Reverting D2503151 to unbreak buck build

[folly.git] / folly / Traits.h

diff --git a/folly/Traits.h b/folly/Traits.h
index 309157c4dfadcf952faddc8284bf004f07a401ac..9701aa1573cd42b31fc585c5594465d1de5e7ebb 100644 (file)
--- a/folly/Traits.h
+++ b/folly/Traits.h
@@ -309,7 +309,7 @@ struct is_negative_impl {
 
 template <typename T>
 struct is_negative_impl<T, false> {
-  constexpr static bool check(T x) { return false; }
+  constexpr static bool check(T) { return false; }
 };
 
 // folly::to integral specializations can end up generating code
@@ -320,67 +320,21 @@ struct is_negative_impl<T, false> {
 #pragma GCC diagnostic ignored "-Wsign-compare"
 
 template <typename RHS, RHS rhs, typename LHS>
-bool less_than_impl(
-  typename std::enable_if<
-    (rhs <= std::numeric_limits<LHS>::max()
-      && rhs > std::numeric_limits<LHS>::min()),
-    LHS
-  >::type const lhs
-) {
-  return lhs < rhs;
-}
-
-template <typename RHS, RHS rhs, typename LHS>
-bool less_than_impl(
-  typename std::enable_if<
-    (rhs > std::numeric_limits<LHS>::max()),
-    LHS
-  >::type const
-) {
-  return true;
-}
-
-template <typename RHS, RHS rhs, typename LHS>
-bool less_than_impl(
-  typename std::enable_if<
-    (rhs <= std::numeric_limits<LHS>::min()),
-    LHS
-  >::type const
-) {
-  return false;
+bool less_than_impl(LHS const lhs) {
+  return
+    rhs > std::numeric_limits<LHS>::max() ? true :
+    rhs <= std::numeric_limits<LHS>::min() ? false :
+    lhs < rhs;
 }
 
 #pragma GCC diagnostic pop
 
 template <typename RHS, RHS rhs, typename LHS>
-bool greater_than_impl(
-  typename std::enable_if<
-    (rhs <= std::numeric_limits<LHS>::max()
-      && rhs >= std::numeric_limits<LHS>::min()),
-    LHS
-  >::type const lhs
-) {
-  return lhs > rhs;
-}
-
-template <typename RHS, RHS rhs, typename LHS>
-bool greater_than_impl(
-  typename std::enable_if<
-    (rhs > std::numeric_limits<LHS>::max()),
-    LHS
-  >::type const
-) {
-  return false;
-}
-
-template <typename RHS, RHS rhs, typename LHS>
-bool greater_than_impl(
-  typename std::enable_if<
-    (rhs < std::numeric_limits<LHS>::min()),
-    LHS
-  >::type const
-) {
-  return true;
+bool greater_than_impl(LHS const lhs) {
+  return
+    rhs > std::numeric_limits<LHS>::max() ? false :
+    rhs < std::numeric_limits<LHS>::min() ? true :
+    lhs > rhs;
 }
 
 } // namespace detail {
@@ -432,6 +386,16 @@ FOLLY_ASSUME_FBVECTOR_COMPATIBLE_1(std::function);
 // Boost
 FOLLY_ASSUME_FBVECTOR_COMPATIBLE_1(boost::shared_ptr);
 
+#define FOLLY_CREATE_HAS_MEMBER_TYPE_TRAITS(classname, type_name) \
+  template <typename T> \
+  struct classname { \
+    template <typename C> \
+    constexpr static bool test(typename C::type_name*) { return true; } \
+    template <typename> \
+    constexpr static bool test(...) { return false; } \
+    constexpr static bool value = test<T>(nullptr); \
+  }
+
 #define FOLLY_CREATE_HAS_MEMBER_FN_TRAITS_IMPL(classname, func_name, cv_qual) \
   template <typename TTheClass_, typename RTheReturn_, typename... TTheArgs_> \
   class classname<TTheClass_, RTheReturn_(TTheArgs_...) cv_qual> { \