diff --git a/core/my_basic.c b/core/my_basic.c
index 5747583..300e80f 100755
--- a/core/my_basic.c
+++ b/core/my_basic.c
@@ -7870,10 +7870,11 @@ _exit:
 /* Call the TOSTRING function of a class instance to format it */
 static int _format_class_to_string(mb_interpreter_t* s, void** l, _class_t* instance, _object_t* out, bool_t* got_tostr) {
 	int result = MB_FUNC_OK;
+	_ls_node_t* tsn = 0;
 
 	mb_assert(s && l && instance && out);
 
-	_ls_node_t* tsn = _search_identifier_in_class(s, instance, _CLASS_TOSTRING_FUNC, 0, 0);
+	tsn = _search_identifier_in_class(s, instance, _CLASS_TOSTRING_FUNC, 0, 0);
 	if(got_tostr) *got_tostr = false;
 	if(tsn) {
 		_object_t* tso = (_object_t*)tsn->data;
diff --git a/shell/main.c b/shell/main.c
index 0dc9638..b2434a3 100755
--- a/shell/main.c
+++ b/shell/main.c
@@ -219,7 +219,7 @@ static void _tidy_mem_pool(bool_t force) {
 		return;
 
 	for(i = 0; i < pool_count; i++) {
-		while((s = pool[i].stack)) {
+		while((s = pool[i].stack) != 0) {
 			pool[i].stack = (char*)_POOL_NODE_NEXT(s);
 			_POOL_NODE_FREE(s);
 		}
@@ -299,7 +299,7 @@ static void _close_mem_pool(void) {
 		return;
 
 	for(i = 0; i < pool_count; i++) {
-		while((s = pool[i].stack)) {
+		while((s = pool[i].stack) != 0) {
 			pool[i].stack = (char*)_POOL_NODE_NEXT(s);
 			_POOL_NODE_FREE(s);
 		}