syntax_data: {"ast_node_type":"other","tokens":[{"end":71,"kind":"keyword","start":0,"text":"(ty::FnPtr(a_sig_tys,"}]}
source_snippet:         (ty::FnPtr(a_sig_tys, a_hdr), ty::FnPtr(b_sig_tys, b_hdr)) => {
context_after:             let fty = relation.relate(a_sig_tys.with(a_hdr), b_sig_tys.with(b_hdr))?;