Function syntex_syntax::parse::new_sub_parser_from_file

pub fn new_sub_parser_from_file<'a>(sess: &'a ParseSess,
                                    path: &Path,
                                    directory_ownership: DirectoryOwnership,
                                    module_name: Option<String>,
                                    sp: Span)
                                    -> Parser<'a>

Given a session, a crate config, a path, and a span, add the file at the given path to the codemap, and return a parser. On an error, use the given span as the source of the problem.