Update test case to conform to new restrictions on casting

Author: jbclements

src/libsyntax/parse/mod.rs

@@ -297,10 +297,9 @@ mod test {
     use std;
     use core::io;
     use core::option::None;
-    use core::str;
     use util::testing::*;
 
-    #[test] fn to_json_str (val: @Encodable<std::json::Encoder>) -> ~str {
+    #[test] fn to_json_str<E : Encodable<std::json::Encoder>>(val: @E) -> ~str {
         do io::with_str_writer |writer| {
             val.encode(~std::json::Encoder(writer));
         }
@@ -312,7 +311,7 @@ mod test {
             @~"fn foo (x : int) { x; }",
             ~[],
             new_parse_sess(None));
-        check_equal(to_json_str(@tts as Encodable::<std::json::Encoder>),
+        check_equal(to_json_str(@tts),
                     ~"[[\"tt_tok\",[null,[\"IDENT\",[\"fn\",false]]]],\
                       [\"tt_tok\",[null,[\"IDENT\",[\"foo\",false]]]],\
                       [\"tt_delim\",[[[\"tt_tok\",[null,[\"LPAREN\",[]]]],\