gistfile1.txt

diff -u b/core/modules/comment/src/CommentFieldItemList.php b/core/modules/comment/src/CommentFieldItemList.php
--- b/core/modules/comment/src/CommentFieldItemList.php
+++ b/core/modules/comment/src/CommentFieldItemList.php
@@ -51,8 +51,11 @@
     }
     if ($operation === 'view') {
       // Only users with either post comments or access comments permisison can
-      // view the field value. The formatter takes care of showing the comment
-      // thread and form based on the individual permissions.
+      // view the field value. The formatter,
+      // Drupal\comment\Plugin\Field\FieldFormatter\CommentDefaultFormatter,
+      // takes care of showing the thread and form based on individual
+      // permissions, so if a user only has ‘post comments’ access, only the
+      // form will be shown and not the comments.
       $result = AccessResult::allowedIfHasPermission($account ?: \Drupal::currentUser(), 'access comments')
         ->orIf(AccessResult::allowedIfHasPermission($account ?: \Drupal::currentUser(), 'post comments'));
       return $return_as_object ? $result : $result->isAllowed();
~