Related cargo issues:
- Automatically activate a dependency if its used elsewhere in dependency graph · Issue #1555 · rust-lang/cargo · GitHub
- Managing the propagation of features across a large workspace is infeasible without tooling support · Issue #9094 · rust-lang/cargo · GitHub
In particular, we should keep in mind Managing the propagation of features across a large workspace is infeasible without tooling support · Issue #9094 · rust-lang/cargo · GitHub
I think more is needed to understanding the motivating use cases. In some situations, this is about cross-cutting functionality which might be better served by Pre-RFC: Mutually-excusive, global features.