Hello, thank you for this great extension!

I think I've spotted some problem. When searching

• ... with a phrase-query like foo <-> bar
• ... using an index of the rum_tsvector_addon_ops operator class
• ... it doesn't find anything.

Let's setup a test table with text values a a, a b, a c and so on.

create extension rum;
create table text_table (id1 serial, t text);
create table rum_tbl (id serial, tsv tsvector);

insert into text_table(t) select chr(i) || ' ' || chr(j) from generate_series(65,90) i, generate_series(65,90) j; 
insert into rum_tbl(tsv) select to_tsvector('simple', t) from  text_table;

Without any index we can query on a <-> b, which works like expected:

select * from rum_tbl where tsv @@ to_tsquery('simple', 'a <-> b');

 id |     tsv     
----+-------------
  2 | 'a':1 'b':2
(1 row)

Now let's create an index using the rum_tsvector_addon_ops operator class:

create index rum_tbl_idx_addon
  on rum_tbl using rum (tsv rum_tsvector_addon_ops, id)
  with (attach ='id', to = 'tsv');

The same query now fails to return the matching row:

select * from rum_tbl where tsv @@ to_tsquery('simple', 'a <-> b');

 id | tsv 
----+-----
(0 rows)

Explain analyze says:

 Bitmap Heap Scan on rum_tbl  (cost=3.33..6.45 rows=4 width=28) (actual time=0.097..0.097 rows=0 loops=1)
   Recheck Cond: (tsv @@ '''a'' <-> ''b'''::tsquery)
   ->  Bitmap Index Scan on rum_tbl_idx_addon  (cost=0.00..3.33 rows=4 width=0) (actual time=0.093..0.093 rows=0 loop
s=1)
         Index Cond: (tsv @@ '''a'' <-> ''b'''::tsquery)

A query using an AND operator works correctly:

select * from rum_tbl where tsv @@ to_tsquery('simple', 'a & b');
-- ... result has 2 rows

Interestingly, the phrase-query also works correctly if we only have a rum_tsvector_ops index:

drop index rum_tbl_idx_addon;
create index rum_tbl_idx
  on rum_tbl using rum (tsv rum_tsvector_ops);

select * from rum_tbl where tsv @@ to_tsquery('simple', 'a <-> b');
-- ... result has 1 row

Tested with PostgreSQL 11.5 and RUM 1.3.7.

Any help greatly appreciated. Thank you in advance!