Comment by LoSboccacc

you're missing the point: it's not about coercion or data types per se, it's whether the error happens at parsing or runtime; of course the software has ways to figure out intention but is it something we actually want?

it's not coincidence that the article complains about the same thing but in reverse:

> This is legal, but only if the subquery returns not more than one row. Otherwise, an error would be raised at run time.

except the 'fix' reintroduce it in a way that's subtler and way hard to detect because now everything is a set even when the intent is to have a scalar.