try to fix gcc bug nlohmann#2

oficsu · Jul 26, 2020 · 7cb074f · 7cb074f
1 parent 700f279
commit 7cb074f
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Showing 3 changed files with 48 additions and 24 deletions.
diff --git a/include/nlohmann/adl_serializer.hpp b/include/nlohmann/adl_serializer.hpp
@@ -20,10 +20,10 @@ struct adl_serializer
  */
  template<typename... Args>
  static auto from_json(Args&& ... args) noexcept(
- noexcept(::nlohmann::from_json.call(adl_tag<ValueType> {}, detail::max_priority_t{}, std::forward<Args>(args)...)))
- -> decltype(::nlohmann::from_json.call(adl_tag<ValueType> {}, detail::max_priority_t{}, std::forward<Args>(args)...))
+ noexcept(::nlohmann::detail::from_json_impl(adl_tag<ValueType> {}, detail::max_priority_t{}, std::forward<Args>(args)...)))
+ -> decltype(::nlohmann::detail::from_json_impl(adl_tag<ValueType> {}, detail::max_priority_t{}, std::forward<Args>(args)...))
  {
- return ::nlohmann::from_json.call(adl_tag<ValueType> {}, detail::max_priority_t{}, std::forward<Args>(args)...);
+ return ::nlohmann::detail::from_json_impl(adl_tag<ValueType> {}, detail::max_priority_t{}, std::forward<Args>(args)...);
  }
 
  /*!

diff --git a/include/nlohmann/detail/conversions/from_json.hpp b/include/nlohmann/detail/conversions/from_json.hpp
@@ -384,26 +384,27 @@ void from_json(const BasicJsonType& j, std::unordered_map<Key, Value, Hash, KeyE
  }
 }
 
-struct from_json_fn
+/// [workaround for gcc](https://gcc.gnu.org/bugzilla/show_bug.cgi?format=multiple&id=52869)
+struct from_json_impl_fn
 {
  template<typename BasicJsonType, typename ValueType, typename... Args>
- auto call(adl_tag<ValueType>, detail::priority_tag<1>, BasicJsonType&& j, Args&& ... args) const
+ auto operator()(adl_tag<ValueType>, detail::priority_tag<1>, BasicJsonType&& j, Args&& ... args) const
  noexcept(noexcept(ValueType::from_json(std::forward<BasicJsonType>(j), std::forward<Args>(args)...)))
  -> decltype(ValueType::from_json(std::forward<BasicJsonType>(j), std::forward<Args>(args)...))
  {
  return ValueType::from_json(std::forward<BasicJsonType>(j), std::forward<Args>(args)...);
  }
 
  template<typename BasicJsonType, typename ValueType, typename... Args>
- auto call(adl_tag<ValueType>, priority_tag<0>, BasicJsonType&& j, Args&& ... args) const
+ auto operator()(adl_tag<ValueType>, priority_tag<0>, BasicJsonType&& j, Args&& ... args) const
  noexcept(noexcept(from_json(std::forward<BasicJsonType>(j), std::forward<Args>(args)..., adl_tag<ValueType> {})))
  -> decltype (from_json(std::forward<BasicJsonType>(j), std::forward<Args>(args)..., adl_tag<ValueType> {}))
  {
  return from_json(std::forward<BasicJsonType>(j), std::forward<Args>(args)..., adl_tag<ValueType> {});
  }
 
  template<typename BasicJsonType, typename ValueType, typename ValueTypeCV, typename... Args>
- auto call(adl_tag<ValueType>, priority_tag<2>, BasicJsonType&& j, ValueTypeCV&& val, Args&& ... args) const
+ auto operator()(adl_tag<ValueType>, priority_tag<2>, BasicJsonType&& j, ValueTypeCV&& val, Args&& ... args) const
  noexcept(noexcept(std::forward<ValueTypeCV>(val).from_json(j, std::forward<Args>(args)...)))
  -> decltype (std::forward<ValueTypeCV>(val).from_json(j, std::forward<Args>(args)...), void())
  {
@@ -413,7 +414,7 @@ struct from_json_fn
  }
 
  template<typename BasicJsonType, typename ValueType, typename ValueTypeCV, typename... Args>
- auto call(adl_tag<ValueType>, priority_tag<1>, BasicJsonType&& j, ValueTypeCV&& val, Args&& ... args) const
+ auto operator()(adl_tag<ValueType>, priority_tag<1>, BasicJsonType&& j, ValueTypeCV&& val, Args&& ... args) const
  noexcept(noexcept(uncvref_t<ValueType>::from_json(std::forward<BasicJsonType>(j), std::forward<ValueTypeCV>(val), std::forward<Args>(args)...)))
  -> decltype(uncvref_t<ValueType>::from_json(std::forward<BasicJsonType>(j), std::forward<ValueTypeCV>(val), std::forward<Args>(args)...), void())
  {
@@ -423,22 +424,33 @@ struct from_json_fn
  }
 
