Fix FileCodeModel's usage of CleanableWeakComHandleTable when an a key is in...

Fix FileCodeModel's usage of CleanableWeakComHandleTable when an a key is in the table but the value is null

src/VisualStudio/Core/Def/Implementation/Interop/CleanableWeakComHandleTable.cs

@@ -197,11 +197,11 @@ public TValue Remove(TKey key)
                 _deadKeySet.Remove(key);
             }
 
-            TValue value;
-            if (TryGetValue(key, out value))
+            WeakComHandle<TValue, TValue> handle;
+            if (_table.TryGetValue(key, out handle))
             {
                 _table.Remove(key);
-                return value;
+                return handle.ComAggregateObject;
             }
 
             return null;
@@ -215,7 +215,7 @@ public bool TryGetValue(TKey key, out TValue value)
             if (_table.TryGetValue(key, out handle))
             {
                 value = handle.ComAggregateObject;
-                return value != null;
+                return true;
             }
 
             value = null;

src/VisualStudio/Core/Impl/CodeModel/FileCodeModel.cs

@@ -206,20 +206,21 @@ internal T GetOrCreateCodeElement<T>(SyntaxNode node)
                 EnvDTE.CodeElement codeElement;
                 if (_codeElementTable.TryGetValue(nodeKey, out codeElement))
                 {
-                    var element = ComAggregate.TryGetManagedObject<AbstractCodeElement>(codeElement);
-                    if (element.IsValidNode())
+                    if (codeElement != null)
                     {
-                        if (codeElement is T)
+                        var element = ComAggregate.TryGetManagedObject<AbstractCodeElement>(codeElement);
+                        if (element.IsValidNode())
                         {
-                            return (T)codeElement;
-                        }
+                            if (codeElement is T)
+                            {
+                                return (T)codeElement;
+                            }
 
-                        throw new InvalidOperationException($"Found a valid code element for {nodeKey}, but it is not of type, {typeof(T).ToString()}");
-                    }
-                    else
-                    {
-                        _codeElementTable.Remove(nodeKey);
+                            throw new InvalidOperationException($"Found a valid code element for {nodeKey}, but it is not of type, {typeof(T).ToString()}");
+                        }
                     }
+
+                    _codeElementTable.Remove(nodeKey);
                 }
             }