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H-G-HristovH-G-Hristov
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[libc++][map] Applied [[nodiscard]]
[[nodiscard]] should be applied to functions where discarding the return value is most likely a correctness issue. https://libcxx.llvm.org/CodingGuidelines.html#apply-nodiscard-where-relevant https://wg21.link/map
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‎libcxx/include/__type_traits/is_generic_transparent_comparator.h‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -17,7 +17,7 @@
1717

1818
_LIBCPP_BEGIN_NAMESPACE_STD
1919

20-
// This traits returns true if the given _Comparator is known to accept any two types for compaison. This is separate
20+
// This trait returns true if the given _Comparator is known to accept any two types for comparison. This is separate
2121
// from `__is_transparent_v`, since that only enables overloads of specific functions, but doesn't give any semantic
2222
// guarantees. This trait guarantess that the comparator simply calls the appropriate comparison functions for any two
2323
// types.

‎libcxx/include/map‎

Lines changed: 59 additions & 45 deletions
Original file line numberDiff line numberDiff line change
@@ -1027,33 +1027,37 @@ public:
10271027

10281028
_LIBCPP_HIDE_FROM_ABI ~map() { static_assert(sizeof(std::__diagnose_non_const_comparator<_Key, _Compare>()), ""); }
10291029

1030-
_LIBCPP_HIDE_FROM_ABI iterator begin() _NOEXCEPT { return __tree_.begin(); }
1031-
_LIBCPP_HIDE_FROM_ABI const_iterator begin() const _NOEXCEPT { return __tree_.begin(); }
1032-
_LIBCPP_HIDE_FROM_ABI iterator end() _NOEXCEPT { return __tree_.end(); }
1033-
_LIBCPP_HIDE_FROM_ABI const_iterator end() const _NOEXCEPT { return __tree_.end(); }
1030+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI iterator begin() _NOEXCEPT { return __tree_.begin(); }
1031+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_iterator begin() const _NOEXCEPT { return __tree_.begin(); }
1032+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI iterator end() _NOEXCEPT { return __tree_.end(); }
1033+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_iterator end() const _NOEXCEPT { return __tree_.end(); }
10341034

1035-
_LIBCPP_HIDE_FROM_ABI reverse_iterator rbegin() _NOEXCEPT { return reverse_iterator(end()); }
1036-
_LIBCPP_HIDE_FROM_ABI const_reverse_iterator rbegin() const _NOEXCEPT { return const_reverse_iterator(end()); }
1037-
_LIBCPP_HIDE_FROM_ABI reverse_iterator rend() _NOEXCEPT { return reverse_iterator(begin()); }
1038-
_LIBCPP_HIDE_FROM_ABI const_reverse_iterator rend() const _NOEXCEPT { return const_reverse_iterator(begin()); }
1035+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI reverse_iterator rbegin() _NOEXCEPT { return reverse_iterator(end()); }
1036+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_reverse_iterator rbegin() const _NOEXCEPT {
1037+
return const_reverse_iterator(end());
1038+
}
1039+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI reverse_iterator rend() _NOEXCEPT { return reverse_iterator(begin()); }
1040+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_reverse_iterator rend() const _NOEXCEPT {
1041+
return const_reverse_iterator(begin());
1042+
}
10391043

1040-
_LIBCPP_HIDE_FROM_ABI const_iterator cbegin() const _NOEXCEPT { return begin(); }
1041-
_LIBCPP_HIDE_FROM_ABI const_iterator cend() const _NOEXCEPT { return end(); }
1042-
_LIBCPP_HIDE_FROM_ABI const_reverse_iterator crbegin() const _NOEXCEPT { return rbegin(); }
1043-
_LIBCPP_HIDE_FROM_ABI const_reverse_iterator crend() const _NOEXCEPT { return rend(); }
1044+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_iterator cbegin() const _NOEXCEPT { return begin(); }
1045+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_iterator cend() const _NOEXCEPT { return end(); }
1046+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_reverse_iterator crbegin() const _NOEXCEPT { return rbegin(); }
1047+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_reverse_iterator crend() const _NOEXCEPT { return rend(); }
10441048

