I only ever recall this happening when someone inadvisedly modified or added a method to a library. In my actual industry practice, type information never did anything to "preserve the internal invariants of other modules." The only time we lamented the lack of type information was in large scale refactorings.
Who says homogeneous collections are the only use case for parametricity?
No one. However, that was your example. My argument is that's a really poor example. And now you are abandoning it.
I don't separate concerns to be “clever”.
I also like separating concerns. I'm also not a dynamic typing bigot, though you seem to be imagining you are arguing with one. You seem to have devolved into abandoning your points of arguments and portraying your discussion partner as a series of strawmen. How in the heck did you get here from parametric algorithms? This smacks of intellectual dishonesty.
“Hubris” is a term I would reserve for those who write large programs whose constituent parts don't have fixed structure
And earlier, you were claiming something about refactoring. Do you see a contradiction here?
