Consider outlives assumptions when proving auto traits for coroutine interiors

1 files changed, 14 insertions, 1 deletions

diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs
index cc3ad921489..458b21da6ce 100644
--- a/compiler/rustc_infer/src/infer/mod.rs
+++ b/compiler/rustc_infer/src/infer/mod.rs
@@ -149,6 +149,13 @@ pub struct InferCtxtInner<'tcx> {
     /// that all type inference variables have been bound and so forth.
     region_obligations: Vec<TypeOutlivesConstraint<'tcx>>,
 
+    /// The outlives bounds that we assume must hold about placeholders that
+    /// come from instantiating the binder of coroutine-witnesses. These bounds
+    /// are deduced from the well-formedness of the witness's types, and are
+    /// necessary because of the way we anonymize the regions in a coroutine,
+    /// which may cause types to no longer be considered well-formed.
+    region_assumptions: Vec<ty::OutlivesPredicate<'tcx, ty::GenericArg<'tcx>>>,
+
     /// Caches for opaque type inference.
     opaque_type_storage: OpaqueTypeStorage<'tcx>,
 }
@@ -164,7 +171,8 @@ impl<'tcx> InferCtxtInner<'tcx> {
             int_unification_storage: Default::default(),
             float_unification_storage: Default::default(),
             region_constraint_storage: Some(Default::default()),
-            region_obligations: vec![],
+            region_obligations: Default::default(),
+            region_assumptions: Default::default(),
             opaque_type_storage: Default::default(),
         }
     }
@@ -175,6 +183,11 @@ impl<'tcx> InferCtxtInner<'tcx> {
     }
 
     #[inline]
+    pub fn region_assumptions(&self) -> &[ty::OutlivesPredicate<'tcx, ty::GenericArg<'tcx>>] {
+        &self.region_assumptions
+    }
+
+    #[inline]
     pub fn projection_cache(&mut self) -> traits::ProjectionCache<'_, 'tcx> {
         self.projection_cache.with_log(&mut self.undo_log)
     }