The "\Drupal\commerce_add_to_cart_link\Controller\AddToCartController::access" method is not callable as a _custom_access callback in route "/add-to-cart/{commerce_product}/{commerce_product_variation}/{token}

Problem/Motivation

When placing an "Add to cart" link in a view for a product variation and clicking it, I get the following error:

BadMethodCallException: The "\Drupal\commerce_add_to_cart_link\Controller\AddToCartController::access" method is not callable as a _custom_access callback in route "/add-to-cart/{commerce_product}/{commerce_product_variation}/{token}" in Drupal\Core\Access\CustomAccessCheck->access() (line 69 of core/lib/Drupal/Core/Access/CustomAccessCheck.php).
call_user_func_array() (Line: 160)
Drupal\Core\Access\AccessManager->performCheck() (Line: 136)
Drupal\Core\Access\AccessManager->check() (Line: 113)
Drupal\Core\Access\AccessManager->checkRequest() (Line: 110)
Drupal\Core\Routing\AccessAwareRouter->checkAccess() (Line: 95)
Drupal\Core\Routing\AccessAwareRouter->matchRequest() (Line: 112)
Symfony\Component\HttpKernel\EventListener\RouterListener->onKernelRequest()
call_user_func() (Line: 142)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch() (Line: 145)
Symfony\Component\HttpKernel\HttpKernel->handleRaw() (Line: 81)
Symfony\Component\HttpKernel\HttpKernel->handle() (Line: 58)
Drupal\Core\StackMiddleware\Session->handle() (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle() (Line: 191)
Drupal\page_cache\StackMiddleware\PageCache->fetch() (Line: 128)
Drupal\page_cache\StackMiddleware\PageCache->lookup() (Line: 82)
Drupal\page_cache\StackMiddleware\PageCache->handle() (Line: 50)
Drupal\ban\BanMiddleware->handle() (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle() (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle() (Line: 49)
Drupal\remove_http_headers\StackMiddleware\RemoveHttpHeadersMiddleware->handle() (Line: 23)
Stack\StackedHttpKernel->handle() (Line: 718)
Drupal\Core\DrupalKernel->handle() (Line: 19)

Steps to reproduce

The clicked URL has the following format:
https://www.example.com/add-to-cart/7/45

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes