why () is () and [] is [] work in other way?

[Chris Angelico]

On Fri, Apr 27, 2012 at 8:04 AM, Ian Kelly <ian.g.kelly at gmail.com> wrote:
> You can't check ref counts at parse time.

I know, and it'd be impossible to recognize at parse time for any but
the most trivial cases (since names can always be rebound). The
detection of temporaries can only be done at run time.

ChrisA