compiler/rustc_infer/src/infer/outlives/mod.rs

   1 //! Various code related to computing outlives relations.
   2
   3 pub mod env;
   4 pub mod obligations;
   5 pub mod verify;
   6
   7 use rustc_middle::traits::query::OutlivesBound;
   8 use rustc_middle::ty;
   9 use rustc_middle::ty::fold::TypeFoldable;
  10
  11 pub fn explicit_outlives_bounds<'tcx>(
  12     param_env: ty::ParamEnv<'tcx>,
  13 ) -> impl Iterator<Item = OutlivesBound<'tcx>> + 'tcx {
  14     debug!("explicit_outlives_bounds()");
  15     param_env
  16         .caller_bounds()
  17         .into_iter()
  18         .map(ty::Predicate::skip_binders)
  19         .filter(|atom| !atom.has_escaping_bound_vars())
  20         .filter_map(move |atom| match atom {
  21             ty::PredicateAtom::Projection(..)
  22             | ty::PredicateAtom::Trait(..)
  23             | ty::PredicateAtom::Subtype(..)
  24             | ty::PredicateAtom::WellFormed(..)
  25             | ty::PredicateAtom::ObjectSafe(..)
  26             | ty::PredicateAtom::ClosureKind(..)
  27             | ty::PredicateAtom::TypeOutlives(..)
  28             | ty::PredicateAtom::ConstEvaluatable(..)
  29             | ty::PredicateAtom::ConstEquate(..)
  30             | ty::PredicateAtom::TypeWellFormedFromEnv(..) => None,
  31             ty::PredicateAtom::RegionOutlives(ty::OutlivesPredicate(r_a, r_b)) => {
  32                 Some(OutlivesBound::RegionSubRegion(r_b, r_a))
  33             }
  34         })
  35 }