Add a temporary hack to divert the parser to an alternate file

src/libsyntax/parse.rs

@@ -175,6 +175,18 @@ fn new_parser_from_file(sess: parse_sess, cfg: ast::crate_cfg,
                         path: &Path) -> Result<Parser, ~str> {
     match io::read_whole_file_str(path) {
       result::Ok(move src) => {
+
+          // HACK: If the file contains a special token use a different
+          // source file. Used to send the stage1+ parser (the stage0 parser
+          // doesn't have this hack) to a different crate file.
+          // Transitional. Remove me.
+          let src = if src.starts_with("// DIVERT") {
+              let actual_path = &path.with_filestem("alternate_crate");
+              result::unwrap(io::read_whole_file_str(actual_path))
+          } else {
+              move src
+          };
+
           let filemap = sess.cm.new_filemap(path.to_str(), @move src);
           let srdr = lexer::new_string_reader(sess.span_diagnostic, filemap,
                                               sess.interner);