librustc: De-@mut the type context's methods table

Author: pcwalton

src/librustc/middle/lint.rs

@@ -1141,7 +1141,14 @@ fn check_missing_doc_method(cx: &Context, m: &ast::method) {
         crate: ast::LOCAL_CRATE,
         node: m.id
     };
-    match cx.tcx.methods.find(&did) {
+
+    let method_opt;
+    {
+        let methods = cx.tcx.methods.borrow();
+        method_opt = methods.get().find(&did).map(|method| *method);
+    }
+
+    match method_opt {
         None => cx.tcx.sess.span_bug(m.span, "missing method descriptor?!"),
         Some(md) => {
             match md.container {

src/librustc/middle/privacy.rs

@@ -340,7 +340,9 @@ impl<'a> PrivacyVisitor<'a> {
                 return Allowable;
             }
             debug!("privacy - is {:?} a public method", did);
-            return match self.tcx.methods.find(&did) {
+
+            let methods = self.tcx.methods.borrow();
+            return match methods.get().find(&did) {
                 Some(meth) => {
                     debug!("privacy - well at least it's a method: {:?}", meth);
                     match meth.container {

src/librustc/middle/ty.rs

@@ -287,7 +287,7 @@ struct ctxt_ {
     node_type_substs: RefCell<HashMap<NodeId, ~[t]>>,
 
     // Maps from a method to the method "descriptor"
-    methods: @mut HashMap<DefId, @Method>,
+    methods: RefCell<HashMap<DefId, @Method>>,
 
     // Maps from a trait def-id to a list of the def-ids of its methods
     trait_method_def_ids: @mut HashMap<DefId, @~[DefId]>,
@@ -998,7 +998,7 @@ pub fn mk_ctxt(s: session::Session,
         tc_cache: @mut HashMap::new(),
         ast_ty_to_ty_cache: @mut HashMap::new(),
         enum_var_cache: @mut HashMap::new(),
-        methods: @mut HashMap::new(),
+        methods: RefCell::new(HashMap::new()),
         trait_method_def_ids: @mut HashMap::new(),
         trait_methods_cache: @mut HashMap::new(),
         impl_trait_cache: @mut HashMap::new(),
@@ -3603,9 +3603,10 @@ pub fn trait_methods(cx: ctxt, trait_did: ast::DefId) -> @~[@Method] {
 }
 
 pub fn method(cx: ctxt, id: ast::DefId) -> @Method {
-    lookup_locally_or_in_crate_store(
-        "methods", id, cx.methods,
-        || @csearch::get_method(cx, id))
+    let mut methods = cx.methods.borrow_mut();
+    lookup_locally_or_in_crate_store("methods", id, methods.get(), || {
+        @csearch::get_method(cx, id)
+    })
 }
 
 pub fn trait_method_def_ids(cx: ctxt, id: ast::DefId) -> @~[DefId] {
@@ -4577,7 +4578,12 @@ pub fn trait_of_method(tcx: ctxt, def_id: ast::DefId)
     if def_id.crate != LOCAL_CRATE {
         return csearch::get_trait_of_method(tcx.cstore, def_id, tcx);
     }
-    match tcx.methods.find(&def_id) {
+    let method;
+    {
+        let methods = tcx.methods.borrow();
+        method = methods.get().find(&def_id).map(|method| *method);
+    }
+    match method {
         Some(method) => {
             match method.container {
                 TraitContainer(def_id) => Some(def_id),
@@ -4596,10 +4602,15 @@ pub fn trait_of_method(tcx: ctxt, def_id: ast::DefId)
 /// Otherwise, return `None`.
 pub fn trait_method_of_method(tcx: ctxt,
                               def_id: ast::DefId) -> Option<ast::DefId> {
-    let name = match tcx.methods.find(&def_id) {
-        Some(method) => method.ident.name,
-        None => return None
-    };
+    let method;
+    {
+        let methods = tcx.methods.borrow();
+        match methods.get().find(&def_id) {
+            Some(m) => method = *m,
+            None => return None,
+        }
+    }
+    let name = method.ident.name;
     match trait_of_method(tcx, def_id) {
         Some(trait_did) => {
             let trait_methods = ty::trait_methods(tcx, trait_did);

src/librustc/middle/typeck/coherence.rs

@@ -366,7 +366,9 @@ impl CoherenceChecker {
             debug!("new_polytype={}", new_polytype.repr(tcx));
 
             tcx.tcache.insert(new_did, new_polytype);
-            tcx.methods.insert(new_did, new_method_ty);
+
+            let mut methods = tcx.methods.borrow_mut();
+            methods.get().insert(new_did, new_method_ty);
 
             // Pair the new synthesized ID up with the
             // ID of the method.

src/librustc/middle/typeck/collect.rs

@@ -213,7 +213,8 @@ pub fn ensure_trait_methods(ccx: &CrateCtxt,
                                           &trait_ty_generics);
                 }
 
-                tcx.methods.insert(ty_method.def_id, ty_method);
+                let mut methods = tcx.methods.borrow_mut();
+                methods.get().insert(ty_method.def_id, ty_method);
             }
 
             // Add an entry mapping
@@ -476,7 +477,9 @@ fn convert_methods(ccx: &CrateCtxt,
                 ty: fty
             });
         write_ty_to_tcx(tcx, m.id, fty);
-        tcx.methods.insert(mty.def_id, mty);
+
+        let mut methods = tcx.methods.borrow_mut();
+        methods.get().insert(mty.def_id, mty);
     }
 
     fn ty_of_method(ccx: &CrateCtxt,