Work around vs2013sp2-3 bug in skstd::unique_ptr.

include/private/SkUniquePtr.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkUniquePtr_DEFINED
 #define SkUniquePtr_DEFINED
 
@@ skipping 30 matching lines @@
         template <typename U> static T* detector(...);
         using type = decltype(detector<remove_reference_t<D>>(0));
     };
 
 public:
     using pointer = typename pointer_type_detector::type;
     using element_type = T;
     using deleter_type = D;
 
 private:
-    template <typename B, bool = std::is_empty<B>::value /*&& !is_final<B>::value*/>
+    template <typename B, bool>
     struct compressed_base : private B {
         /*constexpr*/ compressed_base() : B() {}
         /*constexpr*/ compressed_base(const B& b) : B(b) {}
         /*constexpr*/ compressed_base(B&& b) : B(std::move(b)) {}
         /*constexpr*/ B& get() /*noexcept*/ { return *this; }
         /*constexpr*/ B const& get() const /*noexcept*/ { return *this; }
         void swap(compressed_base&) /*noexcept*/ { }
     };
 
     template <typename B> struct compressed_base<B, false> {
         B fb;
         /*constexpr*/ compressed_base() : B() {}
         /*constexpr*/ compressed_base(const B& b) : fb(b) {}
         /*constexpr*/ compressed_base(B&& b) : fb(std::move(b)) {}
         /*constexpr*/ B& get() /*noexcept*/ { return fb; }
         /*constexpr*/ B const& get() const /*noexcept*/ { return fb; }
         void swap(compressed_base& that) /*noexcept*/ { SkTSwap(fb, that.fB); }
     };
 
-    struct compressed_data : private compressed_base<deleter_type> {
+    // C++14 adds '&& !std::is_final<deleter_type>::value' to the bool condition.
+    // compressed_base_t exists and has this form to work around a bug in vs2013sp2-3
+    using compressed_base_t = compressed_base<deleter_type, std::is_empty<deleter_type>::value>;
+
+    struct compressed_data : private compressed_base_t {
         pointer fPtr;
-        /*constexpr*/ compressed_data() : compressed_base<deleter_type>(), fPtr() {}
+        /*constexpr*/ compressed_data() : compressed_base_t(), fPtr() {}
         /*constexpr*/ compressed_data(const pointer& ptr, const deleter_type& d)
-            : compressed_base<deleter_type>(d), fPtr(ptr) {}
+            : compressed_base_t(d), fPtr(ptr) {}
         template <typename U1, typename U2, typename = enable_if_t<
             is_convertible<U1, pointer>::value && is_convertible<U2, deleter_type>::value
         >> /*constexpr*/ compressed_data(U1&& ptr, U2&& d)
-            : compressed_base<deleter_type>(std::forward<U2>(d)), fPtr(std::forward<U1>(ptr)) {}
+            : compressed_base_t(std::forward<U2>(d)), fPtr(std::forward<U1>(ptr)) {}
         /*constexpr*/ pointer& getPointer() /*noexcept*/ { return fPtr; }
         /*constexpr*/ pointer const& getPointer() const /*noexcept*/ { return fPtr; }
         /*constexpr*/ deleter_type& getDeleter() /*noexcept*/ {
-            return compressed_base<deleter_type>::get();
+            return compressed_base_t::get();
         }
         /*constexpr*/ deleter_type const& getDeleter() const /*noexcept*/ {
-            return compressed_base<deleter_type>::get();
+            return compressed_base_t::get();
         }
         void swap(compressed_data& that) /*noexcept*/ {
-            compressed_base<deleter_type>::swap(static_cast<compressed_base<deleter_type>>(that));
+            compressed_base_t::swap(static_cast<compressed_base_t>(that));
             SkTSwap(fPtr, that.fPtr);
         }
     };
     compressed_data data;
 
 public:
     /*constexpr*/ unique_ptr() /*noexcept*/ : data() {
         static_assert(!std::is_pointer<deleter_type>::value, "Deleter nullptr function pointer!");
     }
 
