From f933e0971bbe85d8dbe938e46b73fc9b0375317f Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Wed, 5 Jun 2019 05:52:58 -0400
Subject: [PATCH] pass a `&mut QueryRegionConstraints` not just outlives
 constraints

---
 src/librustc/infer/canonical/query_response.rs | 10 ++++++----
 src/librustc/traits/query/type_op/mod.rs       | 12 ++++++------
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/src/librustc/infer/canonical/query_response.rs b/src/librustc/infer/canonical/query_response.rs
index b4c46e71b16d..6ce644f84468 100644
--- a/src/librustc/infer/canonical/query_response.rs
+++ b/src/librustc/infer/canonical/query_response.rs
@@ -279,7 +279,7 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
         param_env: ty::ParamEnv<'tcx>,
         original_values: &OriginalQueryValues<'tcx>,
         query_response: &Canonical<'tcx, QueryResponse<'tcx, R>>,
-        output_query_outlives_constraints: &mut Vec<QueryOutlivesConstraint<'tcx>>,
+        output_query_region_constraints: &mut QueryRegionConstraints<'tcx>,
     ) -> InferResult<'tcx, R>
     where
         R: Debug + TypeFoldable<'tcx>,
@@ -305,9 +305,11 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
                 (UnpackedKind::Lifetime(v_o), UnpackedKind::Lifetime(v_r)) => {
                     // To make `v_o = v_r`, we emit `v_o: v_r` and `v_r: v_o`.
                     if v_o != v_r {
-                        output_query_outlives_constraints
+                        output_query_region_constraints
+                            .outlives
                             .push(ty::Binder::dummy(ty::OutlivesPredicate(v_o.into(), v_r)));
-                        output_query_outlives_constraints
+                        output_query_region_constraints
+                            .outlives
                             .push(ty::Binder::dummy(ty::OutlivesPredicate(v_r.into(), v_o)));
                     }
                 }
@@ -333,7 +335,7 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
         }
 
         // ...also include the other query region constraints from the query.
-        output_query_outlives_constraints.extend(
+        output_query_region_constraints.outlives.extend(
             query_response.value.region_constraints.outlives.iter().filter_map(|r_c| {
                 let r_c = substitute_value(self.tcx, &result_subst, r_c);
 
diff --git a/src/librustc/traits/query/type_op/mod.rs b/src/librustc/traits/query/type_op/mod.rs
index bf8cace3a1bb..e2a5cd9670e0 100644
--- a/src/librustc/traits/query/type_op/mod.rs
+++ b/src/librustc/traits/query/type_op/mod.rs
@@ -1,6 +1,6 @@
 use crate::infer::canonical::{
     Canonical, Canonicalized, CanonicalizedQueryResponse, OriginalQueryValues,
-    QueryRegionConstraints, QueryOutlivesConstraint, QueryResponse,
+    QueryRegionConstraints, QueryResponse,
 };
 use crate::infer::{InferCtxt, InferOk};
 use std::fmt;
@@ -85,7 +85,7 @@ pub trait QueryTypeOp<'tcx>: fmt::Debug + Sized + TypeFoldable<'tcx> + 'tcx {
     fn fully_perform_into(
         query_key: ParamEnvAnd<'tcx, Self>,
         infcx: &InferCtxt<'_, 'tcx>,
-        output_query_region_constraints: &mut Vec<QueryOutlivesConstraint<'tcx>>,
+        output_query_region_constraints: &mut QueryRegionConstraints<'tcx>,
     ) -> Fallible<Self::QueryResponse> {
         if let Some(result) = QueryTypeOp::try_fast_path(infcx.tcx, &query_key) {
             return Ok(result);
@@ -141,15 +141,15 @@ where
         self,
         infcx: &InferCtxt<'_, 'tcx>,
     ) -> Fallible<(Self::Output, Option<Rc<QueryRegionConstraints<'tcx>>>)> {
-        let mut outlives = vec![];
-        let r = Q::fully_perform_into(self, infcx, &mut outlives)?;
+        let mut region_constraints = QueryRegionConstraints::default();
+        let r = Q::fully_perform_into(self, infcx, &mut region_constraints)?;
 
         // Promote the final query-region-constraints into a
         // (optional) ref-counted vector:
-        let opt_qrc = if outlives.is_empty() {
+        let opt_qrc = if region_constraints.is_empty() {
             None
         } else {
-            Some(Rc::new(QueryRegionConstraints { outlives }))
+            Some(Rc::new(region_constraints))
         };
 
         Ok((r, opt_qrc))