internal compiler error in gcc trunk when using std::map

[Nathan Ridge]

Hello,
 
I've just build the gcc trunk and tried to compile some code that compiled fine 
with gcc 4.5.
It gave an internal compiler error.
I've reduced it to the following minimal test case:
 
#include <string>
#include <map>
int main()
{
    std::map<std::string, int> m;
    std::pair<std::string, int> p;
    m.insert(p);
    return 0;
}
 
Here's the command used to compile:
 
g++-4.6 --std=c++0x test.cpp
 
Here's the output:
 
In file included from 
/usr/local/lib/gcc/i686-pc-linux-gnu/4.6.0/../../../../include/c++/4.6.0/bits/stl_algobase.h:65:0,
                 from 
/usr/local/lib/gcc/i686-pc-linux-gnu/4.6.0/../../../../include/c++/4.6.0/bits/char_traits.h:41,
                 from 
/usr/local/lib/gcc/i686-pc-linux-gnu/4.6.0/../../../../include/c++/4.6.0/string:42,
                 from ice.cpp:1:
/usr/local/lib/gcc/i686-pc-linux-gnu/4.6.0/../../../../include/c++/4.6.0/bits/stl_pair.h:
 In constructor âconstexpr std::pair<_T1, _T2>::pair(const std::pair<_U1, 
_U2>&) [with _U1 = std::basic_string<char>, _U2 = int, _T1 = const 
std::basic_string<char>, _T2 = int]â:
/usr/local/lib/gcc/i686-pc-linux-gnu/4.6.0/../../../../include/c++/4.6.0/type_traits:780:68:
   instantiated from âconst bool 
std::__is_convertible_helper<std::pair<std::basic_string<char>, int>&, 
std::pair<const std::basic_string<char>, int>, false>::__valueâ
/usr/local/lib/gcc/i686-pc-linux-gnu/4.6.0/../../../../include/c++/4.6.0/type_traits:787:12:
   instantiated from âstd::is_convertible<std::pair<std::basic_string<char>, 
int>&, std::pair<const std::basic_string<char>, int> >â
test.cpp:8:15:   instantiated from here
/usr/local/lib/gcc/i686-pc-linux-gnu/4.6.0/../../../../include/c++/4.6.0/bits/stl_pair.h:107:43:
 internal compiler error: in build_data_member_initialization, at 
cp/semantics.c:5502
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.
 
And here's the output of g++-4.6 -v:
 
Using built-in specs.
COLLECT_GCC=g++-4.6
COLLECT_LTO_WRAPPER=/usr/local/libexec/gcc/i686-pc-linux-gnu/4.6.0/lto-wrapper
Target: i686-pc-linux-gnu
Configured with: ../src/configure --program-suffix=-4.6 --enable-languages=c,c++
Thread model: posix
gcc version 4.6.0 20101209 (experimental) (GCC)
 
Thanks,
Nate.