base(items)

src/DynamicData/Diagnostics/DiagnosticOperators.cs

@@ -23,10 +23,7 @@ public static IObservable<ChangeSummary> CollectUpdateStats<TSource, TKey>(this
         where TSource : notnull
         where TKey : notnull
     {
-        if (source is null)
-        {
-            throw new ArgumentNullException(nameof(source));
-        }
+        source.ThrowArgumentNullExceptionIfNull(nameof(source));
 
         return source.Scan(
             ChangeSummary.Empty,
@@ -56,10 +53,7 @@ public static IObservable<ChangeSummary> CollectUpdateStats<TSource, TKey>(this
     public static IObservable<ChangeSummary> CollectUpdateStats<TSource>(this IObservable<IChangeSet<TSource>> source)
         where TSource : notnull
     {
-        if (source is null)
-        {
-            throw new ArgumentNullException(nameof(source));
-        }
+        source.ThrowArgumentNullExceptionIfNull(nameof(source));
 
         return source.Scan(
             ChangeSummary.Empty,

src/DynamicData/EnumerableEx.cs

@@ -30,21 +30,8 @@ public static IObservable<IChangeSet<TObject, TKey>> AsObservableChangeSet<TObje
         where TObject : notnull
         where TKey : notnull
     {
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(source);
-
-        ArgumentNullException.ThrowIfNull(keySelector);
-#else
-        if (source is null)
-        {
-            throw new ArgumentNullException(nameof(source));
-        }
-
-        if (keySelector is null)
-        {
-            throw new ArgumentNullException(nameof(keySelector));
-        }
-#endif
+        source.ThrowArgumentNullExceptionIfNull(nameof(source));
+        keySelector.ThrowArgumentNullExceptionIfNull(nameof(keySelector));
 
         return Observable.Create<IChangeSet<TObject, TKey>>(
             obs =>
@@ -73,14 +60,7 @@ public static IObservable<IChangeSet<TObject, TKey>> AsObservableChangeSet<TObje
     public static IObservable<IChangeSet<TObject>> AsObservableChangeSet<TObject>(this IEnumerable<TObject> source, bool completable = false)
         where TObject : notnull
     {
-#if NET6_0_OR_GREATER
-        ArgumentNullException.ThrowIfNull(source);
-#else
-        if (source is null)
-        {
-            throw new ArgumentNullException(nameof(source));
-        }
-#endif
+        source.ThrowArgumentNullExceptionIfNull(nameof(source));
 
         return Observable.Create<IChangeSet<TObject>>(
             obs =>

src/DynamicData/Experimental/ExperimentalEx.cs

@@ -24,10 +24,7 @@ public static IWatcher<TObject, TKey> AsWatcher<TObject, TKey>(this IObservable<
         where TObject : notnull
         where TKey : notnull
     {
-        if (source is null)
-        {
-            throw new ArgumentNullException(nameof(source));
-        }
+        source.ThrowArgumentNullExceptionIfNull(nameof(source));
 
         return new Watcher<TObject, TKey>(source, scheduler ?? Scheduler.Default);
     }

src/DynamicData/Kernel/EnumerableEx.cs

@@ -17,10 +17,7 @@ public static class EnumerableEx
     /// <returns>The array of items.</returns>
     public static T[] AsArray<T>(this IEnumerable<T> source)
     {
-        if (source is null)
-        {
-            throw new ArgumentNullException(nameof(source));
-        }
+        source.ThrowArgumentNullExceptionIfNull(nameof(source));
 
         return source as T[] ?? source.ToArray();
     }
@@ -33,10 +30,7 @@ public static T[] AsArray<T>(this IEnumerable<T> source)
     /// <returns>The list.</returns>
     public static List<T> AsList<T>(this IEnumerable<T> source)
     {
-        if (source is null)
-        {
-            throw new ArgumentNullException(nameof(source));
-        }
+        source.ThrowArgumentNullExceptionIfNull(nameof(source));
 
         return source as List<T> ?? source.ToList();
     }
@@ -51,15 +45,8 @@ public static List<T> AsList<T>(this IEnumerable<T> source)
     /// <returns>The enumerable of items.</returns>
     public static IEnumerable<T> Duplicates<T, TValue>(this IEnumerable<T> source, Func<T, TValue> valueSelector)
     {
-        if (source is null)
-        {
-            throw new ArgumentNullException(nameof(source));
-        }
-
-        if (valueSelector is null)
-        {
-            throw new ArgumentNullException(nameof(valueSelector));
-        }
+        source.ThrowArgumentNullExceptionIfNull(nameof(source));
+        valueSelector.ThrowArgumentNullExceptionIfNull(nameof(valueSelector));
 
