Merge pull request #2178 from XiaowenHu96/eqrel_extend_fix

Fix issue #2176

src/interpreter/Relation.h

@@ -432,8 +432,10 @@ class EqrelRelation : public Relation<2, Eqrel> {
 
     void extendAndInsert(const EqrelRelation& rel) {
         auto src = static_cast<EqrelIndex*>(this->main);
-        auto trg = static_cast<EqrelIndex*>(rel.main);
-        src->extendAndInsert(trg);
+        for (auto& trgIndex : rel.indexes) {
+            auto trg = static_cast<EqrelIndex*>(trgIndex.get());
+            src->extendAndInsert(trg);
+        }
     }
 };
 

tests/semantic/eqrel_tests3/c__.csv

@@ -0,0 +1,9 @@
+0	0
+0	1
+0	2
+1	0
+1	1
+1	2
+2	0
+2	1
+2	2

tests/semantic/eqrel_tests3/eqrel_tests3.dl

@@ -4,16 +4,26 @@
 // - https://opensource.org/licenses/UPL
 // - <souffle root>/licenses/SOUFFLE-UPL.txt
 
-// Check that new knowledge generated by inserting into an eqrel is not lost.
+// 1. Check that new knowledge generated by inserting into an eqrel is not lost.
+// 2. Issue #2176
 
 .decl notEqrel(x:number,y:number)
 .decl isEqrel(x:number, y:number) eqrel
+.decl a__(a:number, b:number)
+.decl b__(a:number)
+.decl c__(a:number, b:number)
+
+.output c__, isEqrel, notEqrel // Output relation
 
 notEqrel(x, y) :- isEqrel(x, y).
 isEqrel(x, y) :- notEqrel(x, y).
-
 isEqrel(0,1).
-
 notEqrel(1,2).
 
-.output isEqrel, notEqrel
+a__(b, b) :- notEqrel(b, b).
+a__(b, b) :- isEqrel(a, b), !isEqrel(a, b).  // new rule
+
+b__(b) :- isEqrel(b, a).
+
+c__(a, c) :- a__(e, g), a__(a, e), b__(e), b__(c).
+c__(b, b) :- b__(b).

tests/semantic/eqrel_tests3/eqrel_tests3.err

@@ -0,0 +1,6 @@
+Warning: Variable a only occurs once in file eqrel_tests3.dl at line 26
+b__(b) :- isEqrel(b, a).
+---------------------^---
+Warning: Variable g only occurs once in file eqrel_tests3.dl at line 28
+c__(a, c) :- a__(e, g), a__(a, e), b__(e), b__(c).
+--------------------^------------------------------

tests/semantic/eqrel_tests3/isEqrel.csv

@@ -1,9 +1,9 @@
-0	0
-0	1
-0	2
-1	0
 1	1
+1	0
 1	2
-2	0
+0	1
+0	0
+0	2
 2	1
+2	0
 2	2