Address a few minor IDE warnings.

Ix.NET/Source/Benchmarks.System.Interactive/Program.cs

@@ -10,7 +10,7 @@ namespace Benchmarks.System.Interactive
 {
     internal class Program
     {
-        internal static void Main(string[] args)
+        internal static void Main()
         {
             Console.WriteLine("Effective Ix-version: " + typeof(EnumerableEx).Assembly.GetName().Version);
 

Ix.NET/Source/System.Interactive.Async.Providers.Tests/AssertEx.cs

@@ -36,7 +36,7 @@ namespace Tests
             }
             catch (AggregateException ex)
             {
-                var inner = ex.Flatten().InnerException;
+                _ = ex.Flatten().InnerException;
 
                 // TODO: proper assert; unfortunately there's not always a good call stack
             }

Ix.NET/Source/System.Interactive.Async.Tests/System/Linq/Operators/Never.cs

@@ -2,7 +2,6 @@
 // The .NET Foundation licenses this file to you under the Apache 2.0 License.
 // See the LICENSE file in the project root for more information. 
 
-using System;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
@@ -25,7 +24,7 @@ namespace Tests
         [Fact]
         public async Task CancelToken_UnblocksAsync()
         {
-            var cts = new CancellationTokenSource();
+            using var cts = new CancellationTokenSource();
 
             var en = AsyncEnumerableEx.Never<int>().GetAsyncEnumerator(cts.Token);
 

Ix.NET/Source/System.Interactive.Tests/AssertEx.cs

@@ -42,7 +42,7 @@ namespace Tests
             }
             catch (AggregateException ex)
             {
-                var inner = ex.Flatten().InnerException;
+                _ = ex.Flatten().InnerException;
 
                 // TODO: proper assert; unfortunately there's not always a good call stack
             }

Ix.NET/Source/System.Interactive.Tests/System/Linq/Operators/Publish.cs

@@ -162,7 +162,7 @@ namespace Tests
             AssertThrows<MyException>(() => e2.MoveNext());
         }
 
-        class MyException : Exception
+        private class MyException : Exception
         {
         }
 

Ix.NET/Source/System.Interactive/System/Linq/Operators/IgnoreElements.cs

@@ -24,7 +24,7 @@ namespace System.Linq
 
         private static IEnumerable<TSource> IgnoreElementsCore<TSource>(IEnumerable<TSource> source)
         {
-            foreach (var item in source)
+            foreach (var _ in source)
                 ;
 
             yield break;

Ix.NET/Source/System.Linq.Async.Queryable.Tests/AssertEx.cs

@@ -36,7 +36,7 @@ namespace Tests
             }
             catch (AggregateException ex)
             {
-                var inner = ex.Flatten().InnerException;
+                _ = ex.Flatten().InnerException;
 
                 // TODO: proper assert; unfortunately there's not always a good call stack
             }

Ix.NET/Source/System.Linq.Async.Tests/System/Linq/Operators/ToAsyncEnumerable.cs

@@ -286,7 +286,7 @@ namespace Tests
         [Fact]
         public async Task ToAsyncEnumerable_Observable_Dispose()
         {
-            var stop = new ManualResetEvent(false);
+            using var stop = new ManualResetEvent(false);
 
             var xs = new MyObservable<int>(obs =>
             {
@@ -320,9 +320,9 @@ namespace Tests
         [Fact]
         public async Task ToAsyncEnumerable_Observable_Zip()
         {
-            var subCount = 0;
+            using var stop = new ManualResetEvent(false);
 
-            var stop = new ManualResetEvent(false);
+            var subCount = 0;
 
             var xs = new MyObservable<int>(obs =>
             {
@@ -360,7 +360,7 @@ namespace Tests
         [Fact]
         public async Task ToAsyncEnumerable_Observable_Cancel()
         {
-            var stop = new ManualResetEvent(false);
+            using var stop = new ManualResetEvent(false);
 
             var xs = new MyObservable<int>(obs =>
             {
@@ -380,7 +380,7 @@ namespace Tests
                 return new MyDisposable(cts.Cancel);
             }).ToAsyncEnumerable();
 
-            var c = new CancellationTokenSource();
+            using var c = new CancellationTokenSource();
 
             var e = xs.GetAsyncEnumerator(c.Token);
 
@@ -396,7 +396,7 @@ namespace Tests
         [Fact]
         public async Task ToAsyncEnumerable_Observable6_Async()
         {
-            var stop = new ManualResetEvent(false);
+            using var stop = new ManualResetEvent(false);
 
             var xs = new MyObservable<int>(obs =>
             {

Ix.NET/Source/System.Linq.Async.Tests/System/Linq/Operators/ToObservable.cs

@@ -22,8 +22,9 @@ namespace Tests
         [Fact]
         public void ToObservable1()
         {
+            using var evt = new ManualResetEvent(false);
+
             var fail = false;
-            var evt = new ManualResetEvent(false);
 
             var xs = AsyncEnumerable.Empty<int>().ToObservable();
             xs.Subscribe(new MyObserver<int>(
@@ -49,9 +50,10 @@ namespace Tests
         [Fact]
         public void ToObservable2()
         {
+            using var evt = new ManualResetEvent(false);
+
             var lst = new List<int>();
             var fail = false;
-            var evt = new ManualResetEvent(false);
 
             var xs = Return42.ToObservable();
             xs.Subscribe(new MyObserver<int>(
@@ -78,9 +80,10 @@ namespace Tests
         [Fact]
         public void ToObservable3()
         {
+            using var evt = new ManualResetEvent(false);
+
             var lst = new List<int>();
             var fail = false;
-            var evt = new ManualResetEvent(false);
 
             var xs = AsyncEnumerable.Range(0, 10).ToObservable();
             xs.Subscribe(new MyObserver<int>(
@@ -107,10 +110,11 @@ namespace Tests
         [Fact]
         public void ToObservable4()
         {
+            using var evt = new ManualResetEvent(false);
+
             var ex1 = new Exception("Bang!");
             var ex_ = default(Exception);
             var fail = false;
-            var evt = new ManualResetEvent(false);
 
             var xs = Throw<int>(ex1).ToObservable();
             xs.Subscribe(new MyObserver<int>(
@@ -138,8 +142,9 @@ namespace Tests
         [Fact]
         public void ToObservable_DisposesEnumeratorOnCompletion()
         {
+            using var evt = new ManualResetEvent(false);
+
             var fail = false;
-            var evt = new ManualResetEvent(false);
 
             var ae = AsyncEnumerable.Create(
                 _ => AsyncEnumerator.Create<int>(
@@ -170,8 +175,9 @@ namespace Tests
         [Fact]
         public void ToObservable_DisposesEnumeratorWhenSubscriptionIsDisposed()
         {
+            using var evt = new ManualResetEvent(false);
+
             var fail = false;
-            var evt = new ManualResetEvent(false);
             var subscription = default(IDisposable);
             var subscriptionAssignedTcs = new TaskCompletionSource<object>();
 
@@ -216,9 +222,10 @@ namespace Tests
         [Fact]
         public void ToObservable_DesNotCallMoveNextAgainWhenSubscriptionIsDisposed()
         {
+            using var evt = new ManualResetEvent(false);
+
             var fail = false;
             var moveNextCount = 0;
-            var evt = new ManualResetEvent(false);
             var subscription = default(IDisposable);
             var subscriptionAssignedTcs = new TaskCompletionSource<object>();