/// Error type for topological sort
#[derive(Debug, Copy, Clone)]pubenumTopologicalError<'i, T, G> {/// A task is missing from the list of tasks.
MissingTask {/// Reference of the missing task.
task:&'i T,},/// A group is missing from the list of groups.
MissingGroup {/// Reference of the missing group.
group:&'i G,},}