fn walk_between<'g>(
graph: &'g RetainedDepGraph,
sources: &FxIndexSet<&'g DepNode>,
targets: &FxIndexSet<&'g DepNode>,
) -> FxIndexSet<DepKind>fn walk_between<'g>(
graph: &'g RetainedDepGraph,
sources: &FxIndexSet<&'g DepNode>,
targets: &FxIndexSet<&'g DepNode>,
) -> FxIndexSet<DepKind>