system_block_ip_action() has been removed from core

Drupal 7 shipped with a system_block_ip_action(), which allowed to ban the IP of a comment author through an action (configured via ex. Trigger module or the contributed Rules module).

This action was rarely used, and it was poorly implemented. This meant that there has been a good chance for users of Views Bulk Operations (VBO) and/or Administration Views to ban their very own IPs.

Since Views has been moved into core for Drupal 8, and a simplified VBO functionality might be provided by Drupal core, too, this implementation of the "Block the current user" action (which really meant to say: "Block the author's IP") can no longer reasonably be supported.

The action has been removed from Drupal core, without replacement.