[Bug c/71685] [6 Regression] Segmentation fault in gcc when compiling the attached file.

[wilson at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71685

--- Comment #7 from Jim Wilson <wilson at gcc dot gnu.org> ---
An early exit if type_quals is 0 does not work, as there is at least one place
that deliberately calls c_build_qualified_type with no type qualifiers to
create an unqualified type from a qualified type.  Likewise, my earlier
suggestion of a check for var_type != type can't work as it fails in this case
too.

I can see another possible fix, checking for type_quals non-zero before
clearing the C_TYPE_INCOMPLETE_VARS, but given how complicated this code is
turning out to be, the check for a type main variant is the safest fix.  And I
see that Jakub has just checked in a patch for that solution, so I'm assuming I
don't need to do anymore work on this.