Fixed issue with recursive equality test on maps/lists.

(Would go into infinite loop under certain circumstances.)
Now also bails out much faster in the case where two items are reference equal.

MiniScript-cpp/src/MiniScript/MiniscriptTypes.cpp

@@ -700,7 +700,7 @@ namespace MiniScript {
 			ValuePair(const Value& inA, const Value& inB) : a(inA), b(inB) {}
 			ValuePair() {}
 			bool operator==(const ValuePair& rhs) {
-				// Careful: we muste use RefEqual here to detect reference loops
+				// Careful: we must use RefEqual here to detect reference loops
 				// below; if we used ==, which does a deep comparison, it could
 				// just send us into an infinite recursion right here.
 				return Value::RefEqual(a, rhs.a) && Value::RefEqual(b, rhs.b);
@@ -718,6 +718,7 @@ namespace MiniScript {
 				long aCount = listA.Count();
 				ValueList listB((ListStorage<Value>*)pair.b.data.ref);
 				if (listB.Count() != aCount) return false;
+				if (Value::RefEqual(pair.a, pair.b)) continue;
 				for (int i=0; i < aCount; i++) {
 					ValuePair newPair(listA[i], listB[i]);
 					if (!visited.Contains(newPair)) toDo.push_back(newPair);
@@ -728,6 +729,7 @@ namespace MiniScript {
 				long countA = dictA.Count();
 				ValueDict dictB((DictionaryStorage<Value, Value>*)pair.b.data.ref);
 				if (dictB.Count() != countA) return false;
+				if (Value::RefEqual(pair.a, pair.b)) continue;
 				ValueList keys = dictA.Keys();
 				for (int i=0; i<countA; i++) {
 					Value key = keys[i];

MiniScript-cs/MiniscriptTypes.cs

@@ -190,10 +190,12 @@ protected bool RecursiveEqual(Value rhs) {
 			toDo.Push(new ValuePair() { a = this, b = rhs });
 			while (toDo.Count > 0) {
 				var pair = toDo.Pop();
+
 				visited.Add(pair);
 				if (pair.a is ValList listA) {
 					var listB = pair.b as ValList;
 					if (listB == null) return false;
+					if (Object.ReferenceEquals(listA, listB)) continue;
 					int aCount = listA.values.Count;
 					if (aCount != listB.values.Count) return false;
 					for (int i = 0; i < aCount; i++) {
@@ -203,6 +205,7 @@ protected bool RecursiveEqual(Value rhs) {
 				} else if (pair.a is ValMap mapA) {
 					var mapB = pair.b as ValMap;
 					if (mapB == null) return false;
+					if (Object.ReferenceEquals(mapA, mapB)) continue;
 					if (mapA.map.Count != mapB.map.Count) return false;
 					foreach (KeyValuePair<Value, Value> kv in mapA.map) {
 						Value valFromB;
@@ -265,6 +268,18 @@ protected int RecursiveHash()
 	struct ValuePair {
 		public Value a;
 		public Value b;
+		public override bool Equals(object obj) {
+			if (obj is ValuePair other) {
+				return ReferenceEquals(a, other.a) && ReferenceEquals(b, other.b);
+			}
+			return false;
+		}
+
+		public override int GetHashCode() {
+			unchecked {
+				return ((a != null ? a.GetHashCode() : 0) * 397) ^ (b != null ? b.GetHashCode() : 0);
+			}
+		}
 	}
 
 	public class ValueSorter : IComparer<Value>