---

yaml
---
r: 147701
b: refs/heads/try2
c: 7f816b7
h: refs/heads/master
i:
  147699: 311282f
v: v3

Author: pcwalton

[refs]

@@ -5,7 +5,7 @@ refs/heads/snap-stage3: 78a7676898d9f80ab540c6df5d4c9ce35bb50463
 refs/heads/try: 519addf6277dbafccbb4159db4b710c37eaa2ec5
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
-refs/heads/try2: 8c703643ad0bb1c70c249dc16b5a32e253815be1
+refs/heads/try2: 7f816b7ef4c617eec3d03397f4013c06c9f98ce2
 refs/heads/dist-snap: ba4081a5a8573875fed17545846f6f6902c8ba8d
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596
 refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503

branches/try2/src/librustc/middle/check_const.rs

@@ -15,6 +15,7 @@ use middle::ty;
 use middle::typeck;
 use util::ppaux;
 
+use std::cell::RefCell;
 use syntax::ast::*;
 use syntax::codemap;
 use syntax::{ast_util, ast_map};
@@ -215,7 +216,7 @@ struct env {
     sess: Session,
     ast_map: ast_map::map,
     def_map: resolve::DefMap,
-    idstack: @mut ~[NodeId]
+    idstack: @RefCell<~[NodeId]>,
 }
 
 struct CheckItemRecursionVisitor {
@@ -233,7 +234,7 @@ pub fn check_item_recursion(sess: Session,
         sess: sess,
         ast_map: ast_map,
         def_map: def_map,
-        idstack: @mut ~[]
+        idstack: @RefCell::new(~[]),
     };
 
     let mut visitor = CheckItemRecursionVisitor { env: env };
@@ -242,12 +243,19 @@ pub fn check_item_recursion(sess: Session,
 
 impl Visitor<()> for CheckItemRecursionVisitor {
     fn visit_item(&mut self, it: @item, _: ()) {
-        if self.env.idstack.iter().any(|x| x == &(it.id)) {
-            self.env.sess.span_fatal(self.env.root_it.span, "recursive constant");
+        {
+            let mut idstack = self.env.idstack.borrow_mut();
+            if idstack.get().iter().any(|x| x == &(it.id)) {
+                self.env.sess.span_fatal(self.env.root_it.span,
+                                         "recursive constant");
+            }
+            idstack.get().push(it.id);
         }
-        self.env.idstack.push(it.id);
         visit::walk_item(self, it, ());
-        self.env.idstack.pop();
+        {
+            let mut idstack = self.env.idstack.borrow_mut();
+            idstack.get().pop();
+        }
     }
 
     fn visit_expr(&mut self, e: @Expr, _: ()) {