Make nullopt_t safer

2017-09-29 19:49:46 +01:00
parent f2018a122b
commit 4287be6e74
1 changed files with 5 additions and 2 deletions
--- a/optional.hpp
+++ b/optional.hpp
@@ -19,8 +19,11 @@ namespace tl {
  class optional;

  // [optional.nullopt], no-value state indicator
-  struct nullopt_t{};
-  inline constexpr nullopt_t nullopt;
+  struct nullopt_t{
+      struct do_not_use{};
+      constexpr explicit nullopt(do_not_use, do_not_use) noexcept{}
+  };
+    inline constexpr nullopt_t nullopt{nullopt_t::do_not_use{}, nullopt_t::do_not_use{}};

  // [optional.bad.access], class bad_optional_access
    class bad_optional_access : public std::exception {