[Bug c++/78014] -Wformat -vs- size_t

[joseph at codesourcery dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78014

--- Comment #2 from joseph at codesourcery dot com <joseph at codesourcery dot com> ---
I think this is essentially the same as bug 77970 - making such warnings 
smarter about the case of standard typedefs.

Of course an expression resulting from sizeof must be considered 
appropriate for %zu.  Likewise _Alignof.  Likewise SIZE_MAX, but headers 
or predefines just define it to use an appropriate constant suffix, so 
without looking at the macro being expanded there's nothing to distinguish 
it from any constant where the user wrong such a suffix directly.  
Likewise an expression where the user did "typedef size_t my_size_t;" and 
then used my_size_t.  And what about expressions resulting from arithmetic 
on size_t values?  So it may be hard for the compiler to tell exactly what 
expressions are appropriate for use with %zu (even without direct use of 
__SIZE_TYPE__).