//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++98, c++03, c++11, c++14
// template <class F> unspecified not_fn(F&& f);
#include <functional>
#include <type_traits>
#include <string>
#include <cassert>
#include "test_macros.h"
#include "type_id.h"
///////////////////////////////////////////////////////////////////////////////
// CALLABLE TEST TYPES
///////////////////////////////////////////////////////////////////////////////
bool returns_true() { return true; }
template <class Ret = bool>
struct MoveOnlyCallable {
MoveOnlyCallable(MoveOnlyCallable const&) = delete;
MoveOnlyCallable(MoveOnlyCallable&& other)
: value(other.value)
{ other.value = !other.value; }
template <class ...Args>
Ret operator()(Args&&...) { return Ret{value}; }
explicit MoveOnlyCallable(bool x) : value(x) {}
Ret value;
};
template <class Ret = bool>
struct CopyCallable {
CopyCallable(CopyCallable const& other)
: value(other.value) {}
CopyCallable(CopyCallable&& other)
: value(other.value) { other.value = !other.value; }
template <class ...Args>
Ret operator()(Args&&...) { return Ret{value}; }
explicit CopyCallable(bool x) : value(x) {}
Ret value;
};
template <class Ret = bool>
struct ConstCallable {
ConstCallable(ConstCallable const& other)
: value(other.value) {}
ConstCallable(ConstCallable&& other)
: value(other.value) { other.value = !other.value; }
template <class ...Args>
Ret operator()(Args&&...) const { return Ret{value}; }
explicit ConstCallable(bool x) : value(x) {}
Ret value;
};
template <class Ret = bool>
struct NoExceptCallable {
NoExceptCallable(NoExceptCallable const& other)
: value(other.value) {}
template <class ...Args>
Ret operator()(Args&&...) noexcept { return Ret{value}; }
template <class ...Args>
Ret operator()(Args&&...) const noexcept { return Ret{value}; }
explicit NoExceptCallable(bool x) : value(x) {}
Ret value;
};
struct CopyAssignableWrapper {
CopyAssignableWrapper(CopyAssignableWrapper const&) = default;
CopyAssignableWrapper(CopyAssignableWrapper&&) = default;
CopyAssignableWrapper& operator=(CopyAssignableWrapper const&) = default;
CopyAssignableWrapper& operator=(CopyAssignableWrapper &&) = default;
template <class ...Args>
bool operator()(Args&&...) { return value; }
explicit CopyAssignableWrapper(bool x) : value(x) {}
bool value;
};
struct MoveAssignableWrapper {
MoveAssignableWrapper(MoveAssignableWrapper const&) = delete;
MoveAssignableWrapper(MoveAssignableWrapper&&) = default;
MoveAssignableWrapper& operator=(MoveAssignableWrapper const&) = delete;
MoveAssignableWrapper& operator=(MoveAssignableWrapper &&) = default;
template <class ...Args>
bool operator()(Args&&...) { return value; }
explicit MoveAssignableWrapper(bool x) : value(x) {}
bool value;
};
struct MemFunCallable {
explicit MemFunCallable(bool x) : value(x) {}
bool return_value() const { return value; }
bool return_value_nc() { return value; }
bool value;
};
enum CallType : unsigned {
CT_None,
CT_NonConst = 1,
CT_Const = 2,
CT_LValue = 4,
CT_RValue = 8
};
inline constexpr CallType operator|(CallType LHS, CallType RHS) {
return static_cast<CallType>(static_cast<unsigned>(LHS) | static_cast<unsigned>(RHS));
}
struct ForwardingCallObject {
template <class ...Args>
bool operator()(Args&&...) & {
set_call<Args&&...>(CT_NonConst | CT_LValue);
return true;
}
template <class ...Args>
bool operator()(Args&&...) const & {
set_call<Args&&...>(CT_Const | CT_LValue);
return true;
}
// Don't allow the call operator to be invoked as an rvalue.
