This would probably need some special rules around stuff like:

   typedef struct { ... } foo_t;
   typedef struct { ... } bar_t;
   foo_t foo = (bar_t){ ... };

i.e. these are meant to be named types and thus should remain nominal even though it's technically a typedef. And ditto for similarly defined pointer types etc. But this is a pattern regular enough that it can just be special-cased while still allowing proper structural typing for cases where that's obviously what is intended (i.e. basically everywhere else).