10451049
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return __tree_.size() == 0; }
1046-
_LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __tree_.size(); }
1047-
_LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT { return __tree_.max_size(); }
1050+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __tree_.size(); }
1051+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT { return __tree_.max_size(); }
10481052

1049-
_LIBCPP_HIDE_FROM_ABI mapped_type& operator[](const key_type& __k);
1053+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI mapped_type& operator[](const key_type& __k);
10501054
# ifndef _LIBCPP_CXX03_LANG
1051-
_LIBCPP_HIDE_FROM_ABI mapped_type& operator[](key_type&& __k);
1055+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI mapped_type& operator[](key_type&& __k);
10521056
# endif
10531057

10541058
template <class _Arg,
10551059
__enable_if_t<__is_transparently_comparable_v<_Compare, key_type, __remove_cvref_t<_Arg> >, int> = 0>
1056-
_LIBCPP_HIDE_FROM_ABI mapped_type& at(_Arg&& __arg) {
1060+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI mapped_type& at(_Arg&& __arg) {
10571061
auto [_, __child] = __tree_.__find_equal(__arg);
10581062
if (__child == nullptr)
10591063
std::__throw_out_of_range("map::at: key not found");
@@ -1062,19 +1066,23 @@ public:
10621066

10631067
template <class _Arg,
10641068
__enable_if_t<__is_transparently_comparable_v<_Compare, key_type, __remove_cvref_t<_Arg> >, int> = 0>
1065-
_LIBCPP_HIDE_FROM_ABI const mapped_type& at(_Arg&& __arg) const {
1069+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const mapped_type& at(_Arg&& __arg) const {
10661070
auto [_, __child] = __tree_.__find_equal(__arg);
10671071
if (__child == nullptr)
10681072
std::__throw_out_of_range("map::at: key not found");
10691073
return static_cast<__node_pointer>(__child)->__get_value().second;
10701074
}
10711075

1072-
_LIBCPP_HIDE_FROM_ABI mapped_type& at(const key_type& __k);
1073-
_LIBCPP_HIDE_FROM_ABI const mapped_type& at(const key_type& __k) const;
1076+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI mapped_type& at(const key_type& __k);
1077+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const mapped_type& at(const key_type& __k) const;
10741078

1075-
_LIBCPP_HIDE_FROM_ABI allocator_type get_allocator() const _NOEXCEPT { return allocator_type(__tree_.__alloc()); }
1076-
_LIBCPP_HIDE_FROM_ABI key_compare key_comp() const { return __tree_.value_comp().key_comp(); }
1077-
_LIBCPP_HIDE_FROM_ABI value_compare value_comp() const { return value_compare(__tree_.value_comp().key_comp()); }
1079+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI allocator_type get_allocator() const _NOEXCEPT {
1080+
return allocator_type(__tree_.__alloc());
1081+
}
1082+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI key_compare key_comp() const { return __tree_.value_comp().key_comp(); }
1083+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI value_compare value_comp() const {
1084+
return value_compare(__tree_.value_comp().key_comp());
1085+
}
10781086

10791087
# ifndef _LIBCPP_CXX03_LANG
10801088
template <class... _Args>
@@ -1226,10 +1234,10 @@ public:
12261234
"node_type with incompatible allocator passed to map::insert()");
12271235
return __tree_.template __node_handle_insert_unique<node_type>(__hint.__i_, std::move(__nh));
12281236
}
1229-
_LIBCPP_HIDE_FROM_ABI node_type extract(key_type const& __key) {
1237+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI node_type extract(key_type const& __key) {
12301238
return __tree_.template __node_handle_extract<node_type>(__key);
12311239
}
1232-
_LIBCPP_HIDE_FROM_ABI node_type extract(const_iterator __it) {
1240+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI node_type extract(const_iterator __it) {
12331241
return __tree_.template __node_handle_extract<node_type>(__it.__i_);
12341242
}
12351243
template <class _Compare2>
@@ -1260,44 +1268,48 @@ public:
12601268

12611269
_LIBCPP_HIDE_FROM_ABI void swap(map& __m) _NOEXCEPT_(__is_nothrow_swappable_v<__base>) { __tree_.swap(__m.__tree_); }
12621270