template <class ...Args>
bool operator()(Args&&...) && {
set_call<Args&&...>(CT_NonConst | CT_RValue);
return true;
}
template <class ...Args>
bool operator()(Args&&...) const && {
set_call<Args&&...>(CT_Const | CT_RValue);
return true;
}
template <class ...Args>
static void set_call(CallType type) {
assert(last_call_type == CT_None);
assert(last_call_args == nullptr);
last_call_type = type;
last_call_args = &makeArgumentID<Args...>();
}
template <class ...Args>
static bool check_call(CallType type) {
bool result =
last_call_type == type
&& last_call_args
&& *last_call_args == makeArgumentID<Args...>();
last_call_type = CT_None;
last_call_args = nullptr;
return result;
}
static CallType last_call_type;
static TypeID const* last_call_args;
};
CallType ForwardingCallObject::last_call_type = CT_None;
TypeID const* ForwardingCallObject::last_call_args = nullptr;
///////////////////////////////////////////////////////////////////////////////
// BOOL TEST TYPES
///////////////////////////////////////////////////////////////////////////////
struct EvilBool {
static int bang_called;
EvilBool(EvilBool const&) = default;
EvilBool(EvilBool&&) = default;
friend EvilBool operator!(EvilBool const& other) {
++bang_called;
return EvilBool{!other.value};
}
private:
friend struct MoveOnlyCallable<EvilBool>;
friend struct CopyCallable<EvilBool>;
friend struct NoExceptCallable<EvilBool>;
explicit EvilBool(bool x) : value(x) {}
EvilBool& operator=(EvilBool const& other) = default;
public:
bool value;
};
int EvilBool::bang_called = 0;
struct ExplicitBool {
ExplicitBool(ExplicitBool const&) = default;
ExplicitBool(ExplicitBool&&) = default;
explicit operator bool() const { return value; }
private:
friend struct MoveOnlyCallable<ExplicitBool>;
friend struct CopyCallable<ExplicitBool>;
explicit ExplicitBool(bool x) : value(x) {}
ExplicitBool& operator=(bool x) {
value = x;
return *this;
}
bool value;
};
struct NoExceptEvilBool {
NoExceptEvilBool(NoExceptEvilBool const&) = default;
NoExceptEvilBool(NoExceptEvilBool&&) = default;
NoExceptEvilBool& operator=(NoExceptEvilBool const& other) = default;
explicit NoExceptEvilBool(bool x) : value(x) {}
friend NoExceptEvilBool operator!(NoExceptEvilBool const& other) noexcept {
return NoExceptEvilBool{!other.value};
}
bool value;
};
void constructor_tests()
{
{
using T = MoveOnlyCallable<bool>;
T value(true);
using RetT = decltype(std::not_fn(std::move(value)));
static_assert(std::is_move_constructible<RetT>::value, "");
static_assert(!std::is_copy_constructible<RetT>::value, "");
static_assert(!std::is_move_assignable<RetT>::value, "");
static_assert(!std::is_copy_assignable<RetT>::value, "");
auto ret = std::not_fn(std::move(value));
// test it was moved from
assert(value.value == false);
// test that ret() negates the original value 'true'
assert(ret() == false);
assert(ret(0, 0.0, "blah") == false);
// Move ret and test that it was moved from and that ret2 got the
// original value.
auto ret2 = std::move(ret);
assert(ret() == true);
assert(ret2() == false);
assert(ret2(42) == false);
}
{
using T = CopyCallable<bool>;
T value(false);
using RetT = decltype(std::not_fn(value));
static_assert(std::is_move_constructible<RetT>::value, "");
static_assert(std::is_copy_constructible<RetT>::value, "");
static_assert(!std::is_move_assignable<RetT>::value, "");
static_assert(!std::is_copy_assignable<RetT>::value, "");
auto ret = std::not_fn(value);
// test that value is unchanged (copied not moved)
assert(value.value == false);
// test 'ret' has the original value
assert(ret() == true);
assert(ret(42, 100) == true);
// move from 'ret' and check that 'ret2' has the original value.
auto ret2 = std::move(ret);
assert(ret() == false);
assert(ret2() == true);
assert(ret2("abc") == true);
}
{
using T = CopyAssignableWrapper;
T value(true);
T value2(false);
using RetT = decltype(std::not_fn(value));
static_assert(std::is_move_constructible<RetT>::value, "");
static_assert(std::is_copy_constructible<RetT>::value, "");
LIBCPP_STATIC_ASSERT(std::is_move_assignable<RetT>::value, "");
LIBCPP_STATIC_ASSERT(std::is_copy_assignable<RetT>::value, "");
auto ret = std::not_fn(value);
assert(ret() == false);
auto ret2 = std::not_fn(value2);
assert(ret2() == true);
#if defined(_LIBCPP_VERSION)
ret = ret2;
assert(ret() == true);
assert(ret2() == true);
#endif // _LIBCPP_VERSION
}
{
using T = MoveAssignableWrapper;
T value(true);
T value2(false);
using RetT = decltype(std::not_fn(std::move(value)));
static_assert(std::is_move_constructible<RetT>::value, "");
static_assert(!std::is_copy_constructible<RetT>::value, "");
LIBCPP_STATIC_ASSERT(std::is_move_assignable<RetT>::value, "");
static_assert(!std::is_copy_assignable<RetT>::value, "");
auto ret = std::not_fn(std::move(value));
assert(ret() == false);
auto ret2 = std::not_fn(std::move(value2));
assert(ret2() == true);
#if defined(_LIBCPP_VERSION)
ret = std::move(ret2);
assert(ret() == true);
#endif // _LIBCPP_VERSION
}
}
void return_type_tests()
{
using std::is_same;
{
using T = CopyCallable<bool>;
auto ret = std::not_fn(T{false});
static_assert(is_same<decltype(ret()), bool>::value, "");
static_assert(is_same<decltype(ret("abc")), bool>::value, "");
assert(ret() == true);
}
{
using T = CopyCallable<ExplicitBool>;
auto ret = std::not_fn(T{true});
static_assert(is_same<decltype(ret()), bool>::value, "");
static_assert(is_same<decltype(ret(std::string("abc"))), bool>::value, "");
assert(ret() == false);
}
{
using T = CopyCallable<EvilBool>;
auto ret = std::not_fn(T{false});
static_assert(is_same<decltype(ret()), EvilBool>::value, "");
EvilBool::bang_called = 0;
auto value_ret = ret();
assert(EvilBool::bang_called == 1);
assert(value_ret.value == true);
ret();
assert(EvilBool::bang_called == 2);
}
}
// Other tests only test using objects with call operators. Test various
// other callable types here.
