src/librustc_typeck/outlives/explicit.rs

   1 // Copyright 2013 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use rustc::hir;
  12 use rustc::hir::def_id::{CrateNum, DefId};
  13 use rustc::hir::itemlikevisit::ItemLikeVisitor;
  14 use rustc::ty::{self, TyCtxt};
  15 use util::nodemap::FxHashMap;
  16
  17 use super::utils::*;
  18
  19 pub fn explicit_predicates<'tcx>(
  20     tcx: TyCtxt<'_, 'tcx, 'tcx>,
  21     crate_num: CrateNum,
  22 ) -> FxHashMap<DefId, RequiredPredicates<'tcx>> {
  23     let mut predicates = FxHashMap::default();
  24
  25     // iterate over the entire crate
  26     tcx.hir.krate().visit_all_item_likes(&mut ExplicitVisitor {
  27         tcx: tcx,
  28         explicit_predicates: &mut predicates,
  29         crate_num: crate_num,
  30     });
  31
  32     predicates
  33 }
  34
  35 pub struct ExplicitVisitor<'cx, 'tcx: 'cx> {
  36     tcx: TyCtxt<'cx, 'tcx, 'tcx>,
  37     explicit_predicates: &'cx mut FxHashMap<DefId, RequiredPredicates<'tcx>>,
  38     crate_num: CrateNum,
  39 }
  40
  41 impl<'cx, 'tcx> ItemLikeVisitor<'tcx> for ExplicitVisitor<'cx, 'tcx> {
  42     fn visit_item(&mut self, item: &'tcx hir::Item) {
  43         let def_id = DefId {
  44             krate: self.crate_num,
  45             index: item.hir_id.owner,
  46         };
  47
  48         let mut required_predicates = RequiredPredicates::default();
  49         let local_explicit_predicate = self.tcx.explicit_predicates_of(def_id).predicates;
  50
  51         for pred in local_explicit_predicate.into_iter() {
  52             match pred {
  53                 ty::Predicate::TypeOutlives(predicate) => {
  54                     let ty::OutlivesPredicate(ref ty, ref reg) = predicate.skip_binder();
  55                     insert_outlives_predicate(self.tcx, (*ty).into(), reg, &mut required_predicates)
  56                 }
  57
  58                 ty::Predicate::RegionOutlives(predicate) => {
  59                     let ty::OutlivesPredicate(ref reg1, ref reg2) = predicate.skip_binder();
  60                     insert_outlives_predicate(
  61                         self.tcx,
  62                         (*reg1).into(),
  63                         reg2,
  64                         &mut required_predicates,
  65                     )
  66                 }
  67
  68                 ty::Predicate::Trait(..)
  69                 | ty::Predicate::Projection(..)
  70                 | ty::Predicate::WellFormed(..)
  71                 | ty::Predicate::ObjectSafe(..)
  72                 | ty::Predicate::ClosureKind(..)
  73                 | ty::Predicate::Subtype(..)
  74                 | ty::Predicate::ConstEvaluatable(..) => (),
  75             }
  76         }
  77
  78         self.explicit_predicates.insert(def_id, required_predicates);
  79     }
  80
  81     fn visit_trait_item(&mut self, _trait_item: &'tcx hir::TraitItem) {}
  82
  83     fn visit_impl_item(&mut self, _impl_item: &'tcx hir::ImplItem) {}
  84 }