@@ skipping 114 matching lines @@
         template <typename U> static T* detector(...);
         using type = decltype(detector<remove_reference_t<D>>(0));
     };
 
 public:
     using pointer = typename pointer_type_detector::type;
     using element_type = T;
     using deleter_type = D;
 
 private:
-    template <typename B, bool = std::is_empty<B>::value /*&& !is_final<B>::value*/>
-    struct compressed_base : private B {
+    template <typename B, bool> struct compressed_base : private B {
         /*constexpr*/ compressed_base() : B() {}
         /*constexpr*/ compressed_base(const B& b) : B(b) {}
         /*constexpr*/ compressed_base(B&& b) : B(std::move(b)) {}
         /*constexpr*/ B& get() /*noexcept*/ { return *this; }
         /*constexpr*/ B const& get() const /*noexcept*/ { return *this; }
         void swap(compressed_base&) /*noexcept*/ { }
     };
 
     template <typename B> struct compressed_base<B, false> {
         B fb;
         /*constexpr*/ compressed_base() : B() {}
         /*constexpr*/ compressed_base(const B& b) : fb(b) {}
         /*constexpr*/ compressed_base(B&& b) : fb(std::move(b)) {}
         /*constexpr*/ B& get() /*noexcept*/ { return fb; }
         /*constexpr*/ B const& get() const /*noexcept*/ { return fb; }
         void swap(compressed_base& that) /*noexcept*/ { SkTSwap(fb, that.fB); }
     };
 
-    struct compressed_data : private compressed_base<deleter_type> {
+    // C++14 adds '&& !std::is_final<deleter_type>::value' to the bool condition.
+    // compressed_base_t exists and has this form to work around a bug in vs2013sp2-3
+    using compressed_base_t = compressed_base<deleter_type, std::is_empty<deleter_type>::value>;
+
+    struct compressed_data : private compressed_base_t {
         pointer fPtr;
-        /*constexpr*/ compressed_data() : compressed_base<deleter_type>(), fPtr() {}
+        /*constexpr*/ compressed_data() : compressed_base_t(), fPtr() {}
         /*constexpr*/ compressed_data(const pointer& ptr, const deleter_type& d)
-            : compressed_base<deleter_type>(d), fPtr(ptr) {}
+            : compressed_base_t(d), fPtr(ptr) {}
         template <typename U1, typename U2, typename = enable_if_t<
             is_convertible<U1, pointer>::value && is_convertible<U2, deleter_type>::value
         >> /*constexpr*/ compressed_data(U1&& ptr, U2&& d)
-            : compressed_base<deleter_type>(std::forward<U2>(d)), fPtr(std::forward<U1>(ptr)) {}
+            : compressed_base_t(std::forward<U2>(d)), fPtr(std::forward<U1>(ptr)) {}
         /*constexpr*/ pointer& getPointer() /*noexcept*/ { return fPtr; }
         /*constexpr*/ pointer const& getPointer() const /*noexcept*/ { return fPtr; }
         /*constexpr*/ deleter_type& getDeleter() /*noexcept*/ {
-            return compressed_base<deleter_type>::get();
+            return compressed_base_t::get();
         }
         /*constexpr*/ deleter_type const& getDeleter() const /*noexcept*/ {
-            return compressed_base<deleter_type>::get();
+            return compressed_base_t::get();
         }
         void swap(compressed_data& that) /*noexcept*/ {
-            compressed_base<deleter_type>::swap(static_cast<compressed_base<deleter_type>>(that));
+            compressed_base_t::swap(static_cast<compressed_base_t>(that));
             SkTSwap(fPtr, that.fPtr);
         }
     };
     compressed_data data;
 
 public:
     /*constexpr*/ unique_ptr() /*noexcept*/ : data() {
         static_assert(!std::is_pointer<deleter_type>::value, "Deleter nullptr function pointer!");
     }
 
@@ skipping 119 matching lines @@
 
 template <typename T, typename D>
 inline bool operator!=(std::nullptr_t, const unique_ptr<T, D>& b) /*noexcept*/ {
     //return (bool)b;
     return b.is_attached();
 }
 
 }  // namespace skstd
 
 #endif