[libcxx-commits] [libcxx] [libc++] Mark string functions as [[nodiscard]] (PR #166524)
Nikolas Klauser via libcxx-commits
libcxx-commits at lists.llvm.org
Mon Nov 10 02:18:21 PST 2025
https://github.com/philnik777 updated https://github.com/llvm/llvm-project/pull/166524
>From 761b111422ce0196cb45bfb3b27d09c4533916e6 Mon Sep 17 00:00:00 2001
From: Nikolas Klauser <nikolasklauser at berlin.de>
Date: Wed, 5 Nov 2025 10:40:47 +0100
Subject: [PATCH] [libc++] Mark string functions as [[nodiscard]]
---
libcxx/include/string | 183 ++++++++++--------
.../diagnostics/string.nodiscard.verify.cpp | 115 ++++++++++-
.../strings/basic.string/nonnull.verify.cpp | 2 +
3 files changed, 217 insertions(+), 83 deletions(-)
diff --git a/libcxx/include/string b/libcxx/include/string
index ede42467b99fe..79da203cfdf6f 100644
--- a/libcxx/include/string
+++ b/libcxx/include/string
@@ -1253,45 +1253,55 @@ public:
# endif
_LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& operator=(value_type __c);
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 iterator begin() _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 iterator begin() _NOEXCEPT {
return __make_iterator(__get_pointer());
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_iterator begin() const _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_iterator begin() const _NOEXCEPT {
return __make_const_iterator(__get_pointer());
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 iterator end() _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 iterator end() _NOEXCEPT {
return __make_iterator(__get_pointer() + size());
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_iterator end() const _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_iterator end() const _NOEXCEPT {
return __make_const_iterator(__get_pointer() + size());
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reverse_iterator rbegin() _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reverse_iterator rbegin() _NOEXCEPT {
return reverse_iterator(end());
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reverse_iterator rbegin() const _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reverse_iterator
+ rbegin() const _NOEXCEPT {
return const_reverse_iterator(end());
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reverse_iterator rend() _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reverse_iterator rend() _NOEXCEPT {
return reverse_iterator(begin());
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reverse_iterator rend() const _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reverse_iterator rend() const _NOEXCEPT {
return const_reverse_iterator(begin());
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_iterator cbegin() const _NOEXCEPT { return begin(); }
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_iterator cend() const _NOEXCEPT { return end(); }
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reverse_iterator crbegin() const _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_iterator cbegin() const _NOEXCEPT {
+ return begin();
+ }
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_iterator cend() const _NOEXCEPT {
+ return end();
+ }
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reverse_iterator
+ crbegin() const _NOEXCEPT {
return rbegin();
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reverse_iterator crend() const _NOEXCEPT { return rend(); }
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reverse_iterator crend() const _NOEXCEPT {
+ return rend();
+ }
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type size() const _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type size() const _NOEXCEPT {
return __is_long() ? __get_long_size() : __get_short_size();
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type length() const _NOEXCEPT { return size(); }
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type length() const _NOEXCEPT {
+ return size();
+ }
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type max_size() const _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type max_size() const _NOEXCEPT {
if (size_type __m = __alloc_traits::max_size(__alloc_); __m <= std::numeric_limits<size_type>::max() / 2) {
size_type __res = __m - __alignment;
@@ -1309,7 +1319,7 @@ public:
}
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type capacity() const _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type capacity() const _NOEXCEPT {
return (__is_long() ? __get_long_cap() : static_cast<size_type>(__min_cap)) - 1;
}
@@ -1344,7 +1354,8 @@ public:
return size() == 0;
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reference operator[](size_type __pos) const _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reference
+ operator[](size_type __pos) const _NOEXCEPT {
_LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__pos <= size(), "string index out of bounds");
if (__builtin_constant_p(__pos) && !__fits_in_sso(__pos)) {
return *(__get_long_pointer() + __pos);
@@ -1352,7 +1363,8 @@ public:
return *(data() + __pos);
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference operator[](size_type __pos) _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference
+ operator[](size_type __pos) _NOEXCEPT {
_LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__pos <= size(), "string index out of bounds");
if (__builtin_constant_p(__pos) && !__fits_in_sso(__pos)) {
return *(__get_long_pointer() + __pos);
@@ -1360,8 +1372,8 @@ public:
return *(__get_pointer() + __pos);
}
- _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reference at(size_type __n) const;
- _LIBCPP_CONSTEXPR_SINCE_CXX20 reference at(size_type __n);
+ [[__nodiscard__]] _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reference at(size_type __n) const;
+ [[__nodiscard__]] _LIBCPP_CONSTEXPR_SINCE_CXX20 reference at(size_type __n);
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string& operator+=(const basic_string& __str) {
return append(__str);
@@ -1473,22 +1485,22 @@ public:
_LIBCPP_CONSTEXPR_SINCE_CXX20 void push_back(value_type __c);
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void pop_back();
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference front() _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference front() _NOEXCEPT {
_LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "string::front(): string is empty");
return *__get_pointer();
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reference front() const _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reference front() const _NOEXCEPT {
_LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "string::front(): string is empty");
return *data();
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference back() _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 reference back() _NOEXCEPT {
_LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "string::back(): string is empty");
return *(__get_pointer() + size() - 1);
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reference back() const _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const_reference back() const _NOEXCEPT {
_LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(!empty(), "string::back(): string is empty");
return *(data() + size() - 1);
}
@@ -1761,16 +1773,16 @@ public:
_LIBCPP_CONSTEXPR_SINCE_CXX20 size_type copy(value_type* __s, size_type __n, size_type __pos = 0) const;
# if _LIBCPP_STD_VER <= 20
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string
- substr(size_type __pos = 0, size_type __n = npos) const {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI
+ _LIBCPP_CONSTEXPR_SINCE_CXX20 basic_string substr(size_type __pos = 0, size_type __n = npos) const {
return basic_string(*this, __pos, __n);
}
# else
- _LIBCPP_HIDE_FROM_ABI constexpr basic_string substr(size_type __pos = 0, size_type __n = npos) const& {
+ [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr basic_string substr(size_type __pos = 0, size_type __n = npos) const& {
return basic_string(*this, __pos, __n);
}
- _LIBCPP_HIDE_FROM_ABI constexpr basic_string substr(size_type __pos = 0, size_type __n = npos) && {
+ [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr basic_string substr(size_type __pos = 0, size_type __n = npos) && {
return basic_string(std::move(*this), __pos, __n);
}
# endif
@@ -1790,231 +1802,238 @@ public:
// [string.ops]
// ------------
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const value_type* c_str() const _NOEXCEPT { return data(); }
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const value_type* data() const _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const value_type* c_str() const _NOEXCEPT {
+ return data();
+ }
+
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 const value_type* data() const _NOEXCEPT {
return std::__to_address(__get_pointer());
}
# if _LIBCPP_STD_VER >= 17
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 value_type* data() _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 value_type* data() _NOEXCEPT {
return std::__to_address(__get_pointer());
}
# endif
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 allocator_type get_allocator() const _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 allocator_type get_allocator() const _NOEXCEPT {
return __alloc_;
}
// find
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find(const basic_string& __str, size_type __pos = 0) const _NOEXCEPT {
return std::__str_find<value_type, size_type, traits_type, npos>(data(), size(), __str.data(), __pos, __str.size());
}
template <class _Tp, __enable_if_t<__can_be_converted_to_string_view_v<_CharT, _Traits, _Tp>, int> = 0>
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find(const _Tp& __t, size_type __pos = 0) const _NOEXCEPT {
__self_view __sv = __t;
return std::__str_find<value_type, size_type, traits_type, npos>(data(), size(), __sv.data(), __pos, __sv.size());
}
- _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type find(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT
+ [[__nodiscard__]] _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ find(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT
_LIBCPP_DIAGNOSE_NULLPTR_IF(__n != 0 && __s == nullptr, " if n is not zero") {
_LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string::find(): received nullptr");
return std::__str_find<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find(const value_type* _LIBCPP_DIAGNOSE_NULLPTR __s, size_type __pos = 0) const _NOEXCEPT {
_LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string::find(): received nullptr");