void other_callable_types_test()
{
{ // test with function pointer
auto ret = std::not_fn(returns_true);
assert(ret() == false);
}
{ // test with lambda
auto returns_value = [](bool value) { return value; };
auto ret = std::not_fn(returns_value);
assert(ret(true) == false);
assert(ret(false) == true);
}
{ // test with pointer to member function
MemFunCallable mt(true);
const MemFunCallable mf(false);
auto ret = std::not_fn(&MemFunCallable::return_value);
assert(ret(mt) == false);
assert(ret(mf) == true);
assert(ret(&mt) == false);
assert(ret(&mf) == true);
}
{ // test with pointer to member function
MemFunCallable mt(true);
MemFunCallable mf(false);
auto ret = std::not_fn(&MemFunCallable::return_value_nc);
assert(ret(mt) == false);
assert(ret(mf) == true);
assert(ret(&mt) == false);
assert(ret(&mf) == true);
}
{ // test with pointer to member data
MemFunCallable mt(true);
const MemFunCallable mf(false);
auto ret = std::not_fn(&MemFunCallable::value);
assert(ret(mt) == false);
assert(ret(mf) == true);
assert(ret(&mt) == false);
assert(ret(&mf) == true);
}
}
void throws_in_constructor_test()
{
#ifndef TEST_HAS_NO_EXCEPTIONS
struct ThrowsOnCopy {
ThrowsOnCopy(ThrowsOnCopy const&) {
throw 42;
}
ThrowsOnCopy() = default;
bool operator()() const {
assert(false);
#if defined(TEST_COMPILER_C1XX)
__assume(0);
#else
__builtin_unreachable();
#endif
}
};
{
ThrowsOnCopy cp;
try {
(void)std::not_fn(cp);
assert(false);
} catch (int const& value) {
assert(value == 42);
}
}
#endif
}
void call_operator_sfinae_test() {
{ // wrong number of arguments
using T = decltype(std::not_fn(returns_true));
static_assert(std::is_invocable<T>::value, ""); // callable only with no args
static_assert(!std::is_invocable<T, bool>::value, "");
}
{ // violates const correctness (member function pointer)
using T = decltype(std::not_fn(&MemFunCallable::return_value_nc));
static_assert(std::is_invocable<T, MemFunCallable&>::value, "");
static_assert(!std::is_invocable<T, const MemFunCallable&>::value, "");
}
{ // violates const correctness (call object)
using Obj = CopyCallable<bool>;
using NCT = decltype(std::not_fn(Obj{true}));
using CT = const NCT;
static_assert(std::is_invocable<NCT>::value, "");
static_assert(!std::is_invocable<CT>::value, "");
}
{ // returns bad type with no operator!
