[libcxx-commits] [libcxx] 7ad0051 - [libc++][NFC] Mark LWG2731 as complete

[Joe Loser via libcxx-commits]

Author: Joe Loser
Date: 2021-10-26T13:46:00-04:00
New Revision: 7ad00511e4ab3190515501aa05e3e3b4a48a0c00

URL: https://github.com/llvm/llvm-project/commit/7ad00511e4ab3190515501aa05e3e3b4a48a0c00
DIFF: https://github.com/llvm/llvm-project/commit/7ad00511e4ab3190515501aa05e3e3b4a48a0c00.diff

LOG: [libc++][NFC] Mark LWG2731 as complete

Mark LWG2731 as complete. The type alias `mutex_type` is only provided if
`scoped_lock` is given one mutex type and it has been implemented that
way since the beginning of Clang 5 it seems. There already are tests for
verifying existence (and lack thereof) for `mutex_type` type alias
depending on the number of mutex types, so there is nothing to
do for this LWG issue.

Reviewed By: Quuxplusone, Mordante, #libc

Differential Revision: https://reviews.llvm.org/D112462

Added: 
    

Modified: 
    libcxx/docs/Status/Cxx2bIssues.csv
    libcxx/include/mutex
    libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/types.pass.cpp

Removed: 
    


################################################################################
diff  --git a/libcxx/docs/Status/Cxx2bIssues.csv b/libcxx/docs/Status/Cxx2bIssues.csv
index 93ef7246eb520..9384357f86206 100644
--- a/libcxx/docs/Status/Cxx2bIssues.csv
+++ b/libcxx/docs/Status/Cxx2bIssues.csv
@@ -11,7 +11,7 @@
 "`3447 <https://wg21.link/LWG3447>`__","Deduction guides for ``take_view`` and ``drop_view`` have 
diff erent constraints","November 2020","|Complete|","14.0"
 "`3450 <https://wg21.link/LWG3450>`__","The const overloads of ``take_while_view::begin/end`` are underconstrained","November 2020","","","|ranges|"
 "`3464 <https://wg21.link/LWG3464>`__","``istream::gcount()`` can overflow","November 2020","",""
-"`2731 <https://wg21.link/LWG2731>`__","Existence of ``lock_guard<MutexTypes...>::mutex_type`` typedef unclear","November 2020","",""
+"`2731 <https://wg21.link/LWG2731>`__","Existence of ``lock_guard<MutexTypes...>::mutex_type`` typedef unclear","November 2020","|Complete|","5.0"
 "`2743 <https://wg21.link/LWG2743>`__","P0083R3 ``node_handle`` private members missing ""exposition only"" comment","November 2020","",""
 "`2820 <https://wg21.link/LWG2820>`__","Clarify ``<cstdint>`` macros","November 2020","",""
 "`3120 <https://wg21.link/LWG3120>`__","Unclear behavior of ``monotonic_buffer_resource::release()``","November 2020","",""

diff  --git a/libcxx/include/mutex b/libcxx/include/mutex
index eb8e54ad44214..ee1a62a1331d0 100644
--- a/libcxx/include/mutex
+++ b/libcxx/include/mutex
@@ -112,7 +112,7 @@ template <class... MutexTypes>
 class scoped_lock // C++17
 {
 public:
-    using mutex_type = Mutex;  // If MutexTypes... consists of the single type Mutex
+    using mutex_type = Mutex;  // Only if sizeof...(MutexTypes) == 1
 
     explicit scoped_lock(MutexTypes&... m);
     scoped_lock(adopt_lock_t, MutexTypes&... m);

diff  --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/types.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/types.pass.cpp
index 7cec5dffd8205..8caa621aa417e 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/types.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.scoped/types.pass.cpp
@@ -11,11 +11,11 @@
 
 // <mutex>
 
-// template <class Mutex...>
+// template <class... MutexTypes>
 // class scoped_lock
 // {
 // public:
-//     typedef Mutex mutex_type;  // only if sizeof...(Mutex) == 1
+//     typedef Mutex mutex_type;  // Only if sizeof...(MutexTypes) == 1
 //     ...
 // };