syntax_data: {"ast_node_type":"function","tokens":[{"end":45,"kind":"keyword","start":0,"text":"fn"}]}
source_snippet:     fn relate<R: TypeRelation<TyCtxt<'tcx>>>(
context_before: impl<'tcx> Relate<TyCtxt<'tcx>> for ty::Term<'tcx> {
context_after:         relation: &mut R,