From 0da0457593c5c1cb09f6197782ca73617860e897 Mon Sep 17 00:00:00 2001
From: varkor <github@varkor.com>
Date: Wed, 20 Feb 2019 12:47:19 +0000
Subject: [PATCH] Clean up some generic substs handling

---
 src/librustc/infer/opaque_types/mod.rs     | 11 ++++++++---
 src/librustc/infer/outlives/obligations.rs | 20 +++++++++++++-------
 src/librustc_typeck/check/regionck.rs      | 22 ++++++++++++++--------
 3 files changed, 35 insertions(+), 18 deletions(-)

diff --git a/src/librustc/infer/opaque_types/mod.rs b/src/librustc/infer/opaque_types/mod.rs
index 159bc1ceae2..1b7ecc7c3a6 100644
--- a/src/librustc/infer/opaque_types/mod.rs
+++ b/src/librustc/infer/opaque_types/mod.rs
@@ -381,10 +381,15 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                         substs,
                         item_def_id: _,
                     }) => {
-                        for r in substs.regions() {
-                            bound_region(r);
+                        for k in substs {
+                            match k.unpack() {
+                                UnpackedKind::Lifetime(lt) => bound_region(lt),
+                                UnpackedKind::Type(ty) => types.push(ty),
+                                UnpackedKind::Const(_) => {
+                                    // Const parameters don't impose constraints.
+                                }
+                            }
                         }
-                        types.extend(substs.types());
                     }
 
                     Component::EscapingProjection(more_components) => {
diff --git a/src/librustc/infer/outlives/obligations.rs b/src/librustc/infer/outlives/obligations.rs
index bbda3d2fdbf..ee660328485 100644
--- a/src/librustc/infer/outlives/obligations.rs
+++ b/src/librustc/infer/outlives/obligations.rs
@@ -67,6 +67,7 @@ use crate::hir;
 use crate::traits::ObligationCause;
 use crate::ty::outlives::Component;
 use crate::ty::{self, Region, Ty, TyCtxt, TypeFoldable};
+use crate::ty::subst::UnpackedKind;
 
 impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
     /// Registers that the given region obligation must be resolved
@@ -430,13 +431,18 @@ where
         if approx_env_bounds.is_empty() && trait_bounds.is_empty() && needs_infer {
             debug!("projection_must_outlive: no declared bounds");
 
-            for component_ty in projection_ty.substs.types() {
-                self.type_must_outlive(origin.clone(), component_ty, region);
-            }
-
-            for r in projection_ty.substs.regions() {
-                self.delegate
-                    .push_sub_region_constraint(origin.clone(), region, r);
+            for k in projection_ty.substs {
+                match k.unpack() {
+                    UnpackedKind::Lifetime(lt) => {
+                        self.delegate.push_sub_region_constraint(origin.clone(), region, lt);
+                    }
+                    UnpackedKind::Type(ty) => {
+                        self.type_must_outlive(origin.clone(), ty, region);
+                    }
+                    UnpackedKind::Const(_) => {
+                        // Const parameters don't impose constraints.
+                    }
+                }
             }
 
             return;
diff --git a/src/librustc_typeck/check/regionck.rs b/src/librustc_typeck/check/regionck.rs
index b549986777c..a03d33a3ef5 100644
--- a/src/librustc_typeck/check/regionck.rs
+++ b/src/librustc_typeck/check/regionck.rs
@@ -81,7 +81,7 @@ use rustc::hir::def_id::DefId;
 use rustc::infer::outlives::env::OutlivesEnvironment;
 use rustc::infer::{self, RegionObligation, SuppressRegionErrors};
 use rustc::ty::adjustment;
-use rustc::ty::subst::SubstsRef;
+use rustc::ty::subst::{SubstsRef, UnpackedKind};
 use rustc::ty::{self, Ty};
 
 use rustc::hir::intravisit::{self, NestedVisitorMap, Visitor};
@@ -1407,13 +1407,19 @@ impl<'a, 'gcx, 'tcx> RegionCtxt<'a, 'gcx, 'tcx> {
 
         let origin = infer::ParameterInScope(origin, expr_span);
 
-        for region in substs.regions() {
-            self.sub_regions(origin.clone(), expr_region, region);
-        }
-
-        for ty in substs.types() {
-            let ty = self.resolve_type(ty);
-            self.type_must_outlive(origin.clone(), ty, expr_region);
+        for kind in substs {
+            match kind.unpack() {
+                UnpackedKind::Lifetime(lt) => {
+                    self.sub_regions(origin.clone(), expr_region, lt);
+                }
+                UnpackedKind::Type(ty) => {
+                    let ty = self.resolve_type(ty);
+                    self.type_must_outlive(origin.clone(), ty, expr_region);
+                }
+                UnpackedKind::Const(_) => {
+                    // Const parameters don't impose constraints.
+                }
+            }
         }
     }
 }