Fixes after rebase

Author: canndrew

Diff for: src/librustc/infer/canonical.rs

@@ -609,12 +609,6 @@ impl<'cx, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for Canonicalizer<'cx, 'gcx, 'tcx>
                 bug!("encountered a canonical type during canonicalization")
             }
 
-            // Replace a `()` that "would've fallen back" to `!` with just `()`.
-            ty::TyTuple(ref tys, true) => {
-                assert!(tys.is_empty());
-                self.tcx().mk_nil()
-            }
-
             ty::TyClosure(..)
             | ty::TyGenerator(..)
             | ty::TyGeneratorWitness(..)
@@ -634,7 +628,7 @@ impl<'cx, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for Canonicalizer<'cx, 'gcx, 'tcx>
             | ty::TyFnPtr(_)
             | ty::TyDynamic(..)
             | ty::TyNever
-            | ty::TyTuple(_, false)
+            | ty::TyTuple(..)
             | ty::TyProjection(..)
             | ty::TyForeign(..)
             | ty::TyParam(..)

Diff for: src/librustc/traits/query/dropck_outlives.rs

@@ -236,7 +236,7 @@ fn trivial_dropck_outlives<'cx, 'tcx>(tcx: TyCtxt<'cx, '_, 'tcx>, ty: Ty<'tcx>)
 
         // (T1..Tn) and closures have same properties as T1..Tn --
         // check if *any* of those are trivial.
-        ty::TyTuple(ref tys, _) => tys.iter().cloned().all(|t| trivial_dropck_outlives(tcx, t)),
+        ty::TyTuple(ref tys) => tys.iter().cloned().all(|t| trivial_dropck_outlives(tcx, t)),
         ty::TyClosure(def_id, ref substs) => substs
             .upvar_tys(def_id, tcx)
             .all(|t| trivial_dropck_outlives(tcx, t)),

Diff for: src/librustc_traits/dropck_outlives.rs

@@ -184,7 +184,7 @@ fn dtorck_constraint_for_ty<'a, 'gcx, 'tcx>(
             dtorck_constraint_for_ty(tcx, span, for_ty, depth + 1, ety)
         }
 
-        ty::TyTuple(tys, _) => tys.iter()
+        ty::TyTuple(tys) => tys.iter()
             .map(|ty| dtorck_constraint_for_ty(tcx, span, for_ty, depth + 1, ty))
             .collect(),