[libcxx] r323385 - Implement LWG2783: stack::emplace() and queue::emplace() should return decltype(auto)
Marshall Clow via cfe-commits
cfe-commits at lists.llvm.org
Wed Jan 24 14:42:25 PST 2018
Author: marshall
Date: Wed Jan 24 14:42:25 2018
New Revision: 323385
URL: http://llvm.org/viewvc/llvm-project?rev=323385&view=rev
Log:
Implement LWG2783: stack::emplace() and queue::emplace() should return decltype(auto)
Modified:
libcxx/trunk/include/queue
libcxx/trunk/include/stack
libcxx/trunk/test/std/containers/container.adaptors/queue/queue.defn/emplace.pass.cpp
libcxx/trunk/test/std/containers/container.adaptors/stack/stack.defn/emplace.pass.cpp
libcxx/trunk/www/cxx2a_status.html
Modified: libcxx/trunk/include/queue
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/queue?rev=323385&r1=323384&r2=323385&view=diff
==============================================================================
--- libcxx/trunk/include/queue (original)
+++ libcxx/trunk/include/queue Wed Jan 24 14:42:25 2018
@@ -290,7 +290,7 @@ public:
template <class... _Args>
_LIBCPP_INLINE_VISIBILITY
#if _LIBCPP_STD_VER > 14
- reference emplace(_Args&&... __args)
+ decltype(auto) emplace(_Args&&... __args)
{ return c.emplace_back(_VSTD::forward<_Args>(__args)...);}
#else
void emplace(_Args&&... __args)
Modified: libcxx/trunk/include/stack
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/stack?rev=323385&r1=323384&r2=323385&view=diff
==============================================================================
--- libcxx/trunk/include/stack (original)
+++ libcxx/trunk/include/stack Wed Jan 24 14:42:25 2018
@@ -199,7 +199,7 @@ public:
template <class... _Args>
_LIBCPP_INLINE_VISIBILITY
#if _LIBCPP_STD_VER > 14
- reference emplace(_Args&&... __args)
+ decltype(auto) emplace(_Args&&... __args)
{ return c.emplace_back(_VSTD::forward<_Args>(__args)...);}
#else
void emplace(_Args&&... __args)
Modified: libcxx/trunk/test/std/containers/container.adaptors/queue/queue.defn/emplace.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/containers/container.adaptors/queue/queue.defn/emplace.pass.cpp?rev=323385&r1=323384&r2=323385&view=diff
==============================================================================
--- libcxx/trunk/test/std/containers/container.adaptors/queue/queue.defn/emplace.pass.cpp (original)
+++ libcxx/trunk/test/std/containers/container.adaptors/queue/queue.defn/emplace.pass.cpp Wed Jan 24 14:42:25 2018
@@ -1,6 +1,6 @@
//===----------------------------------------------------------------------===//
//
-// The LLVM Compiler Infrastructure
+// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
@@ -11,36 +11,55 @@
// <queue>
-// template <class... Args> reference emplace(Args&&... args);
-// return type is 'reference' in C++17; 'void' before
+// template <class... Args> decltype(auto) emplace(Args&&... args);
+// return type is 'decltype(auto)' in C++17; 'void' before
+// whatever the return type of the underlying container's emplace_back() returns.
#include <queue>
#include <cassert>
+#include <list>
#include "test_macros.h"
#include "../../../Emplaceable.h"
+template <typename Queue>
+void test_return_type() {
+ typedef typename Queue::container_type Container;
+ typedef typename Container::value_type value_type;
+ typedef decltype(std::declval<Queue>().emplace(std::declval<value_type &>())) queue_return_type;
+
+#if TEST_STD_VER > 14
+ typedef decltype(std::declval<Container>().emplace_back(std::declval<value_type>())) container_return_type;
+ static_assert(std::is_same<queue_return_type, container_return_type>::value, "");
+#else
+ static_assert(std::is_same<queue_return_type, void>::value, "");
+#endif
+}
+
int main()
{
- typedef Emplaceable T;
- std::queue<Emplaceable> q;
+ test_return_type<std::queue<int> > ();
+ test_return_type<std::queue<int, std::list<int> > > ();
+
+ typedef Emplaceable T;
+ std::queue<Emplaceable> q;
#if TEST_STD_VER > 14
- T& r1 = q.emplace(1, 2.5);
- assert(&r1 == &q.back());
- T& r2 = q.emplace(2, 3.5);
- assert(&r2 == &q.back());
- T& r3 = q.emplace(3, 4.5);
- assert(&r3 == &q.back());
- assert(&r1 == &q.front());
+ T& r1 = q.emplace(1, 2.5);
+ assert(&r1 == &q.back());
+ T& r2 = q.emplace(2, 3.5);
+ assert(&r2 == &q.back());
+ T& r3 = q.emplace(3, 4.5);
+ assert(&r3 == &q.back());
+ assert(&r1 == &q.front());
#else
- q.emplace(1, 2.5);
- q.emplace(2, 3.5);
- q.emplace(3, 4.5);
+ q.emplace(1, 2.5);
+ q.emplace(2, 3.5);
+ q.emplace(3, 4.5);
#endif
- assert(q.size() == 3);
- assert(q.front() == Emplaceable(1, 2.5));
- assert(q.back() == Emplaceable(3, 4.5));
+ assert(q.size() == 3);
+ assert(q.front() == Emplaceable(1, 2.5));
+ assert(q.back() == Emplaceable(3, 4.5));
}
Modified: libcxx/trunk/test/std/containers/container.adaptors/stack/stack.defn/emplace.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/containers/container.adaptors/stack/stack.defn/emplace.pass.cpp?rev=323385&r1=323384&r2=323385&view=diff
==============================================================================
--- libcxx/trunk/test/std/containers/container.adaptors/stack/stack.defn/emplace.pass.cpp (original)
+++ libcxx/trunk/test/std/containers/container.adaptors/stack/stack.defn/emplace.pass.cpp Wed Jan 24 14:42:25 2018
@@ -11,20 +11,39 @@
// <stack>
-// template <class... Args> reference emplace(Args&&... args);
-// return type is 'reference' in C++17; 'void' before
+// template <class... Args> decltype(auto) emplace(Args&&... args);
+// return type is 'decltype(auto)' in C++17; 'void' before
+// whatever the return type of the underlying container's emplace_back() returns.
