Convert Object::cast_to() to the static version

Currently we rely on some undefined behavior when Object->cast_to() gets
called with a Null pointer. This used to work fine with GCC < 6 but
newer versions of GCC remove all codepaths in which the this pointer is
Null. However, the non-static cast_to() was supposed to be null safe.

This patch makes cast_to() Null safe and removes the now redundant Null
checks where they existed.

It is explained in this article: https://www.viva64.com/en/b/0226/

1 files changed, 5 insertions, 5 deletions

diff --git a/scene/gui/tab_container.cpp b/scene/gui/tab_container.cpp
index d32b899de..8afcc896a 100644
--- a/scene/gui/tab_container.cpp
+++ b/scene/gui/tab_container.cpp
@@ -230,7 +230,7 @@ void TabContainer::_notification(int p_what) {
 				tab_style->draw(canvas, tab_rect);
 
 				// Draw the tab contents.
-				Control *control = tabs[i + first_tab_cache]->cast_to<Control>();
+				Control *control = Object::cast_to<Control>(tabs[i + first_tab_cache]);
 				String text = control->has_meta("_tab_name") ? String(tr(String(control->get_meta("_tab_name")))) : String(control->get_name());
 
 				int x_content = tab_rect.position.x + tab_style->get_margin(MARGIN_LEFT);
@@ -293,7 +293,7 @@ void TabContainer::_notification(int p_what) {
 }
 
 int TabContainer::_get_tab_width(int p_index) const {
-	Control *control = _get_tabs()[p_index]->cast_to<Control>();
+	Control *control = Object::cast_to<Control>(_get_tabs()[p_index]);
 	if (!control || control->is_set_as_toplevel())
 		return 0;
 
@@ -332,7 +332,7 @@ Vector<Control *> TabContainer::_get_tabs() const {
 	Vector<Control *> controls;
 	for (int i = 0; i < get_child_count(); i++) {
 
-		Control *control = get_child(i)->cast_to<Control>();
+		Control *control = Object::cast_to<Control>(get_child(i));
 		if (!control || control->is_toplevel_control())
 			continue;
 
@@ -350,7 +350,7 @@ void TabContainer::add_child_notify(Node *p_child) {
 
 	Control::add_child_notify(p_child);
 
-	Control *c = p_child->cast_to<Control>();
+	Control *c = Object::cast_to<Control>(p_child);
 	if (!c)
 		return;
 	if (c->is_set_as_toplevel())
@@ -616,7 +616,7 @@ Size2 TabContainer::get_minimum_size() const {
 
 void TabContainer::set_popup(Node *p_popup) {
 	ERR_FAIL_NULL(p_popup);
-	popup = p_popup->cast_to<Popup>();
+	popup = Object::cast_to<Popup>(p_popup);
 	update();
 }