Fix minor compiler warnings

NRefactory/ICSharpCode.NRefactory.CSharp/Refactoring/CodeIssues/OptionalParameterCouldBeSkippedIssue.cs

@@ -84,7 +84,6 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 				});
 				var issueMessage = ctx.TranslateString("Argument is identical to the default value");
 				var lastPositionalArgument = redundantArguments.FirstOrDefault(expression => !(expression is NamedArgumentExpression));
-				bool hasNamedArguments = false;
 
 				foreach (var argument in redundantArguments) {
 					var localArgument = argument;
@@ -100,7 +99,6 @@ namespace ICSharpCode.NRefactory.CSharp.Refactoring
 							var newInvocation = generateReplacement(node, newArgumentList);
 							script.Replace(node, newInvocation);
 						}));
-						hasNamedArguments = true;
 					} else {
 						var title = ctx.TranslateString("Remove this and the following positional arguments");
 						actions.Add(new CodeAction(title, script => {

NRefactory/ICSharpCode.NRefactory.VB/Visitors/CSharpToVBConverterVisitor.cs

@@ -800,7 +800,7 @@ namespace ICSharpCode.NRefactory.VB.Visitors
 			
 			throw new NotImplementedException();
 			
-			return EndNode(queryGroupClause, op);
+			//return EndNode(queryGroupClause, op);
 		}
 		
 		public AstNode VisitAttribute(CSharp.Attribute attribute, object data)

NRefactory/ICSharpCode.NRefactory/TypeSystem/CecilLoader.cs

@@ -87,6 +87,7 @@ namespace ICSharpCode.NRefactory.TypeSystem
 		/// Warning: if delay-loading is used and the type system is accessed by multiple threads,
 		/// the callback may be invoked concurrently on multiple threads.
 		/// </remarks>
+		[CLSCompliant(false)]
 		public Action<IUnresolvedEntity, MemberReference> OnEntityLoaded { get; set; }
 		
 		/// <summary>