I'm not sure if this is relevant to this specific PR, but I am encountering something related. I have a table with a column of type char that I want to convert to type double. Most values are doubles, but there are a few 'nan' values (characters). I noticed that
try_cast({{ adapter.quote("MY_COLUMN") }}) as double) as numeric_column
would convert everything to a double, but when I the run

select *
from table
where numeric_column is NULL

I didn't see the expected rows where there was 'nan' returned as NULL. However, if I instead run
try_cast(nullif({{ adapter.quote("MY_COLUMN") }}, 'nan') as double) as numeric_column
then the query returns the expected amount of null entries. Is this expected behavior?

That sounds like expected behavior to me yes. NaN is different from NULL.