PR c++/85462
* cp-tree.h (tinst_level): Remove in_system_header_p member,
change refcount member from unsigned char to unsigned short,
add refcount_infinity static data member, adjust comments.
* pt.c (tinst_level::refcount_infinity): Define.
(inc_refcount_use): Remove assert, don't increment if refcount
is already refcount_infinity, adjust comment.
(dec_refcount_use): Remove assert, don't decrement if refcount
is refcount_infinity, adjust comment.
(push_tinst_level_loc): Formatting fix.
* g++.dg/cpp0x/pr85462.C: New test.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@259516 138bc75d-0d04-0410-961f-82ee72b054a4