[munk-a]

I agree, but in that case you're fighting against the typing system more than typing itself, whatever you are doing with that thing and however you would abstractly define that type (maybe as "We expect this thing to have the type of the thing that terrible third party library usually gives us back") you will make assumptions based on the fact that that value is actually one of those and you never want those assumptions violated. In this case the typing system is too restrictive and it might be a case where duck-typing would come in handy (since you can usually post-apply types in that sort of a setting).