Convert alt to match. Stop parsing alt

src/libsyntax/ast.rs

@@ -193,7 +193,7 @@ enum vstore {
 }
 
 pure fn is_blockish(p: ast::proto) -> bool {
-    alt p {
+    match p {
       proto_block => true,
       proto_bare | proto_uniq | proto_box => false
     }