other: FirLiteralExpression<*>
    ): FirLiteralExpression<*>? {
        if (value == null || other.value == null) return null
        // NB: some utils accept very general types, and due to the way operation map works, we should up-cast rhs type.
        val rightType = when {
            function.symbol.callableId.isStringEquals -> CompileTimeType.ANY
            function.symbol.callableId.isStringPlus -> CompileTimeType.ANY