Let me give an example. I have an (unreleased, DarkPAN) module, List::Part::SmartMatch, which uses the "Smart"match operator ~~ to do matching on a criterion. I don't want to rename this module to List::Part::SmartMatch::5_010 , because actually that module does not care about what the smartmatch operator does. And it's highly unlikely that any user of this module wants anything else than "their view" of how "Smart"match currently behaves.

I presume that maybe with 5.016 or later, the ~~ operator gets fixed, but if I had to specify one fixed version for my modules semantics, it would have to stay forever with the broken smartmatch semantics to no fault of its own.

This is one case where it would help to either be able to specify "Infinite" upwards compatibility (at least from the foreseeable future), or a convenient way to specify "I want the smartmatch behaviour that my caller expects". Except that the latter would basically be dynamic runtime dispatch of operators, which would be convenient for my case but horrible overkill in the general case.