Distinguish finite slice views from cycles

internal/engine/value_operation.go

@@ -21,6 +21,7 @@ type valueVisit struct {
 	typeOf reflect.Type
 	kind   reflect.Kind
 	ptr    uintptr
+	length int
 }
 
 // valueOperation owns one traversal's cycle and budget state and reuses the
@@ -107,6 +108,9 @@ func visitFor(value reflect.Value) (valueVisit, bool) {
 			return valueVisit{}, false
 		}
 		visit.ptr = value.Pointer()
+		if value.Kind() == reflect.Slice {
+			visit.length = value.Len()
+		}
 	case reflect.Map:
 		if value.Len() == 0 {
 			return valueVisit{}, false