I think I agree with you (though I would favor T, U, V as the sequence). What would the alternative look like in what you wrote? In and Out? Range and Domain?

I think I agree with you (though I would favor T, U, V as the sequence). What would the alternative look like in what you wrote? In and Out? Range and Domain? Generic type variables are often too abstract to give a sensible name to. This is the one "bad habit" that I think is a bit silly - naming conventions can vary by project.