I am working on upgrading a module and there is a use statement
use DrupalCoreCacheCacheBackendInterface;
What is the point of using an interface like that? Interfaces dont have actual code and this .module file doesnt inherit from that interface.
Now when the module is in enabled i get
Error: Cannot instantiate interface DrupalCoreCacheCacheBackendInterface in /srv/www/mydev/current/core/lib/Drupal/Component/DependencyInjection/Container.php, line 265
and the only lines I can find relating to the cache interface are
Drupal::cache('libraries')->deleteAll(); Drupal::cache('libraries')->set($name, $library);
So I am confused as to why this is supposed to clear the cache?
Or is it that it is not supposed work and the latest version of the module is not complete yet?