Drop volatile

Author: ldionne

libcxx/include/__type_traits/desugars_to.h

@@ -53,17 +53,11 @@ template <class _CanonicalTag, class _Operation, class... _Args>
 inline const bool __desugars_to_v = false;
 
 // For the purpose of determining whether something desugars to something else,
-// we disregard the cv-refs of the operation itself.
+// we disregard const and ref qualifiers on the operation itself.
 template <class _CanonicalTag, class _Operation, class... _Args>
 inline const bool __desugars_to_v<_CanonicalTag, _Operation const, _Args...> =
     __desugars_to_v<_CanonicalTag, _Operation, _Args...>;
 template <class _CanonicalTag, class _Operation, class... _Args>
-inline const bool __desugars_to_v<_CanonicalTag, _Operation volatile, _Args...> =
-    __desugars_to_v<_CanonicalTag, _Operation, _Args...>;
-template <class _CanonicalTag, class _Operation, class... _Args>
-inline const bool __desugars_to_v<_CanonicalTag, _Operation const volatile, _Args...> =
-    __desugars_to_v<_CanonicalTag, _Operation, _Args...>;
-template <class _CanonicalTag, class _Operation, class... _Args>
 inline const bool __desugars_to_v<_CanonicalTag, _Operation&, _Args...> =
     __desugars_to_v<_CanonicalTag, _Operation, _Args...>;
 template <class _CanonicalTag, class _Operation, class... _Args>

libcxx/test/libcxx/type_traits/desugars_to.compile.pass.cpp

@@ -28,21 +28,15 @@ void tests() {
     static_assert(!std::__desugars_to_v<Tag, Foo>, "");
   }
 
-  // Make sure that __desugars_to bypasses cv and ref qualifiers on the operation
+  // Make sure that __desugars_to bypasses const and ref qualifiers on the operation
   {
     static_assert(std::__desugars_to_v<Tag, Operation>, ""); // no quals
     static_assert(std::__desugars_to_v<Tag, Operation const>, "");
-    static_assert(std::__desugars_to_v<Tag, Operation volatile>, "");
-    static_assert(std::__desugars_to_v<Tag, Operation const volatile>, "");
 
     static_assert(std::__desugars_to_v<Tag, Operation&>, "");
     static_assert(std::__desugars_to_v<Tag, Operation const&>, "");
-    static_assert(std::__desugars_to_v<Tag, Operation volatile&>, "");
-    static_assert(std::__desugars_to_v<Tag, Operation const volatile&>, "");
 
     static_assert(std::__desugars_to_v<Tag, Operation&&>, "");
     static_assert(std::__desugars_to_v<Tag, Operation const&&>, "");
-    static_assert(std::__desugars_to_v<Tag, Operation volatile&&>, "");
-    static_assert(std::__desugars_to_v<Tag, Operation const volatile&&>, "");
   }
 }