Fix #1509: Show error message that unresolved entities cannot be analyzed.

ILSpy/Analyzers/AnalyzerSearchTreeNode.cs

@@ -52,9 +52,7 @@ namespace ICSharpCode.ILSpy.Analyzers
 
 		protected IEnumerable<AnalyzerTreeNode> FetchChildren(CancellationToken ct)
 		{
-			if (symbol is IEntity entity) {
-				var module = entity.ParentModule.PEFile;
-				var ts = new DecompilerTypeSystem(module, module.GetAssemblyResolver());
+			if (symbol is IEntity) {
 				var context = new AnalyzerContext() {
 					CancellationToken = ct,
 					Language = Language,

ILSpy/Analyzers/AnalyzerTreeView.cs

@@ -109,6 +109,11 @@ namespace ICSharpCode.ILSpy.Analyzers
 				throw new ArgumentNullException(nameof(entity));
 			}
 
+			if (entity.MetadataToken.IsNil) {
+				MessageBox.Show(Properties.Resources.CannotAnalyzeMissingRef, "ILSpy");
+				return;
+			}
+
 			switch (entity) {
 				case ITypeDefinition td:
 					ShowOrFocus(new AnalyzedTypeTreeNode(td));

ILSpy/Properties/Resources.Designer.cs

@@ -330,6 +330,15 @@ namespace ICSharpCode.ILSpy.Properties {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Entity could not be resolved. Cannot analyze entities from missing assembly references. Add the missing reference and try again..
+        /// </summary>
+        public static string CannotAnalyzeMissingRef {
+            get {
+                return ResourceManager.GetString("CannotAnalyzeMissingRef", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Check again.
         /// </summary>
@@ -1476,7 +1485,7 @@ namespace ICSharpCode.ILSpy.Properties {
         }
         
         /// <summary>
-        ///   查找类似 Search MSDN... 的本地化字符串。
+        ///   Looks up a localized string similar to Search MSDN....
         /// </summary>
         public static string SearchMSDN {
             get {

ILSpy/Properties/Resources.resx

@@ -726,4 +726,7 @@
   <data name="SearchMSDN" xml:space="preserve">
     <value>Search MSDN...</value>
   </data>
+  <data name="CannotAnalyzeMissingRef" xml:space="preserve">
+    <value>Entity could not be resolved. Cannot analyze entities from missing assembly references. Add the missing reference and try again.</value>
+  </data>
 </root>