.../Drupal/Component/Plugin/Discovery/CachedDiscoveryInterface.php |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/core/lib/Drupal/Component/Plugin/Discovery/CachedDiscoveryInterface.php b/core/lib/Drupal/Component/Plugin/Discovery/CachedDiscoveryInterface.php
index fc07024..a78c1ab 100644
--- a/core/lib/Drupal/Component/Plugin/Discovery/CachedDiscoveryInterface.php
+++ b/core/lib/Drupal/Component/Plugin/Discovery/CachedDiscoveryInterface.php
@@ -14,6 +14,10 @@
 
   /**
    * Clears static and persistent plugin definition caches.
+   *
+   * Don't resort to calling \Drupal::cache()->delete() and friends to make
+   * Drupal detect new or updated plugin definitions, always use this method on
+   * the appropriate plugin type's plugin manager!
    */
   public function clearCachedDefinitions();