[Bug c++/39637] New: ICE on ill-formed sizeof() in variadic template

[sebor at roguewave dot com]

gcc 4.3.2 fails with an ICE on the following ill-formed program. A fairly
recent (but not the most recent) version of 4.4 also fails.

$ cat t.C && g++ -dumpversion && g++ t.C -std=c++0x
template <class... Types>
void f (Types...)
{
    enum { e = sizeof (Types) };
};

int main ()
{
    f (0);
}
4.3.2
t.C: In function ‘void f(Types ...) [with Types = int]’:
t.C:9:   instantiated from here
t.C:4: internal compiler error: in dependent_type_p, at cp/pt.c:15758
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://bugzilla.redhat.com/bugzilla> for instructions.
Preprocessed source stored into /tmp/cca3TXk5.out file, please attach this to
your bugreport.


$ g++ -v && g++ t.C
Using built-in specs.
Target: x86_64-unknown-linux-gnu
Configured with: /home/sebor/gcc/trunk/configure
--prefix=/build/sebor/bin/gcc-4.4.0 --enable-languages=c,c++
--with-mpfr=/usr/local/mpfr-2.3.1
Thread model: posix
gcc version 4.4.0 20081105 (experimental) (GCC) 
t.C:1: warning: variadic templates only available with -std=c++0x or
-std=gnu++0x
t.C:2: warning: variadic templates only available with -std=c++0x or
-std=gnu++0x
t.C: In function ‘void f(Types ...) [with Types = int]’:
t.C:9:   instantiated from here
t.C:4: internal compiler error: in dependent_type_p, at cp/pt.c:15922
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.


-- 
           Summary: ICE on ill-formed sizeof(<parameter-pack>) in variadic
                    template
           Product: gcc
           Version: 4.3.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: sebor at roguewave dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39637