Auto merge of #22541 - Manishearth:rollup, r=Gankro 1.0.0-alpha.2

Continued from #22520

1 files changed, 25 insertions, 22 deletions

diff --git a/src/librustc/middle/infer/lub.rs b/src/librustc/middle/infer/lub.rs
index 204560e87ee..3570effa9fa 100644
--- a/src/librustc/middle/infer/lub.rs
+++ b/src/librustc/middle/infer/lub.rs
@@ -9,13 +9,10 @@
 // except according to those terms.
 
 use super::combine::*;
-use super::equate::Equate;
-use super::glb::Glb;
 use super::higher_ranked::HigherRankedRelations;
 use super::lattice::*;
-use super::sub::Sub;
-use super::{cres, InferCtxt};
-use super::{TypeTrace, Subtype};
+use super::{cres};
+use super::{Subtype};
 
 use middle::ty::{BuiltinBounds};
 use middle::ty::{self, Ty};
@@ -34,15 +31,30 @@ pub fn Lub<'f, 'tcx>(cf: CombineFields<'f, 'tcx>) -> Lub<'f, 'tcx> {
 }
 
 impl<'f, 'tcx> Combine<'tcx> for Lub<'f, 'tcx> {
-    fn infcx<'a>(&'a self) -> &'a InferCtxt<'a, 'tcx> { self.fields.infcx }
-    fn tag(&self) -> String { "lub".to_string() }
-    fn a_is_expected(&self) -> bool { self.fields.a_is_expected }
-    fn trace(&self) -> TypeTrace<'tcx> { self.fields.trace.clone() }
+    fn tag(&self) -> String { "Lub".to_string() }
+    fn fields<'a>(&'a self) -> &'a CombineFields<'a, 'tcx> { &self.fields }
 
-    fn equate<'a>(&'a self) -> Equate<'a, 'tcx> { Equate(self.fields.clone()) }
-    fn sub<'a>(&'a self) -> Sub<'a, 'tcx> { Sub(self.fields.clone()) }
-    fn lub<'a>(&'a self) -> Lub<'a, 'tcx> { Lub(self.fields.clone()) }
-    fn glb<'a>(&'a self) -> Glb<'a, 'tcx> { Glb(self.fields.clone()) }
+    fn tys_with_variance(&self, v: ty::Variance, a: Ty<'tcx>, b: Ty<'tcx>)
+                         -> cres<'tcx, Ty<'tcx>>
+    {
+        match v {
+            ty::Invariant => self.equate().tys(a, b),
+            ty::Covariant => self.tys(a, b),
+            ty::Bivariant => self.bivariate().tys(a, b),
+            ty::Contravariant => self.glb().tys(a, b),
+        }
+    }
+
+    fn regions_with_variance(&self, v: ty::Variance, a: ty::Region, b: ty::Region)
+                             -> cres<'tcx, ty::Region>
+    {
+        match v {
+            ty::Invariant => self.equate().regions(a, b),
+            ty::Covariant => self.regions(a, b),
+            ty::Bivariant => self.bivariate().regions(a, b),
+            ty::Contravariant => self.glb().regions(a, b),
+        }
+    }
 
     fn mts(&self, a: &ty::mt<'tcx>, b: &ty::mt<'tcx>) -> cres<'tcx, ty::mt<'tcx>> {
         let tcx = self.tcx();
@@ -70,10 +82,6 @@ impl<'f, 'tcx> Combine<'tcx> for Lub<'f, 'tcx> {
         }
     }
 
-    fn contratys(&self, a: Ty<'tcx>, b: Ty<'tcx>) -> cres<'tcx, Ty<'tcx>> {
-        self.glb().tys(a, b)
-    }
-
     fn unsafeties(&self, a: Unsafety, b: Unsafety) -> cres<'tcx, Unsafety> {
         match (a, b) {
           (Unsafety::Unsafe, _) | (_, Unsafety::Unsafe) => Ok(Unsafety::Unsafe),
@@ -90,11 +98,6 @@ impl<'f, 'tcx> Combine<'tcx> for Lub<'f, 'tcx> {
         Ok(a.intersection(b))
     }
 
-    fn contraregions(&self, a: ty::Region, b: ty::Region)
-                    -> cres<'tcx, ty::Region> {
-        self.glb().regions(a, b)
-    }
-
     fn regions(&self, a: ty::Region, b: ty::Region) -> cres<'tcx, ty::Region> {
         debug!("{}.regions({}, {})",
                self.tag(),