1 files changed, 5 insertions, 1 deletions
diff --git a/src/libsyntax/parse/token.rs b/src/libsyntax/parse/token.rs
index ef1d0f4bc47..dbc1e8b34e3 100644
--- a/src/libsyntax/parse/token.rs
+++ b/src/libsyntax/parse/token.rs
@@ -96,7 +96,10 @@ enum whole_nt {
     w_ty(  @ast::ty),
     w_ident(str_num, bool),
     w_path(@ast::path),
-    w_tt(ast::token_tree),
+    // TODO: this seems to cause infinite recursion in
+    // type_structually_contains if it's not an @-box. We should at least get
+    // failure instead.
+    w_tt(@ast::token_tree),
 }
 
 fn binop_to_str(o: binop) -> str {
@@ -190,6 +193,7 @@ fn to_str(in: interner<@str>, t: token) -> str {
               w_stmt(*) { "statement" } w_pat(*) { "pattern" }
               w_expr(*) { "expression" } w_ty(*) { "type" }
               w_ident(*) { "identifier" } w_path(*) { "path" }
+              w_tt(*) { "tt" }
         }
       }
     }