fix SD-1888 - NullReferenceException in ExpressionNode.EvaluateExpression

src/AddIns/Debugger/Debugger.AddIn/Pads/Commands/WatchPadCommands.cs

@@ -3,9 +3,11 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Windows.Forms;
 
 using Debugger.AddIn.Pads;
+using Debugger.AddIn.Pads.Controls;
 using Debugger.AddIn.TreeModel;
 using ICSharpCode.Core;
 using ICSharpCode.Core.Presentation;
@@ -43,7 +45,7 @@ namespace Debugger.AddIn
 					                        language == "VB" || language == "VBNet" ? SupportedLanguage.VBNet : SupportedLanguage.CSharp).ToSharpTreeNode();
 					var list = pad.WatchList;
 					
-					if(!list.WatchItems.Contains(text))
+					if(!list.WatchItems.Any(n => text.Node.FullName == ((TreeNodeWrapper)n).Node.FullName))
 						list.WatchItems.Add(text);
 				}
 				

src/AddIns/Debugger/Debugger.AddIn/Pads/Controls/TreeNodeWrapper.cs

@@ -25,17 +25,6 @@ namespace Debugger.AddIn.Pads.Controls
 		
 		public TreeNode Node { get; private set; }
 		
-		public override bool Equals(object obj)
-		{
-			var w = obj as TreeNodeWrapper;
-			return w != null && Node.Equals(w.Node);
-		}
-		
-		public override int GetHashCode()
-		{
-			return Node.GetHashCode();
-		}
-		
 		public override object Text {
 			get { return Node.Name; }
 		}
@@ -82,7 +71,7 @@ namespace Debugger.AddIn.Pads.Controls
 			                             language == "VB" || language == "VBNet" ? SupportedLanguage.VBNet : SupportedLanguage.CSharp);
 
 			var node = text.ToSharpTreeNode();
-			if (!WatchPad.Instance.WatchList.WatchItems.Contains(node))
+			if (!WatchPad.Instance.WatchList.WatchItems.Any(n => text.FullName == ((TreeNodeWrapper)n).Node.FullName))
 				WatchPad.Instance.WatchList.WatchItems.Add(node);
 			
 			WatchPad.Instance.RefreshPad();

src/AddIns/Debugger/Debugger.AddIn/TreeModel/ExpressionNode.cs

@@ -77,8 +77,6 @@ namespace Debugger.AddIn.TreeModel
 		
 		public override string FullName {
 			get {
-				if (!evaluated) EvaluateExpression();
-				
 				return this.expression.PrettyPrint() ?? Name.Trim();
 			}
 		}
@@ -158,6 +156,7 @@ namespace Debugger.AddIn.TreeModel
 			Value val;
 			try {
 				var process = WindowsDebugger.DebuggedProcess;
+				if (process == null) return;
 				StackFrame frame = process.GetCurrentExecutingFrame();
 				if (frame == null) return;
 				var debugger = (WindowsDebugger)DebuggerService.CurrentDebugger;