When build the following code with GCC 4.8.1:

struct C
{
    constexpr int fun (int x)
    {
        return x + 1;
    }

    int a = 2;
    int b = fun(a);
};

C c;

int main() {}

GCC told me : 

internal compiler error : segmentation fault.

In my opinion, it should present more meaningful result, such as the non-static function 'fun' cannot be used in inline initialization ...