{"ast_node_type":"other","tokens":[{"end":65,"kind":"keyword","start":0,"text":"AstFragment::OptExpr(None)"}]}
                    AstFragment::OptExpr(None) => unreachable!(),
                    AstFragment::OptExpr(Some(expr)) => pprust::expr_to_string(expr),
                    AstFragment::MethodReceiverExpr(expr) => pprust::expr_to_string(expr),