move refcells out from RegionVarBindings and up into InferCtxt

Author: nikomatsakis

src/librustc/infer/equate.rs

@@ -104,7 +104,7 @@ impl<'combine, 'infcx, 'gcx, 'tcx> TypeRelation<'infcx, 'gcx, 'tcx>
                a,
                b);
         let origin = Subtype(self.fields.trace.clone());
-        self.fields.infcx.region_vars.make_eqregion(origin, a, b);
+        self.fields.infcx.region_vars.borrow_mut().make_eqregion(origin, a, b);
         Ok(a)
     }
 

src/librustc/infer/fudge.rs

@@ -78,7 +78,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                         self.type_variables.borrow_mut().types_created_since_snapshot(
                             &snapshot.type_snapshot);
                     let region_vars =
-                        self.region_vars.vars_created_since_snapshot(
+                        self.region_vars.borrow().vars_created_since_snapshot(
                             &snapshot.region_vars_snapshot);
 
                     Ok((type_variables, region_vars, value))

src/librustc/infer/glb.rs

@@ -67,7 +67,7 @@ impl<'combine, 'infcx, 'gcx, 'tcx> TypeRelation<'infcx, 'gcx, 'tcx>
                b);
 
         let origin = Subtype(self.fields.trace.clone());
-        Ok(self.fields.infcx.region_vars.glb_regions(self.tcx(), origin, a, b))
+        Ok(self.fields.infcx.region_vars.borrow_mut().glb_regions(self.tcx(), origin, a, b))
     }
 
     fn binders<T>(&mut self, a: &ty::Binder<T>, b: &ty::Binder<T>)

src/librustc/infer/higher_ranked/mod.rs

@@ -176,9 +176,9 @@ impl<'a, 'gcx, 'tcx> CombineFields<'a, 'gcx, 'tcx> {
                                      .filter(|&r| r != representative)
                 {
                     let origin = SubregionOrigin::Subtype(self.trace.clone());
-                    self.infcx.region_vars.make_eqregion(origin,
-                                                         *representative,
-                                                         *region);
+                    self.infcx.region_vars.borrow_mut().make_eqregion(origin,
+                                                                      *representative,
+                                                                      *region);
                 }
             }
 
@@ -427,7 +427,7 @@ impl<'a, 'gcx, 'tcx> CombineFields<'a, 'gcx, 'tcx> {
         fn fresh_bound_variable<'a, 'gcx, 'tcx>(infcx: &InferCtxt<'a, 'gcx, 'tcx>,
                                                 debruijn: ty::DebruijnIndex)
                                                 -> ty::Region<'tcx> {
-            infcx.region_vars.new_bound(infcx.tcx, debruijn)
+            infcx.region_vars.borrow_mut().new_bound(infcx.tcx, debruijn)
         }
     }
 }
@@ -481,7 +481,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                        r: ty::Region<'tcx>,
                        directions: TaintDirections)
                        -> FxHashSet<ty::Region<'tcx>> {
-        self.region_vars.tainted(self.tcx, &snapshot.region_vars_snapshot, r, directions)
+        self.region_vars.borrow().tainted(self.tcx, &snapshot.region_vars_snapshot, r, directions)
     }
 
     fn region_vars_confined_to_snapshot(&self,
@@ -539,7 +539,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
          */
 
         let mut region_vars =
-            self.region_vars.vars_created_since_snapshot(&snapshot.region_vars_snapshot);
+            self.region_vars.borrow().vars_created_since_snapshot(&snapshot.region_vars_snapshot);
 
         let escaping_types =
             self.type_variables.borrow_mut().types_escaping_snapshot(&snapshot.type_snapshot);
@@ -581,7 +581,9 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
         where T : TypeFoldable<'tcx>
     {
         let (result, map) = self.tcx.replace_late_bound_regions(binder, |br| {
-            self.region_vars.push_skolemized(self.tcx, br, &snapshot.region_vars_snapshot)
+            self.region_vars.borrow_mut().push_skolemized(self.tcx,
+                                                          br,
+                                                          &snapshot.region_vars_snapshot)
         });
 
