Fixing a handful of warnings that showed up since the upgrade to .NET Core 2 (#411)

src/Microsoft.SqlTools.Hosting/Hosting/IHostedService.cs

@@ -67,13 +67,13 @@ namespace Microsoft.SqlTools.Hosting
             }
         }
 
-        protected async Task<T> HandleRequestAsync<T>(Func<Task<T>> handler, RequestContext<T> requestContext, string requestType)
+        protected async Task<THandler> HandleRequestAsync<THandler>(Func<Task<THandler>> handler, RequestContext<THandler> requestContext, string requestType)
         {
             Logger.Write(LogLevel.Verbose, requestType);
 
             try
             {
-                T result = await handler();
+                THandler result = await handler();
                 await requestContext.SendResult(result);
                 return result;
             }
@@ -81,7 +81,7 @@ namespace Microsoft.SqlTools.Hosting
             {
                 await requestContext.SendError(ex.ToString());
             }
-            return default(T);
+            return default(THandler);
         }
 
         public abstract void InitializeService(IProtocolEndpoint serviceHost);

src/Microsoft.SqlTools.Hosting/Hosting/ServiceHostBase.cs

@@ -12,7 +12,6 @@ namespace Microsoft.SqlTools.Hosting
 {
     public abstract class ServiceHostBase : ProtocolEndpoint
     {
-        private bool isStarted;
         private TaskCompletionSource<bool> serverExitedTask;
 
         protected ServiceHostBase(ChannelBase serverChannel) : 
@@ -25,6 +24,7 @@ namespace Microsoft.SqlTools.Hosting
             // Register handlers for server lifetime messages
             
             this.SetEventHandler(ExitNotification.Type, this.HandleExitNotification);
+            this.serverExitedTask = new TaskCompletionSource<bool>();
 
             return Task.FromResult(true);
         }

src/Microsoft.SqlTools.ServiceLayer/Admin/Common/ICloneable.cs

@@ -1,12 +0,0 @@
-//
-// Copyright (c) Microsoft. All rights reserved.
-// Licensed under the MIT license. See LICENSE file in the project root for full license information.
-//
-
-namespace System
-{
-    internal interface ICloneable
-    {
-        object Clone();
-    }
-}

src/Microsoft.SqlTools.ServiceLayer/QueryExecution/ResultOnlyContext.cs

@@ -21,10 +21,11 @@ namespace Microsoft.SqlTools.ServiceLayer.QueryExecution
             origContext = context;
         }
 
-        public virtual async Task SendEvent<TParams>(EventType<TParams> eventType, TParams eventParams)
+        public virtual Task SendEvent<TParams>(EventType<TParams> eventType, TParams eventParams)
         {
             // no op to swallow events
             // in the future this could be used to roll up events and send them back in the result
+            return Task.FromResult(true);
         }
     }
 }

test/Microsoft.SqlTools.ServiceLayer.IntegrationTests/Connection/ReliableConnectionTests.cs

@@ -933,8 +933,7 @@ namespace Microsoft.SqlTools.ServiceLayer.IntegrationTests.Connection
         [Fact]
         public void StatementCompletedTests()
         {
-            bool handlerCalled = false;
+            StatementCompletedEventHandler handler = (s, e) => { }; 
-            StatementCompletedEventHandler handler = (s, e) => handlerCalled = true; 
             var command = new DbCommandWrapper(new SqlCommand());
             command.StatementCompleted += handler;
             command.StatementCompleted -= handler;