{"ast_node_type":"variable","tokens":[{"end":43,"kind":"keyword","start":0,"text":"let"}]}
        let fun_ty = self.return_type(ctx);
    fn make_ret_ty(&self, ctx: &AssistContext<'_>, module: hir::Module) -> Option<ast::RetType> {
        let handler = FlowHandler::from_ret_ty(self, &fun_ty);