src/librustc_typeck/outlives/explicit.rs

   1 use rustc_data_structures::fx::FxHashMap;
   2 use rustc_hir::def_id::DefId;
   3 use rustc_middle::ty::{self, OutlivesPredicate, TyCtxt};
   4
   5 use super::utils::*;
   6
   7 #[derive(Debug)]
   8 pub struct ExplicitPredicatesMap<'tcx> {
   9     map: FxHashMap<DefId, RequiredPredicates<'tcx>>,
  10 }
  11
  12 impl<'tcx> ExplicitPredicatesMap<'tcx> {
  13     pub fn new() -> ExplicitPredicatesMap<'tcx> {
  14         ExplicitPredicatesMap { map: FxHashMap::default() }
  15     }
  16
  17     pub fn explicit_predicates_of(
  18         &mut self,
  19         tcx: TyCtxt<'tcx>,
  20         def_id: DefId,
  21     ) -> &RequiredPredicates<'tcx> {
  22         self.map.entry(def_id).or_insert_with(|| {
  23             let predicates = if def_id.is_local() {
  24                 tcx.explicit_predicates_of(def_id)
  25             } else {
  26                 tcx.predicates_of(def_id)
  27             };
  28             let mut required_predicates = RequiredPredicates::default();
  29
  30             // process predicates and convert to `RequiredPredicates` entry, see below
  31             for &(predicate, span) in predicates.predicates {
  32                 match predicate.kind() {
  33                     ty::PredicateKind::TypeOutlives(predicate) => {
  34                         let OutlivesPredicate(ref ty, ref reg) = predicate.skip_binder();
  35                         insert_outlives_predicate(
  36                             tcx,
  37                             (*ty).into(),
  38                             reg,
  39                             span,
  40                             &mut required_predicates,
  41                         )
  42                     }
  43
  44                     ty::PredicateKind::RegionOutlives(predicate) => {
  45                         let OutlivesPredicate(ref reg1, ref reg2) = predicate.skip_binder();
  46                         insert_outlives_predicate(
  47                             tcx,
  48                             (*reg1).into(),
  49                             reg2,
  50                             span,
  51                             &mut required_predicates,
  52                         )
  53                     }
  54
  55                     ty::PredicateKind::Trait(..)
  56                     | ty::PredicateKind::Projection(..)
  57                     | ty::PredicateKind::WellFormed(..)
  58                     | ty::PredicateKind::ObjectSafe(..)
  59                     | ty::PredicateKind::ClosureKind(..)
  60                     | ty::PredicateKind::Subtype(..)
  61                     | ty::PredicateKind::ConstEvaluatable(..)
  62                     | ty::PredicateKind::ConstEquate(..) => (),
  63                 }
  64             }
  65
  66             required_predicates
  67         })
  68     }
  69 }