Re: BUG #15458: pg_typeof inconsistency on negative integer constantlimits

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.

Greetings,

Andres Freund