From 01fcd5b91875fe016c77ce276aa3199df3387020 Mon Sep 17 00:00:00 2001
From: Ziyang Hu <hu.ziyang@cantab.net>
Date: Tue, 11 Jun 2024 17:04:46 +0800
Subject: [PATCH] Fixes https://github.com/cozodb/cozo/issues/265

---
 cozo-core/src/query/logical.rs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/cozo-core/src/query/logical.rs b/cozo-core/src/query/logical.rs
index 6efb5856..27ff49b1 100644
--- a/cozo-core/src/query/logical.rs
+++ b/cozo-core/src/query/logical.rs
@@ -9,7 +9,7 @@
 use std::collections::BTreeSet;
 
 use itertools::Itertools;
-use miette::{bail, ensure, Diagnostic, Result};
+use miette::{bail, ensure, Diagnostic, Result, miette};
 use thiserror::Error;
 
 use crate::data::expr::Expr;
@@ -201,7 +201,9 @@ impl InputAtom {
                 let mut args = args
                     .into_iter()
                     .map(|a| a.do_disjunctive_normal_form(gen, tx));
-                let mut result = args.next().unwrap()?;
+                let mut result = args
+                    .next()
+                    .ok_or_else(|| miette!("empty conjunction"))??;
                 for a in args {
                     result = result.conjunctive_to_disjunctive_de_morgen(a?)
                 }