From f077c14d470665b8d88b339c689ab26ac0697a5f Mon Sep 17 00:00:00 2001
From: Ichthyostega <prg@ichthyostega.de>
Date: Tue, 5 Jan 2016 21:59:42 +0100
Subject: [PATCH] compiler evolution: get rid of a gcc-4.7 workaround

our minimal compiler requirement is gcc-4.9 since the
transition to Debian/Jessie as reference system.

gcc-4.9 is known to treat SFINAE on private fields properly
---
 src/lib/meta/virtual-copy-support.hpp         | 25 +++----------------
 src/lib/variant.hpp                           |  2 +-
 .../meta/virtual-copy-support-test.cpp        | 11 --------
 3 files changed, 4 insertions(+), 34 deletions(-)

diff --git a/src/lib/meta/virtual-copy-support.hpp b/src/lib/meta/virtual-copy-support.hpp
index dc9be739b..47720630f 100644
--- a/src/lib/meta/virtual-copy-support.hpp
+++ b/src/lib/meta/virtual-copy-support.hpp
@@ -117,10 +117,6 @@
 #include <type_traits>
 #include <utility>
 
-namespace lib {
-namespace time{
-  class Time;   // forward declaration for GCC 4.7 workaround
-}}
 
 namespace lib {
 namespace meta{
@@ -242,26 +238,11 @@ namespace meta{
   
   namespace { // helpers to select suitable variant of copy support...
     
-    /** workaround for GCC 4.7: need to exclude some types,
-     *  since they raise private access violation during probing.
-     *  Actually, in C++11 such a case should trigger substitution
-     *  failure, not an compilation error */
-    template<class X>
-    struct can_use_assignment
-      : is_copy_assignable<X>
-      { };
-    
-    template<>
-    struct can_use_assignment<lib::time::Time>
-      { static constexpr bool value = false; };
-    
-    
-    
     template<class X>
     struct supports_only_move
       : __and_<is_move_constructible<X>
               ,__not_<is_copy_constructible<X>>
-              ,__not_<can_use_assignment<X>>
+              ,__not_<is_copy_assignable<X>>
               >
       { };
     
@@ -269,7 +250,7 @@ namespace meta{
     struct supports_cloning
       : __and_<is_move_constructible<X>
               ,is_copy_constructible<X>
-              ,__not_<can_use_assignment<X>>
+              ,__not_<is_copy_assignable<X>>
               >
       { };
     
@@ -277,7 +258,7 @@ namespace meta{
     struct supports_copy_and_assignment
       : __and_<is_move_constructible<X>
               ,is_copy_constructible<X>
-              ,can_use_assignment<X>
+              ,is_copy_assignable<X>
               >
       { };
   }
diff --git a/src/lib/variant.hpp b/src/lib/variant.hpp
index b7d056b96..6c7db32ae 100644
--- a/src/lib/variant.hpp
+++ b/src/lib/variant.hpp
@@ -418,7 +418,7 @@ namespace lib {
           using RawType = typename remove_reference<X>::type;
           static_assert (meta::isInList<RawType, typename TYPES::List>(),
                          "Type error: the given variant could never hold the required type");
-          static_assert (meta::can_use_assignment<RawType>::value, "target type does not support assignment");
+          static_assert (std::is_copy_assignable<RawType>::value, "target type does not support assignment");
           
           buff<RawType>() = forward<X>(x);
           return *this;
diff --git a/tests/library/meta/virtual-copy-support-test.cpp b/tests/library/meta/virtual-copy-support-test.cpp
index fce2e9180..64214da35 100644
--- a/tests/library/meta/virtual-copy-support-test.cpp
+++ b/tests/library/meta/virtual-copy-support-test.cpp
@@ -241,17 +241,6 @@ namespace test {
   }//(End)Test fixture
   
   
-// GCC 4.7 workaround
-// SFINAE does not work properly on private functions
-// instead of dropping the template instance, it causes compilation failure
-
-}//now in namespace meta
-  
-  template<char c>
-  struct can_use_assignment<test::UnAssignable<c>>
-    { static constexpr bool value = false; };
-  
-namespace test {