Fix possible null de-reference

ILSpy/ExtensionMethods.cs

@@ -29,6 +29,8 @@ using ICSharpCode.Decompiler.Metadata;
 using ICSharpCode.Decompiler.TypeSystem;
 using ICSharpCode.ILSpyX;
 
+using TomsToolbox.Essentials;
+
 namespace ICSharpCode.ILSpy
 {
 	/// <summary>
@@ -124,9 +126,9 @@ namespace ICSharpCode.ILSpy
 				for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
 				{
 					DependencyObject child = VisualTreeHelper.GetChild(depObj, i);
-					if (child != null && child is T)
+					if (child is T dependencyObject)
 					{
-						return (T)child;
+						return dependencyObject;
 					}
 
 					T? childItem = FindVisualChild<T>(child);
@@ -177,17 +179,18 @@ namespace ICSharpCode.ILSpy
 				else
 					output.AppendLine("-------------------------------------------------");
 				output.AppendLine("Error(s) loading plugin: " + item.PluginName);
-				if (item.Exception is System.Reflection.ReflectionTypeLoadException)
+				if (item.Exception is System.Reflection.ReflectionTypeLoadException exception)
 				{
-					var e = (System.Reflection.ReflectionTypeLoadException)item.Exception;
-					foreach (var ex in e.LoaderExceptions)
+					foreach (var ex in exception.LoaderExceptions.ExceptNullItems())
 					{
 						output.AppendLine(ex.ToString());
 						output.AppendLine();
 					}
 				}
 				else
+				{
 					output.AppendLine(item.Exception.ToString());
+				}
 			}
 
 			return true;