         debug!("skolemize_bound_regions(binder={:?}, result={:?}, map={:?})",
@@ -766,7 +768,9 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
     {
         debug!("pop_skolemized({:?})", skol_map);
         let skol_regions: FxHashSet<_> = skol_map.values().cloned().collect();
-        self.region_vars.pop_skolemized(self.tcx, &skol_regions, &snapshot.region_vars_snapshot);
+        self.region_vars.borrow_mut().pop_skolemized(self.tcx,
+                                                     &skol_regions,
+                                                     &snapshot.region_vars_snapshot);
         if !skol_map.is_empty() {
             self.projection_cache.borrow_mut().rollback_skolemized(
                 &snapshot.projection_cache_snapshot);

src/librustc/infer/lexical_region_resolve/graphviz.rs

@@ -113,8 +113,7 @@ pub fn maybe_print_constraints_for<'a, 'gcx, 'tcx>(
         }
     };
 
-    let constraints = &*region_vars.constraints.borrow();
-    match dump_region_constraints_to(region_rels, constraints, &output_path) {
+    match dump_region_constraints_to(region_rels, &region_vars.constraints, &output_path) {
         Ok(()) => {}
         Err(e) => {
             let msg = format!("io error dumping region constraints: {}", e);

src/librustc/infer/lexical_region_resolve/mod.rs

@@ -80,7 +80,7 @@ impl<'tcx> RegionVarBindings<'tcx> {
     /// constraints, assuming such values can be found; if they cannot,
     /// errors are reported.
     pub fn resolve_regions(
-        &self,
+        &mut self,
         region_rels: &RegionRelations<'_, '_, 'tcx>,
     ) -> (
         LexicalRegionResolutions<'tcx>,
@@ -114,7 +114,7 @@ impl<'tcx> RegionVarBindings<'tcx> {
 
             (&ReVar(v_id), _) | (_, &ReVar(v_id)) => {
                 span_bug!(
-                    (*self.var_origins.borrow())[v_id.index as usize].span(),
+                    self.var_origins[v_id.index as usize].span(),
                     "lub_concrete_regions invoked with non-concrete \
                      regions: {:?}, {:?}",
                     a,
@@ -183,7 +183,7 @@ impl<'tcx> RegionVarBindings<'tcx> {
     }
 
     fn infer_variable_values(
-        &self,
+        &mut self,
         region_rels: &RegionRelations<'_, '_, 'tcx>,
         errors: &mut Vec<RegionResolutionError<'tcx>>,
     ) -> LexicalRegionResolutions<'tcx> {
@@ -222,12 +222,12 @@ impl<'tcx> RegionVarBindings<'tcx> {
             "----() Start constraint listing (context={:?}) ()----",
             free_regions.context
         );
-        for (idx, (constraint, _)) in self.constraints.borrow().iter().enumerate() {
+        for (idx, (constraint, _)) in self.constraints.iter().enumerate() {
             debug!("Constraint {} => {:?}", idx, constraint);
         }
     }
 
-    fn expand_givens(&self, graph: &RegionGraph) {
+    fn expand_givens(&mut self, graph: &RegionGraph) {
         // Givens are a kind of horrible hack to account for
         // constraints like 'c <= '0 that are known to hold due to
         // closure signatures (see the comment above on the `givens`
@@ -238,15 +238,14 @@ impl<'tcx> RegionVarBindings<'tcx> {
         //     and   '0 <= '1
         //     then  'c <= '1
 
