Fixed the INSERT INTO ... SELECT bug reported by Ivan Prenosil in fb-devel.

src/common/classes/stack.h

@@ -199,6 +199,30 @@ namespace Firebird {
 			Stack<Object, Capacity>& stack;
 		};
 
+		// Restore the stack when we go out of scope.
+		class AutoRestore
+		{
+		public:
+			AutoRestore(Stack<Object, Capacity>& s)
+				: stack(s),
+				  count(s.getCount())
+			{
+			}
+
+			~AutoRestore()
+			{
+				size_t currentCount = stack.getCount();
+				fb_assert(currentCount >= count);
+
+				while (currentCount-- > count)
+					stack.pop();
+			}
+
+		private:
+			Stack<Object, Capacity>& stack;
+			size_t count;
+		};
+
 		class iterator;
 		friend class iterator;
 

src/dsql/StmtNodes.cpp

@@ -5497,6 +5497,7 @@ DmlNode* StoreNode::parse(thread_db* tdbb, MemoryPool& pool, CompilerScratch* cs
 StmtNode* StoreNode::internalDsqlPass(DsqlCompilerScratch* dsqlScratch, bool updateOrInsert)
 {
 	thread_db* tdbb = JRD_get_thread_data();
+	DsqlContextStack::AutoRestore autoContext(*dsqlScratch->context);
 
 	dsqlScratch->getStatement()->setType(DsqlCompiledStatement::TYPE_INSERT);