{"ast_node_type":"variable","tokens":[{"end":78,"kind":"keyword","start":0,"text":"if"}]}
                            if let FnRetTy::Ty(ref ret_ty) = sig.decl.output {
                            // FIXME(workingjubilee): properly lint on acceptable input types.
                                self.dcx().emit_err(errors::AbiMustNotHaveReturnType {