Equalities in C# UP-Propagation (#6786)

* Query Boolean Assignment in the UP

* UP's decide ref arguments => next_split

* Fixed wrapper

* More fixes

* Equalities in C# UP-Propagation

---------

Co-authored-by: Nikolaj Bjorner <nbjorner@microsoft.com>

src/api/dotnet/UserPropagator.cs

@@ -254,9 +254,19 @@ namespace Microsoft.Z3
         /// Propagate consequence
         /// </summary>
         public void Propagate(IEnumerable<Expr> terms, Expr conseq)
+        {
+            Propagate(terms, new EqualityPairs(), conseq);
+        }
+
+        /// <summary>
+        /// Propagate consequence
+        /// </summary>
+        public void Propagate(IEnumerable<Expr> terms, EqualityPairs equalities, Expr conseq)
         {
             var nTerms = Z3Object.ArrayToNative(terms.ToArray());
-            Native.Z3_solver_propagate_consequence(ctx.nCtx, this.callback, (uint)nTerms.Length, nTerms, 0u, null, null, conseq.NativeObject);
+            var nLHS = Z3Object.ArrayToNative(equalities.LHS.ToArray());
+            var nRHS = Z3Object.ArrayToNative(equalities.RHS.ToArray());
+            Native.Z3_solver_propagate_consequence(ctx.nCtx, this.callback, (uint)nTerms.Length, nTerms, (uint)equalities.Count, nLHS, nRHS, conseq.NativeObject);
         }
 
 
@@ -375,4 +385,72 @@ namespace Microsoft.Z3
             }
         }
     }
+
+    /// <summary>
+    /// A list of equalities used as justifications for propagation
+    /// </summary>
+    public class EqualityPairs {
+
+        readonly List<Expr> lhsList = new List<Expr>();
+        readonly List<Expr> rhsList = new List<Expr>();
+
+        /// <summary>
+        /// The left hand sides of the equalities
+        /// </summary>
+        public Expr[] LHS => lhsList.ToArray();
+
+        /// <summary>
+        /// The right hand sides of the equalities
+        /// </summary>
+        public Expr[] RHS => rhsList.ToArray();
+
+        /// <summary>
+        /// The number of equalities
+        /// </summary>
+        public int Count => lhsList.Count;
+
+        /// <summary>
+        /// Adds an equality to the list. The sorts of the arguments have to be the same.
+        /// <param name="lhs">The left hand side of the equality</param>
+        /// <param name="rhs">The right hand side of the equality</param>
+        /// </summary>
+        public void Add(Expr lhs, Expr rhs) {
+            lhsList.Add(lhs);
+            rhsList.Add(rhs);
+        }
+
+        /// <summary>
+        /// Checks if two equality lists are equal.
+        /// The function does not take symmetries, shuffling, or duplicates into account.
+        /// </summary>
+        public override bool Equals(object obj) {
+            if (ReferenceEquals(this, obj))
+                return true;
+            if (!(obj is EqualityPairs other))
+                return false;
+            if (lhsList.Count != other.lhsList.Count)
+                return false;
+            for (int i = 0; i < lhsList.Count; i++) {
+                if (!lhsList[i].Equals(other.lhsList[i]))
+                    return false;
+            }
+            return true;
+        }
+
+        /// <summary>
+        /// Gets a hash code for the list of equalities
+        /// </summary>
+        public override int GetHashCode() {
+            int hash = lhsList.Count;
+            unchecked {
+                for (int i = 0; i < lhsList.Count; i++) {
+                    hash ^= lhsList[i].GetHashCode();
+                    hash *= 17;
+                    hash ^= rhsList[i].GetHashCode();
+                    hash *= 29;
+                }
+                return hash;
+            }
+        }
+    }
 }

src/api/java/NativeStatic.txt

@@ -226,6 +226,7 @@ DLL_VIS JNIEXPORT void JNICALL Java_com_microsoft_z3_Native_propagateAdd(JNIEnv
   }
 }
 
+
 DLL_VIS JNIEXPORT bool JNICALL Java_com_microsoft_z3_Native_propagateNextSplit(JNIEnv * jenv, jclass cls, jobject jobj, jlong ctx, jlong solver, jlong javainfo, jlong e, long idx, int phase) {
   JavaInfo *info = (JavaInfo*)javainfo;
   Z3_solver_callback cb = info->cb;