fix build errors

fmtlib · Oct 24, 2020 · 404fb19 · 404fb19
1 parent 8702f3a
commit 404fb19
Showing 1 changed file with 24 additions and 6 deletions.
diff --git a/include/fmt/ranges.h b/include/fmt/ranges.h
@@ -110,17 +110,33 @@ auto range_end(T const (&arr)[N]) -> T const* {
   return arr + N;
 }
 
+template <typename T, typename Enable = void>
+struct has_member_fn_begin_end_t : std::false_type {};
+
+template <typename T>
+struct has_member_fn_begin_end_t<T, void_t<decltype(std::declval<T>().begin()),
+                                           decltype(std::declval<T>().end())>>
+    : std::true_type {};
+
 // Member function overload
 template <typename T>
 auto range_begin(T&& rng) FMT_DECLTYPE_RETURN(static_cast<T&&>(rng).begin());
 template <typename T>
 auto range_end(T&& rng) FMT_DECLTYPE_RETURN(static_cast<T&&>(rng).end());
 
-// ADL overload
+// ADL overload. Only participates in overload resolution if member functions
+// are not found.
 template <typename T>
-auto range_begin(T& rng) FMT_DECLTYPE_RETURN(begin(static_cast<T&&>(rng)));
+auto range_begin(T&& rng)
+    -> enable_if_t<!has_member_fn_begin_end_t<T&&>::value,
+                   decltype(begin(static_cast<T&&>(rng)))> {
+  return begin(static_cast<T&&>(rng));
+}
 template <typename T>
-auto range_end(T& rng) FMT_DECLTYPE_RETURN(end(static_cast<T&&>(rng)));
+auto range_end(T&& rng) -> enable_if_t<!has_member_fn_begin_end_t<T&&>::value,
+                                       decltype(end(static_cast<T&&>(rng)))> {
+  return end(static_cast<T&&>(rng));
+}
 
 template <typename T, typename Enable = void>
 struct has_const_begin_end : std::false_type {};
@@ -142,7 +158,7 @@ struct has_mutable_begin_end<
 
 template <typename T>
 struct is_range_<T, void>
-    : std::integral_constant<bool, ((has_const_begin_end<T>::value) or
+    : std::integral_constant<bool, ((has_const_begin_end<T>::value) ||
                                     (has_mutable_begin_end<T>::value))> {};
 
 template <typename T, typename Enable = void> struct range_to_view;
@@ -158,7 +174,7 @@ struct range_to_view<T, enable_if_t<has_const_begin_end<T>::value>> {
 };
 
 template <typename T>
-struct range_to_view<T, enable_if_t<not has_const_begin_end<T>::value and
+struct range_to_view<T, enable_if_t<!has_const_begin_end<T>::value &&
                                     has_mutable_begin_end<T>::value>> {
   struct view_t {
     T m_range_copy;
@@ -168,6 +184,7 @@ struct range_to_view<T, enable_if_t<not has_const_begin_end<T>::value and
   };
   static auto view(T const& range) -> view_t { return {range}; }
 };
+#  undef FMT_DECLTYPE_RETURN
 #endif
 
 /// tuple_size and tuple_element check.
@@ -225,7 +242,8 @@ template <class Tuple, class F> void for_each(Tuple&& tup, F&& f) {
 }
 
 template <typename Range>
-using value_type = remove_cvref_t<decltype(*detail::range_begin(std::declval<Range>()))>;
+using value_type =
+    remove_cvref_t<decltype(*detail::range_begin(std::declval<Range>()))>;
 
 template <typename Arg, FMT_ENABLE_IF(!is_like_std_string<
                                       typename std::decay<Arg>::type>::value)>