include more universe information in debug! printouts

Author: nikomatsakis

src/librustc/infer/higher_ranked/mod.rs

@@ -96,10 +96,15 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         let (result, map) = self.tcx.replace_bound_vars(binder, fld_r, fld_t);
 
         debug!(
-            "replace_bound_vars_with_placeholders(binder={:?}, result={:?}, map={:?})",
+            "replace_bound_vars_with_placeholders(\
+                next_universe={:?}, \
+                binder={:?}, \
+                result={:?}, \
+                map={:?})",
+            next_universe,
             binder,
             result,
-            map
+            map,
         );
 
         (result, map)

src/librustc/infer/region_constraints/mod.rs

@@ -514,8 +514,8 @@ impl<'tcx> RegionConstraintCollector<'tcx> {
             self.undo_log.push(AddVar(vid));
         }
         debug!(
-            "created new region variable {:?} with origin {:?}",
-            vid, origin
+            "created new region variable {:?} in {:?} with origin {:?}",
+            vid, universe, origin
         );
         return vid;
     }
@@ -671,6 +671,7 @@ impl<'tcx> RegionConstraintCollector<'tcx> {
             self.make_subregion(origin, sup, sub);
 
             if let (ty::ReVar(sub), ty::ReVar(sup)) = (*sub, *sup) {
+                debug!("make_eqregion: uniying {:?} with {:?}", sub, sup);
                 self.unification_table.union(sub, sup);
                 self.any_unifications = true;
             }

src/librustc/infer/type_variable.rs

@@ -188,7 +188,13 @@ impl<'tcx> TypeVariableTable<'tcx> {
         });
         assert_eq!(eq_key.vid.index, index as u32);
 
-        debug!("new_var(index={:?}, diverging={:?}, origin={:?}", eq_key.vid, diverging, origin);
+        debug!(
+            "new_var(index={:?}, universe={:?}, diverging={:?}, origin={:?}",
+            eq_key.vid,
+            universe,
+            diverging,
+            origin,
+        );
 
         eq_key.vid
     }