         return source.GroupBy(valueSelector).Where(group => group.Count() > 1).SelectMany(t => t);
     }
@@ -86,20 +73,9 @@ public static IEnumerable<T> Duplicates<T, TValue>(this IEnumerable<T> source, F
     /// <returns>A result as specified by the result selector.</returns>
     public static IEnumerable<TResult> IndexOfMany<TObject, TResult>(this IEnumerable<TObject> source, IEnumerable<TObject> itemsToFind, Func<TObject, int, TResult> resultSelector)
     {
-        if (source is null)
-        {
-            throw new ArgumentNullException(nameof(source));
-        }
-
-        if (itemsToFind is null)
-        {
-            throw new ArgumentNullException(nameof(itemsToFind));
-        }
-
-        if (resultSelector is null)
-        {
-            throw new ArgumentNullException(nameof(resultSelector));
-        }
+        source.ThrowArgumentNullExceptionIfNull(nameof(source));
+        itemsToFind.ThrowArgumentNullExceptionIfNull(nameof(itemsToFind));
+        resultSelector.ThrowArgumentNullExceptionIfNull(nameof(resultSelector));
 
         var indexed = source.Select((element, index) => new { Element = element, Index = index });
         return itemsToFind.Join(indexed, left => left, right => right.Element, (_, right) => right).Select(x => resultSelector(x.Element, x.Index));

src/DynamicData/Kernel/EnumeratorIList.cs

@@ -8,14 +8,13 @@
 // Lifted from here /~https://github.com/benaadams/Ben.Enumerable. Many thanks to the genius of the man.
 namespace DynamicData.Kernel;
 
-[SuppressMessage("StyleCop.CSharp.MaintainabilityRules", "SA1402:File may only contain a single type", Justification = "Same class name, different generics.")]
 internal struct EnumeratorIList<T>(IList<T> list) : IEnumerator<T>
 {
     private int _index = -1;
 
-    public T Current => list[_index];
+    public readonly T Current => list[_index];
 
-    object? IEnumerator.Current => Current;
+    readonly object? IEnumerator.Current => Current;
 
     public bool MoveNext()
     {

src/DynamicData/Kernel/Error.cs

@@ -2,8 +2,6 @@
 // Roland Pheasant licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for full license information.
 
-#pragma warning disable 1591
-
 namespace DynamicData.Kernel;
 
 /// <summary>
@@ -17,6 +15,7 @@ namespace DynamicData.Kernel;
 /// <param name="exception">The exception that caused the error.</param>
 /// <param name="value">The value for the error.</param>
 /// <param name="key">The key for the error.</param>
+[System.Diagnostics.CodeAnalysis.SuppressMessage("Naming", "CA1716:Identifiers should not match keywords", Justification = "By Design.")]
 public sealed class Error<TObject, TKey>(Exception? exception, TObject value, TKey key) : IKeyValue<TObject, TKey>, IEquatable<Error<TObject, TKey>>
     where TKey : notnull
 {
@@ -78,7 +77,7 @@ public override int GetHashCode()
         {
             var hashCode = EqualityComparer<TKey>.Default.GetHashCode(Key);
             hashCode = (hashCode * 397) ^ (Value is null ? 0 : EqualityComparer<TObject>.Default.GetHashCode(Value));
-            hashCode = (hashCode * 397) ^ (Exception is not null ? Exception.GetHashCode() : 0);
+            hashCode = (hashCode * 397) ^ (Exception?.GetHashCode() ?? 0);
             return hashCode;
         }
     }

src/DynamicData/Kernel/InternalEx.cs

@@ -78,10 +78,7 @@ public static IDisposable ScheduleRecurringAction(this IScheduler scheduler, Tim
     /// <returns>A disposable that will stop the schedule.</returns>
     public static IDisposable ScheduleRecurringAction(this IScheduler scheduler, Func<TimeSpan> interval, Action action)
     {
-        if (interval is null)
-        {
-            throw new ArgumentNullException(nameof(interval));
-        }
+        interval.ThrowArgumentNullExceptionIfNull(nameof(interval));
 
         return scheduler.Schedule(
             interval(),
@@ -95,12 +92,7 @@ public static IDisposable ScheduleRecurringAction(this IScheduler scheduler, Fun
 
     internal static void OnNext(this ISubject<Unit> source) => source.OnNext(Unit.Default);
 
-    internal static void Swap<TSwap>(ref TSwap t1, ref TSwap t2)
-    {
-        var temp = t1;
-        t1 = t2;
-        t2 = temp;
-    }
+    internal static void Swap<TSwap>(ref TSwap t1, ref TSwap t2) => (t2, t1) = (t1, t2);
 
     internal static IObservable<Unit> ToUnit<T>(this IObservable<T> source) => source.Select(_ => Unit.Default);
 

src/DynamicData/Kernel/OptionElse.cs

@@ -22,10 +22,7 @@ public sealed class OptionElse
     /// <exception cref="ArgumentNullException">action.</exception>
     public void Else(Action action)
     {
-        if (action is null)
-        {
-            throw new ArgumentNullException(nameof(action));
-        }
+        action.ThrowArgumentNullExceptionIfNull(nameof(action));
 
         if (_shouldRunAction)
         {