Re: BUG #15458: pg_typeof inconsistency on negative integer constant limits

On Wednesday, October 24, 2018 4:54:32 PM EDT Andres Freund wrote:
> Hi,
> 
> On 2018-10-24 20:47:21 +0000, PG Bug reporting form wrote:
> > The following bug has been logged on the website:
> > 
> > Bug reference:      15458
> > Logged by:          Elvis Pranskevichus
> > Email address:      elprans@gmail.com
> > PostgreSQL version: 11.0
> > Operating system:   x86_64-pc-linux-gnu
> > Description:
> > 
> > There seems to be an inconsistency in how the parser and the integer
> > input functions interpret the integers at the negative limit (-2 ^
> > 31 and -2 ^ 63):
> > 
> > 
> > SELECT pg_typeof(-2147483648);
> > 
> >  pg_typeof
> > 
> > -----------
> > 
> >  integer
> > 
> > (1 row)
> > 
> > But:
> > 
> > SELECT -2147483648::integer;
> > ERROR:  integer out of range
> > 
> > 
> > The same issue applies to int8 as well.
> > 
> > PG_INT32_MIN is explicitly defined as -(2 ^ 31 - 1), and it seems
> > inconsistent that the parser does not respect that when determining
> > the type of numeric constants.
> 
> It's just a precedence issue. :: binds with higher precedence, so the
> above is actually -(2147483648::integer), rather than
> (-2147483648)::integer. Therefore you get an overflow.

Ah, you're right.  Sorry for the noise.


                              Elvis