  template<typename BasicJsonType, typename ValueType, typename ValueTypeCV, typename... Args>
- auto call(adl_tag<ValueType>, priority_tag<0>, BasicJsonType&& j, ValueTypeCV&& val, Args&& ... args) const
+ auto operator()(adl_tag<ValueType>, priority_tag<0>, BasicJsonType&& j, ValueTypeCV&& val, Args&& ... args) const
  noexcept(noexcept(from_json(j, std::forward<ValueTypeCV>(val), std::forward<Args>(args)...)))
  -> decltype(from_json(j, std::forward<ValueTypeCV>(val), std::forward<Args>(args)...), void())
  {
  static_assert(std::is_same<uncvref_t<ValueType>, uncvref_t<ValueTypeCV>>::value,
  "ValueType and ValueTypeCV should be same");
  from_json(j, std::forward<ValueTypeCV>(val), std::forward<Args>(args)...);
  }
+};
 
+/// namespace to hold default `from_json` function
+/// to see why this is required:
+/// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4381.html
+namespace
+{
+constexpr const auto& from_json_impl = detail::static_const<detail::from_json_impl_fn>::value;
+} // namespace
+
+struct from_json_fn
+{
  //
  template<typename BasicJsonType, typename ValueType, typename... Args>
  auto operator()(BasicJsonType&& j, ValueType&& val, Args&& ... args) const
- noexcept(noexcept(call(adl_tag<ValueType> {}, max_priority_t{}, j, val, std::forward<Args>(args)...)))
- -> decltype(call(adl_tag<uncvref_t<ValueType>> {}, max_priority_t{}, j, val, std::forward<Args>(args)...), void())
+ noexcept(noexcept(from_json_impl(adl_tag<ValueType> {}, max_priority_t{}, j, val, std::forward<Args>(args)...)))
+ -> decltype(from_json_impl(adl_tag<uncvref_t<ValueType>> {}, max_priority_t{}, j, val, std::forward<Args>(args)...), void())
  {
- call(adl_tag<uncvref_t<ValueType>> {}, max_priority_t{}, j, val, std::forward<Args>(args)...);
+ from_json_impl(adl_tag<uncvref_t<ValueType>> {}, max_priority_t{}, j, val, std::forward<Args>(args)...);
  }
 };
 } // namespace detail

diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
@@ -3806,26 +3806,27 @@ void from_json(const BasicJsonType& j, std::unordered_map<Key, Value, Hash, KeyE
  }
 }
 
-struct from_json_fn
+/// [workaround for gcc](https://gcc.gnu.org/bugzilla/show_bug.cgi?format=multiple&id=52869)
+struct from_json_impl_fn
 {
  template<typename BasicJsonType, typename ValueType, typename... Args>
- auto call(adl_tag<ValueType>, detail::priority_tag<1>, BasicJsonType&& j, Args&& ... args) const
+ auto operator()(adl_tag<ValueType>, detail::priority_tag<1>, BasicJsonType&& j, Args&& ... args) const
  noexcept(noexcept(ValueType::from_json(std::forward<BasicJsonType>(j), std::forward<Args>(args)...)))
  -> decltype(ValueType::from_json(std::forward<BasicJsonType>(j), std::forward<Args>(args)...))
  {
  return ValueType::from_json(std::forward<BasicJsonType>(j), std::forward<Args>(args)...);
  }
 
  template<typename BasicJsonType, typename ValueType, typename... Args>
- auto call(adl_tag<ValueType>, priority_tag<0>, BasicJsonType&& j, Args&& ... args) const
+ auto operator()(adl_tag<ValueType>, priority_tag<0>, BasicJsonType&& j, Args&& ... args) const
  noexcept(noexcept(from_json(std::forward<BasicJsonType>(j), std::forward<Args>(args)..., adl_tag<ValueType> {})))
  -> decltype (from_json(std::forward<BasicJsonType>(j), std::forward<Args>(args)..., adl_tag<ValueType> {}))
  {
  return from_json(std::forward<BasicJsonType>(j), std::forward<Args>(args)..., adl_tag<ValueType> {});
  }
 
