more_specialized_fn contains
/* All things being equal, if the next argument is a pack expansion
for one function but not for the other, prefer the
non-variadic function. */
if ((better1 > 0) - (better2 > 0) == 0
&& args1 && TREE_VALUE (args1)
&& args2 && TREE_VALUE (args2))
{
if (TREE_CODE (TREE_VALUE (args1)) == TYPE_PACK_EXPANSION)
return TREE_CODE (TREE_VALUE (args2)) == TYPE_PACK_EXPANSION ? 0 : -1;
else if (TREE_CODE (TREE_VALUE (args2)) == TYPE_PACK_EXPANSION)
return 1;
}
which makes us prefer a non-variadic option even when deduction failed in both
directions, which makes variadic-crash1.C pass purely by accident. This also
makes us prefer an unused default argument to a function parameter pack.
--
Summary: [c++0x] bogus variadic partial ordering code
Product: gcc
Version: 4.5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: jason at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41958
