Compiling with:
g++ uninit_reference.cpp -o uninit_reference.o -std=gnu++0x -c

class Outer 
{
  public:
  Outer()
  : i(*this)
  {
  }

  class Inner 
  {
    public:
    Inner(Outer& o)
    : o(o)
    {
    }

    private:
    Outer& o;
  };

  private:
  Inner i;
};

class A {
  Outer o;
};

int main()
{
  A *a = new A;

  return 0;
}

uninit_reference.cpp: In function ‘int main()’:
uninit_reference.cpp:31:14: error: uninitialized reference member in ‘class A’
using ‘new’
uninit_reference.cpp:18:12: note: ‘Outer::Inner::o’ should be initialized

Configured with: ../gcc-svn/configure --prefix=/home/jarryd/gcc-latest-install
--enable-languages=c,c++ : (reconfigured) ../gcc-svn/configure
--prefix=/home/jarryd/gcc-latest-install --enable-languages=c,c++ --no-create
--no-recursion : (reconfigured) ../gcc-svn/configure
--prefix=/home/jarryd/gcc-latest-install --enable-languages=c,c++ --no-create
--no-recursion : (reconfigured) ../gcc-svn/configure
--prefix=/home/jarryd/gcc-latest-install --enable-languages=c,c++ --no-create
--no-recursion : (reconfigured) ../gcc-svn/configure
--prefix=/home/jarryd/gcc-latest-install --enable-languages=c,c++ --no-create
--no-recursion : (reconfigured) ../gcc-svn/configure
--prefix=/home/jarryd/gcc-latest-install --enable-languages=c,c++ --no-create
--no-recursion : (reconfigured) ../gcc-svn/configure
--prefix=/home/jarryd/gcc-latest-install --enable-languages=c,c++ --no-create
--no-recursion : (reconfigured) ../gcc-svn/configure
--prefix=/home/jarryd/gcc-latest-install --enable-languages=c,c++ --no-create
--no-recursion
Thread model: posix
gcc version 4.6.0 20100425 (experimental) (GCC)


-- 
           Summary: invalid uninitialized reference in class
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jarrydb at cse dot unsw dot edu dot au
 GCC build triplet: x86_64-unknown-linux-gnu
  GCC host triplet: x86_64-unknown-linux-gnu
GCC target triplet: x86_64-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43890