return std::__str_find<value_type, size_type, traits_type, npos>(
data(), size(), __s, __pos, traits_type::length(__s));
}
- _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type find(value_type __c, size_type __pos = 0) const _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type find(value_type __c, size_type __pos = 0) const _NOEXCEPT {
return std::__str_find<value_type, size_type, traits_type, npos>(data(), size(), __c, __pos);
}
// rfind
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
rfind(const basic_string& __str, size_type __pos = npos) const _NOEXCEPT {
return std::__str_rfind<value_type, size_type, traits_type, npos>(
data(), size(), __str.data(), __pos, __str.size());
}
template <class _Tp, __enable_if_t<__can_be_converted_to_string_view_v<_CharT, _Traits, _Tp>, int> = 0>
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
rfind(const _Tp& __t, size_type __pos = npos) const _NOEXCEPT {
__self_view __sv = __t;
return std::__str_rfind<value_type, size_type, traits_type, npos>(data(), size(), __sv.data(), __pos, __sv.size());
}
- _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type rfind(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT
+ [[__nodiscard__]] _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ rfind(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT
_LIBCPP_DIAGNOSE_NULLPTR_IF(__n != 0 && __s == nullptr, " if n is not zero") {
_LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string::rfind(): received nullptr");
return std::__str_rfind<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
rfind(const value_type* _LIBCPP_DIAGNOSE_NULLPTR __s, size_type __pos = npos) const _NOEXCEPT {
_LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string::rfind(): received nullptr");
return std::__str_rfind<value_type, size_type, traits_type, npos>(
data(), size(), __s, __pos, traits_type::length(__s));
}
- _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type rfind(value_type __c, size_type __pos = npos) const _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ rfind(value_type __c, size_type __pos = npos) const _NOEXCEPT {
return std::__str_rfind<value_type, size_type, traits_type, npos>(data(), size(), __c, __pos);
}
// find_first_of
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find_first_of(const basic_string& __str, size_type __pos = 0) const _NOEXCEPT {
return std::__str_find_first_of<value_type, size_type, traits_type, npos>(
data(), size(), __str.data(), __pos, __str.size());
}
template <class _Tp, __enable_if_t<__can_be_converted_to_string_view_v<_CharT, _Traits, _Tp>, int> = 0>
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find_first_of(const _Tp& __t, size_type __pos = 0) const _NOEXCEPT {
__self_view __sv = __t;
return std::__str_find_first_of<value_type, size_type, traits_type, npos>(
data(), size(), __sv.data(), __pos, __sv.size());
}
- _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find_first_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT
_LIBCPP_DIAGNOSE_NULLPTR_IF(__n != 0 && __s == nullptr, " if n is not zero") {
_LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string::find_first_of(): received nullptr");
return std::__str_find_first_of<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find_first_of(const value_type* _LIBCPP_DIAGNOSE_NULLPTR __s, size_type __pos = 0) const _NOEXCEPT {
_LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string::find_first_of(): received nullptr");
return std::__str_find_first_of<value_type, size_type, traits_type, npos>(
data(), size(), __s, __pos, traits_type::length(__s));
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find_first_of(value_type __c, size_type __pos = 0) const _NOEXCEPT {
return find(__c, __pos);
}
// find_last_of
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find_last_of(const basic_string& __str, size_type __pos = npos) const _NOEXCEPT {
return std::__str_find_last_of<value_type, size_type, traits_type, npos>(
data(), size(), __str.data(), __pos, __str.size());
}
template <class _Tp, __enable_if_t<__can_be_converted_to_string_view_v<_CharT, _Traits, _Tp>, int> = 0>
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find_last_of(const _Tp& __t, size_type __pos = npos) const _NOEXCEPT {
__self_view __sv = __t;
return std::__str_find_last_of<value_type, size_type, traits_type, npos>(
data(), size(), __sv.data(), __pos, __sv.size());
}
- _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find_last_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT
_LIBCPP_DIAGNOSE_NULLPTR_IF(__n != 0 && __s == nullptr, " if n is not zero") {
_LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string::find_last_of(): received nullptr");
return std::__str_find_last_of<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find_last_of(const value_type* _LIBCPP_DIAGNOSE_NULLPTR __s, size_type __pos = npos) const _NOEXCEPT {
_LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string::find_last_of(): received nullptr");
return std::__str_find_last_of<value_type, size_type, traits_type, npos>(
data(), size(), __s, __pos, traits_type::length(__s));
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find_last_of(value_type __c, size_type __pos = npos) const _NOEXCEPT {
return rfind(__c, __pos);
}
