Indeed, I ran two tests (missing indirect dependency, stale indirect dependency version) and it refused to compile both. Either what I said was never true, or it was only true for earlier versions of the `go` command. Nevertheless, adjusted accordingly, I believe the following statement is true: `go mod tidy` doesn't change versions in go.mod unless it needs to, to satisfy the other dependencies listed in go.mod, or to fill in a missing dependency for an import in code. It would be nice if there were a flag to turn off the latter behavior, though.