[Bug c/82909] Scope of type defined by offsetof() macro

[joseph at codesourcery dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82909

--- Comment #1 from joseph at codesourcery dot com <joseph at codesourcery dot com> ---
On Wed, 8 Nov 2017, tydeman at tybor dot com wrote:

> /*
>  * C standard appears to be unclear on scope of new type defined in
>  * offsetof() macro.  Some compilers accept; some reject.
>  * This is related to C Defect Report 496.
>  */
> 
> #include <stddef.h>     /* offsetof() */
> 
> int main(void){
> 
>   if( 0 == (int)offsetof( struct s4 {int i4;}, i4 ) ){
>     struct s4 s43;      /* OK here */
>   }
>   {
>     struct s4 s44;      /* Should(?) be OK here */
>   }

This is accepted for -std=c89 (where selection statements don't introduce 
block scopes) and rejected for -std=c99 and -std=c11 (where selection 
statements do introduce block scopes; C11 6.8.4p3).  I don't see a bug 
here; what do you think should behave differently?