[Bug debug/69518] [6 Regression] Flag -g causes "error: type variant has different TYPE_VFIELD"

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69518

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |jakub at gcc dot gnu.org

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 37518
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37518&action=edit
gcc6-pr69518.patch

Untested fix.  The problem is that when type variants are created, the generic
code copies there also the TYPE_VFIELD aka C_TYPE_INCOMPLETE_VARS.  We clear it
only in the main type variant, but not in other variants, so if not anything
else, it is at least undesirable for GC purposes, plus we leak the C FE use of
that field into the middle-end.