// find_first_not_of
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find_first_not_of(const basic_string& __str, size_type __pos = 0) const _NOEXCEPT {
return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>(
data(), size(), __str.data(), __pos, __str.size());
}
template <class _Tp, __enable_if_t<__can_be_converted_to_string_view_v<_CharT, _Traits, _Tp>, int> = 0>
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find_first_not_of(const _Tp& __t, size_type __pos = 0) const _NOEXCEPT {
__self_view __sv = __t;
return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>(
data(), size(), __sv.data(), __pos, __sv.size());
}
- _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find_first_not_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT
_LIBCPP_DIAGNOSE_NULLPTR_IF(__n != 0 && __s == nullptr, " if n is not zero") {
_LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string::find_first_not_of(): received nullptr");
return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find_first_not_of(const value_type* _LIBCPP_DIAGNOSE_NULLPTR __s, size_type __pos = 0) const _NOEXCEPT {
_LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string::find_first_not_of(): received nullptr");
return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>(
data(), size(), __s, __pos, traits_type::length(__s));
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find_first_not_of(value_type __c, size_type __pos = 0) const _NOEXCEPT {
return std::__str_find_first_not_of<value_type, size_type, traits_type, npos>(data(), size(), __c, __pos);
}
// find_last_not_of
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find_last_not_of(const basic_string& __str, size_type __pos = npos) const _NOEXCEPT {
return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>(
data(), size(), __str.data(), __pos, __str.size());
}
template <class _Tp, __enable_if_t<__can_be_converted_to_string_view_v<_CharT, _Traits, _Tp>, int> = 0>
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find_last_not_of(const _Tp& __t, size_type __pos = npos) const _NOEXCEPT {
__self_view __sv = __t;
return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>(
data(), size(), __sv.data(), __pos, __sv.size());
}
- _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find_last_not_of(const value_type* __s, size_type __pos, size_type __n) const _NOEXCEPT
_LIBCPP_DIAGNOSE_NULLPTR_IF(__n != 0 && __s == nullptr, " if n is not zero") {
_LIBCPP_ASSERT_NON_NULL(__n == 0 || __s != nullptr, "string::find_last_not_of(): received nullptr");
return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>(data(), size(), __s, __pos, __n);
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find_last_not_of(const value_type* _LIBCPP_DIAGNOSE_NULLPTR __s, size_type __pos = npos) const _NOEXCEPT {
_LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string::find_last_not_of(): received nullptr");
return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>(
data(), size(), __s, __pos, traits_type::length(__s));
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 size_type
find_last_not_of(value_type __c, size_type __pos = npos) const _NOEXCEPT {
return std::__str_find_last_not_of<value_type, size_type, traits_type, npos>(data(), size(), __c, __pos);
}
// compare
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 int compare(const basic_string& __str) const _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 int
+ compare(const basic_string& __str) const _NOEXCEPT {
return compare(__self_view(__str));
}
template <class _Tp, __enable_if_t<__can_be_converted_to_string_view_v<_CharT, _Traits, _Tp>, int> = 0>
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 int compare(const _Tp& __t) const _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 int compare(const _Tp& __t) const _NOEXCEPT {
__self_view __sv = __t;
size_t __lhs_sz = size();
size_t __rhs_sz = __sv.size();
@@ -2029,18 +2048,18 @@ public:
}
template <class _Tp, __enable_if_t<__can_be_converted_to_string_view_v<_CharT, _Traits, _Tp>, int> = 0>
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 int
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 int
compare(size_type __pos1, size_type __n1, const _Tp& __t) const {
__self_view __sv = __t;
return compare(__pos1, __n1, __sv.data(), __sv.size());
}
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 int
+ [[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 int
compare(size_type __pos1, size_type __n1, const basic_string& __str) const {
return compare(__pos1, __n1, __str.data(), __str.size());
}
- _LIBCPP_CONSTEXPR_SINCE_CXX20 int
+ [[__nodiscard__]] _LIBCPP_CONSTEXPR_SINCE_CXX20 int
compare(size_type __pos1, size_type __n1, const basic_string& __str, size_type __pos2, size_type __n2 = npos) const {
return compare(__pos1, __n1, __self_view(__str), __pos2, __n2);
}
@@ -2049,53 +2068,56 @@ public:
__enable_if_t<__can_be_converted_to_string_view_v<_CharT, _Traits, _Tp> &&
!is_same<__remove_cvref_t<_Tp>, basic_string>::value,
int> = 0>
- inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 int
+ [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 int
compare(size_type __pos1, size_type __n1, const _Tp& __t, size_type __pos2, size_type __n2 = npos) const {
__self_view __sv = __t;
return __self_view(*this).substr(__pos1, __n1).compare(__sv.substr(__pos2, __n2));
