https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77650
--- Comment #1 from joseph at codesourcery dot com <joseph at codesourcery dot com> --- On Mon, 19 Sep 2016, msebor at gcc dot gnu.org wrote: > While testing my patch for C++ bug 71912 and gathering material for WG14 paper > N2083 I noticed that GCC isn't completely consistent in diagnosing invalid > uses > of flexible array members. In the following example, it rejects the > definition > of struct Y with a hard error because the flexible array member a is followed > by another member, j. But GCC issues only a pedantic warning for the similar > definition of struct T where the flexible array member defined in a nested > struct is also followed by another member. I think it would be better (more > consistent and safer(*)) if both structs were rejected with an error. The nested struct is accepted to work with glibc headers, as I noted in <https://gcc.gnu.org/ml/gcc-patches/2002-08/msg01149.html>. gconv.h has typedef struct __gconv_info { size_t __nsteps; struct __gconv_step *__steps; __extension__ struct __gconv_step_data __data __flexarr; } *__gconv_t; and _G_config.h has typedef union { struct __gconv_info __cd; struct { struct __gconv_info __cd; struct __gconv_step_data __data; } __combined; } _G_iconv_t; where the inner struct has struct __gconv_info (which ends with a flexible array member) followed by another struct.
