At least with -fsanitize=address -fno-sanitize-recover=address -fsanitize=undefined -fno-sanitize-recover=undefined:
```
/home/rusty/devel/cvs/ccan/ccan/tcon/test/compile_fail-container1.c:Compile gave warnings without -DFAIL:
In file included from /home/rusty/devel/cvs/ccan/ccan/tcon/test/compile_fail-container1.c:3:
/home/rusty/devel/cvs/ccan/ccan/tcon/tcon.h: In function ‘main’:
/home/rusty/devel/cvs/ccan/ccan/tcon/tcon.h:332:25: warning: ‘innerp’ may be used uninitialized [-Wmaybe-uninitialized]
332 | canary, tcon_container_of_((member_ptr), \
| ^~~~~~~~~~~~~~~~~~
/home/rusty/devel/cvs/ccan/ccan/tcon/tcon.h:335:21: note: by argument 1 of type ‘const void *’ to ‘tcon_container_of_’ declared here
335 | static inline void *tcon_container_of_(const void *member_ptr, size_t offset)
| ^~~~~~~~~~~~~~~~~~
/home/rusty/devel/cvs/ccan/ccan/tcon/test/compile_fail-container1.c:28:22: note: ‘ovar’ declared here
28 | struct outer ovar;
| ^~~~