1263-
_LIBCPP_HIDE_FROM_ABI iterator find(const key_type& __k) { return __tree_.find(__k); }
1264-
_LIBCPP_HIDE_FROM_ABI const_iterator find(const key_type& __k) const { return __tree_.find(__k); }
1271+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI iterator find(const key_type& __k) { return __tree_.find(__k); }
1272+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_iterator find(const key_type& __k) const { return __tree_.find(__k); }
12651273
# if _LIBCPP_STD_VER >= 14
12661274
template <typename _K2,
12671275
enable_if_t<__is_transparent_v<_Compare, _K2> || __is_transparently_comparable_v<_Compare, key_type, _K2>,
12681276
int> = 0>
1269-
_LIBCPP_HIDE_FROM_ABI iterator find(const _K2& __k) {
1277+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI iterator find(const _K2& __k) {
12701278
return __tree_.find(__k);
12711279
}
12721280
template <typename _K2,
12731281
enable_if_t<__is_transparent_v<_Compare, _K2> || __is_transparently_comparable_v<_Compare, key_type, _K2>,
12741282
int> = 0>
1275-
_LIBCPP_HIDE_FROM_ABI const_iterator find(const _K2& __k) const {
1283+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_iterator find(const _K2& __k) const {
12761284
return __tree_.find(__k);
12771285
}
12781286
# endif
12791287

1280-
_LIBCPP_HIDE_FROM_ABI size_type count(const key_type& __k) const { return __tree_.__count_unique(__k); }
1288+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI size_type count(const key_type& __k) const {
1289+
return __tree_.__count_unique(__k);
1290+
}
12811291
# if _LIBCPP_STD_VER >= 14
12821292
template <typename _K2, enable_if_t<__is_transparent_v<_Compare, _K2>, int> = 0>
1283-
_LIBCPP_HIDE_FROM_ABI size_type count(const _K2& __k) const {
1293+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI size_type count(const _K2& __k) const {
12841294
return __tree_.__count_multi(__k);
12851295
}
12861296
# endif
12871297

12881298
# if _LIBCPP_STD_VER >= 20
1289-
_LIBCPP_HIDE_FROM_ABI bool contains(const key_type& __k) const { return find(__k) != end(); }
1299+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI bool contains(const key_type& __k) const { return find(__k) != end(); }
12901300
template <typename _K2,
12911301
enable_if_t<__is_transparent_v<_Compare, _K2> || __is_transparently_comparable_v<_Compare, key_type, _K2>,
12921302
int> = 0>
1293-
_LIBCPP_HIDE_FROM_ABI bool contains(const _K2& __k) const {
1303+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI bool contains(const _K2& __k) const {
12941304
return find(__k) != end();
12951305
}
12961306
# endif // _LIBCPP_STD_VER >= 20
12971307

1298-
_LIBCPP_HIDE_FROM_ABI iterator lower_bound(const key_type& __k) { return __tree_.__lower_bound_unique(__k); }
1308+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI iterator lower_bound(const key_type& __k) {
1309+
return __tree_.__lower_bound_unique(__k);
1310+
}
12991311

1300-
_LIBCPP_HIDE_FROM_ABI const_iterator lower_bound(const key_type& __k) const {
1312+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_iterator lower_bound(const key_type& __k) const {
13011313
return __tree_.__lower_bound_unique(__k);
13021314
}
13031315

@@ -1307,52 +1319,54 @@ public:
13071319
template <typename _K2,
13081320
enable_if_t<__is_transparent_v<_Compare, _K2> || __is_transparently_comparable_v<_Compare, key_type, _K2>,
13091321
int> = 0>
1310-
_LIBCPP_HIDE_FROM_ABI iterator lower_bound(const _K2& __k) {
1322+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI iterator lower_bound(const _K2& __k) {
13111323
return __tree_.__lower_bound_multi(__k);
13121324
}
13131325

13141326
template <typename _K2,
13151327
enable_if_t<__is_transparent_v<_Compare, _K2> || __is_transparently_comparable_v<_Compare, key_type, _K2>,
13161328
int> = 0>
1317-
_LIBCPP_HIDE_FROM_ABI const_iterator lower_bound(const _K2& __k) const {
1329+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_iterator lower_bound(const _K2& __k) const {
13181330
return __tree_.__lower_bound_multi(__k);
13191331
}
13201332
# endif
13211333

