[
    Expression {
        expr: Concat {
            left: Concat {
                left: LiteralString {
                    value: "foo",
                },
                span: (
                    1,
                    13,
                ),
                right: LiteralString {
                    value: "bar",
                },
            },
            span: (
                1,
                21,
            ),
            right: LiteralString {
                value: "baz",
            },
        },
    },
]