diff --git a/src/librustc/middle/trans/context.rs b/src/librustc/middle/trans/context.rs
index 2d8fdde7e98..778a50b5684 100644
--- a/src/librustc/middle/trans/context.rs
+++ b/src/librustc/middle/trans/context.rs
@@ -27,7 +27,7 @@ use middle::trans::type_::Type;
 
 use util::sha2::Sha256;
 
-use std::cell::RefCell;
+use std::cell::{Cell, RefCell};
 use std::c_str::ToCStr;
 use std::hashmap::{HashMap, HashSet};
 use std::local_data;
@@ -55,7 +55,7 @@ pub struct CrateContext {
      tydescs: RefCell<HashMap<ty::t, @mut tydesc_info>>,
      // Set when running emit_tydescs to enforce that no more tydescs are
      // created.
-     finished_tydescs: bool,
+     finished_tydescs: Cell<bool>,
      // Track mapping of external ids to local items imported for inlining
      external: RefCell<HashMap<ast::DefId, Option<ast::NodeId>>>,
      // Backwards version of the `external` map (inlined items to where they
@@ -189,7 +189,7 @@ impl CrateContext {
                   item_symbols: RefCell::new(HashMap::new()),
                   link_meta: link_meta,
                   tydescs: RefCell::new(HashMap::new()),
-                  finished_tydescs: false,
+                  finished_tydescs: Cell::new(false),
                   external: RefCell::new(HashMap::new()),
                   external_srcs: RefCell::new(HashMap::new()),
                   non_inlineable_statics: RefCell::new(HashSet::new()),
diff --git a/src/librustc/middle/trans/glue.rs b/src/librustc/middle/trans/glue.rs
index 32b4bb489a1..ad5e4e8942c 100644
--- a/src/librustc/middle/trans/glue.rs
+++ b/src/librustc/middle/trans/glue.rs
@@ -589,7 +589,7 @@ pub fn incr_refcnt_of_boxed(cx: @Block, box_ptr: ValueRef) {
 pub fn declare_tydesc(ccx: &mut CrateContext, t: ty::t) -> @mut tydesc_info {
     // If emit_tydescs already ran, then we shouldn't be creating any new
     // tydescs.
-    assert!(!ccx.finished_tydescs);
+    assert!(!ccx.finished_tydescs.get());
 
     let llty = type_of(ccx, t);
 
@@ -694,7 +694,7 @@ pub fn make_generic_glue(ccx: @mut CrateContext,
 pub fn emit_tydescs(ccx: &mut CrateContext) {
     let _icx = push_ctxt("emit_tydescs");
     // As of this point, allow no more tydescs to be created.
-    ccx.finished_tydescs = true;
+    ccx.finished_tydescs.set(true);
     let glue_fn_ty = Type::generic_glue_fn(ccx).ptr_to();
     let mut tyds = ccx.tydescs.borrow_mut();
     for (_, &val) in tyds.get().iter() {