Use the TypeGraph from NRefactory; remove the one from SharpDevelop.

src/AddIns/DisplayBindings/AvalonEdit.AddIn/Src/ContextActions/FindDerivedClassesOrOverrides.cs

@@ -33,9 +33,15 @@ namespace ICSharpCode.AvalonEdit.AddIn.ContextActions
 		}
 		
 		#region Derived Classes
+		static ITreeNode<ITypeDefinition> BuildDerivedTypesGraph(ITypeDefinition baseClass)
+		{
+			var rootNode = FindReferenceService.BuildDerivedTypesGraph(baseClass);
+			return TreeNode<ITypeDefinition>.FromGraph(rootNode, n => n.DerivedTypes, n => n.TypeDefinition);
+		}
+		
 		static ContextActionsPopup MakePopupWithDerivedClasses(ITypeDefinition baseClass)
 		{
-			var derivedClassesTree = FindReferenceService.BuildDerivedTypesGraph(baseClass).ConvertToDerivedTypeTree();
+			var derivedClassesTree = BuildDerivedTypesGraph(baseClass);
 			var popupViewModel = new ContextActionsViewModel();
 			popupViewModel.Title = MenuService.ConvertLabel(StringParser.Parse(
 				"${res:SharpDevelop.Refactoring.ClassesDerivingFrom}", new StringTagPair("Name", baseClass.Name)));
@@ -54,7 +60,7 @@ namespace ICSharpCode.AvalonEdit.AddIn.ContextActions
 		#region Overrides
 		static ContextActionsPopup MakePopupWithOverrides(IMember member)
 		{
-			var derivedClassesTree = FindReferenceService.BuildDerivedTypesGraph(member.DeclaringTypeDefinition).ConvertToDerivedTypeTree();
+			var derivedClassesTree = BuildDerivedTypesGraph(member.DeclaringTypeDefinition);
 			var popupViewModel = new ContextActionsViewModel {
 				Title = MenuService.ConvertLabel(StringParser.Parse(
 					"${res:SharpDevelop.Refactoring.OverridesOf}",

src/Main/Base/Project/Src/Services/RefactoringService/FindReferenceService.cs

@@ -7,6 +7,7 @@ using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using ICSharpCode.Core;
+using ICSharpCode.NRefactory.Analysis;
 using ICSharpCode.NRefactory.TypeSystem;
 using ICSharpCode.NRefactory.TypeSystem.Implementation;
 using ICSharpCode.SharpDevelop.Editor.Search;
@@ -169,10 +170,10 @@ namespace ICSharpCode.SharpDevelop.Refactoring
 			if (baseType == null)
 				throw new ArgumentNullException("baseType");
 			var solutionSnapshot = GetSolutionSnapshot(baseType.Compilation);
-			var compilations = GetProjectsThatCouldReferenceEntity(baseType).Select(p => solutionSnapshot.GetCompilation(p));
+			var assemblies = GetProjectsThatCouldReferenceEntity(baseType).Select(p => solutionSnapshot.GetCompilation(p).MainAssembly);
-			var graph = BuildTypeInheritanceGraph(compilations);
+			var graph = new TypeGraph(assemblies);
-			TypeGraphNode node;
+			var node = graph.GetNode(baseType);
-			if (graph.TryGetValue(new AssemblyQualifiedTypeName(baseType), out node)) {
+			if (node != null) {
 				// only derived types were requested, so don't return the base types
 				// (this helps the GC to collect the unused parts of the graph more quickly)
 				node.BaseTypes.Clear();
@@ -181,40 +182,6 @@ namespace ICSharpCode.SharpDevelop.Refactoring
 				return new TypeGraphNode(baseType);
 			}
 		}
-		
-		/// <summary>
-		/// Builds a graph of all type definitions in the specified set of project contents.
-		/// </summary>
-		/// <remarks>The resulting graph may be cyclic if there are cyclic type definitions.</remarks>
-		static Dictionary<AssemblyQualifiedTypeName, TypeGraphNode> BuildTypeInheritanceGraph(IEnumerable<ICompilation> compilations)
-		{
-			if (compilations == null)
-				throw new ArgumentNullException("projectContents");
-			Dictionary<AssemblyQualifiedTypeName, TypeGraphNode> dict = new Dictionary<AssemblyQualifiedTypeName, TypeGraphNode>();
-			foreach (ICompilation compilation in compilations) {
-				foreach (ITypeDefinition typeDef in compilation.MainAssembly.GetAllTypeDefinitions()) {
-					// Overwrite previous entry - duplicates can occur if there are multiple versions of the
-					// same project loaded in the solution (e.g. separate .csprojs for separate target frameworks)
-					dict[new AssemblyQualifiedTypeName(typeDef)] = new TypeGraphNode(typeDef);
-				}
-			}
-			foreach (ICompilation compilation in compilations) {
-				foreach (ITypeDefinition typeDef in compilation.MainAssembly.GetAllTypeDefinitions()) {
-					TypeGraphNode typeNode = dict[new AssemblyQualifiedTypeName(typeDef)];
-					foreach (IType baseType in typeDef.DirectBaseTypes) {
-						ITypeDefinition baseTypeDef = baseType.GetDefinition();
-						if (baseTypeDef != null) {
-							TypeGraphNode baseTypeNode;
-							if (dict.TryGetValue(new AssemblyQualifiedTypeName(baseTypeDef), out baseTypeNode)) {
-								typeNode.BaseTypes.Add(baseTypeNode);
-								baseTypeNode.DerivedTypes.Add(typeNode);
-							}
-						}
-					}
-				}
-			}
-			return dict;
-		}
 		#endregion
 	}
 	

src/Main/Base/Project/Src/Services/RefactoringService/TypeGraphNode.cs

@@ -22,6 +22,7 @@ using ICSharpCode.NRefactory.TypeSystem;
 
 namespace ICSharpCode.SharpDevelop.Refactoring
 {
+	/*
 	public sealed class TypeGraphNode
 	{
 		internal readonly ITypeDefinition typeDef;
@@ -54,5 +55,5 @@ namespace ICSharpCode.SharpDevelop.Refactoring
 		{
 			return TreeNode<ITypeDefinition>.FromGraph(this, n => n.derivedTypes, n => n.typeDef);
 		}
-	}
+	}*/
 }

src/Main/Base/Project/Util/TreeNode.cs

@@ -19,7 +19,7 @@ namespace ICSharpCode.SharpDevelop
 		IEnumerable<ITreeNode<TContent>> Children { get; }
 	}
 	
-	sealed class TreeNode<TContent> : ITreeNode<TContent>
+	public sealed class TreeNode<TContent> : ITreeNode<TContent>
 	{
 		public TreeNode(TContent content)
 		{