pub fn create_session(
    sopts: Options,
    cfg: FxHashSet<(String, Option<String>)>,
    check_cfg: CheckCfg,
    diagnostic_output: DiagnosticOutput,
    file_loader: Option<Box<dyn FileLoader + Send + Sync + 'static>>,
    input_path: Option<PathBuf>,
    lint_caps: FxHashMap<LintId, Level>,
    make_codegen_backend: Option<Box<dyn FnOnce(&Options) -> Box<dyn CodegenBackend> + Send>>,
    descriptions: Registry
) -> (Lrc<Session>, Lrc<Box<dyn CodegenBackend>>)