[Bug middle-end/93582] [10 Regression] -Warray-bounds gives error: array subscript 0 is outside array bounds of struct E[1]

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93582

--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
This is about us not accepting the code anymore, I think it's what libXt relies
on.  Quoting Adam J.:

"Where GRABEXT here is just doing the standard C trick for incrementing
past the current struct and returning a (differently typed) pointer to
the data beyond:

#define GRABEXT(p) ((XtServerGrabExtPtr)((p)+1))"

I'm not sure if we want to break this though the code certainly look dubious. 
clang currently accepts it.