A forked copy of Doctrine's SimpleAnnotationReader is now provided by Drupal core and should be used instead of Doctrine's own version

Because the Doctrine project is removing the SimpleAnnotationReader class Drupal core has forked this class to provide the current annotation parsing functionality. No change is needed for any modules that are using annotation plugin discovery.

Any modules that are using the \Doctrine\Common\Annotations\SimpleAnnotationReader class directly should switch to using the forked version \Drupal\Component\Annotation\Doctrine\SimpleAnnotationReader. When Drupal upgrades its version of Doctrine to 2.0 or above the \Doctrine\Common\Annotations\SimpleAnnotationReader class will no longer be available and classes using it will cause a fatal error.