1 files changed, 26 insertions, 0 deletions
diff --git a/src/ui/debug.c b/src/ui/debug.c
new file mode 100644
index 0000000..d4f2e94
--- /dev/null
+++ b/src/ui/debug.c
@@ -0,0 +1,26 @@
+#ifndef NDEBUG
+
+#include <assert.h>
+
+#include "ui.internal.h"
+
+struct ui_window_base *ui__check_cast_to_base(void *obj)
+{
+  return obj; /* this cast always succeeds */
+}
+
+struct ui_window_dock *ui__check_cast_to_dock(void *obj)
+{
+  struct ui_window_base *base = obj;
+  assert(base->type == UI__WINDOW_TYPE_DOCK);
+  return obj;
+}
+
+struct ui_window_root *ui__check_cast_to_root(void *obj)
+{
+  struct ui_window_base *base = obj;
+  assert(base->type == UI__WINDOW_TYPE_ROOT);
+  return obj;
+}
+
+#endif