IDEA-154443 Speed search is broken in Structure popup

platform/editor-ui-api/src/com/intellij/ide/util/treeView/NodeDescriptor.java

@@ -66,7 +66,10 @@ public abstract class NodeDescriptor<E> {
   public abstract E getElement();
 
   public String toString() {
-    return String.valueOf(myName);
+    // NB!: this method may return null if node is not valid
+    // it contradicts the specification, but the fix breaks existing behaviour
+    // see com.intellij.ide.util.FileStructurePopup#getSpeedSearchText
+    return myName;
   }
 
   /**

platform/lang-impl/src/com/intellij/ide/util/FileStructurePopup.java

@@ -996,7 +996,8 @@ public class FileStructurePopup implements Disposable, TreeActionsOwner {
       }
       return text;
     }
-
+    // NB!: this point is achievable if the following method returns null
+    // see com.intellij.ide.util.treeView.NodeDescriptor.toString
     if (userObject instanceof StructureViewComponent.StructureViewTreeElementWrapper) {
       return ApplicationManager.getApplication().runReadAction(new Computable<String>() {
         @Nullable