auto fn = [](auto x) { return x; };
using T = decltype(std::not_fn(fn));
static_assert(std::is_invocable<T, bool>::value, "");
static_assert(!std::is_invocable<T, std::string>::value, "");
}
}
void call_operator_forwarding_test()
{
using Fn = ForwardingCallObject;
auto obj = std::not_fn(Fn{});
const auto& c_obj = obj;
{ // test zero args
obj();
assert(Fn::check_call<>(CT_NonConst | CT_LValue));
std::move(obj)();
assert(Fn::check_call<>(CT_NonConst | CT_RValue));
c_obj();
assert(Fn::check_call<>(CT_Const | CT_LValue));
std::move(c_obj)();
assert(Fn::check_call<>(CT_Const | CT_RValue));
}
{ // test value categories
int x = 42;
const int cx = 42;
obj(x);
assert(Fn::check_call<int&>(CT_NonConst | CT_LValue));
obj(cx);
assert(Fn::check_call<const int&>(CT_NonConst | CT_LValue));
obj(std::move(x));
assert(Fn::check_call<int&&>(CT_NonConst | CT_LValue));
obj(std::move(cx));
assert(Fn::check_call<const int&&>(CT_NonConst | CT_LValue));
obj(42);
assert(Fn::check_call<int&&>(CT_NonConst | CT_LValue));
}
{ // test value categories - rvalue
int x = 42;
const int cx = 42;
std::move(obj)(x);
assert(Fn::check_call<int&>(CT_NonConst | CT_RValue));
std::move(obj)(cx);
assert(Fn::check_call<const int&>(CT_NonConst | CT_RValue));
std::move(obj)(std::move(x));
assert(Fn::check_call<int&&>(CT_NonConst | CT_RValue));
std::move(obj)(std::move(cx));
assert(Fn::check_call<const int&&>(CT_NonConst | CT_RValue));
std::move(obj)(42);
assert(Fn::check_call<int&&>(CT_NonConst | CT_RValue));
}
{ // test value categories - const call
int x = 42;
const int cx = 42;
c_obj(x);
assert(Fn::check_call<int&>(CT_Const | CT_LValue));
c_obj(cx);
assert(Fn::check_call<const int&>(CT_Const | CT_LValue));
c_obj(std::move(x));
assert(Fn::check_call<int&&>(CT_Const | CT_LValue));
c_obj(std::move(cx));
assert(Fn::check_call<const int&&>(CT_Const | CT_LValue));
c_obj(42);
assert(Fn::check_call<int&&>(CT_Const | CT_LValue));
}
{ // test value categories - const call rvalue
int x = 42;
const int cx = 42;
std::move(c_obj)(x);
assert(Fn::check_call<int&>(CT_Const | CT_RValue));
std::move(c_obj)(cx);
assert(Fn::check_call<const int&>(CT_Const | CT_RValue));
std::move(c_obj)(std::move(x));
assert(Fn::check_call<int&&>(CT_Const | CT_RValue));
std::move(c_obj)(std::move(cx));
assert(Fn::check_call<const int&&>(CT_Const | CT_RValue));
std::move(c_obj)(42);
assert(Fn::check_call<int&&>(CT_Const | CT_RValue));
}
{ // test multi arg
const double y = 3.14;
std::string s = "abc";
obj(42, std::move(y), s, std::string{"foo"});
Fn::check_call<int&&, const double&&, std::string&, std::string&&>(CT_NonConst | CT_LValue);
std::move(obj)(42, std::move(y), s, std::string{"foo"});
Fn::check_call<int&&, const double&&, std::string&, std::string&&>(CT_NonConst | CT_RValue);
c_obj(42, std::move(y), s, std::string{"foo"});
Fn::check_call<int&&, const double&&, std::string&, std::string&&>(CT_Const | CT_LValue);
std::move(c_obj)(42, std::move(y), s, std::string{"foo"});
Fn::check_call<int&&, const double&&, std::string&, std::string&&>(CT_Const | CT_RValue);
}
}
void call_operator_noexcept_test()
{
{
using T = ConstCallable<bool>;
T value(true);
auto ret = std::not_fn(value);
static_assert(!noexcept(ret()), "call should not be noexcept");
auto const& cret = ret;
static_assert(!noexcept(cret()), "call should not be noexcept");
}
{
using T = NoExceptCallable<bool>;
T value(true);
auto ret = std::not_fn(value);
LIBCPP_STATIC_ASSERT(noexcept(!_VSTD::__invoke(value)), "");
#if TEST_STD_VER > 14
static_assert(noexcept(!std::invoke(value)), "");
#endif
static_assert(noexcept(ret()), "call should be noexcept");
auto const& cret = ret;
static_assert(noexcept(cret()), "call should be noexcept");
}
{
using T = NoExceptCallable<NoExceptEvilBool>;
T value(true);
auto ret = std::not_fn(value);
static_assert(noexcept(ret()), "call should not be noexcept");
auto const& cret = ret;
static_assert(noexcept(cret()), "call should not be noexcept");
}
{
using T = NoExceptCallable<EvilBool>;
T value(true);
auto ret = std::not_fn(value);
static_assert(!noexcept(ret()), "call should not be noexcept");
auto const& cret = ret;
static_assert(!noexcept(cret()), "call should not be noexcept");
}
}
void test_lwg2767() {
// See https://cplusplus.github.io/LWG/lwg-defects.html#2767
struct Abstract { virtual void f() const = 0; };
struct Derived : public Abstract { void f() const {} };
struct F { bool operator()(Abstract&&) { return false; } };
{
Derived d;
Abstract &a = d;
bool b = std::not_fn(F{})(std::move(a));
assert(b);
}
}
int main()
{
constructor_tests();
return_type_tests();
other_callable_types_test();
throws_in_constructor_test();
call_operator_sfinae_test(); // somewhat of an extension
call_operator_forwarding_test();
call_operator_noexcept_test();
test_lwg2767();
}