Generalize the replace-late-bound-regions function to operate

over anything that is foldable, not just fn signatures.

Author: nikomatsakis

src/librustc/middle/typeck/check/mod.rs

@@ -97,11 +97,8 @@ use middle::typeck::astconv::{ast_region_to_region, ast_ty_to_ty};
 use middle::typeck::astconv;
 use middle::typeck::check::_match::pat_ctxt;
 use middle::typeck::check::method::{AutoderefReceiver};
-use middle::typeck::check::method::{AutoderefReceiverFlag};
 use middle::typeck::check::method::{CheckTraitsAndInherentMethods};
-use middle::typeck::check::method::{DontAutoderefReceiver};
-use middle::typeck::check::method::{IgnoreStaticMethods, ReportStaticMethods};
-use middle::typeck::check::regionmanip::replace_late_bound_regions_in_fn_sig;
+use middle::typeck::check::regionmanip::replace_late_bound_regions;
 use middle::typeck::CrateCtxt;
 use middle::typeck::infer::{resolve_type, force_tvar};
 use middle::typeck::infer;
@@ -529,7 +526,7 @@ fn check_fn<'a, 'tcx>(ccx: &'a CrateCtxt<'a, 'tcx>,
 
     // First, we have to replace any bound regions in the fn type with free ones.
     // The free region references will be bound the node_id of the body block.
-    let (_, fn_sig) = replace_late_bound_regions_in_fn_sig(tcx, fn_sig, |br| {
+    let (_, fn_sig) = replace_late_bound_regions(tcx, fn_sig.binder_id, fn_sig, |br| {
         ty::ReFree(ty::FreeRegion {scope_id: body.id, bound_region: br})
     });
 
@@ -1531,6 +1528,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         &self.inh.infcx
     }
 
+    pub fn sess(&self) -> &Session {
+        &self.tcx().sess
+    }
+
     pub fn err_count_since_creation(&self) -> uint {
         self.ccx.tcx.sess.err_count() - self.err_count_on_creation
     }
@@ -2890,7 +2891,7 @@ fn check_expr_with_unifier(fcx: &FnCtxt,
 
         // Replace any bound regions that appear in the function
         // signature with region variables
-        let (_, fn_sig) = replace_late_bound_regions_in_fn_sig(fcx.tcx(), fn_sig, |br| {
+        let (_, fn_sig) = replace_late_bound_regions(fcx.tcx(), fn_sig.binder_id, fn_sig, |br| {
             fcx.infcx().next_region_var(infer::LateBoundRegion(call_expr.span, br))
         });
 
@@ -3346,8 +3347,8 @@ fn check_expr_with_unifier(fcx: &FnCtxt,
             match expected_sty {
                 Some(ty::ty_closure(ref cenv)) => {
                     let (_, sig) =
-                        replace_late_bound_regions_in_fn_sig(
-                            tcx, &cenv.sig,
+                        replace_late_bound_regions(
+                            tcx, cenv.sig.binder_id, &cenv.sig,
                             |_| fcx.inh.infcx.fresh_bound_region(expr.id));
                     let onceness = match (&store, &cenv.store) {
                         // As the closure type and onceness go, only three

src/librustc/middle/typeck/check/regionmanip.rs

@@ -13,7 +13,7 @@
 use middle::subst::{ParamSpace, Subst, Substs};
 use middle::ty;
 use middle::ty_fold;
-use middle::ty_fold::TypeFolder;
+use middle::ty_fold::{TypeFolder, TypeFoldable};
 
 use syntax::ast;
 
@@ -23,31 +23,34 @@ use util::ppaux::Repr;
 
 // Helper functions related to manipulating region types.
 
-pub fn replace_late_bound_regions_in_fn_sig(
-        tcx: &ty::ctxt,
-        fn_sig: &ty::FnSig,
-        mapf: |ty::BoundRegion| -> ty::Region)
-        -> (HashMap<ty::BoundRegion,ty::Region>, ty::FnSig) {
-    debug!("replace_late_bound_regions_in_fn_sig({})", fn_sig.repr(tcx));
+pub fn replace_late_bound_regions<T>(
+    tcx: &ty::ctxt,
+    binder_id: ast::NodeId,
+    value: &T,
+    map_fn: |ty::BoundRegion| -> ty::Region)
+    -> (HashMap<ty::BoundRegion,ty::Region>, T)
+    where T : TypeFoldable + Repr
+{
+    debug!("replace_late_bound_regions(binder_id={}, value={})",
+           binder_id, value.repr(tcx));
 
