{"ast_node_type":"other","tokens":[{"end":20,"kind":"keyword","start":0,"text":"match"}]}
        match self {
    pub(crate) fn emit(&self, cx: &MirBorrowckCtxt<'_, '_, 'tcx>, diag: &mut Diag<'_>) -> String {
            &AnnotatedBorrowFnSignature::Closure { argument_ty, argument_span } => {