diff options
Diffstat (limited to 'boost/hana/fwd/zero.hpp')
| -rw-r--r-- | boost/hana/fwd/zero.hpp | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/boost/hana/fwd/zero.hpp b/boost/hana/fwd/zero.hpp index 412614786d..fcbcfcc372 100644 --- a/boost/hana/fwd/zero.hpp +++ b/boost/hana/fwd/zero.hpp @@ -35,7 +35,9 @@ BOOST_HANA_NAMESPACE_BEGIN struct zero_impl : zero_impl<M, when<true>> { }; template <typename M> - struct zero_t; + struct zero_t { + constexpr decltype(auto) operator()() const; + }; template <typename M> constexpr zero_t<M> zero{}; |