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Merged
merged 6 commits into from
Nov 22, 2025
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Merged

[libc++][any] Applied [[nodiscard]] #168826

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7910416
[libc++][any] Applied `[[nodiscard]]`
H-G-Hristov Nov 20, 2025
da2b700
Formatting
H-G-Hristov Nov 20, 2025
541aec4
Merge branch 'main' into hgh/libcxx/nodiscard-to-any
H-G-Hristov Nov 20, 2025
6890692
Fix formatting
H-G-Hristov Nov 20, 2025
6f2551e
Merge branch 'main' into hgh/libcxx/nodiscard-to-any
H-G-Hristov Nov 22, 2025
aa066f2
Merge branch 'main' into hgh/libcxx/nodiscard-to-any
H-G-Hristov Nov 22, 2025
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18 changes: 9 additions & 9 deletions libcxx/include/any
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Expand Up @@ -262,10 +262,10 @@ public:
_LIBCPP_HIDE_FROM_ABI void swap(any& __rhs) _NOEXCEPT;

// 6.3.4 any observers
_LIBCPP_HIDE_FROM_ABI bool has_value() const _NOEXCEPT { return __h_ != nullptr; }
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI bool has_value() const _NOEXCEPT { return __h_ != nullptr; }

# if _LIBCPP_HAS_RTTI
_LIBCPP_HIDE_FROM_ABI const type_info& type() const _NOEXCEPT {
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI const type_info& type() const _NOEXCEPT {
if (__h_) {
return *static_cast<type_info const*>(this->__call(_Action::_TypeInfo));
} else {
Expand Down Expand Up @@ -492,17 +492,17 @@ inline _LIBCPP_HIDE_FROM_ABI void any::swap(any& __rhs) _NOEXCEPT {
inline _LIBCPP_HIDE_FROM_ABI void swap(any& __lhs, any& __rhs) _NOEXCEPT { __lhs.swap(__rhs); }

template <class _Tp, class... _Args>
inline _LIBCPP_HIDE_FROM_ABI any make_any(_Args&&... __args) {
[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI any make_any(_Args&&... __args) {
return any(in_place_type<_Tp>, std::forward<_Args>(__args)...);
}

template <class _Tp, class _Up, class... _Args>
inline _LIBCPP_HIDE_FROM_ABI any make_any(initializer_list<_Up> __il, _Args&&... __args) {
[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI any make_any(initializer_list<_Up> __il, _Args&&... __args) {
return any(in_place_type<_Tp>, __il, std::forward<_Args>(__args)...);
}

template <class _ValueType>
inline _LIBCPP_HIDE_FROM_ABI _ValueType any_cast(any const& __v) {
[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI _ValueType any_cast(any const& __v) {
using _RawValueType = __remove_cvref_t<_ValueType>;
static_assert(is_constructible<_ValueType, _RawValueType const&>::value,
"ValueType is required to be a const lvalue reference "
Expand All @@ -514,7 +514,7 @@ inline _LIBCPP_HIDE_FROM_ABI _ValueType any_cast(any const& __v) {
}

template <class _ValueType>
inline _LIBCPP_HIDE_FROM_ABI _ValueType any_cast(any& __v) {
[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI _ValueType any_cast(any& __v) {
using _RawValueType = __remove_cvref_t<_ValueType>;
static_assert(is_constructible<_ValueType, _RawValueType&>::value,
"ValueType is required to be an lvalue reference "
Expand All @@ -526,7 +526,7 @@ inline _LIBCPP_HIDE_FROM_ABI _ValueType any_cast(any& __v) {
}

template <class _ValueType>
inline _LIBCPP_HIDE_FROM_ABI _ValueType any_cast(any&& __v) {
[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI _ValueType any_cast(any&& __v) {
using _RawValueType = __remove_cvref_t<_ValueType>;
static_assert(is_constructible<_ValueType, _RawValueType>::value,
"ValueType is required to be an rvalue reference "
Expand All @@ -538,7 +538,7 @@ inline _LIBCPP_HIDE_FROM_ABI _ValueType any_cast(any&& __v) {
}

template <class _ValueType>
inline _LIBCPP_HIDE_FROM_ABI add_pointer_t<add_const_t<_ValueType>> any_cast(any const* __any) _NOEXCEPT {
[[nodiscard]] inline _LIBCPP_HIDE_FROM_ABI add_pointer_t<add_const_t<_ValueType>> any_cast(any const* __any) _NOEXCEPT {
static_assert(!is_void_v<_ValueType>, "_ValueType may not be void.");
static_assert(!is_reference<_ValueType>::value, "_ValueType may not be a reference.");
return std::any_cast<_ValueType>(const_cast<any*>(__any));
Expand All @@ -555,7 +555,7 @@ inline _LIBCPP_HIDE_FROM_ABI _RetType __pointer_or_func_cast(void*, /*IsFunction
}

template <class _ValueType>
_LIBCPP_HIDE_FROM_ABI add_pointer_t<_ValueType> any_cast(any* __any) _NOEXCEPT {
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI add_pointer_t<_ValueType> any_cast(any* __any) _NOEXCEPT {
using __any_imp::_Action;
static_assert(!is_void_v<_ValueType>, "_ValueType may not be void.");
static_assert(!is_reference<_ValueType>::value, "_ValueType may not be a reference.");
Expand Down
45 changes: 45 additions & 0 deletions libcxx/test/libcxx/utilities/any/nodiscard.verify.cpp
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@@ -0,0 +1,45 @@
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// REQUIRES: std-at-least-c++17

