Bug: Segmentation fault matching on unwound results

[Brad-Edwards]

Imported from kuzudb/kuzu#6048
Original URL: kuzudb#6048
Original author: @mdbenito
Original created at: 2025-10-05T14:25:38Z
Kuzu v0.11.2, Ubuntu 24.04

Create a db with a duplicate edge

CREATE NODE TABLE Person(name STRING PRIMARY KEY);
CREATE REL TABLE LivesWith(FROM Person TO Person);
CREATE (p:Person {name: 'Alice'});
CREATE (p:Person {name: 'Bob'});
MATCH (p:Person {name: 'Alice'}), (q:Person {name: 'Bob'}) CREATE (p)-[:LivesWith]->(q);
MATCH (p:Person {name: 'Alice'}), (q:Person {name: 'Bob'}) CREATE (p)-[:LivesWith]->(q);

Then try to delete duplicate edges with the following query:

MATCH (a)-[r:LivesWith]->(b)
WITH collect(r) AS rs
WITH rs[2:] AS dups
UNWIND dups AS d
MATCH (a)-[s:LivesWith]->(b)
WHERE s=d
DELETE s;

On my system this fails with

Segmentation fault (core dumped)

(As a side note, it would be nice to be able to just DELETE d, but the binder refuses with Error: Binder exception: Cannot delete expression d with type VARIABLE. Expect node or rel pattern.)