babel is exporting "this" as undefined

using ember-cli@1.13.2 and emberjs@1.13.2.

Source emberjs model

export default DS.Model.extend({
    name: DS.attr('string'),

    displayName : Ember.computed('name', () => {
      return this.get('name');
    })
});

Translated model

'use strict';

var _this = undefined;

exports['default'] = DS['default'].Model.extend({
    name: DS['default'].attr('string'),

    displayName: Ember.computed('name', function () {
        return _this.get('name'); //at this point _this is undefined
    })
});

The trouble is that _this is never set the the model. Why is this the case?