// Check that functions are marked [[nodiscard]]

#include <any>
#include <utility>
#include <vector>

#include "test_macros.h"

void test() {
std::any a{94};

// expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
a.has_value();
#if !defined(TEST_HAS_NO_RTTI)
// expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
a.type();
#endif

// expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
std::make_any<int>(82);
// expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
std::make_any<std::vector<int>>({94, 82, 50});

// expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
std::any_cast<const int&>(std::as_const(a));
// expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
std::any_cast<int&>(a);
// expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
std::any_cast<int&&>(std::move(a));

// expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
std::any_cast<int*>(&a);
// expected-warning@+1 {{ignoring return value of function declared with 'nodiscard' attribute}}
std::any_cast<const int*>(&std::as_const(a));
}
12 changes: 6 additions & 6 deletions .../utilities/any/any.nonmembers/any.cast/any_cast_request_invalid_value_category.verify.cpp
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Expand Up @@ -23,31 +23,31 @@ void test_const_lvalue_cast_request_non_const_lvalue() {
const std::any a;
// expected-error-re@any:* {{static assertion failed{{.*}}ValueType is required to be a const lvalue reference or a CopyConstructible type}}
// expected-error@any:* {{drops 'const' qualifier}}
std::any_cast<TestType&>(a); // expected-note {{requested here}}
(void)std::any_cast<TestType&>(a); // expected-note {{requested here}}

const std::any a2(42);
// expected-error-re@any:* {{static assertion failed{{.*}}ValueType is required to be a const lvalue reference or a CopyConstructible type}}
// expected-error@any:* {{drops 'const' qualifier}}
std::any_cast<int&>(a2); // expected-note {{requested here}}
(void)std::any_cast<int&>(a2); // expected-note {{requested here}}
}

void test_lvalue_any_cast_request_rvalue() {
std::any a;
// expected-error-re@any:* {{static assertion failed{{.*}}ValueType is required to be an lvalue reference or a CopyConstructible type}}
std::any_cast<TestType&&>(a); // expected-note {{requested here}}
(void)std::any_cast<TestType&&>(a); // expected-note {{requested here}}

std::any a2(42);
// expected-error-re@any:* {{static assertion failed{{.*}}ValueType is required to be an lvalue reference or a CopyConstructible type}}
std::any_cast<int&&>(a2); // expected-note {{requested here}}
(void)std::any_cast<int&&>(a2); // expected-note {{requested here}}
}

void test_rvalue_any_cast_request_lvalue() {
std::any a;
// expected-error-re@any:* {{static assertion failed{{.*}}ValueType is required to be an rvalue reference or a CopyConstructible type}}
// expected-error@any:* {{non-const lvalue reference to type 'TestType' cannot bind to a temporary}}
std::any_cast<TestType&>(std::move(a)); // expected-note {{requested here}}
(void)std::any_cast<TestType&>(std::move(a)); // expected-note {{requested here}}

// expected-error-re@any:* {{static assertion failed{{.*}}ValueType is required to be an rvalue reference or a CopyConstructible type}}
// expected-error@any:* {{non-const lvalue reference to type 'int' cannot bind to a temporary}}
std::any_cast<int&>(42);
(void)std::any_cast<int&>(42);
}
8 changes: 4 additions & 4 deletions libcxx/test/std/utilities/any/any.nonmembers/any.cast/const_correctness.verify.cpp
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Expand Up @@ -31,14 +31,14 @@ void test() {
std::any a;

// expected-error-re@any:* {{static assertion failed{{.*}}ValueType is required to be a const lvalue reference or a CopyConstructible type}}
std::any_cast<TestType&>(static_cast<std::any const&>(a)); // expected-note {{requested here}}
(void)std::any_cast<TestType&>(static_cast<std::any const&>(a)); // expected-note {{requested here}}

// expected-error-re@any:* {{static assertion failed{{.*}}ValueType is required to be a const lvalue reference or a CopyConstructible type}}
std::any_cast<TestType&&>(static_cast<std::any const&>(a)); // expected-note {{requested here}}
(void)std::any_cast<TestType&&>(static_cast<std::any const&>(a)); // expected-note {{requested here}}

// expected-error-re@any:* {{static assertion failed{{.*}}ValueType is required to be a const lvalue reference or a CopyConstructible type}}
std::any_cast<TestType2&>(static_cast<std::any const&&>(a)); // expected-note {{requested here}}
(void)std::any_cast<TestType2&>(static_cast<std::any const&&>(a)); // expected-note {{requested here}}

