Fix atomic_ref<int8_t>::operator--(int) compiler error (#1303)

stl/inc/atomic

@@ -1365,7 +1365,7 @@ struct _Atomic_integral<_Ty, 1> : _Atomic_storage<_Ty> { // atomic integral oper
     }
 
     _TVal operator--(int) noexcept {
-        return static_cast<_Ty>(_InterlockedExchangeAdd8(_Atomic_address_as<char>(this->_Storage), -1));
+        return static_cast<_TVal>(_InterlockedExchangeAdd8(_Atomic_address_as<char>(this->_Storage), -1));
     }
 
     _TVal operator--() noexcept {
@@ -1810,6 +1810,22 @@ struct _Atomic_integral_facade<_Ty&> : _Atomic_integral<_Ty&> {
         return fetch_add(_Negate(_Operand), _Order);
     }
 
+    _Ty operator++(int) const noexcept {
+        return const_cast<_Atomic_integral_facade*>(this)->_Base::operator++(0);
+    }
+
+    _Ty operator++() const noexcept {
+        return const_cast<_Atomic_integral_facade*>(this)->_Base::operator++();
+    }
+
+    _Ty operator--(int) const noexcept {
+        return const_cast<_Atomic_integral_facade*>(this)->_Base::operator--(0);
+    }
+
+    _Ty operator--() const noexcept {
+        return const_cast<_Atomic_integral_facade*>(this)->_Base::operator--();
+    }
+
     _Ty operator+=(const _Ty _Operand) const noexcept {
         return static_cast<_Ty>(fetch_add(_Operand) + _Operand);
     }

tests/std/tests/P0019R8_atomic_ref/test.cpp

@@ -94,40 +94,72 @@ void test_int_ops() {
     const std::atomic_ref rx(v);
     const std::atomic_ref ry(v);
 
-    vx.fetch_add(0x10);
-    rx.fetch_add(0x10);
+    assert(vx.fetch_add(0x10) == 0x40);
+    assert(rx.fetch_add(0x10) == 0x40);
 
     assert(vx.load() == 0x50);
     assert(vy.load() == 0x40);
     assert(rx.load() == 0x50);
     assert(ry.load() == 0x50);
 
-    vx.fetch_sub(0x8);
-    rx.fetch_sub(0x8);
+    assert(vx.fetch_sub(0x8) == 0x50);
+    assert(rx.fetch_sub(0x8) == 0x50);
 
     assert(vx.load() == 0x48);
     assert(vy.load() == 0x40);
     assert(rx.load() == 0x48);
     assert(ry.load() == 0x48);
 
-    vx.fetch_or(0xF);
-    rx.fetch_or(0xF);
+    assert(vx.fetch_or(0xF) == 0x48);
+    assert(rx.fetch_or(0xF) == 0x48);
 
     assert(vx.load() == 0x4F);
     assert(vy.load() == 0x40);
     assert(rx.load() == 0x4F);
     assert(ry.load() == 0x4F);
 
-    vx.fetch_and(0x3C);
-    rx.fetch_and(0x3C);
+    assert(vx.fetch_and(0x3C) == 0x4F);
+    assert(rx.fetch_and(0x3C) == 0x4F);
 
     assert(vx.load() == 0xC);
     assert(vy.load() == 0x40);
     assert(rx.load() == 0xC);
     assert(ry.load() == 0xC);
 
-    vx.fetch_xor(0x3F);
-    rx.fetch_xor(0x3F);
+    assert(vx.fetch_xor(0x3F) == 0xC);
+    assert(rx.fetch_xor(0x3F) == 0xC);
+
+    assert(vx.load() == 0x33);
+    assert(vy.load() == 0x40);
+    assert(rx.load() == 0x33);
+    assert(ry.load() == 0x33);
+
+    assert(vx-- == 0x33);
+    assert(rx-- == 0x33);
+
+    assert(vx.load() == 0x32);
+    assert(vy.load() == 0x40);
+    assert(rx.load() == 0x32);
+    assert(ry.load() == 0x32);
+
+    assert(--vx == 0x31);
+    assert(--rx == 0x31);
+
+    assert(vx.load() == 0x31);
+    assert(vy.load() == 0x40);
+    assert(rx.load() == 0x31);
+    assert(ry.load() == 0x31);
+
+    assert(vx++ == 0x31);
+    assert(rx++ == 0x31);
+
+    assert(vx.load() == 0x32);
+    assert(vy.load() == 0x40);
+    assert(rx.load() == 0x32);
+    assert(ry.load() == 0x32);
+
+    assert(++vx == 0x33);
+    assert(++rx == 0x33);
 
     assert(vx.load() == 0x33);
     assert(vy.load() == 0x40);
@@ -145,16 +177,16 @@ void test_float_ops() {
     const std::atomic_ref rx(v);
     const std::atomic_ref ry(v);
 
-    vx.fetch_add(0x10);
-    rx.fetch_add(0x10);
+    assert(vx.fetch_add(0x10) == 0x40);
+    assert(rx.fetch_add(0x10) == 0x40);
 
     assert(vx.load() == 0x50);
     assert(vy.load() == 0x40);
     assert(rx.load() == 0x50);
     assert(ry.load() == 0x50);
 
-    vx.fetch_sub(0x8);
-    rx.fetch_sub(0x8);
+    assert(vx.fetch_sub(0x8) == 0x50);
+    assert(rx.fetch_sub(0x8) == 0x50);
 
     assert(vx.load() == 0x48);
     assert(vy.load() == 0x40);
@@ -180,16 +212,16 @@ void test_ptr_ops() {
     const std::atomic_ref rx(v);
     const std::atomic_ref ry(v);
 
-    vx.fetch_add(0x10);
-    rx.fetch_add(0x10);
+    assert(vx.fetch_add(0x10) == a);
+    assert(rx.fetch_add(0x10) == a);
 
     assert(vx.load() == a + 0x10);
     assert(vy.load() == a);
     assert(rx.load() == a + 0x10);
     assert(ry.load() == a + 0x10);
 
-    vx.fetch_sub(0x8);
-    rx.fetch_sub(0x8);
+    assert(vx.fetch_sub(0x8) == a + 0x10);
+    assert(rx.fetch_sub(0x8) == a + 0x10);
 
     assert(vx.load() == a + 0x8);
     assert(vy.load() == a);
@@ -203,6 +235,38 @@ void test_ptr_ops() {
     assert(vy.load() == a);
     assert(rx.load() == a + 0x10);
     assert(ry.load() == a + 0x10);
+
+    assert(vx-- == a + 0x10);
+    assert(rx-- == a + 0x10);
+
+    assert(vx.load() == a + 0xF);
+    assert(vy.load() == a);
+    assert(rx.load() == a + 0xF);
+    assert(ry.load() == a + 0xF);
+
+    assert(--vx == a + 0xE);
+    assert(--rx == a + 0xE);
+
+    assert(vx.load() == a + 0xE);
+    assert(vy.load() == a);
+    assert(rx.load() == a + 0xE);
+    assert(ry.load() == a + 0xE);
+
+    assert(vx++ == a + 0xE);
+    assert(rx++ == a + 0xE);
+
+    assert(vx.load() == a + 0xF);
+    assert(vy.load() == a);
+    assert(rx.load() == a + 0xF);
+    assert(ry.load() == a + 0xF);
+
+    assert(++vx == a + 0x10);
+    assert(++rx == a + 0x10);
+
+    assert(vx.load() == a + 0x10);
+    assert(vy.load() == a);
+    assert(rx.load() == a + 0x10);
+    assert(ry.load() == a + 0x10);
 }
 
 int main() {