Context does not contain expression BACK(1).expr_1. #555

Context does not contain expression BACK(1).expr_1. Available expressions: [BACK(1).clerk, BACK(1).comment, BACK(1).customer_key, BACK(1).key, BACK(1).order_date, BACK(1).order_priority, BACK(1).order_status, BACK(1).order_year, BACK(1).ship_priority, BACK(1).total_price, comment, commit_date, discount, expr_1, extended_price, line_number, order_key, part_key, quantity, receipt_date, return_flag, ship_date, ship_instruct, ship_mode, status, supplier_key, tax]

# Get order years
distinct_years = orders.CALCULATE(
    order_year=YEAR(order_date)
).PARTITION(
    name="years", by=order_year
).CALCULATE(
    year=order_year
)

# Get customer base
cust_base = customers.CALCULATE(
    c_id=key,
)

# CROSS join customer base with distinct years to get all combinations of customers and years
cust_years = cust_base.CROSS(distinct_years)

# Reproduce issue
result = cust_years.CALCULATE(
    year=year,
    bug=SUM(orders.WHERE(YEAR(order_date) == year).lines.extended_price),
    #opt1=SUM(orders.WHERE(YEAR(order_date) == order_year).lines.extended_price),
    #opt2=SUM(orders.WHERE(YEAR(order_date) == year).total_price)
).ORDER_BY(year.ASC())

  orders
  ├── order_date
  ├── customer [one member of customers]
  └── lines [multiple lines]

  lines
  ├── extended_price
  └── order [one member of orders]

  customers
  ├── key
  └── orders [multiple orders]