while (fs && fs->fullscreen_mode == CF_NONE)
fs = fs->parent;
+ /* fs must be non-NULL since the workspace con doesn’t have CF_NONE and
+ * there always has to be a workspace con in the hierarchy. */
+ assert(fs != NULL);
/* The most common case is we hit the workspace level. In this
* situation, changing focus is also harmless. */
assert(fs->fullscreen_mode != CF_NONE);