-        let mut givens = self.givens.borrow_mut();
-        let seeds: Vec<_> = givens.iter().cloned().collect();
+        let seeds: Vec<_> = self.givens.iter().cloned().collect();
         for (r, vid) in seeds {
             let seed_index = NodeIndex(vid.index as usize);
             for succ_index in graph.depth_traverse(seed_index, OUTGOING) {
                 let succ_index = succ_index.0 as u32;
                 if succ_index < self.num_vars() {
                     let succ_vid = RegionVid { index: succ_index };
-                    givens.insert((r, succ_vid));
+                    self.givens.insert((r, succ_vid));
                 }
             }
         }
@@ -292,7 +291,7 @@ impl<'tcx> RegionVarBindings<'tcx> {
         // Check if this relationship is implied by a given.
         match *a_region {
             ty::ReEarlyBound(_) | ty::ReFree(_) => {
-                if self.givens.borrow().contains(&(a_region, b_vid)) {
+                if self.givens.contains(&(a_region, b_vid)) {
                     debug!("given");
                     return false;
                 }
@@ -333,8 +332,7 @@ impl<'tcx> RegionVarBindings<'tcx> {
         var_data: &mut LexicalRegionResolutions<'tcx>,
         errors: &mut Vec<RegionResolutionError<'tcx>>,
     ) {
-        let constraints = self.constraints.borrow();
-        for (constraint, origin) in constraints.iter() {
+        for (constraint, origin) in &self.constraints {
             debug!(
                 "collect_errors: constraint={:?} origin={:?}",
                 constraint,
@@ -392,7 +390,7 @@ impl<'tcx> RegionVarBindings<'tcx> {
             }
         }
 
-        for verify in self.verifys.borrow().iter() {
+        for verify in &self.verifys {
             debug!("collect_errors: verify={:?}", verify);
             let sub = var_data.normalize(verify.region);
 
@@ -488,8 +486,6 @@ impl<'tcx> RegionVarBindings<'tcx> {
     fn construct_graph(&self) -> RegionGraph<'tcx> {
         let num_vars = self.num_vars();
 
-        let constraints = self.constraints.borrow();
-
         let mut graph = graph::Graph::new();
 
         for _ in 0..num_vars {
@@ -504,7 +500,7 @@ impl<'tcx> RegionVarBindings<'tcx> {
         let dummy_source = graph.add_node(());
         let dummy_sink = graph.add_node(());
 
-        for (constraint, _) in constraints.iter() {
+        for (constraint, _) in &self.constraints {
             match *constraint {
                 Constraint::VarSubVar(a_id, b_id) => {
                     graph.add_edge(
@@ -564,7 +560,7 @@ impl<'tcx> RegionVarBindings<'tcx> {
         for lower_bound in &lower_bounds {
             for upper_bound in &upper_bounds {
                 if !region_rels.is_subregion_of(lower_bound.region, upper_bound.region) {
-                    let origin = (*self.var_origins.borrow())[node_idx.index as usize].clone();
+                    let origin = self.var_origins[node_idx.index as usize].clone();
                     debug!(
                         "region inference error at {:?} for {:?}: SubSupConflict sub: {:?} \
                          sup: {:?}",
@@ -586,7 +582,7 @@ impl<'tcx> RegionVarBindings<'tcx> {
         }
 
         span_bug!(
-            (*self.var_origins.borrow())[node_idx.index as usize].span(),
+            self.var_origins[node_idx.index as usize].span(),
             "collect_error_for_expanding_node() could not find \
              error for var {:?}, lower_bounds={:?}, \
              upper_bounds={:?}",
@@ -671,7 +667,7 @@ impl<'tcx> RegionVarBindings<'tcx> {
                     Constraint::RegSubVar(region, _) | Constraint::VarSubReg(_, region) => {
                         state.result.push(RegionAndOrigin {
                             region,
-                            origin: this.constraints.borrow().get(&edge.data).unwrap().clone(),
+                            origin: this.constraints.get(&edge.data).unwrap().clone(),
                         });
                     }
 
@@ -694,7 +690,7 @@ impl<'tcx> RegionVarBindings<'tcx> {
             changed = false;
             iteration += 1;
             debug!("---- {} Iteration {}{}", "#", tag, iteration);
-            for (constraint, origin) in self.constraints.borrow().iter() {
+            for (constraint, origin) in &self.constraints {
                 let edge_changed = body(constraint, origin);
                 if edge_changed {
                     debug!("Updated due to constraint {:?}", constraint);

src/librustc/infer/lub.rs

@@ -67,7 +67,7 @@ impl<'combine, 'infcx, 'gcx, 'tcx> TypeRelation<'infcx, 'gcx, 'tcx>
                b);
 
         let origin = Subtype(self.fields.trace.clone());
-        Ok(self.fields.infcx.region_vars.lub_regions(self.tcx(), origin, a, b))
+        Ok(self.fields.infcx.region_vars.borrow_mut().lub_regions(self.tcx(), origin, a, b))
     }
 
     fn binders<T>(&mut self, a: &ty::Binder<T>, b: &ty::Binder<T>)

src/librustc/infer/mod.rs

@@ -104,7 +104,7 @@ pub struct InferCtxt<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
     float_unification_table: RefCell<UnificationTable<ty::FloatVid>>,
 