// expected-error-re@any:* {{static assertion failed{{.*}}ValueType is required to be a const lvalue reference or a CopyConstructible type}}
std::any_cast<TestType2&&>(static_cast<std::any const&&>(a)); // expected-note {{requested here}}
(void)std::any_cast<TestType2&&>(static_cast<std::any const&&>(a)); // expected-note {{requested here}}
}
8 changes: 4 additions & 4 deletions libcxx/test/std/utilities/any/any.nonmembers/any.cast/not_copy_constructible.verify.cpp
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Expand Up @@ -45,13 +45,13 @@ struct no_move {
void test() {
std::any a;
// expected-error-re@any:* {{static assertion failed{{.*}}ValueType is required to be an lvalue reference or a CopyConstructible type}}
std::any_cast<no_copy>(static_cast<std::any&>(a)); // expected-note {{requested here}}
(void)std::any_cast<no_copy>(static_cast<std::any&>(a)); // expected-note {{requested here}}

// expected-error-re@any:* {{static assertion failed{{.*}}ValueType is required to be a const lvalue reference or a CopyConstructible type}}
std::any_cast<no_copy>(static_cast<std::any const&>(a)); // expected-note {{requested here}}
(void)std::any_cast<no_copy>(static_cast<std::any const&>(a)); // expected-note {{requested here}}

std::any_cast<no_copy>(static_cast<std::any&&>(a)); // OK
(void)std::any_cast<no_copy>(static_cast<std::any&&>(a)); // OK

// expected-error-re@any:* {{static assertion failed{{.*}}ValueType is required to be an rvalue reference or a CopyConstructible type}}
std::any_cast<no_move>(static_cast<std::any&&>(a));
(void)std::any_cast<no_move>(static_cast<std::any&&>(a));
}
16 changes: 8 additions & 8 deletions libcxx/test/std/utilities/any/any.nonmembers/any.cast/reference_types.verify.cpp
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Expand Up @@ -22,28 +22,28 @@ void test() {
std::any a = 1;

// expected-error-re@any:* 1 {{static assertion failed{{.*}}_ValueType may not be a reference.}}
std::any_cast<int&>(&a); // expected-note {{requested here}}
(void)std::any_cast<int&>(&a); // expected-note {{requested here}}

// expected-error-re@any:* 1 {{static assertion failed{{.*}}_ValueType may not be a reference.}}
std::any_cast<int&&>(&a); // expected-note {{requested here}}
(void)std::any_cast<int&&>(&a); // expected-note {{requested here}}

// expected-error-re@any:* 1 {{static assertion failed{{.*}}_ValueType may not be a reference.}}
std::any_cast<int const&>(&a); // expected-note {{requested here}}
(void)std::any_cast<int const&>(&a); // expected-note {{requested here}}

// expected-error-re@any:* 1 {{static assertion failed{{.*}}_ValueType may not be a reference.}}
std::any_cast<int const&&>(&a); // expected-note {{requested here}}
(void)std::any_cast<int const&&>(&a); // expected-note {{requested here}}

const std::any& a2 = a;

// expected-error-re@any:* 1 {{static assertion failed{{.*}}_ValueType may not be a reference.}}
std::any_cast<int&>(&a2); // expected-note {{requested here}}
(void)std::any_cast<int&>(&a2); // expected-note {{requested here}}

// expected-error-re@any:* 1 {{static assertion failed{{.*}}_ValueType may not be a reference.}}
std::any_cast<int&&>(&a2); // expected-note {{requested here}}
(void)std::any_cast<int&&>(&a2); // expected-note {{requested here}}

// expected-error-re@any:* 1 {{static assertion failed{{.*}}_ValueType may not be a reference.}}
std::any_cast<int const&>(&a2); // expected-note {{requested here}}
(void)std::any_cast<int const&>(&a2); // expected-note {{requested here}}

// expected-error-re@any:* 1 {{static assertion failed{{.*}}_ValueType may not be a reference.}}
std::any_cast<int const&&>(&a2); // expected-note {{requested here}}
(void)std::any_cast<int const&&>(&a2); // expected-note {{requested here}}
}
4 changes: 2 additions & 2 deletions libcxx/test/std/utilities/any/any.nonmembers/any.cast/void.verify.cpp
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Expand Up @@ -23,12 +23,12 @@ void test() {
const std::any ca = 1;

// expected-error-re@any:* {{static assertion failed{{.*}}_ValueType may not be void.}}
std::any_cast<void>(&ca); // expected-note {{requested here}}
(void)std::any_cast<void>(&ca); // expected-note {{requested here}}
}
{
std::any a = 1;

// expected-error-re@any:* {{static assertion failed{{.*}}_ValueType may not be void.}}
std::any_cast<void>(&a); // expected-note {{requested here}}
(void)std::any_cast<void>(&a); // expected-note {{requested here}}
}
}
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