Make optional's secret constructor private (#4961)

Author: CaseyCarter

stl/inc/optional

@@ -214,6 +214,16 @@ class optional : private _SMF_control<_Optional_construct_base<_Ty>, _Ty> {
 private:
     using _Mybase = _SMF_control<_Optional_construct_base<_Ty>, _Ty>;
 
+    template <class>
+    friend class optional;
+
+#if _HAS_CXX23
+    template <class _Fn, class _Ux>
+    constexpr optional(_Construct_from_invoke_result_tag _Tag, _Fn&& _Func, _Ux&& _Arg)
+        noexcept(noexcept(static_cast<_Ty>(_STD invoke(_STD forward<_Fn>(_Func), _STD forward<_Ux>(_Arg)))))
+        : _Mybase(_Tag, _STD forward<_Fn>(_Func), _STD forward<_Ux>(_Arg)) {}
+#endif // _HAS_CXX23
+
 public:
     static_assert(!_Is_any_of_v<remove_cv_t<_Ty>, nullopt_t, in_place_t>,
         "T in optional<T> must be a type other than nullopt_t or in_place_t (N4950 [optional.optional.general]/3).");
@@ -273,13 +283,6 @@ public:
         }
     }
 
-#if _HAS_CXX23
-    template <class _Fn, class _Ux>
-    constexpr optional(_Construct_from_invoke_result_tag _Tag, _Fn&& _Func, _Ux&& _Arg)
-        noexcept(noexcept(static_cast<_Ty>(_STD invoke(_STD forward<_Fn>(_Func), _STD forward<_Ux>(_Arg)))))
-        : _Mybase(_Tag, _STD forward<_Fn>(_Func), _STD forward<_Ux>(_Arg)) {}
-#endif // _HAS_CXX23
-
     _CONSTEXPR20 optional& operator=(nullopt_t) noexcept {
         reset();
         return *this;

tests/libcxx/expected_results.txt

@@ -1225,9 +1225,6 @@ std/numerics/c.math/hermite.pass.cpp FAIL
 # Not analyzed. Test coverage for LLVM-104496 uses span<Incomplete>.
 std/containers/views/views.span/span.cons/copy.pass.cpp FAIL
 
-# Not analyzed. LLVM-103409 added a test to verify that std::optional's internal constructors aren't visible to users.
-std/utilities/optional/optional.object/optional.object.ctor/gh_101960_internal_ctor.compile.pass.cpp FAIL
-
 
 # *** XFAILS WHICH PASS ***
 # These tests contain `// XFAIL: msvc` comments, which accurately describe runtime failures for x86 and x64.