ClassBrowser: Broken base types when project contains references to assemblies somewhere in file system (neither output dir, nor GAC).

src/Main/Base/Project/Dom/ClassBrowser/BaseTypesTreeNode.cs

@@ -104,12 +104,18 @@ namespace ICSharpCode.SharpDevelop.Dom.ClassBrowser
 					// Look at referenced assemblies
 					if ((assemblyModel.References != null) && (assemblyParserService != null)) {
 						foreach (var referencedAssemblyName in assemblyModel.References.AssemblyNames) {
-							DefaultAssemblySearcher searcher = new DefaultAssemblySearcher(assemblyModel.Location);
+							CombinedAssemblySearcher searcher = new CombinedAssemblySearcher();
+							if ((assemblyModel.Context != null) && (assemblyModel.Context.Project != null)) {
+								searcher.AddSearcher(new ProjectAssemblyReferenceSearcher(assemblyModel.Context.Project));
+							}
+							searcher.AddSearcher(new DefaultAssemblySearcher(assemblyModel.Location));
 							var resolvedFile = searcher.FindAssembly(referencedAssemblyName.AssemblyName);
-							var referenceAssemblyModel = assemblyParserService.GetAssemblyModel(resolvedFile);
-							resolveTypeDefModel = referenceAssemblyModel.TopLevelTypeDefinitions[baseTypeDefinition.FullTypeName];
-							if (resolveTypeDefModel != null) {
-								return resolveTypeDefModel;
+							if (resolvedFile != null) {
+								var referenceAssemblyModel = assemblyParserService.GetAssemblyModel(resolvedFile);
+								resolveTypeDefModel = referenceAssemblyModel.TopLevelTypeDefinitions[baseTypeDefinition.FullTypeName];
+								if (resolveTypeDefModel != null) {
+									return resolveTypeDefModel;
+								}
 							}
 						}
 					}