First part of P0600 - '[[nodiscard] in the standard library'. Mark the 'empty()' methods of all the containers as nodiscard. If you're calling empty() w/o looking at the result, you probably meanto to call 'clear()'. c++2a only

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@318269 91177308-0d34-0410-b5e6-96231b3b80d8

17 files changed, 476 insertions, 0 deletions

diff --git a/test/std/containers/associative/map/map.access/empty.fail.cpp b/test/std/containers/associative/map/map.access/empty.fail.cpp
new file mode 100644
index 000000000..14ac13c99
--- /dev/null
+++ b/test/std/containers/associative/map/map.access/empty.fail.cpp
@@ -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.
+//
+//===----------------------------------------------------------------------===//
+
+// <map>
+
+// class map
+
+// 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 <map>
+
+#include "test_macros.h"
+
+int main ()
+{
+    std::map<int, int> c;
+    c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/test/std/containers/associative/multimap/empty.fail.cpp b/test/std/containers/associative/multimap/empty.fail.cpp
new file mode 100644
index 000000000..12ca05ef1
--- /dev/null
+++ b/test/std/containers/associative/multimap/empty.fail.cpp
@@ -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.
+//
+//===----------------------------------------------------------------------===//
+
+// <map>
+
+// class multimap
+
+// 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 <map>
+
+#include "test_macros.h"
+
+int main ()
+{
+    std::multimap<int, int> c;
+    c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/test/std/containers/associative/multiset/empty.fail.cpp b/test/std/containers/associative/multiset/empty.fail.cpp
new file mode 100644
index 000000000..2169a07e4
--- /dev/null
+++ b/test/std/containers/associative/multiset/empty.fail.cpp
@@ -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.
+//
+//===----------------------------------------------------------------------===//
+
+// <set>
+
+// class multiset
+
+// 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 <set>
+
+#include "test_macros.h"
+
+int main ()
+{
+    std::multiset<int> c;
+    c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/test/std/containers/associative/set/empty.fail.cpp b/test/std/containers/associative/set/empty.fail.cpp
new file mode 100644
index 000000000..0eea6fb67
--- /dev/null
+++ b/test/std/containers/associative/set/empty.fail.cpp
@@ -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.
+//
+//===----------------------------------------------------------------------===//
+
+// <set>
+
+// class set
+
+// 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 <set>
+
+#include "test_macros.h"
+
+int main ()
+{
+    std::set<int> c;
+    c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/test/std/containers/container.adaptors/priority.queue/priqueue.members/empty.fail.cpp b/test/std/containers/container.adaptors/priority.queue/priqueue.members/empty.fail.cpp
new file mode 100644
index 000000000..c034f22b7
--- /dev/null
+++ b/test/std/containers/container.adaptors/priority.queue/priqueue.members/empty.fail.cpp
@@ -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.
+//
+//===----------------------------------------------------------------------===//
+
+// <queue>
+
+// class priority_queue
+
+// 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 <queue>
+
+#include "test_macros.h"
+
+int main ()
+{
+    std::priority_queue<int> c;
+    c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/test/std/containers/container.adaptors/queue/queue.defn/empty.fail.cpp b/test/std/containers/container.adaptors/queue/queue.defn/empty.fail.cpp
new file mode 100644
index 000000000..ce017d2dd
--- /dev/null
+++ b/test/std/containers/container.adaptors/queue/queue.defn/empty.fail.cpp
@@ -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.
+//
+//===----------------------------------------------------------------------===//
+
+// <queue>
+
+// class queue
+
+// 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 <queue>
+
+#include "test_macros.h"
+
+int main ()
+{
+    std::queue<int> c;
+    c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/test/std/containers/container.adaptors/stack/stack.defn/empty.fail.cpp b/test/std/containers/container.adaptors/stack/stack.defn/empty.fail.cpp
new file mode 100644
index 000000000..001a38fe3
--- /dev/null
+++ b/test/std/containers/container.adaptors/stack/stack.defn/empty.fail.cpp
@@ -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.
+//
+//===----------------------------------------------------------------------===//
+
+// <stack>
+
+// class stack
+
+// 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 <stack>
+
+#include "test_macros.h"
+
+int main ()
+{
+    std::stack<int> c;
+    c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/test/std/containers/sequences/array/empty.fail.cpp b/test/std/containers/sequences/array/empty.fail.cpp
new file mode 100644
index 000000000..85bf5a7c9
--- /dev/null
+++ b/test/std/containers/sequences/array/empty.fail.cpp
@@ -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.
+//
+//===----------------------------------------------------------------------===//
+
+// <array>
+
+// class array
+
+// 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 <array>
+
+#include "test_macros.h"
+
+int main ()
+{
+    std::array<int, 1> c;
+    c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/test/std/containers/sequences/deque/deque.capacity/empty.fail.cpp b/test/std/containers/sequences/deque/deque.capacity/empty.fail.cpp
new file mode 100644
