[Bug c++/54947] New: [4.7/4.8 Regression] [C++11] lambda cannot capture-by-copy inside braced-init-list

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54947

             Bug #: 54947
           Summary: [4.7/4.8 Regression] [C++11] lambda cannot
                    capture-by-copy inside braced-init-list
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Keywords: rejects-valid
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: r...@gcc.gnu.org
            Blocks: 54367


struct X
{
  template<typename L>
    X(L)
    { }
};

template<typename A>
  void
  test()
  {
    int i = 0;

    A a_ok_1( [=] { return i; } );  // OK
    A a_ok_2( [i] { return i; } );  // OK

    A a_err_1{ [i] { return i; } };  // error
    A a_err_2{ [=] { return i; } };  // error
  }

int main()
{
  test<X>();
}


lam.cc:17:17: error: the value of ‘i’ is not usable in a constant expression
     A a_err_1{ [i] { return i; } };  // error
                 ^
lam.cc:12:9: note: ‘int i’ is not const
     int i = 0;
         ^
lam.cc:18:17: error: expression ‘<erroneous-expression> =
<erroneous-expression>’ is not a constant-expression
     A a_err_2{ [=] { return i; } };  // error
                 ^

There's no error when using direct-initialization, only list-initialization.
No error if test() is not a function template.

Works fine with 4.6 and clang++