From 835d38a22b32875782e257c7b063e3077e430e05 Mon Sep 17 00:00:00 2001
From: ToruNiina <niina.toru.68u@gmail.com>
Date: Mon, 17 Jun 2024 00:21:11 +0900
Subject: [PATCH] feat: add SFINAE to result template ctor

---
 include/toml11/result.hpp | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/include/toml11/result.hpp b/include/toml11/result.hpp
index 1da4aee..c931aee 100644
--- a/include/toml11/result.hpp
+++ b/include/toml11/result.hpp
@@ -186,14 +186,16 @@ struct result
     result(success_type s): is_ok_(true),  succ(std::move(s)) {}
     result(failure_type f): is_ok_(false), fail(std::move(f)) {}
 
-    template<typename U, cxx::enable_if_t<
-        std::is_convertible<cxx::remove_cvref_t<U>, value_type>::value,
-        std::nullptr_t> = nullptr>
+    template<typename U, cxx::enable_if_t<cxx::conjunction<
+            cxx::negation<std::is_same<cxx::remove_cvref_t<U>, value_type>>,
+            std::is_convertible<cxx::remove_cvref_t<U>, value_type>
+        >::value, std::nullptr_t> = nullptr>
     result(success<U> s): is_ok_(true),  succ(std::move(s.value)) {}
 
-    template<typename U, cxx::enable_if_t<
-        std::is_convertible<cxx::remove_cvref_t<U>, error_type>::value,
-        std::nullptr_t> = nullptr>
+    template<typename U, cxx::enable_if_t<cxx::conjunction<
+            cxx::negation<std::is_same<cxx::remove_cvref_t<U>, error_type>>,
+            std::is_convertible<cxx::remove_cvref_t<U>, error_type>
+        >::value, std::nullptr_t> = nullptr>
     result(failure<U> f): is_ok_(false), fail(std::move(f.value)) {}
 
     result& operator=(success_type s)
@@ -306,7 +308,12 @@ struct result
         return *this;
     }
 
-    template<typename U, typename F>
+    template<typename U, typename F, cxx::enable_if_t<cxx::conjunction<
+            cxx::negation<std::is_same<cxx::remove_cvref_t<U>, value_type>>,
+            cxx::negation<std::is_same<cxx::remove_cvref_t<F>, error_type>>,
+            std::is_convertible<cxx::remove_cvref_t<U>, value_type>,
+            std::is_convertible<cxx::remove_cvref_t<F>, error_type>
+        >::value, std::nullptr_t> = nullptr>
     result(result<U, F> other): is_ok_(other.is_ok())
     {
         if(other.is_ok())
@@ -322,7 +329,13 @@ struct result
             (void)tmp;
         }
     }
-    template<typename U, typename F>
+
+    template<typename U, typename F, cxx::enable_if_t<cxx::conjunction<
+            cxx::negation<std::is_same<cxx::remove_cvref_t<U>, value_type>>,
+            cxx::negation<std::is_same<cxx::remove_cvref_t<F>, error_type>>,
+            std::is_convertible<cxx::remove_cvref_t<U>, value_type>,
+            std::is_convertible<cxx::remove_cvref_t<F>, error_type>
+        >::value, std::nullptr_t> = nullptr>
     result& operator=(result<U, F> other)
     {
         this->cleanup();