expand_expr -> expander().fold_expr
expand_expr -> expander().fold_expr

brandonson/docopt.rs,birkenfeld/docopt.rs,zsiciarz/docopt.rs,alexcrichton/docopt.rs,birkenfeld/docopt.rs,zsiciarz/docopt.rs,alexcrichton/docopt.rs,brandonson/docopt.rs,birkenfeld/docopt.rs,zsiciarz/docopt.rs,brandonson/docopt.rs