[
    Expression {
        expr: Infix {
            lhs: Infix {
                lhs: LiteralString {
                    value: "foo",
                },
                op: Concat,
                rhs: LiteralString {
                    value: "bar",
                },
            },
            op: Concat,
            rhs: LiteralString {
                value: "baz",
            },
        },
    },
]