[Bug c/90677] [9 Regression] gcc-9.1.0 fails to build __gcc_diag__ souce: error: 'cgraph_node' is not defined as a type

[ebotcazou at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90677

Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
                 CC|                            |ebotcazou at gcc dot gnu.org
         Resolution|FIXED                       |---

--- Comment #14 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
The fix breaks the build of earlier GCCs with the C++ compiler:

extern void foo (int, int, const char *, ...)
  __attribute__ ((__format__ (__gcc_tdiag__, 3, 4)));
struct cgraph_node;
extern void bar (struct cgraph_node *);

t.cpp:2:52: error: 'cgraph_node' is not defined as a type
    2 |   __attribute__ ((__format__ (__gcc_tdiag__, 3, 4)));
      |