[Bug c++/59991] New: Recursive lambda capture in C++1y constexpr function template causes internal compiler error

[pkeir at outlook dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59991

            Bug ID: 59991
           Summary: Recursive lambda capture in C++1y constexpr function
                    template causes internal compiler error
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pkeir at outlook dot com

Created attachment 31987
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=31987&action=edit
The test case which produces the internal compiler error

The code below uses the C++1y feature of allowing declarations in constexpr
functions, but r should not be included in the lambda's capture list. There is
also an issue with excessive recursive template instantiation. In any case, the
code produces an internal compiler error starting with:

internal compiler error: in tsubst, at cp/pt.c:11350
   auto f = [r,x]() { return r(x); };

The full output and test case is attached. This was run under Ubuntu 13.10.

// $ g++ --version
// g++ (GCC) 4.9.0 20131201 (experimental)

template <typename T>
constexpr int r(T x) {
  auto f = [r,x]() { return r(x); };
  return 0;
}

int main(int argc, char *argv[])
{
  r(0);
  return 0;
}