index 000000000..adfd5f2d8
--- /dev/null
+++ b/test/std/containers/sequences/deque/deque.capacity/empty.fail.cpp
@@ -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.
+//
+//===----------------------------------------------------------------------===//
+
+// <deque>
+
+// class deque
+
+// 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 <deque>
+
+#include "test_macros.h"
+
+int main ()
+{
+    std::deque<int> c;
+    c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/test/std/containers/sequences/forwardlist/empty.fail.cpp b/test/std/containers/sequences/forwardlist/empty.fail.cpp
new file mode 100644
index 000000000..78928b480
--- /dev/null
+++ b/test/std/containers/sequences/forwardlist/empty.fail.cpp
@@ -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.
+//
+//===----------------------------------------------------------------------===//
+
+// <forward_list>
+
+// class forward_list
+
+// 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 <forward_list>
+
+#include "test_macros.h"
+
+int main ()
+{
+    std::forward_list<int> c;
+    c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/test/std/containers/sequences/list/list.capacity/empty.fail.cpp b/test/std/containers/sequences/list/list.capacity/empty.fail.cpp
new file mode 100644
index 000000000..fe0387c83
--- /dev/null
+++ b/test/std/containers/sequences/list/list.capacity/empty.fail.cpp
@@ -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.
+//
+//===----------------------------------------------------------------------===//
+
+// <list>
+
+// class list
+
+// 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 <list>
+
+#include "test_macros.h"
+
+int main ()
+{
+    std::list<int> c;
+    c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/test/std/containers/sequences/vector.bool/empty.fail.cpp b/test/std/containers/sequences/vector.bool/empty.fail.cpp
new file mode 100644
index 000000000..99c245d0c
--- /dev/null
+++ b/test/std/containers/sequences/vector.bool/empty.fail.cpp
@@ -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.
+//
+//===----------------------------------------------------------------------===//
+
+// <vector>
+
+// class vector
+
+// 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 <vector>
+
+#include "test_macros.h"
+
+int main ()
+{
+    std::vector<bool> c;
+    c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/test/std/containers/sequences/vector/vector.capacity/empty.fail.cpp b/test/std/containers/sequences/vector/vector.capacity/empty.fail.cpp
new file mode 100644
index 000000000..abfdfbfb9
--- /dev/null
+++ b/test/std/containers/sequences/vector/vector.capacity/empty.fail.cpp
@@ -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.
+//
+//===----------------------------------------------------------------------===//
+
+// <vector>
+
+// class vector
+
+// 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 <vector>
+
+#include "test_macros.h"
+
+int main ()
+{
+    std::vector<int> c;
+    c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/test/std/containers/unord/unord.map/empty.fail.cpp b/test/std/containers/unord/unord.map/empty.fail.cpp
new file mode 100644
index 000000000..1c67169bb
--- /dev/null
+++ b/test/std/containers/unord/unord.map/empty.fail.cpp
@@ -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.
+//
+//===----------------------------------------------------------------------===//
+
+// <unordered_map>
+
+// class unordered_map
+
+// 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 <unordered_map>
+
+#include "test_macros.h"
+
+int main ()
+{
+    std::unordered_map<int, int> c;
+    c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/test/std/containers/unord/unord.multimap/empty.fail.cpp b/test/std/containers/unord/unord.multimap/empty.fail.cpp
new file mode 100644
index 000000000..7e3a6f4b9
--- /dev/null
+++ b/test/std/containers/unord/unord.multimap/empty.fail.cpp
@@ -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.
+//
+//===----------------------------------------------------------------------===//
+
+// <unordered_map>
+
+// class unordered_multimap
+
+// 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 <unordered_map>
+
+#include "test_macros.h"
+
+int main ()
+{
+    std::unordered_multimap<int, int> c;
+    c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/test/std/containers/unord/unord.multiset/empty.fail.cpp b/test/std/containers/unord/unord.multiset/empty.fail.cpp
new file mode 100644
index 000000000..8e068a4e1
--- /dev/null
+++ b/test/std/containers/unord/unord.multiset/empty.fail.cpp
@@ -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.
+//
+//===----------------------------------------------------------------------===//
+
+// <unordered_set>
+
+// class unordered_multiset
+
+// 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 <unordered_set>
+
+#include "test_macros.h"
+
+int main ()
+{
+    std::unordered_multiset<int> c;
+    c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+}
diff --git a/test/std/containers/unord/unord.set/empty.fail.cpp b/test/std/containers/unord/unord.set/empty.fail.cpp
new file mode 100644
index 000000000..23603c261
--- /dev/null
+++ b/test/std/containers/unord/unord.set/empty.fail.cpp
@@ -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.
+//
+//===----------------------------------------------------------------------===//
+
+// <unordered_set>
+
+// class unordered_set
+
+// 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 <unordered_set>
+
+#include "test_macros.h"
+
+int main ()
+{
+    std::unordered_set<int> c;
+    c.empty();  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+}