  template<typename BasicJsonType, typename ValueType, typename ValueTypeCV, typename... Args>
- auto call(adl_tag<ValueType>, priority_tag<2>, BasicJsonType&& j, ValueTypeCV&& val, Args&& ... args) const
+ auto operator()(adl_tag<ValueType>, priority_tag<2>, BasicJsonType&& j, ValueTypeCV&& val, Args&& ... args) const
  noexcept(noexcept(std::forward<ValueTypeCV>(val).from_json(j, std::forward<Args>(args)...)))
  -> decltype (std::forward<ValueTypeCV>(val).from_json(j, std::forward<Args>(args)...), void())
  {
@@ -3835,7 +3836,7 @@ struct from_json_fn
  }
 
  template<typename BasicJsonType, typename ValueType, typename ValueTypeCV, typename... Args>
- auto call(adl_tag<ValueType>, priority_tag<1>, BasicJsonType&& j, ValueTypeCV&& val, Args&& ... args) const
+ auto operator()(adl_tag<ValueType>, priority_tag<1>, BasicJsonType&& j, ValueTypeCV&& val, Args&& ... args) const
  noexcept(noexcept(uncvref_t<ValueType>::from_json(std::forward<BasicJsonType>(j), std::forward<ValueTypeCV>(val), std::forward<Args>(args)...)))
  -> decltype(uncvref_t<ValueType>::from_json(std::forward<BasicJsonType>(j), std::forward<ValueTypeCV>(val), std::forward<Args>(args)...), void())
  {
@@ -3845,22 +3846,33 @@ struct from_json_fn
  }
 
  template<typename BasicJsonType, typename ValueType, typename ValueTypeCV, typename... Args>
- auto call(adl_tag<ValueType>, priority_tag<0>, BasicJsonType&& j, ValueTypeCV&& val, Args&& ... args) const
+ auto operator()(adl_tag<ValueType>, priority_tag<0>, BasicJsonType&& j, ValueTypeCV&& val, Args&& ... args) const
  noexcept(noexcept(from_json(j, std::forward<ValueTypeCV>(val), std::forward<Args>(args)...)))
  -> decltype(from_json(j, std::forward<ValueTypeCV>(val), std::forward<Args>(args)...), void())
  {
  static_assert(std::is_same<uncvref_t<ValueType>, uncvref_t<ValueTypeCV>>::value,
  "ValueType and ValueTypeCV should be same");
  from_json(j, std::forward<ValueTypeCV>(val), std::forward<Args>(args)...);
  }
+};
 
+/// namespace to hold default `from_json` function
+/// to see why this is required:
+/// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4381.html
+namespace
+{
+constexpr const auto& from_json_impl = detail::static_const<detail::from_json_impl_fn>::value;
+} // namespace
+
+struct from_json_fn
+{
  //
  template<typename BasicJsonType, typename ValueType, typename... Args>
  auto operator()(BasicJsonType&& j, ValueType&& val, Args&& ... args) const
- noexcept(noexcept(call(adl_tag<ValueType> {}, max_priority_t{}, j, val, std::forward<Args>(args)...)))
- -> decltype(call(adl_tag<uncvref_t<ValueType>> {}, max_priority_t{}, j, val, std::forward<Args>(args)...), void())
+ noexcept(noexcept(from_json_impl(adl_tag<ValueType> {}, max_priority_t{}, j, val, std::forward<Args>(args)...)))
+ -> decltype(from_json_impl(adl_tag<uncvref_t<ValueType>> {}, max_priority_t{}, j, val, std::forward<Args>(args)...), void())
  {
- call(adl_tag<uncvref_t<ValueType>> {}, max_priority_t{}, j, val, std::forward<Args>(args)...);
+ from_json_impl(adl_tag<uncvref_t<ValueType>> {}, max_priority_t{}, j, val, std::forward<Args>(args)...);
  }
 };
 } // namespace detail
@@ -4449,10 +4461,10 @@ struct adl_serializer
  */
  template<typename... Args>
  static auto from_json(Args&& ... args) noexcept(
- noexcept(::nlohmann::from_json.call(adl_tag<ValueType> {}, detail::max_priority_t{}, std::forward<Args>(args)...)))
- -> decltype(::nlohmann::from_json.call(adl_tag<ValueType> {}, detail::max_priority_t{}, std::forward<Args>(args)...))
+ noexcept(::nlohmann::detail::from_json_impl(adl_tag<ValueType> {}, detail::max_priority_t{}, std::forward<Args>(args)...)))
+ -> decltype(::nlohmann::detail::from_json_impl(adl_tag<ValueType> {}, detail::max_priority_t{}, std::forward<Args>(args)...))
  {
- return ::nlohmann::from_json.call(adl_tag<ValueType> {}, detail::max_priority_t{}, std::forward<Args>(args)...);
+ return ::nlohmann::detail::from_json_impl(adl_tag<ValueType> {}, detail::max_priority_t{}, std::forward<Args>(args)...);
  }
 
  /*!