@Nullable
 protected VirtualFile findClassFile(String className) {
   final CompilerModuleExtension extension =
       ModuleRootManager.getInstance(myModule).getModuleExtension(CompilerModuleExtension.class);
   //noinspection ConstantConditions
   return extension.getCompilerOutputPath().findChild(className + ".class");
 }
 private static void removeModuleOutput(Module module, List<VirtualFile> from) {
   final CompilerModuleExtension extension =
       ModuleRootManager.getInstance(module).getModuleExtension(CompilerModuleExtension.class);
   from.remove(extension.getCompilerOutputPath());
   from.remove(extension.getCompilerOutputPathForTests());
 }