Issue #22975: Close block at right place.
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 5234901..f25f6c8 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -9880,8 +9880,8 @@
             Py_UCS4 * to_ = (Py_UCS4 *)((data)) + (start); \
             for (; i_ < (length); ++i_, ++to_) *to_ = (value); \
             break; \
-        default: assert(0); \
         } \
+        default: assert(0); \
         } \
     } while (0)