has-block does not work

templates.application.hbs

<MyComponent>foobar</MyComponent>

templates.components.my-component.hbs

<p>
  {{#if has-block}}
    <code>has-block</code> <strong>does</strong> work right in 3.4
    <em>{{yield}}</em>
  {{else}}
    <code>has-block</code> does <strong>not</strong> work right in 3.4
  {{/if}}
</p>

<p>
  {{#if hasBlock}}
    <code>hasBlock</code> <strong>does</strong> work right in 3.4
    <em>{{yield}}</em>
  {{else}}
    <code>hasBlock</code> does <strong>not</strong> work right in 3.4
  {{/if}}
</p>

twiddle.json

{
  "version": "0.15.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.4.3",
    "ember-template-compiler": "3.4.3",
    "ember-testing": "3.4.3"
  },
  "addons": {
    "ember-data": "3.4.2"
  }
}