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[libc++][queue] Applied [[nodiscard]] #169469

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Merged
merged 2 commits into from
Nov 27, 2025
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[libc++][queue] Applied [[nodiscard]] #169469

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[libc++][queue] Applied `[[nodiscard]]`
H-G-Hristov Nov 25, 2025
532c86c
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H-G-Hristov Nov 26, 2025
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16 changes: 9 additions & 7 deletions libcxx/include/queue
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Original file line number Diff line number Diff line change
Expand Up @@ -376,12 +376,12 @@ public:
# endif // _LIBCPP_CXX03_LANG

[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI bool empty() const { return c.empty(); }
_LIBCPP_HIDE_FROM_ABI size_type size() const { return c.size(); }
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI size_type size() const { return c.size(); }

_LIBCPP_HIDE_FROM_ABI reference front() { return c.front(); }
_LIBCPP_HIDE_FROM_ABI const_reference front() const { return c.front(); }
_LIBCPP_HIDE_FROM_ABI reference back() { return c.back(); }
_LIBCPP_HIDE_FROM_ABI const_reference back() const { return c.back(); }
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI reference front() { return c.front(); }
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_reference front() const { return c.front(); }
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI reference back() { return c.back(); }
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI const_reference back() const { return c.back(); }

_LIBCPP_HIDE_FROM_ABI void push(const value_type& __v) { c.push_back(__v); }
# ifndef _LIBCPP_CXX03_LANG
Expand Down Expand Up @@ -664,8 +664,10 @@ public:
# endif

[[__nodiscard__]] _LIBCPP_CONSTEXPR_SINCE_CXX26 _LIBCPP_HIDE_FROM_ABI bool empty() const { return c.empty(); }
_LIBCPP_CONSTEXPR_SINCE_CXX26 _LIBCPP_HIDE_FROM_ABI size_type size() const { return c.size(); }
_LIBCPP_CONSTEXPR_SINCE_CXX26 _LIBCPP_HIDE_FROM_ABI const_reference top() const { return c.front(); }
[[__nodiscard__]] _LIBCPP_CONSTEXPR_SINCE_CXX26 _LIBCPP_HIDE_FROM_ABI size_type size() const { return c.size(); }
[[__nodiscard__]] _LIBCPP_CONSTEXPR_SINCE_CXX26 _LIBCPP_HIDE_FROM_ABI const_reference top() const {
return c.front();
}

_LIBCPP_CONSTEXPR_SINCE_CXX26 _LIBCPP_HIDE_FROM_ABI void push(const value_type& __v);
# ifndef _LIBCPP_CXX03_LANG
Expand Down
26 changes: 19 additions & 7 deletions libcxx/test/libcxx/diagnostics/queue.nodiscard.verify.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -12,12 +12,24 @@

#include <queue>

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

q.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
q.size(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
q.front(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
cq.front(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
q.back(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
cq.back(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
}

{
std::priority_queue<int> pq;

void test_priority_queue() {
std::priority_queue<int> priority_queue;
priority_queue.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
pq.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
pq.size(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
pq.top(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
}
}
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