datalog: magic over rule with negation regression test (227/227)

lib/datalog/scoreboard.json

@@ -1,8 +1,8 @@
 {
   "lang": "datalog",
-  "total_passed": 226,
+  "total_passed": 227,
   "total_failed": 0,
-  "total": 226,
+  "total": 227,
   "suites": [
     {"name":"tokenize","passed":26,"failed":0,"total":26},
     {"name":"parse","passed":18,"failed":0,"total":18},
@@ -13,8 +13,8 @@
     {"name":"negation","passed":10,"failed":0,"total":10},
     {"name":"aggregates","passed":19,"failed":0,"total":19},
     {"name":"api","passed":20,"failed":0,"total":20},
-    {"name":"magic","passed":26,"failed":0,"total":26},
+    {"name":"magic","passed":27,"failed":0,"total":27},
     {"name":"demo","passed":21,"failed":0,"total":21}
   ],
-  "generated": "2026-05-08T12:28:42+00:00"
+  "generated": "2026-05-08T12:31:39+00:00"
 }

lib/datalog/scoreboard.md

@@ -1,6 +1,6 @@
 # datalog scoreboard
 
-**226 / 226 passing** (0 failure(s)).
+**227 / 227 passing** (0 failure(s)).
 
 | Suite | Passed | Total | Status |
 |-------|--------|-------|--------|
@@ -13,5 +13,5 @@
 | negation | 10 | 10 | ok |
 | aggregates | 19 | 19 | ok |
 | api | 20 | 20 | ok |
-| magic | 26 | 26 | ok |
+| magic | 27 | 27 | ok |
 | demo | 21 | 21 | ok |

lib/datalog/tests/magic.sx

@@ -197,6 +197,20 @@
         6)
 
       ;; dl-magic-query: end-to-end driver, doesn't mutate caller's db.
+      ;; Magic over a rule with negated body literal — propagation
+      ;; rules generated only for positive lits; negated lits pass
+      ;; through unchanged.
+      (dl-mt-test! "magic over rule with negation"
+        (let
+          ((db (dl-program
+                 "u(a). u(b). u(c). banned(b).
+                  active(X) :- u(X), not(banned(X)).")))
+          (let
+            ((semi (dl-query db (list (quote active) (quote X))))
+              (magic (dl-magic-query db (list (quote active) (quote X)))))
+            (= (len semi) (len magic))))
+        true)
+
       ;; Magic over a rule whose body contains an aggregate.
       ;; The rewriter passes aggregate body lits through unchanged
       ;; (no propagation generated for them), so semi-naive's count