fn collect_slot_roots(
hir: &Hir<'_>,
expression: &Expr<'_>,
storage_aliases: &HashMap<VariableId, HashSet<VariableId>>,
slot_aliases: &HashMap<VariableId, HashSet<VariableId>>,
call_returns: &HashMap<ExprId, Vec<HashSet<VariableId>>>,
variables: &mut HashSet<VariableId>,
)