1322-
_LIBCPP_HIDE_FROM_ABI iterator upper_bound(const key_type& __k) { return __tree_.__upper_bound_unique(__k); }
1334+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI iterator upper_bound(const key_type& __k) {
1335+
return __tree_.__upper_bound_unique(__k);
1336+
}
13231337

1324-
_LIBCPP_HIDE_FROM_ABI const_iterator upper_bound(const key_type& __k) const {
1338+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_iterator upper_bound(const key_type& __k) const {
13251339
return __tree_.__upper_bound_unique(__k);
13261340
}
13271341

13281342
# if _LIBCPP_STD_VER >= 14
13291343
template <typename _K2,
13301344
enable_if_t<__is_transparent_v<_Compare, _K2> || __is_transparently_comparable_v<_Compare, key_type, _K2>,
13311345
int> = 0>
1332-
_LIBCPP_HIDE_FROM_ABI iterator upper_bound(const _K2& __k) {
1346+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI iterator upper_bound(const _K2& __k) {
13331347
return __tree_.__upper_bound_multi(__k);
13341348
}
13351349
template <typename _K2,
13361350
enable_if_t<__is_transparent_v<_Compare, _K2> || __is_transparently_comparable_v<_Compare, key_type, _K2>,
13371351
int> = 0>
1338-
_LIBCPP_HIDE_FROM_ABI const_iterator upper_bound(const _K2& __k) const {
1352+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_iterator upper_bound(const _K2& __k) const {
13391353
return __tree_.__upper_bound_multi(__k);
13401354
}
13411355
# endif
13421356

1343-
_LIBCPP_HIDE_FROM_ABI pair<iterator, iterator> equal_range(const key_type& __k) {
1357+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI pair<iterator, iterator> equal_range(const key_type& __k) {
13441358
return __tree_.__equal_range_unique(__k);
13451359
}
1346-
_LIBCPP_HIDE_FROM_ABI pair<const_iterator, const_iterator> equal_range(const key_type& __k) const {
1360+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI pair<const_iterator, const_iterator> equal_range(const key_type& __k) const {
13471361
return __tree_.__equal_range_unique(__k);
13481362
}
13491363
# if _LIBCPP_STD_VER >= 14
13501364
template <typename _K2, enable_if_t<__is_transparent_v<_Compare, _K2>, int> = 0>
1351-
_LIBCPP_HIDE_FROM_ABI pair<iterator, iterator> equal_range(const _K2& __k) {
1365+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI pair<iterator, iterator> equal_range(const _K2& __k) {
13521366
return __tree_.__equal_range_multi(__k);
13531367
}
13541368
template <typename _K2, enable_if_t<__is_transparent_v<_Compare, _K2>, int> = 0>
1355-
_LIBCPP_HIDE_FROM_ABI pair<const_iterator, const_iterator> equal_range(const _K2& __k) const {
1369+
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI pair<const_iterator, const_iterator> equal_range(const _K2& __k) const {
13561370
return __tree_.__equal_range_multi(__k);
13571371
}
13581372
# endif

‎libcxx/test/libcxx/containers/associative/map/at.abort.pass.cpp‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -28,6 +28,6 @@ void exit_success(int) { std::_Exit(EXIT_SUCCESS); }
2828
int main(int, char**) {
2929
std::signal(SIGABRT, exit_success);
3030
std::map<int, int> map;
31-
map.at(1);
31+
(void)map.at(1);
3232
return EXIT_FAILURE;
3333
}

‎libcxx/test/libcxx/containers/associative/map/at.const.abort.pass.cpp‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -28,6 +28,6 @@ void exit_success(int) { std::_Exit(EXIT_SUCCESS); }
2828
int main(int, char**) {
2929
std::signal(SIGABRT, exit_success);
3030
std::map<int, int> const map;
31-
map.at(1);
31+
(void)map.at(1);
3232
return EXIT_FAILURE;
3333
}

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