TypeError: Class constructor Promise cannot be invoked without 'new'

[RobbieTheWagner]

I am seeing TypeError: Class constructor Promise cannot be invoked without 'new' when running ember beta or canary and including ie 11 as a target. It seems to bee coming from this file https://github.com/emberjs/ember-test-helpers/blob/master/addon-test-support/%40ember/test-helpers/-utils.ts

Not exactly sure what the issue is, as the built output looks much different, but perhaps someone here knows the issue?

You can see the failures here: ember-learn/ember-cli-addon-docs#401

[amk221]

Also experiencing this, all my builds have started failing on Travis

[RobbieTheWagner]

This was an issue in Ember itself. Should be fixed by emberjs/ember.js#18281