gcc/g++ internal error (c++ templated lambda)

Question

i was just making a few changes to my program, when all of a sudden g++ complained with an internal compiler error.

Clang however compiles it without any problems and also does not give any warnings, that would indicate anything weird.

I distilled the problem down to this:

#include <functional>

template<typename T>
class A{
    T someVar;
};

template<typename T>
class B {
        int x;

        std::function<A<double>(A<int>&)> someLambda = [&](A<int>& aInt){
            int xVar = x;
            A<double> aRet;
            return aRet;
        };
};

int main(int argc, char** argv){
    B<int> a;
    return 0;
}

I tried both GCC 4.9.2 and 4.8.4, with both failing (internal compiler error).

Flags I used:

g++ -std=c++11 -O0 -g -Wall main.cpp -o gccBin

clang++ -std=c++11 -O0 -g -Wall main.cpp -o clangBin

main.cpp: In instantiation of 'struct B<int>::<lambda(class A<int>&)>':
main.cpp:10:7:   required from here
main.cpp:14:24: internal compiler error: in tsubst_copy, at cp/pt.c:12569
             int xVar = x;
                        ^
libbacktrace could not find executable to open
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

Clang++(3.5.1) compiles it without a problem, as I mentioned. I also tried multiple machines, everywhere the same.

Is there some kind of error I overlooked? I searched a bit on the internet and the only similar problems i could find should have been fixed by now (as the bugtracker states).

Could maybe someone try and run this code on their machine or give other advice?

Thank you,

Lazarus

Answer 1

It's a compiler bug. Just go ahead and file a bug report to the GCC dudes!