diff --git a/src/symbol.rs b/src/symbol.rs
index a93339180..d30cd15c8 100644
--- a/src/symbol.rs
+++ b/src/symbol.rs
@@ -1,5 +1,5 @@
 use syntax::ast;
-use syntax::symbol::Symbol;
+use syntax::symbol::{InternedString, Symbol};
 
 //////////////////////////////////////////////////////////////////////////////
 
@@ -25,6 +25,12 @@ impl ToSymbol for ast::Ident {
     }
 }
 
+impl ToSymbol for InternedString {
+    fn to_symbol(&self) -> Symbol {
+        Symbol::intern(self)
+    }
+}
+
 impl<'a, T> ToSymbol for &'a T where T: ToSymbol {
     fn to_symbol(&self) -> Symbol {
         (**self).to_symbol()