注意：undefined属性：stdclass :: $ comment_body中的
需要删除字段注释_body eNcase for field permise是为所有内容类型继承的，这就是为什么创建另一个字段并且删除此字段的原因。
I deleted the comment body from the content type settings, and replaced it with another field. When posting comments, I get this error:
Notice: Undefined property: stdClass::$comment_body in function
comment_submit()(line 2201 in file /modules/comment/comment.module).
Can this error be avoided?
It was needed to delete the field comment_body becase field permissions are inherited for all the content types and that is why another field was created and this one was deleted.
There is also a patch which actually needs review in Drupal Core concerning this issue: https://www.drupal.org/node/2717717
I applied it and it works.
First delete that field and clean Drupal's Cache, if that doesn't work just try to use this patch:
I recovered comments with recreating the tables (take care: all the comments will be removed):
and reset statistics with:
UPDATE node_comment_statistics SET comment_count = 0;
Where to get SQL query to recreate them? Get it from another Drupal installation with comments.