1 files changed, 69 insertions, 0 deletions
diff --git a/compiler/rustc_typeck/src/outlives/explicit.rs b/compiler/rustc_typeck/src/outlives/explicit.rs
new file mode 100644
index 000000000..7534482cc
--- /dev/null
+++ b/compiler/rustc_typeck/src/outlives/explicit.rs
@@ -0,0 +1,69 @@
+use rustc_data_structures::fx::FxHashMap;
+use rustc_hir::def_id::DefId;
+use rustc_middle::ty::{self, OutlivesPredicate, TyCtxt};
+
+use super::utils::*;
+
+#[derive(Debug)]
+pub struct ExplicitPredicatesMap<'tcx> {
+    map: FxHashMap<DefId, ty::EarlyBinder<RequiredPredicates<'tcx>>>,
+}
+
+impl<'tcx> ExplicitPredicatesMap<'tcx> {
+    pub fn new() -> ExplicitPredicatesMap<'tcx> {
+        ExplicitPredicatesMap { map: FxHashMap::default() }
+    }
+
+    pub(crate) fn explicit_predicates_of(
+        &mut self,
+        tcx: TyCtxt<'tcx>,
+        def_id: DefId,
+    ) -> &ty::EarlyBinder<RequiredPredicates<'tcx>> {
+        self.map.entry(def_id).or_insert_with(|| {
+            let predicates = if def_id.is_local() {
+                tcx.explicit_predicates_of(def_id)
+            } else {
+                tcx.predicates_of(def_id)
+            };
+            let mut required_predicates = RequiredPredicates::default();
+
+            // process predicates and convert to `RequiredPredicates` entry, see below
+            for &(predicate, span) in predicates.predicates {
+                match predicate.kind().skip_binder() {
+                    ty::PredicateKind::TypeOutlives(OutlivesPredicate(ty, reg)) => {
+                        insert_outlives_predicate(
+                            tcx,
+                            ty.into(),
+                            reg,
+                            span,
+                            &mut required_predicates,
+                        )
+                    }
+
+                    ty::PredicateKind::RegionOutlives(OutlivesPredicate(reg1, reg2)) => {
+                        insert_outlives_predicate(
+                            tcx,
+                            reg1.into(),
+                            reg2,
+                            span,
+                            &mut required_predicates,
+                        )
+                    }
+
+                    ty::PredicateKind::Trait(..)
+                    | ty::PredicateKind::Projection(..)
+                    | ty::PredicateKind::WellFormed(..)
+                    | ty::PredicateKind::ObjectSafe(..)
+                    | ty::PredicateKind::ClosureKind(..)
+                    | ty::PredicateKind::Subtype(..)
+                    | ty::PredicateKind::Coerce(..)
+                    | ty::PredicateKind::ConstEvaluatable(..)
+                    | ty::PredicateKind::ConstEquate(..)
+                    | ty::PredicateKind::TypeWellFormedFromEnv(..) => (),
+                }
+            }
+
+            ty::EarlyBinder(required_predicates)
+        })
+    }
+}