From 7b089c0095dcd66c86dcc1d8312b2c1612b4ae9e Mon Sep 17 00:00:00 2001
From: "A. Jiang" <de34@live.cn>
Date: Sat, 1 Jul 2023 14:58:44 +0800
Subject: [PATCH] Make `function::target` return null function pointers without
 cast

---
 stl/inc/functional                                | 12 ++++++++++--
 .../Dev11_0535636_functional_overhaul/test.cpp    | 15 +++++++++++++++
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/stl/inc/functional b/stl/inc/functional
index e0e6564285..c66eedfef9 100644
--- a/stl/inc/functional
+++ b/stl/inc/functional
@@ -1134,12 +1134,20 @@ public:
 
     template <class _Fx>
     _NODISCARD _Fx* target() noexcept {
-        return reinterpret_cast<_Fx*>(const_cast<void*>(this->_Target(typeid(_Fx))));
+        if constexpr (is_function_v<_Fx>) {
+            return nullptr;
+        } else {
+            return reinterpret_cast<_Fx*>(const_cast<void*>(this->_Target(typeid(_Fx))));
+        }
     }
 
     template <class _Fx>
     _NODISCARD const _Fx* target() const noexcept {
-        return reinterpret_cast<const _Fx*>(this->_Target(typeid(_Fx)));
+        if constexpr (is_function_v<_Fx>) {
+            return nullptr;
+        } else {
+            return reinterpret_cast<const _Fx*>(this->_Target(typeid(_Fx)));
+        }
     }
 #else // _HAS_STATIC_RTTI
     const type_info& target_type() const noexcept = delete; // requires static RTTI
diff --git a/tests/std/tests/Dev11_0535636_functional_overhaul/test.cpp b/tests/std/tests/Dev11_0535636_functional_overhaul/test.cpp
index a83150a9f3..51151f4a36 100644
--- a/tests/std/tests/Dev11_0535636_functional_overhaul/test.cpp
+++ b/tests/std/tests/Dev11_0535636_functional_overhaul/test.cpp
@@ -1615,6 +1615,11 @@ void test_function() {
         assert(f.target<short (*)(long)>() == nullptr);
         assert(c.target<short (*)(long)>() == nullptr);
 
+        assert(f.target<int(int)>() == nullptr);
+        assert(c.target<int(int)>() == nullptr);
+        assert(f.target<short(long)>() == nullptr);
+        assert(c.target<short(long)>() == nullptr);
+
         f = triple;
         assert(f(1000) == 3000);
         assert(f.target_type() == typeid(int (*)(int)));
@@ -1623,6 +1628,11 @@ void test_function() {
         assert(f.target<short (*)(long)>() == nullptr);
         assert(c.target<short (*)(long)>() == nullptr);
 
+        assert(f.target<int(int)>() == nullptr);
+        assert(c.target<int(int)>() == nullptr);
+        assert(f.target<short(long)>() == nullptr);
+        assert(c.target<short(long)>() == nullptr);
+
         f = short_long;
         assert(f(1000) == 29);
         assert(f.target_type() == typeid(short (*)(long)));
@@ -1630,6 +1640,11 @@ void test_function() {
         assert(c.target<int (*)(int)>() == nullptr);
         assert(*f.target<short (*)(long)>() == &short_long);
         assert(*c.target<short (*)(long)>() == &short_long);
+
+        assert(f.target<int(int)>() == nullptr);
+        assert(c.target<int(int)>() == nullptr);
+        assert(f.target<short(long)>() == nullptr);
+        assert(c.target<short(long)>() == nullptr);
     }