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[libc++][deque] Applied [[nodiscard]] #169745

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Merged
merged 1 commit into from
Nov 27, 2025
Merged

[libc++][deque] Applied [[nodiscard]] #169745

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52 changes: 30 additions & 22 deletions libcxx/include/deque
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Original file line number Diff line number Diff line change
Expand Up @@ -715,45 +715,53 @@ public:

// iterators:

_LIBCPP_HIDE_FROM_ABI iterator begin() _NOEXCEPT {
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI iterator begin() _NOEXCEPT {
__map_pointer __mp = __map_.begin() + __start_ / __block_size;
return iterator(__mp, __map_.empty() ? 0 : *__mp + __start_ % __block_size);
}

_LIBCPP_HIDE_FROM_ABI const_iterator begin() const _NOEXCEPT {
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_iterator begin() const _NOEXCEPT {
__map_const_pointer __mp = static_cast<__map_const_pointer>(__map_.begin() + __start_ / __block_size);
return const_iterator(__mp, __map_.empty() ? 0 : *__mp + __start_ % __block_size);
}

_LIBCPP_HIDE_FROM_ABI iterator end() _NOEXCEPT {
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI iterator end() _NOEXCEPT {
size_type __p = size() + __start_;
__map_pointer __mp = __map_.begin() + __p / __block_size;
return iterator(__mp, __map_.empty() ? 0 : *__mp + __p % __block_size);
}

_LIBCPP_HIDE_FROM_ABI const_iterator end() const _NOEXCEPT {
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_iterator end() const _NOEXCEPT {
size_type __p = size() + __start_;
__map_const_pointer __mp = static_cast<__map_const_pointer>(__map_.begin() + __p / __block_size);
return const_iterator(__mp, __map_.empty() ? 0 : *__mp + __p % __block_size);
}

_LIBCPP_HIDE_FROM_ABI reverse_iterator rbegin() _NOEXCEPT { return reverse_iterator(end()); }
_LIBCPP_HIDE_FROM_ABI const_reverse_iterator rbegin() const _NOEXCEPT { return const_reverse_iterator(end()); }
_LIBCPP_HIDE_FROM_ABI reverse_iterator rend() _NOEXCEPT { return reverse_iterator(begin()); }
_LIBCPP_HIDE_FROM_ABI const_reverse_iterator rend() const _NOEXCEPT { return const_reverse_iterator(begin()); }
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI reverse_iterator rbegin() _NOEXCEPT { return reverse_iterator(end()); }
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_reverse_iterator rbegin() const _NOEXCEPT {
return const_reverse_iterator(end());
}
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI reverse_iterator rend() _NOEXCEPT { return reverse_iterator(begin()); }
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_reverse_iterator rend() const _NOEXCEPT {
return const_reverse_iterator(begin());
}

_LIBCPP_HIDE_FROM_ABI const_iterator cbegin() const _NOEXCEPT { return begin(); }
_LIBCPP_HIDE_FROM_ABI const_iterator cend() const _NOEXCEPT { return end(); }
_LIBCPP_HIDE_FROM_ABI const_reverse_iterator crbegin() const _NOEXCEPT { return const_reverse_iterator(end()); }
_LIBCPP_HIDE_FROM_ABI const_reverse_iterator crend() const _NOEXCEPT { return const_reverse_iterator(begin()); }
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_iterator cbegin() const _NOEXCEPT { return begin(); }
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_iterator cend() const _NOEXCEPT { return end(); }
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_reverse_iterator crbegin() const _NOEXCEPT {
return const_reverse_iterator(end());
}
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_reverse_iterator crend() const _NOEXCEPT {
return const_reverse_iterator(begin());
}

// capacity:
_LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __size(); }
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI size_type size() const _NOEXCEPT { return __size(); }

_LIBCPP_HIDE_FROM_ABI size_type& __size() _NOEXCEPT { return __size_; }
_LIBCPP_HIDE_FROM_ABI const size_type& __size() const _NOEXCEPT { return __size_; }

_LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT {
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT {
return std::min<size_type>(__alloc_traits::max_size(__alloc()), numeric_limits<difference_type>::max());
}
_LIBCPP_HIDE_FROM_ABI void resize(size_type __n);
Expand All @@ -762,14 +770,14 @@ public:
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI bool empty() const _NOEXCEPT { return size() == 0; }

// element access:
_LIBCPP_HIDE_FROM_ABI reference operator[](size_type __i) _NOEXCEPT;
_LIBCPP_HIDE_FROM_ABI const_reference operator[](size_type __i) const _NOEXCEPT;
_LIBCPP_HIDE_FROM_ABI reference at(size_type __i);
_LIBCPP_HIDE_FROM_ABI const_reference at(size_type __i) const;
_LIBCPP_HIDE_FROM_ABI reference front() _NOEXCEPT;
_LIBCPP_HIDE_FROM_ABI const_reference front() const _NOEXCEPT;
_LIBCPP_HIDE_FROM_ABI reference back() _NOEXCEPT;
_LIBCPP_HIDE_FROM_ABI const_reference back() const _NOEXCEPT;
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI reference operator[](size_type __i) _NOEXCEPT;
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_reference operator[](size_type __i) const _NOEXCEPT;
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI reference at(size_type __i);
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_reference at(size_type __i) const;
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI reference front() _NOEXCEPT;
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_reference front() const _NOEXCEPT;
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI reference back() _NOEXCEPT;
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_reference back() const _NOEXCEPT;

// 23.2.2.3 modifiers:
_LIBCPP_HIDE_FROM_ABI void push_front(const value_type& __v);
Expand Down
30 changes: 28 additions & 2 deletions libcxx/test/libcxx/diagnostics/deque.nodiscard.verify.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,32 @@
#include <deque>

void test() {
std::deque<int> deque;
deque.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
std::deque<int> d;
const std::deque<int> cd;

d.begin(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
cd.begin(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
d.end(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
cd.end(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
d.rbegin(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
cd.rbegin(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
d.rend(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
cd.rend(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
cd.cbegin(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
cd.cend(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
cd.crbegin(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
cd.crend(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}

d.size(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
d.max_size(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
d.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}

d[0]; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
cd[0]; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
d.at(0); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
cd.at(0); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
d.front(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
cd.front(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
d.back(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
cd.back(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
}
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