{"ast_node_type":"function","tokens":[{"end":44,"kind":"keyword","start":0,"text":"fn"}]}
    fn from(mbe: mbe::ExpandError) -> Self {
impl From<mbe::ExpandError> for ExpandError {
        ExpandError { inner: Arc::new((ExpandErrorKind::Mbe(mbe.inner.1.clone()), mbe.inner.0)) }