Errors not printed in CI environment

[bhollis]

I have an issue where awesome-typescript-loader will not print out the TS errors when running in Travis CI: https://travis-ci.org/DestinyItemManager/DIM/builds/526111148?utm_source=github_status&utm_medium=notification

Instead, it prints:

Error: Tap function (tapPromise) did not return promise (returned undefined)
    at AsyncSeriesHook.eval [as callAsync] (eval at create (/home/travis/build/DestinyItemManager/DIM/node_modules/tapable/lib/HookCodeFactory.js:33:10), <anonymous>:46:9)
    at AsyncSeriesHook.lazyCompileHook (/home/travis/build/DestinyItemManager/DIM/node_modules/tapable/lib/Hook.js:154:20)
    at onCompiled (/home/travis/build/DestinyItemManager/DIM/node_modules/webpack/lib/Compiler.js:234:21)
    at hooks.afterCompile.callAsync.err (/home/travis/build/DestinyItemManager/DIM/node_modules/webpack/lib/Compiler.js:631:15)
    at _err0 (eval at create (/home/travis/build/DestinyItemManager/DIM/node_modules/tapable/lib/HookCodeFactory.js:33:10), <anonymous>:11:1)
    at /home/travis/build/DestinyItemManager/DIM/node_modules/awesome-typescript-loader/src/instance.ts:523:16

Weirdly I haven't been able to repro this locally.