1 files changed, 9 insertions, 0 deletions
diff --git a/src/libsyntax/util/interner.rs b/src/libsyntax/util/interner.rs
index 75bcac1b163..cda1c6c0df3 100644
--- a/src/libsyntax/util/interner.rs
+++ b/src/libsyntax/util/interner.rs
@@ -16,6 +16,7 @@
 #[macro_escape];
 
 use core::prelude::*;
+use core::cmp::Equiv;
 use core::hashmap::HashMap;
 
 pub struct Interner<T> {
@@ -67,6 +68,14 @@ pub impl<T:Eq + IterBytes + Hash + Const + Copy> Interner<T> {
     fn get(&self, idx: uint) -> T { self.vect[idx] }
 
     fn len(&self) -> uint { let vect = &*self.vect; vect.len() }
+
+    fn find_equiv<Q:Hash + IterBytes + Equiv<T>>(&self, val: &Q)
+                                              -> Option<uint> {
+        match self.map.find_equiv(val) {
+            Some(v) => Some(*v),
+            None => None,
+        }
+    }
 }
 
 /* Key for thread-local data for sneaking interner information to the