Store `crate_disambiguator` as an `InternedString`

We used to use `Name`, but the session outlives the tokenizer, which
means that attempts to read this field after trans has complete
otherwise panic. All reads want an `InternedString` anyhow.

2 files changed, 6 insertions, 3 deletions

diff --git a/src/librustc/session/mod.rs b/src/librustc/session/mod.rs
index 5901c42b525..cee18232ec9 100644
--- a/src/librustc/session/mod.rs
+++ b/src/librustc/session/mod.rs
@@ -80,7 +80,7 @@ pub struct Session {
     // forms a unique global identifier for the crate. It is used to allow
     // multiple crates with the same name to coexist. See the
     // trans::back::symbol_names module for more information.
-    pub crate_disambiguator: Cell<ast::Name>,
+    pub crate_disambiguator: RefCell<token::InternedString>,
     pub features: RefCell<feature_gate::Features>,
 
     /// The maximum recursion limit for potentially infinitely recursive
@@ -106,6 +106,9 @@ pub struct Session {
 }
 
 impl Session {
+    pub fn local_crate_disambiguator(&self) -> token::InternedString {
+        self.crate_disambiguator.borrow().clone()
+    }
     pub fn struct_span_warn<'a, S: Into<MultiSpan>>(&'a self,
                                                     sp: S,
                                                     msg: &str)
@@ -438,7 +441,7 @@ pub fn build_session_(sopts: config::Options,
         plugin_attributes: RefCell::new(Vec::new()),
         crate_types: RefCell::new(Vec::new()),
         dependency_formats: RefCell::new(FnvHashMap()),
-        crate_disambiguator: Cell::new(token::intern("")),
+        crate_disambiguator: RefCell::new(token::intern("").as_str()),
         features: RefCell::new(feature_gate::Features::new()),
         recursion_limit: Cell::new(64),
         next_node_id: Cell::new(1),
diff --git a/src/librustc/ty/context.rs b/src/librustc/ty/context.rs
index 56938a7a838..5444dd94761 100644
--- a/src/librustc/ty/context.rs
+++ b/src/librustc/ty/context.rs
@@ -504,7 +504,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
 
     pub fn crate_disambiguator(self, cnum: ast::CrateNum) -> token::InternedString {
         if cnum == LOCAL_CRATE {
-            self.sess.crate_disambiguator.get().as_str()
+            self.sess.local_crate_disambiguator()
         } else {
             self.sess.cstore.crate_disambiguator(cnum)
         }