diff --git a/src/common/classes/array.h b/src/common/classes/array.h
index 48a9c6867a..bf4a2deda2 100644
--- a/src/common/classes/array.h
+++ b/src/common/classes/array.h
@@ -133,7 +133,7 @@ public:
 		memmove(data + index + 1, data + index, sizeof(T) * (count++ - index));
 		data[index] = item;
 	}
-	void insert(int index, Array<T>& L) {
+	void insert(int index, const Array<T, Storage>& L) {
 		fb_assert(index >= 0 && index <= count);
 		ensureCapacity(count + L.count);
 		memmove(data + index + L.count, data + index, sizeof(T) * (count - index));
diff --git a/src/common/classes/objects_array.h b/src/common/classes/objects_array.h
index c07877ace3..933c89f2a2 100644
--- a/src/common/classes/objects_array.h
+++ b/src/common/classes/objects_array.h
@@ -47,11 +47,13 @@ namespace Firebird
 			iterator(ObjectsArray *l, int p) : lst(l), pos(p) { }
 		public:
 			iterator() : lst(0), pos(0) { }
+/*
 			iterator& operator=(ObjectsArray& a)
 			{
-				lst = a.l;
+				lst = &a;
 				pos = 0;
 			}
+ */
 			iterator& operator++() {++pos; return (*this);}
 			iterator operator++(int) {iterator tmp = *this; ++pos; 
 									  return tmp;}
diff --git a/src/common/classes/stack.h b/src/common/classes/stack.h
index 8ff1161d90..2867cda33c 100644
--- a/src/common/classes/stack.h
+++ b/src/common/classes/stack.h
@@ -3,24 +3,25 @@
  *	MODULE:		stack.h
  *	DESCRIPTION:	Stack.
  *
- * The contents of this file are subject to the Interbase Public
- * License Version 1.0 (the "License"); you may not use this file
- * except in compliance with the License. You may obtain a copy
- * of the License at http://www.Inprise.com/IPL.html
+ *  The contents of this file are subject to the Initial
+ *  Developer's Public License Version 1.0 (the "License");
+ *  you may not use this file except in compliance with the
+ *  License. You may obtain a copy of the License at
+ *  http://www.ibphoenix.com/main.nfs?a=ibphoenix&page=ibp_idpl.
  *
- * Software distributed under the License is distributed on an
- * "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express
- * or implied. See the License for the specific language governing
- * rights and limitations under the License.
+ *  Software distributed under the License is distributed AS IS,
+ *  WITHOUT WARRANTY OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing rights
+ *  and limitations under the License.
  *
- * Stack is implemented as a linked list of vectors.
- * This makes implementation of merge and split operations
- * enough efficcient for large stacks (used in opt.cpp).
+ *  The Original Code was created by Alexander Peshkoff
+ *  for the Firebird Open Source RDBMS project.
  *
- * Created by: Alex Peshkov <peshkoff@mail.ru>
+ *  Copyright (c) 2004 Alexander Peshkoff <peshkoff@mail.ru>
+ *  and all contributors signed below.
  *
- * All Rights Reserved.
- * Contributor(s): ______________________________________.
+ *  All Rights Reserved.
+ *  Contributor(s): ______________________________________.
  *
  */
 
@@ -80,6 +81,7 @@ namespace Firebird {
 
 			void split(int elem, Entry* target) 
 			{
+				fb_assert(elem > 0 && elem < count);
 				memcpy(target->data, data, elem * sizeof(Object));
 				target->count += elem;
 				count -= elem;
@@ -126,12 +128,15 @@ namespace Firebird {
 			return tmp;
 		}
 
-		Stack<Object, Capacity>& operator= (Stack<Object, Capacity>& s) {
+	private:
+		Stack<Object, Capacity>& operator= (Stack<Object, Capacity>& s);
+
+	public:
+		void takeOwnership (Stack<Object, Capacity>& s) {
 			fb_assert(&getPool() == &s.getPool());
 			delete stk;
 			stk = s.stk;
 			s.stk = 0;
-			return *this;
 		}
 
 		class iterator {
@@ -151,7 +156,7 @@ namespace Firebird {
 			{
 				fb_assert(stk);
 				if (--elem <= 0) {
-					if ((stk = stk->next))
+					if ((stk = stk->next)) 
 					{
 						elem = stk->getCount();
 					}
diff --git a/src/jrd/opt.cpp b/src/jrd/opt.cpp
index f7a399d51c..4409a82163 100644
--- a/src/jrd/opt.cpp
+++ b/src/jrd/opt.cpp
@@ -5247,7 +5247,7 @@ static bool gen_sort_merge(thread_db* tdbb, OptimizerBlk* opt, RiverStack& org_r
 			river1->riv_rsb = gen_boolean(tdbb, opt, river1->riv_rsb, node);
 		}
 		set_inactive(opt, river1);
-		org_rivers = newRivers;
+		org_rivers.takeOwnership(newRivers);
 
 		for (stream_nr = 0, fv = flag_vector; 
 			stream_nr < opt->opt_csb->csb_n_stream; stream_nr++)