}
- _LIBCPP_CONSTEXPR_SINCE_CXX20 int compare(const value_type* _LIBCPP_DIAGNOSE_NULLPTR __s) const _NOEXCEPT {
+ [[__nodiscard__]] _LIBCPP_CONSTEXPR_SINCE_CXX20 int
+ compare(const value_type* _LIBCPP_DIAGNOSE_NULLPTR __s) const _NOEXCEPT {
_LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string::compare(): received nullptr");
return compare(0, npos, __s, traits_type::length(__s));
}
- _LIBCPP_CONSTEXPR_SINCE_CXX20 int
+ [[__nodiscard__]] _LIBCPP_CONSTEXPR_SINCE_CXX20 int
compare(size_type __pos1, size_type __n1, const value_type* _LIBCPP_DIAGNOSE_NULLPTR __s) const {
_LIBCPP_ASSERT_NON_NULL(__s != nullptr, "string::compare(): received nullptr");
return compare(__pos1, __n1, __s, traits_type::length(__s));
}
- _LIBCPP_CONSTEXPR_SINCE_CXX20 int
+ [[__nodiscard__]] _LIBCPP_CONSTEXPR_SINCE_CXX20 int
compare(size_type __pos1, size_type __n1, const value_type* __s, size_type __n2) const
_LIBCPP_DIAGNOSE_NULLPTR_IF(__n2 != 0 && __s == nullptr, " if n2 is not zero");
// starts_with
# if _LIBCPP_STD_VER >= 20
- constexpr _LIBCPP_HIDE_FROM_ABI bool starts_with(__self_view __sv) const noexcept {
+ [[__nodiscard__]] constexpr _LIBCPP_HIDE_FROM_ABI bool starts_with(__self_view __sv) const noexcept {
return __self_view(typename __self_view::__assume_valid(), data(), size()).starts_with(__sv);
}
- constexpr _LIBCPP_HIDE_FROM_ABI bool starts_with(value_type __c) const noexcept {
+ [[__nodiscard__]] constexpr _LIBCPP_HIDE_FROM_ABI bool starts_with(value_type __c) const noexcept {
return !empty() && _Traits::eq(front(), __c);
}
- constexpr _LIBCPP_HIDE_FROM_ABI bool starts_with(const value_type* _LIBCPP_DIAGNOSE_NULLPTR __s) const noexcept {
+ [[__nodiscard__]] constexpr _LIBCPP_HIDE_FROM_ABI bool
+ starts_with(const value_type* _LIBCPP_DIAGNOSE_NULLPTR __s) const noexcept {
return starts_with(__self_view(__s));
}
// ends_with
- constexpr _LIBCPP_HIDE_FROM_ABI bool ends_with(__self_view __sv) const noexcept {
+ [[__nodiscard__]] constexpr _LIBCPP_HIDE_FROM_ABI bool ends_with(__self_view __sv) const noexcept {
return __self_view(typename __self_view::__assume_valid(), data(), size()).ends_with(__sv);
}
- constexpr _LIBCPP_HIDE_FROM_ABI bool ends_with(value_type __c) const noexcept {
+ [[__nodiscard__]] constexpr _LIBCPP_HIDE_FROM_ABI bool ends_with(value_type __c) const noexcept {
return !empty() && _Traits::eq(back(), __c);
}
- constexpr _LIBCPP_HIDE_FROM_ABI bool ends_with(const value_type* _LIBCPP_DIAGNOSE_NULLPTR __s) const noexcept {
+ [[__nodiscard__]] constexpr _LIBCPP_HIDE_FROM_ABI bool
+ ends_with(const value_type* _LIBCPP_DIAGNOSE_NULLPTR __s) const noexcept {
return ends_with(__self_view(__s));
}
# endif
@@ -2103,15 +2125,16 @@ public:
// contains
# if _LIBCPP_STD_VER >= 23
- constexpr _LIBCPP_HIDE_FROM_ABI bool contains(__self_view __sv) const noexcept {
+ [[__nodiscard__]] constexpr _LIBCPP_HIDE_FROM_ABI bool contains(__self_view __sv) const noexcept {
return __self_view(typename __self_view::__assume_valid(), data(), size()).contains(__sv);
}
- constexpr _LIBCPP_HIDE_FROM_ABI bool contains(value_type __c) const noexcept {
+ [[__nodiscard__]] constexpr _LIBCPP_HIDE_FROM_ABI bool contains(value_type __c) const noexcept {
return __self_view(typename __self_view::__assume_valid(), data(), size()).contains(__c);
}
- constexpr _LIBCPP_HIDE_FROM_ABI bool contains(const value_type* _LIBCPP_DIAGNOSE_NULLPTR __s) const {
+ [[__nodiscard__]] constexpr _LIBCPP_HIDE_FROM_ABI bool
+ contains(const value_type* _LIBCPP_DIAGNOSE_NULLPTR __s) const {
return __self_view(typename __self_view::__assume_valid(), data(), size()).contains(__s);
}
# endif
diff --git a/libcxx/test/libcxx/diagnostics/string.nodiscard.verify.cpp b/libcxx/test/libcxx/diagnostics/string.nodiscard.verify.cpp
index d421eaf5cb8f1..f020516a2495a 100644
--- a/libcxx/test/libcxx/diagnostics/string.nodiscard.verify.cpp
+++ b/libcxx/test/libcxx/diagnostics/string.nodiscard.verify.cpp
@@ -11,13 +11,122 @@
// check that <string> functions are marked [[nodiscard]]
#include <string>
+#include <string_view>
#include "test_macros.h"
+std::string prval();
+
void test() {
- std::string string;
- string.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ std::string str;
+ const std::string cstr;
+ std::string_view sv;
+
+ str[0]; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ cstr[0]; // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.at(0); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ cstr.at(0); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+ str.c_str(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.data(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ cstr.data(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+ str.substr(0); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ prval().substr(0); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+ str.front(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ cstr.front(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.back(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ cstr.back(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+ str.begin(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ cstr.begin(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.end(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ cstr.end(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+ str.rbegin(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ cstr.rbegin(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.rend(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ cstr.rend(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+ str.cbegin(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.cend(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+ str.crbegin(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.crend(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+ str.capacity(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.empty(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.length(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.size(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.max_size(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.get_allocator(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+ str.find(str); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.find(sv); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.find(' '); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.find(""); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.find("", 0, 0); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+ str.rfind(str); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.rfind(sv); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.rfind(' '); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.rfind(""); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.rfind("", 0, 0); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+ // clang-format off
+ str.find_first_of(str); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.find_first_of(sv); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.find_first_of(' '); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.find_first_of(""); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.find_first_of("", 0, 0); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+ str.find_last_of(str); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.find_last_of(sv); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.find_last_of(' '); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.find_last_of(""); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.find_last_of("", 0, 0); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+ str.find_first_not_of(str); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.find_first_not_of(sv); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.find_first_not_of(' '); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.find_first_not_of(""); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.find_first_not_of("", 0, 0); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+ str.find_last_not_of(str); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.find_last_not_of(sv); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.find_last_not_of(' '); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.find_last_not_of(""); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.find_last_not_of("", 0, 0); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+ str.compare(str); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.compare(sv); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.compare(0, 0, sv); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.compare(0, 0, sv, 0); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.compare(0, 0, str); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.compare(0, 0, str, 0); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.compare(""); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.compare(0, 0, ""); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.compare(0, 0, "", 0); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ // clang-format on
+
+#if TEST_STD_VER >= 20
+ str.starts_with(sv); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.starts_with(' '); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.starts_with(""); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+ str.ends_with(sv); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.ends_with(' '); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.ends_with(""); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+#endif
+
+#if TEST_STD_VER >= 23
+ str.contains(sv); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.contains(' '); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.contains(""); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+#endif
+
#if TEST_STD_VER >= 26
- string.subview(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
+ str.subview(); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
#endif
}
diff --git a/libcxx/test/libcxx/strings/basic.string/nonnull.verify.cpp b/libcxx/test/libcxx/strings/basic.string/nonnull.verify.cpp
index f428c49fd05f4..c9df9f061905e 100644
--- a/libcxx/test/libcxx/strings/basic.string/nonnull.verify.cpp
+++ b/libcxx/test/libcxx/strings/basic.string/nonnull.verify.cpp
@@ -13,6 +13,8 @@
// Clang 19 and AppleClang don't have diagnose_if with diagnostic flags
// UNSUPPORTED: clang-19, apple-clang-17
+// ADDITIONAL_COMPILE_FLAGS: -Wno-unused-result
+
#include <string>
#include "test_macros.h"
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