datalog: mixed-EDB+IDB-same-relation regression test (220/220)

lib/datalog/scoreboard.json

@@ -1,13 +1,13 @@
 {
   "lang": "datalog",
-  "total_passed": 219,
+  "total_passed": 220,
   "total_failed": 0,
-  "total": 219,
+  "total": 220,
   "suites": [
     {"name":"tokenize","passed":26,"failed":0,"total":26},
     {"name":"parse","passed":18,"failed":0,"total":18},
     {"name":"unify","passed":28,"failed":0,"total":28},
-    {"name":"eval","passed":28,"failed":0,"total":28},
+    {"name":"eval","passed":29,"failed":0,"total":29},
     {"name":"builtins","passed":19,"failed":0,"total":19},
     {"name":"semi_naive","passed":8,"failed":0,"total":8},
     {"name":"negation","passed":10,"failed":0,"total":10},
@@ -16,5 +16,5 @@
     {"name":"magic","passed":22,"failed":0,"total":22},
     {"name":"demo","passed":21,"failed":0,"total":21}
   ],
-  "generated": "2026-05-08T10:23:54+00:00"
+  "generated": "2026-05-08T10:27:32+00:00"
 }

lib/datalog/scoreboard.md

@@ -1,13 +1,13 @@
 # datalog scoreboard
 
-**219 / 219 passing** (0 failure(s)).
+**220 / 220 passing** (0 failure(s)).
 
 | Suite | Passed | Total | Status |
 |-------|--------|-------|--------|
 | tokenize | 26 | 26 | ok |
 | parse | 18 | 18 | ok |
 | unify | 28 | 28 | ok |
-| eval | 28 | 28 | ok |
+| eval | 29 | 29 | ok |
 | builtins | 19 | 19 | ok |
 | semi_naive | 8 | 8 | ok |
 | negation | 10 | 10 | ok |

lib/datalog/tests/eval.sx

@@ -273,6 +273,17 @@
           (dl-saturated? db))
         false)
 
+      ;; A relation can be both EDB-seeded and rule-derived;
+      ;; saturate combines facts + derivations.
+      (dl-et-test-set! "mixed EDB + IDB same relation"
+        (dl-query
+          (dl-program
+            "link(a, b). link(c, d). link(e, c).
+             via(a, e).
+             link(X, Y) :- via(X, M), link(M, Y).")
+          (list (quote link) (quote a) (quote X)))
+        (list {:X (quote b)} {:X (quote c)}))
+
       (dl-et-test! "saturated? after assert"
         (let ((db (dl-program
                     "parent(a, b).