[Bug c++/65919] Regression - GCC 5.1 with options "-g -std=c++14" fails to compile multiple lambdas used as default function parameters

[maltsevm at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65919

Mikhail Maltsev <maltsevm at gmail dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |maltsevm at gmail dot com

--- Comment #1 from Mikhail Maltsev <maltsevm at gmail dot com> ---
Reduced testcase:

template <typename> class function;
template <typename> class _Base_manager {
public:
  void _M_manager();
  template <typename _Tp> static bool _M_not_empty_function(_Tp);
};

template <typename, typename> class A;
template <typename _Functor, typename... _ArgTypes>
class A<void(_ArgTypes...), _Functor> : public _Base_manager<_Functor> {};

template <typename _Res, typename... _ArgTypes>
class function<_Res(_ArgTypes...)> {
  template <typename, typename> using _Requires = int;

public:
  template <typename _Functor, typename = _Requires<_Functor, void>>
  function(_Functor);
};

template <typename _Res, typename... _ArgTypes>
template <typename _Functor, typename>
function<_Res(_ArgTypes...)>::function(_Functor p1) {
  A<_Res(), _Functor>::_M_not_empty_function(p1);
}

struct B {
  static void do_things(function<void()> = [] {}, function<void()> = [] {});
};

int main() {
  B::do_things();
}