     let mut map = HashMap::new();
-    let fn_sig = {
-        let mut f = ty_fold::RegionFolder::regions(tcx, |r| {
-            debug!("region r={}", r.to_string());
+    let new_value = {
+        let mut folder = ty_fold::RegionFolder::regions(tcx, |r| {
             match r {
-                ty::ReLateBound(s, br) if s == fn_sig.binder_id => {
-                    * match map.entry(br) {
-                        Vacant(entry) => entry.set(mapf(br)),
-                        Occupied(entry) => entry.into_mut(),
+                ty::ReLateBound(s, br) if s == binder_id => {
+                    match map.entry(br) {
+                        Vacant(entry) => *entry.set(map_fn(br)),
+                        Occupied(entry) => *entry.into_mut(),
                     }
                 }
                 _ => r
             }
         });
-        ty_fold::super_fold_sig(&mut f, fn_sig)
+        value.fold_with(&mut folder)
     };
     debug!("resulting map: {}", map);
-    (map, fn_sig)
+    (map, new_value)
 }
 
 pub enum WfConstraint {

src/librustc/middle/typeck/check/wf.rs

@@ -15,7 +15,7 @@ use middle::ty;
 use middle::ty_fold::{TypeFolder, TypeFoldable};
 use middle::typeck::astconv::AstConv;
 use middle::typeck::check::{FnCtxt, Inherited, blank_fn_ctxt, vtable2, regionck};
-use middle::typeck::check::regionmanip::replace_late_bound_regions_in_fn_sig;
+use middle::typeck::check::regionmanip::replace_late_bound_regions;
 use middle::typeck::CrateCtxt;
 use util::ppaux::Repr;
 
@@ -373,8 +373,8 @@ impl<'cx,'tcx> TypeFolder<'tcx> for BoundsChecker<'cx,'tcx> {
                 self.binding_count += 1;
 
                 let (_, fn_sig) =
-                    replace_late_bound_regions_in_fn_sig(
-                        self.fcx.tcx(), fn_sig,
+                    replace_late_bound_regions(
+                        self.fcx.tcx(), fn_sig.binder_id, fn_sig,
                         |br| ty::ReFree(ty::FreeRegion{scope_id: self.scope_id,
                                                        bound_region: br}));
 

src/librustc/middle/typeck/infer/mod.rs

@@ -28,7 +28,7 @@ use middle::ty::{TyVid, IntVid, FloatVid, RegionVid};
 use middle::ty;
 use middle::ty_fold;
 use middle::ty_fold::{TypeFolder, TypeFoldable};
-use middle::typeck::check::regionmanip::replace_late_bound_regions_in_fn_sig;
+use middle::typeck::check::regionmanip::replace_late_bound_regions;
 use std::cell::{RefCell};
 use std::collections::HashMap;
 use std::rc::Rc;
@@ -962,7 +962,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
                                                         HashMap<ty::BoundRegion,
                                                                 ty::Region>) {
         let (map, fn_sig) =
-            replace_late_bound_regions_in_fn_sig(self.tcx, fsig, |br| {
+            replace_late_bound_regions(self.tcx, fsig.binder_id, fsig, |br| {
                 let rvar = self.next_region_var(
                     BoundRegionInFnType(trace.origin.span(), br));
                 debug!("Bound region {} maps to {}",

src/librustc/middle/typeck/infer/sub.rs

@@ -12,7 +12,7 @@
 use middle::ty::{BuiltinBounds};
 use middle::ty;
 use middle::ty::TyVar;
-use middle::typeck::check::regionmanip::replace_late_bound_regions_in_fn_sig;
+use middle::typeck::check::regionmanip::replace_late_bound_regions;
 use middle::typeck::infer::combine::*;
 use middle::typeck::infer::{cres, CresCompare};
 use middle::typeck::infer::equate::Equate;
@@ -189,7 +189,7 @@ impl<'f, 'tcx> Combine<'tcx> for Sub<'f, 'tcx> {
         // Second, we instantiate each bound region in the supertype with a
         // fresh concrete region.
         let (skol_map, b_sig) = {
-            replace_late_bound_regions_in_fn_sig(self.fields.infcx.tcx, b, |br| {
+            replace_late_bound_regions(self.fields.infcx.tcx, b.binder_id, b, |br| {
                 let skol = self.fields.infcx.region_vars.new_skolemized(br);
                 debug!("Bound region {} skolemized to {}",
                        bound_region_to_string(self.fields.infcx.tcx, "", false, br),