[libcxx] r318378 - More of P0600 - '[[nodiscard]] in the Library' mark empty() as nodiscard in filesystem::path

[Marshall Clow via cfe-commits]

Author: marshall
Date: Wed Nov 15 21:48:32 2017
New Revision: 318378

URL: http://llvm.org/viewvc/llvm-project?rev=318378&view=rev
Log:
More of P0600 - '[[nodiscard]] in the Library' mark empty() as nodiscard in filesystem::path

Added:
    libcxx/trunk/test/std/experimental/filesystem/class.path/path.member/path.decompose/empty.fail.cpp
Modified:
    libcxx/trunk/include/experimental/filesystem
    libcxx/trunk/test/std/experimental/filesystem/class.path/path.member/path.decompose/path.decompose.pass.cpp

Modified: libcxx/trunk/include/experimental/filesystem
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/experimental/filesystem?rev=318378&r1=318377&r2=318378&view=diff
==============================================================================
--- libcxx/trunk/include/experimental/filesystem (original)
+++ libcxx/trunk/include/experimental/filesystem Wed Nov 15 21:48:32 2017
@@ -972,7 +972,8 @@ public:
     _LIBCPP_INLINE_VISIBILITY path extension()      const { return string_type(__extension()); }
 
     // query
-    _LIBCPP_INLINE_VISIBILITY bool empty() const _NOEXCEPT { return __pn_.empty(); }
+    _LIBCPP_NODISCARD_AFTER_CXX17 _LIBCPP_INLINE_VISIBILITY 
+    bool empty() const _NOEXCEPT { return __pn_.empty(); }
 
     _LIBCPP_INLINE_VISIBILITY bool has_root_name()      const { return !__root_name().empty(); }
     _LIBCPP_INLINE_VISIBILITY bool has_root_directory() const { return !__root_directory().empty(); }

Added: libcxx/trunk/test/std/experimental/filesystem/class.path/path.member/path.decompose/empty.fail.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/experimental/filesystem/class.path/path.member/path.decompose/empty.fail.cpp?rev=318378&view=auto
==============================================================================
--- libcxx/trunk/test/std/experimental/filesystem/class.path/path.member/path.decompose/empty.fail.cpp (added)
+++ libcxx/trunk/test/std/experimental/filesystem/class.path/path.member/path.decompose/empty.fail.cpp Wed Nov 15 21:48:32 2017
@@ -0,0 +1,28 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+//                     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.
+//
+//===----------------------------------------------------------------------===//
+
+// <experimental/filesystem>
+
+// class path
+
+// bool empty() const noexcept;
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
+// UNSUPPORTED: clang-3.3, clang-3.4, clang-3.5, clang-3.6, clang-3.7, clang-3.8
+
+#include <experimental/filesystem>
+
+#include "test_macros.h"
+
+int main ()
+{
+    std::experimental::filesystem::path c;
+    c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+}

Modified: libcxx/trunk/test/std/experimental/filesystem/class.path/path.member/path.decompose/path.decompose.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/experimental/filesystem/class.path/path.member/path.decompose/path.decompose.pass.cpp?rev=318378&r1=318377&r2=318378&view=diff
==============================================================================
--- libcxx/trunk/test/std/experimental/filesystem/class.path/path.member/path.decompose/path.decompose.pass.cpp (original)
+++ libcxx/trunk/test/std/experimental/filesystem/class.path/path.member/path.decompose/path.decompose.pass.cpp Wed Nov 15 21:48:32 2017
@@ -177,7 +177,8 @@ void decompFilenameTest()
   for (auto const & TC : FilenameTestCases) {
     path p(TC.raw);
     assert(p == TC.raw);
-
+    ASSERT_NOEXCEPT(p.empty());
+    
     assert(p.filename() == TC.filename);
     assert(p.has_filename() != TC.filename.empty());