| use hir::Node; |
| use rustc::hir; |
| use rustc::hir::def_id::{CrateNum, DefId, LOCAL_CRATE}; |
| use rustc::ty::query::Providers; |
| use rustc::ty::subst::GenericArgKind; |
| use rustc::ty::{self, CratePredicatesMap, TyCtxt}; |
| use rustc_span::symbol::sym; |
| use rustc_span::Span; |
| |
| mod explicit; |
| mod implicit_infer; |
| /// Code to write unit test for outlives. |
| pub mod test; |
| mod utils; |
| |
| pub fn provide(providers: &mut Providers<'_>) { |
| *providers = Providers { inferred_outlives_of, inferred_outlives_crate, ..*providers }; |
| } |
| |
| fn inferred_outlives_of(tcx: TyCtxt<'_>, item_def_id: DefId) -> &[(ty::Predicate<'_>, Span)] { |
| let id = tcx.hir().as_local_hir_id(item_def_id).expect("expected local def-id"); |
| |
| match tcx.hir().get(id) { |
| Node::Item(item) => match item.kind { |
| hir::ItemKind::Struct(..) | hir::ItemKind::Enum(..) | hir::ItemKind::Union(..) => { |
| let crate_map = tcx.inferred_outlives_crate(LOCAL_CRATE); |
| |
| let predicates = crate_map.predicates.get(&item_def_id).map(|p| *p).unwrap_or(&[]); |
| |
| if tcx.has_attr(item_def_id, sym::rustc_outlives) { |
| let mut pred: Vec<String> = predicates |
| .iter() |
| .map(|(out_pred, _)| match out_pred { |
| ty::Predicate::RegionOutlives(p) => p.to_string(), |
| ty::Predicate::TypeOutlives(p) => p.to_string(), |
| err => bug!("unexpected predicate {:?}", err), |
| }) |
| .collect(); |
| pred.sort(); |
| |
| let span = tcx.def_span(item_def_id); |
| let mut err = tcx.sess.struct_span_err(span, "rustc_outlives"); |
| for p in &pred { |
| err.note(p); |
| } |
| err.emit(); |
| } |
| |
| debug!("inferred_outlives_of({:?}) = {:?}", item_def_id, predicates); |
| |
| predicates |
| } |
| |
| _ => &[], |
| }, |
| |
| _ => &[], |
| } |
| } |
| |
| fn inferred_outlives_crate(tcx: TyCtxt<'_>, crate_num: CrateNum) -> &CratePredicatesMap<'_> { |
| assert_eq!(crate_num, LOCAL_CRATE); |
| |
| // Compute a map from each struct/enum/union S to the **explicit** |
| // outlives predicates (`T: 'a`, `'a: 'b`) that the user wrote. |
| // Typically there won't be many of these, except in older code where |
| // they were mandatory. Nonetheless, we have to ensure that every such |
| // predicate is satisfied, so they form a kind of base set of requirements |
| // for the type. |
| |
| // Compute the inferred predicates |
| let mut exp_map = explicit::ExplicitPredicatesMap::new(); |
| |
| let global_inferred_outlives = implicit_infer::infer_predicates(tcx, &mut exp_map); |
| |
| // Convert the inferred predicates into the "collected" form the |
| // global data structure expects. |
| // |
| // FIXME -- consider correcting impedance mismatch in some way, |
| // probably by updating the global data structure. |
| let predicates = global_inferred_outlives |
| .iter() |
| .map(|(&def_id, set)| { |
| let predicates = &*tcx.arena.alloc_from_iter(set.iter().filter_map( |
| |(ty::OutlivesPredicate(kind1, region2), &span)| match kind1.unpack() { |
| GenericArgKind::Type(ty1) => Some(( |
| ty::Predicate::TypeOutlives(ty::Binder::bind(ty::OutlivesPredicate( |
| ty1, region2, |
| ))), |
| span, |
| )), |
| GenericArgKind::Lifetime(region1) => Some(( |
| ty::Predicate::RegionOutlives(ty::Binder::bind(ty::OutlivesPredicate( |
| region1, region2, |
| ))), |
| span, |
| )), |
| GenericArgKind::Const(_) => { |
| // Generic consts don't impose any constraints. |
| None |
| } |
| }, |
| )); |
| (def_id, predicates) |
| }) |
| .collect(); |
| |
| tcx.arena.alloc(ty::CratePredicatesMap { predicates }) |
| } |