{"ast_node_type":"other","tokens":[{"end":112,"kind":"keyword","start":0,"text":"//"}]}
                        // Inject empty string before placeholders when not already preceded by a literal piece.
                    &FormatArgsPiece::Placeholder(_) => {
                        if i == 0 || matches!(fmt.template[i - 1], FormatArgsPiece::Placeholder(_))