Function expand_body 

fn expand_body<'tcx>(
    tcx: TyCtxt<'tcx>,
    def_id: DefId,
    body: &DefBody,
    exprs: &[Expr],
    params: &[String],
    param_tys: &[String],
) -> Vec<Property<'tcx>>

Expand a DefBody into the property list it denotes.

and produces multiple Property values (the caller’s requires list is already a conjunction); or produces a single Property::Or property whose groups encode the DNF groups.