Re: [PATCH] PR 70564 disambiguate constructors for not_fn call wrapper

[Jonathan Wakely <jwakely@redhat.com>]

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On 05/10/16 12:31 +0100, Jonathan Wakely wrote:
>Tested powerpc64le-linux, committing to trunk and gcc-6-branch.

And here's the slightly diffeernt patch for the branch (because we
only have experimental::not_fn there, not std::not_fn).



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commit 2484aeb5b25372c3a7833a000b798e3bf6f41c6b
Author: redi <redi@138bc75d-0d04-0410-961f-82ee72b054a4>
Date:   Wed Oct 5 12:01:36 2016 +0000

    PR 70564 disambiguate constructor for not_fn call wrapper
    
    	PR libstdc++/70564
    	* include/experimental/functional (_Not_fn): Add second parameter to
    	disambiguate copying from initialization by not_fn.
    	(not_fn): Add second argument to initialization.
    	* testsuite/experimental/functional/not_fn.cc: Copy call wrapper using
    	direct-initialization. Test abstract class.

diff --git a/libstdc++-v3/include/experimental/functional b/libstdc++-v3/include/experimental/functional
index 0b91dcd..6a21caf 100644
--- a/libstdc++-v3/include/experimental/functional
+++ b/libstdc++-v3/include/experimental/functional
@@ -387,7 +387,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     public:
       template<typename _Fn2>
 	explicit
-	_Not_fn(_Fn2&& __fn) : _M_fn(std::forward<_Fn2>(__fn)) { }
+	_Not_fn(_Fn2&& __fn, int) : _M_fn(std::forward<_Fn2>(__fn)) { }
 
       _Not_fn(const _Not_fn& __fn) = default;
       _Not_fn(_Not_fn&& __fn) = default;
@@ -431,7 +431,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     noexcept(std::is_nothrow_constructible<std::decay_t<_Fn>, _Fn&&>::value)
     {
       using __maybe_type = _Maybe_wrap_member_pointer<std::decay_t<_Fn>>;
-      return _Not_fn<typename __maybe_type::type>{std::forward<_Fn>(__fn)};
+      return _Not_fn<typename __maybe_type::type>{std::forward<_Fn>(__fn), 0};
     }
 
 _GLIBCXX_END_NAMESPACE_VERSION
diff --git a/libstdc++-v3/testsuite/experimental/functional/not_fn.cc b/libstdc++-v3/testsuite/experimental/functional/not_fn.cc
index 3096eaa..b69d3ac 100644
--- a/libstdc++-v3/testsuite/experimental/functional/not_fn.cc
+++ b/libstdc++-v3/testsuite/experimental/functional/not_fn.cc
@@ -76,10 +76,30 @@ test03()
   VERIFY( not_fn(&X::b)(x) );
 }
 
+void
+test04()
+{
+  struct abstract { virtual void f() = 0; };
+  struct derived : abstract { void f() { } };
+  struct F { bool operator()(abstract&) { return false; } };
+  F f;
+  derived d;
+  VERIFY( not_fn(f)(d) );
+}
+
+void
+test05()
+{
+  auto nf = std::experimental::not_fn([] { return false; });
+  auto copy(nf); // PR libstdc++/70564
+}
+
 int
 main()
 {
   test01();
   test02();
   test03();
+  test04();
+  test05();
 }