100% with you on greppability as an underrated design skill interested in 'library versions as types' and have been thinking about this problem on and off. ver

100% with you on greppability as an underrated design skill interested in 'library versions as types' and have been thinking about this problem on and off. version numbers are a proxy for the combination of: 1) call signature, and 2) internal semantics linters / typesystems are good at (1). If we had a system that could do (2), version numbers would be less necessary and compatibility could be proof-based. (Well, to the extent that the semantic assertions are valid).