See my comment https://github.com/barryvdh/laravel-ide-helper/pull/765#issuecomment-471014271:
The change in #765 made anonymous functions get reflected with `ReflectionMethod` instead of `ReflectionFunction`, which makes it lose the doc comment. This means that the generated helpers are missing their return types. This is because Closure is also an object and callable.
To fix it, Closure should be excluded from that new condition.