syntax_data: {"ast_node_type":"function","tokens":[{"end":70,"kind":"keyword","start":0,"text":"fn"}]}
source_snippet:             fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
context_before:         $(#[allow(unused_lifetimes)] impl<'tcx> fmt::Display for $ty {
context_after:                 ty::tls::with(|tcx| {