I have a query that use array_agg with distinct as an argument and is not accepted on postgres 9.6.

I created this sample to illustrate the issue:

create table numbers (id integer primary key, name varchar(10));
insert into numbers values(1,'one');
insert into numbers values(2,'two');

postgres 9.4

select array_agg(distinct(id)) from numbers;
 array_agg 
-----------
 {1,2}

postgres 9.6

ERROR:  function array_agg(integer) is not unique
LINE 1: select array_agg(distinct(id)) from numbers;
               ^
HINT:  Could not choose a best candidate function. 
You might need to add explicit type casts.

What do I need to change in order to get this result on postgres 9.6?

Thanks.

This is what I get checking the functions:

nspname | proname | proargtypes 
------------+-----------+--------------------- 
pg_catalog | array_agg | [0:0]={anyarray} 
public | array_agg | [0:0]={anyelement} 
pg_catalog | array_agg | [0:0]={anynonarray

Now, I found the issue thanks to the comment by pozs. I remove the public definition of the aggregated function and it worked.

The issue was just on the database that I was working on, as I found some people saying that the sample worked for them I created a new database an run the example. And then the only change there was the aggregate function definitions.