{"ast_node_type":"function","tokens":[{"end":83,"kind":"keyword","start":0,"text":"fn"}]}
    fn into_diag_arg(self, path: &mut Option<std::path::PathBuf>) -> DiagArgValue {
impl<I: rustc_type_ir::Interner> IntoDiagArg for rustc_type_ir::ExistentialTraitRef<I> {
        self.to_string().into_diag_arg(path)