CRTP does not seem to work together with variadic templates.
On a larger program, type canonization seems to be faulty and leads to a g++
crash.
Source code:
struct a {};
template < typename T, typename ENCLOSING >
struct base;
template < typename ENCLOSING >
struct base< a, ENCLOSING >
{};
template < typename... T >
struct derived
: public base< T, derived< T... > >...
{};
int main()
{
derived< a > instance;
base< a, derived< a > >& a_instance = instance;
}
Output of g++ variadic-crtp.cc -std=c++0x:
variadic-crtp.cc: In function 'int main()':
variadic-crtp.cc:18:41: error: invalid initialization of reference of type
'base<a, derived<a> >&' from expression of type 'derived<a>'
Output of g++ -v:
Using built-in specs.
Target: i386-apple-darwin9
Configured with: ../gcc-4.5-20091001/configure --prefix=/opt/local
--build=i386-apple-darwin9 --enable-languages=c,c++,objc,obj-c++
--libdir=/opt/local/lib/gcc45 --includedir=/opt/local/include/gcc45
--infodir=/opt/local/share/info --mandir=/opt/local/share/man
--with-local-prefix=/opt/local --with-system-zlib --disable-nls
--program-suffix=-mp-4.5 --with-gxx-include-dir=/opt/local/include/gcc45/c++/
--with-gmp=/opt/local --with-mpfr=/opt/local
Thread model: posix
gcc version 4.5.0 20091001 (experimental) (GCC)
--
Summary: Canonical type with variadic templates and CRTP
Product: gcc
Version: 4.5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: alban dot linard at gmail dot com
GCC build triplet: i686-apple-darwin9
GCC host triplet: i686-apple-darwin9
GCC target triplet: i686-apple-darwin9
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41752
