I'm not sure what this means; would it be worth rewriting the error message? If there is a particular dependency creating the incompatibility with the tool, maybe it's helpful to print it so the user can figure out how their setup is strange?

This happened for me on https://github.com/a-b-street/abstreet/blob/master/Cargo.toml.

Super awesome tool; thank you for creating it! I remember puzzling through the rough equivalent of cargo hackerman dupes back in https://old.reddit.com/r/rust/comments/cqceu4/common_crates_in_cargo_workspace_recompiled/. Your tool will save me loads of time going forward.