From 99b6821d33d032566025b7de67d39710dd6516ba Mon Sep 17 00:00:00 2001
From: Eisuke Kawashima <e-kwsm@users.noreply.github.com>
Date: Fri, 26 Aug 2022 21:42:19 +0900
Subject: [PATCH] refactor(IsSafePtr): comply with type_traits

---
 src/bin/libint/iter.h      |  2 +-
 src/bin/libint/smart_ptr.h | 24 ++++++------------------
 2 files changed, 7 insertions(+), 19 deletions(-)

diff --git a/src/bin/libint/iter.h b/src/bin/libint/iter.h
index d8ec7628a..54b0197ab 100644
--- a/src/bin/libint/iter.h
+++ b/src/bin/libint/iter.h
@@ -168,7 +168,7 @@ namespace libint2 {
     typename SubIteratorBase<T,P>::cp_rettype
     SubIteratorBase<T,P>::pelem() const
     {
-      return PElemImpl<iter_type,detail::IsSafePtr<iref>::result>::pelem(elem());
+      return PElemImpl<iter_type,detail::IsSafePtr<iref>::value>::pelem(elem());
     }
 
 #if 0
diff --git a/src/bin/libint/smart_ptr.h b/src/bin/libint/smart_ptr.h
index a727a825d..91755d35f 100644
--- a/src/bin/libint/smart_ptr.h
+++ b/src/bin/libint/smart_ptr.h
@@ -21,6 +21,7 @@
 #ifndef _libint2_src_bin_libint_smartptr_h_
 #define _libint2_src_bin_libint_smartptr_h_
 
+#include <type_traits>
 #include <libint2/config.h>
 
 #if HAVE_SHARED_PTR_IN_BOOST
@@ -50,27 +51,14 @@
 namespace libint2 {
 namespace detail {
 /** Can be used to determine whether a type is a SafePtr */
+template <typename>
+struct IsSafePtrHelper : std::false_type {};
 template <typename T>
-struct IsSafePtr {
-  enum { result = false };
-};
+struct IsSafePtrHelper<SafePtr<T>> : std::true_type {};
 
 template <typename T>
-struct IsSafePtr< SafePtr<T> > {
-  enum { result = true };
-};
-template <typename T>
-struct IsSafePtr< const SafePtr<T> > {
-  enum { result = true };
-};
-template <typename T>
-struct IsSafePtr< SafePtr<T>& > {
-  enum { result = true };
-};
-template <typename T>
-struct IsSafePtr< const SafePtr<T>& > {
-  enum { result = true };
-};
+struct IsSafePtr : IsSafePtrHelper<typename std::remove_const<
+                         typename std::remove_reference<T>::type>::type> {};
 }  // namespace detail
 }  // namespace libint2