Column descriptions don't pick up variables

[enfeizhan]

sqlmesh version: 0.209.0

I am trying to use variables for column descriptions. Here is a simple example:

MODEL (
  name test.test,
  kind FULL,
  description @VAR('test_var_1'),
  column_descriptions (
    id = @VAR('test_var_2')
  )
);
SELECT 1 as id

With config.yaml:

variables:
  test_var_1: "1"
  test_var_2: "2"

The variable works well with description in the MODEL block. But it gets this error for column descriptions: 'NoneType' object has no attribute 'parts'.

If my use of variables in column names has not been the expected user behaviour, it would be great to have it for documenting columns programmatically.

By the way, it would also be great to have dot-lookups like @VAR('parent.child').