Failed to resolve directive. Почему не устанавливается локальная директива?

<template lang="pug">
  button.btn
    slot
</template>

<script>
  export default {
    directives: {
      light: { bind () { console.log('test') } }
    }
  }
</script>

<template lang="pug">
  ui-button(v-light) Button
</template>

<script>
  import UiButton from '~components/ui/button.vue'

  export default {
    components: { UiButton }
  }
</script>