{"ast_node_type":"other","tokens":[{"end":47,"kind":"keyword","start":0,"text":"//"}]}
        // when the return type is a type alias
        let mut v = TraitObjectVisitor(vec![]);
        if let Some(hir::FnDecl { output: hir::FnRetTy::Return(hir_output), .. }) = self.hir_fn_decl_by_hir_id(hir_id)