     // For region variables.
-    region_vars: RegionVarBindings<'tcx>,
+    region_vars: RefCell<RegionVarBindings<'tcx>>,
 
     // Once region inference is done, the values for each variable.
     lexical_region_resolutions: RefCell<Option<LexicalRegionResolutions<'tcx>>>,
@@ -424,7 +424,7 @@ impl<'a, 'gcx, 'tcx> InferCtxtBuilder<'a, 'gcx, 'tcx> {
             type_variables: RefCell::new(type_variable::TypeVariableTable::new()),
             int_unification_table: RefCell::new(UnificationTable::new()),
             float_unification_table: RefCell::new(UnificationTable::new()),
-            region_vars: RegionVarBindings::new(),
+            region_vars: RefCell::new(RegionVarBindings::new()),
             lexical_region_resolutions: RefCell::new(None),
             selection_cache: traits::SelectionCache::new(),
             evaluation_cache: traits::EvaluationCache::new(),
@@ -767,7 +767,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
             type_snapshot: self.type_variables.borrow_mut().snapshot(),
             int_snapshot: self.int_unification_table.borrow_mut().snapshot(),
             float_snapshot: self.float_unification_table.borrow_mut().snapshot(),
-            region_vars_snapshot: self.region_vars.start_snapshot(),
+            region_vars_snapshot: self.region_vars.borrow_mut().start_snapshot(),
             was_in_snapshot: in_snapshot,
             // Borrow tables "in progress" (i.e. during typeck)
             // to ban writes from within a snapshot to them.
@@ -802,6 +802,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
             .borrow_mut()
             .rollback_to(float_snapshot);
         self.region_vars
+            .borrow_mut()
             .rollback_to(region_vars_snapshot);
     }
 
@@ -830,6 +831,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
             .borrow_mut()
             .commit(float_snapshot);
         self.region_vars
+            .borrow_mut()
             .commit(region_vars_snapshot);
     }
 
@@ -885,7 +887,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                      sub: ty::Region<'tcx>,
                      sup: ty::RegionVid)
     {
-        self.region_vars.add_given(sub, sup);
+        self.region_vars.borrow_mut().add_given(sub, sup);
     }
 
     pub fn can_sub<T>(&self,
@@ -925,7 +927,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                        a: ty::Region<'tcx>,
                        b: ty::Region<'tcx>) {
         debug!("sub_regions({:?} <: {:?})", a, b);
-        self.region_vars.make_subregion(origin, a, b);
+        self.region_vars.borrow_mut().make_subregion(origin, a, b);
     }
 
     pub fn equality_predicate(&self,
@@ -1028,7 +1030,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
 
     pub fn next_region_var(&self, origin: RegionVariableOrigin)
                            -> ty::Region<'tcx> {
-        self.tcx.mk_region(ty::ReVar(self.region_vars.new_region_var(origin)))
+        self.tcx.mk_region(ty::ReVar(self.region_vars.borrow_mut().new_region_var(origin)))
     }
 
     /// Create a region inference variable for the given
@@ -1124,7 +1126,8 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                                                region_context,
                                                region_map,
                                                free_regions);
-        let (lexical_region_resolutions, errors) = self.region_vars.resolve_regions(&region_rels);
+        let (lexical_region_resolutions, errors) =
+            self.region_vars.borrow_mut().resolve_regions(&region_rels);
 
         let old_value = self.lexical_region_resolutions.replace(Some(lexical_region_resolutions));
         assert!(old_value.is_none());
@@ -1362,7 +1365,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
                a,
                bound);
 
-        self.region_vars.verify_generic_bound(origin, kind, a, bound);
+        self.region_vars.borrow_mut().verify_generic_bound(origin, kind, a, bound);
     }
 
     pub fn type_moves_by_default(&self,