From a66fcca9c9c279db5ab804734a0310b6aec60415 Mon Sep 17 00:00:00 2001
From: Patrick Walton <pcwalton@mimiga.net>
Date: Thu, 19 Dec 2013 19:05:11 -0800
Subject: [PATCH] librustc: De-`@mut` `destructors` in the type context

---
 src/librustc/middle/ty.rs                  | 4 ++--
 src/librustc/middle/typeck/check/method.rs | 3 ++-
 src/librustc/middle/typeck/coherence.rs    | 3 ++-
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/librustc/middle/ty.rs b/src/librustc/middle/ty.rs
index 1d0bc49b8c9..acfe26d2817 100644
--- a/src/librustc/middle/ty.rs
+++ b/src/librustc/middle/ty.rs
@@ -330,7 +330,7 @@ struct ctxt_ {
     destructor_for_type: RefCell<HashMap<ast::DefId, ast::DefId>>,
 
     // A method will be in this list if and only if it is a destructor.
-    destructors: @mut HashSet<ast::DefId>,
+    destructors: RefCell<HashSet<ast::DefId>>,
 
     // Maps a trait onto a list of impls of that trait.
     trait_impls: @mut HashMap<ast::DefId, @mut ~[@Impl]>,
@@ -1004,7 +1004,7 @@ pub fn mk_ctxt(s: session::Session,
         provided_method_sources: RefCell::new(HashMap::new()),
         supertraits: RefCell::new(HashMap::new()),
         destructor_for_type: RefCell::new(HashMap::new()),
-        destructors: @mut HashSet::new(),
+        destructors: RefCell::new(HashSet::new()),
         trait_impls: @mut HashMap::new(),
         inherent_impls:  @mut HashMap::new(),
         impls:  @mut HashMap::new(),
diff --git a/src/librustc/middle/typeck/check/method.rs b/src/librustc/middle/typeck/check/method.rs
index 56e9f6be55e..524eb6282a8 100644
--- a/src/librustc/middle/typeck/check/method.rs
+++ b/src/librustc/middle/typeck/check/method.rs
@@ -1151,7 +1151,8 @@ impl<'a> LookupContext<'a> {
         let bad;
         match candidate.origin {
             method_static(method_id) => {
-                bad = self.tcx().destructors.contains(&method_id);
+                let destructors = self.tcx().destructors.borrow();
+                bad = destructors.get().contains(&method_id);
             }
             // XXX: does this properly enforce this on everything now
             // that self has been merged in? -sully
diff --git a/src/librustc/middle/typeck/coherence.rs b/src/librustc/middle/typeck/coherence.rs
index 0371f877f4f..aef94e2ec94 100644
--- a/src/librustc/middle/typeck/coherence.rs
+++ b/src/librustc/middle/typeck/coherence.rs
@@ -709,7 +709,8 @@ impl CoherenceChecker {
                                                      .borrow_mut();
                     destructor_for_type.get().insert(type_def_id,
                                                      method_def_id);
-                    tcx.destructors.insert(method_def_id);
+                    let mut destructors = tcx.destructors.borrow_mut();
+                    destructors.get().insert(method_def_id);
                 }
                 _ => {
                     // Destructors only work on nominal types.