#include <stack>
#include <cassert>
+#include <vector>
#include "test_macros.h"
#include "../../../Emplaceable.h"
+template <typename Stack>
+void test_return_type() {
+ typedef typename Stack::container_type Container;
+ typedef typename Container::value_type value_type;
+ typedef decltype(std::declval<Stack>().emplace(std::declval<value_type &>())) stack_return_type;
+
+#if TEST_STD_VER > 14
+ typedef decltype(std::declval<Container>().emplace_back(std::declval<value_type>())) container_return_type;
+ static_assert(std::is_same<stack_return_type, container_return_type>::value, "");
+#else
+ static_assert(std::is_same<stack_return_type, void>::value, "");
+#endif
+}
+
int main()
{
+ test_return_type<std::stack<int> > ();
+ test_return_type<std::stack<int, std::vector<int> > > ();
+
typedef Emplaceable T;
- std::stack<Emplaceable> q;
+ std::stack<Emplaceable> q;
#if TEST_STD_VER > 14
T& r1 = q.emplace(1, 2.5);
assert(&r1 == &q.top());
Modified: libcxx/trunk/www/cxx2a_status.html
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/www/cxx2a_status.html?rev=323385&r1=323384&r2=323385&view=diff
==============================================================================
--- libcxx/trunk/www/cxx2a_status.html (original)
+++ libcxx/trunk/www/cxx2a_status.html Wed Jan 24 14:42:25 2018
@@ -54,7 +54,7 @@
<!--
<tr><td><a href="https://wg21.link/n3346">3346</a></td><td>LWG</td><td>Terminology for Container Element Requirements - Rev 1</td><td>Kona</td><td>Complete</td><td>3.4</td></tr>
-->
- <tr><td><a href="https://wg21.link/P0463R1">P0463R1</a></td><td>LWG</td><td>Endian just Endian</td><td>Toronto</td><td><I>In progress</I></td><td>7.0</td></tr>
+ <tr><td><a href="https://wg21.link/P0463R1">P0463R1</a></td><td>LWG</td><td>Endian just Endian</td><td>Toronto</td><td>Complete</td><td>7.0</td></tr>
<tr><td><a href="https://wg21.link/P0674R1">P0674R1</a></td><td>LWG</td><td>Extending make_shared to Support Arrays</td><td>Toronto</td><td></td><td></td></tr>
<tr><td></td><td></td><td></td><td></td><td></td><td></td></tr>
@@ -94,7 +94,7 @@
<tr><td><a href="https://wg21.link/LWG2444">2444</a></td><td>Inconsistent complexity for <tt>std::sort_heap</tt></td><td>Toronto</td><td></td></tr>
<tr><td><a href="https://wg21.link/LWG2593">2593</a></td><td>Moved-from state of Allocators</td><td>Toronto</td><td></td></tr>
<tr><td><a href="https://wg21.link/LWG2597">2597</a></td><td><tt>std::log</tt> misspecified for complex numbers</td><td>Toronto</td><td></td></tr>
- <tr><td><a href="https://wg21.link/LWG2783">2783</a></td><td><tt>stack::emplace()</tt> and <tt>queue::emplace()</tt> should return <tt>decltype(auto)</tt></td><td>Toronto</td><td></td></tr>
+ <tr><td><a href="https://wg21.link/LWG2783">2783</a></td><td><tt>stack::emplace()</tt> and <tt>queue::emplace()</tt> should return <tt>decltype(auto)</tt></td><td>Toronto</td><td>Complete</td></tr>
<tr><td><a href="https://wg21.link/LWG2932">2932</a></td><td>Constraints on parallel algorithm implementations are underspecified</td><td>Toronto</td><td></td></tr>
<tr><td><a href="https://wg21.link/LWG2937">2937</a></td><td>Is <tt>equivalent("existing_thing", "not_existing_thing")</tt> an error</td><td>Toronto</td><td>Complete</td></tr>
<tr><td><a href="https://wg21.link/LWG2940">2940</a></td><td><tt>result_of</tt> specification also needs a little cleanup</td><td>Toronto</td><td></td></tr>
@@ -135,7 +135,7 @@
<!-- <tr><td></td><td></td><td></td><td></td></tr> -->
</table>
- <p>Last Updated: 22-Jan-2018</p>
+ <p>Last Updated: 24-Jan-2018</p>
</div>
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