Breaks with implicit service class

Problem/Motivation

This breaks

services:
  Drupal\my_module\MyService:
    tags:
      - hooks

and needs that workaround:
services:
Drupal\my_module\MyService:
class: Drupal\my_module\MyService
tags:
- hooks

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes