llvm-project/clang/test/SemaCXX/lambda-expressions.cpp

633 lines
18 KiB
C++

// RUN: %clang_cc1 -std=c++14 -Wno-unused-value -fsyntax-only -verify -fblocks %s
namespace std { class type_info; };
namespace ExplicitCapture {
class C {
int Member;
static void Overload(int);
void Overload();
virtual C& Overload(float);
void ImplicitThisCapture() {
[](){(void)Member;}; // expected-error {{'this' cannot be implicitly captured in this context}}
[&](){(void)Member;};
[this](){(void)Member;};
[this]{[this]{};};
[]{[this]{};};// expected-error {{'this' cannot be implicitly captured in this context}}
[]{Overload(3);};
[]{Overload();}; // expected-error {{'this' cannot be implicitly captured in this context}}
[]{(void)typeid(Overload());};
[]{(void)typeid(Overload(.5f));};// expected-error {{'this' cannot be implicitly captured in this context}}
}
};
void f() {
[this] () {}; // expected-error {{'this' cannot be captured in this context}}
}
}
namespace ReturnDeduction {
void test() {
[](){ return 1; };
[](){ return 1; };
[](){ return ({return 1; 1;}); };
[](){ return ({return 'c'; 1;}); }; // expected-error {{must match previous return type}}
[]()->int{ return 'c'; return 1; };
[](){ return 'c'; return 1; }; // expected-error {{must match previous return type}}
[]() { return; return (void)0; };
[](){ return 1; return 1; };
}
}
namespace ImplicitCapture {
void test() {
int a = 0; // expected-note 5 {{declared}}
[]() { return a; }; // expected-error {{variable 'a' cannot be implicitly captured in a lambda with no capture-default specified}} expected-note {{begins here}}
[&]() { return a; };
[=]() { return a; };
[=]() { int* b = &a; }; // expected-error {{cannot initialize a variable of type 'int *' with an rvalue of type 'const int *'}}
[=]() { return [&]() { return a; }; };
[]() { return [&]() { return a; }; }; // expected-error {{variable 'a' cannot be implicitly captured in a lambda with no capture-default specified}} expected-note {{lambda expression begins here}}
[]() { return ^{ return a; }; };// expected-error {{variable 'a' cannot be implicitly captured in a lambda with no capture-default specified}} expected-note {{lambda expression begins here}}
[]() { return [&a] { return a; }; }; // expected-error 2 {{variable 'a' cannot be implicitly captured in a lambda with no capture-default specified}} expected-note 2 {{lambda expression begins here}}
[=]() { return [&a] { return a; }; }; //
const int b = 2;
[]() { return b; };
union { // expected-note {{declared}}
int c;
float d;
};
d = 3;
[=]() { return c; }; // expected-error {{unnamed variable cannot be implicitly captured in a lambda expression}}
__block int e; // expected-note 2{{declared}}
[&]() { return e; }; // expected-error {{__block variable 'e' cannot be captured in a lambda expression}}
[&e]() { return e; }; // expected-error {{__block variable 'e' cannot be captured in a lambda expression}}
int f[10]; // expected-note {{declared}}
[&]() { return f[2]; };
(void) ^{ return []() { return f[2]; }; }; // expected-error {{variable 'f' cannot be implicitly captured in a lambda with no capture-default specified}} \
// expected-note{{lambda expression begins here}}
struct G { G(); G(G&); int a; }; // expected-note 6 {{not viable}}
G g;
[=]() { const G* gg = &g; return gg->a; };
[=]() { return [=]{ const G* gg = &g; return gg->a; }(); }; // expected-error {{no matching constructor for initialization of 'G'}}
(void)^{ return [=]{ const G* gg = &g; return gg->a; }(); }; // expected-error 2 {{no matching constructor for initialization of 'const G'}}
const int h = a; // expected-note {{declared}}
[]() { return h; }; // expected-error {{variable 'h' cannot be implicitly captured in a lambda with no capture-default specified}} expected-note {{lambda expression begins here}}
// References can appear in constant expressions if they are initialized by
// reference constant expressions.
int i;
int &ref_i = i; // expected-note {{declared}}
[] { return ref_i; }; // expected-error {{variable 'ref_i' cannot be implicitly captured in a lambda with no capture-default specified}} expected-note {{lambda expression begins here}}
static int j;
int &ref_j = j;
[] { return ref_j; }; // ok
}
}
namespace SpecialMembers {
void f() {
auto a = []{}; // expected-note 2{{here}} expected-note 2{{candidate}}
decltype(a) b; // expected-error {{no matching constructor}}
decltype(a) c = a;
decltype(a) d = static_cast<decltype(a)&&>(a);
a = a; // expected-error {{copy assignment operator is implicitly deleted}}
a = static_cast<decltype(a)&&>(a); // expected-error {{copy assignment operator is implicitly deleted}}
}
struct P {
P(const P&) = delete; // expected-note 2{{deleted here}}
};
struct Q {
~Q() = delete; // expected-note {{deleted here}}
};
struct R {
R(const R&) = default;
R(R&&) = delete;
R &operator=(const R&) = delete;
R &operator=(R&&) = delete;
};
void g(P &p, Q &q, R &r) {
// FIXME: The note attached to the second error here is just amazingly bad.
auto pp = [p]{}; // expected-error {{deleted constructor}} expected-error {{deleted copy constructor of '(lambda}}
// expected-note@-1 {{copy constructor of '' is implicitly deleted because field '' has a deleted copy constructor}}
auto qq = [q]{}; // expected-error {{deleted function}} expected-note {{because}}
auto a = [r]{}; // expected-note 2{{here}}
decltype(a) b = a;
decltype(a) c = static_cast<decltype(a)&&>(a); // ok, copies R
a = a; // expected-error {{copy assignment operator is implicitly deleted}}
a = static_cast<decltype(a)&&>(a); // expected-error {{copy assignment operator is implicitly deleted}}
}
}
namespace PR12031 {
struct X {
template<typename T>
X(const T&);
~X();
};
void f(int i, X x);
void g() {
const int v = 10;
f(v, [](){});
}
}
namespace Array {
int &f(int *p);
char &f(...);
void g() {
int n = -1;
[=] {
int arr[n]; // VLA
} ();
const int m = -1;
[] {
int arr[m]; // expected-error{{negative size}}
} ();
[&] {
int arr[m]; // expected-error{{negative size}}
} ();
[=] {
int arr[m]; // expected-error{{negative size}}
} ();
[m] {
int arr[m]; // expected-error{{negative size}}
} ();
}
}
void PR12248()
{
unsigned int result = 0;
auto l = [&]() { ++result; };
}
namespace ModifyingCapture {
void test() {
int n = 0;
[=] {
n = 1; // expected-error {{cannot assign to a variable captured by copy in a non-mutable lambda}}
};
}
}
namespace VariadicPackExpansion {
template<typename T, typename U> using Fst = T;
template<typename...Ts> bool g(Fst<bool, Ts> ...bools);
template<typename...Ts> bool f(Ts &&...ts) {
return g<Ts...>([&ts] {
if (!ts)
return false;
--ts;
return true;
} () ...);
}
void h() {
int a = 5, b = 2, c = 3;
while (f(a, b, c)) {
}
}
struct sink {
template<typename...Ts> sink(Ts &&...) {}
};
template<typename...Ts> void local_class() {
sink {
[] (Ts t) {
struct S : Ts {
void f(Ts t) {
Ts &that = *this;
that = t;
}
Ts g() { return *this; };
};
S s;
s.f(t);
return s;
} (Ts()).g() ...
};
};
struct X {}; struct Y {};
template void local_class<X, Y>();
template<typename...Ts> void nested(Ts ...ts) {
f(
// Each expansion of this lambda implicitly captures all of 'ts', because
// the inner lambda also expands 'ts'.
[&] {
return ts + [&] { return f(ts...); } ();
} () ...
);
}
template void nested(int, int, int);
template<typename...Ts> void nested2(Ts ...ts) { // expected-note 2{{here}}
// Capture all 'ts', use only one.
f([&ts...] { return ts; } ()...);
// Capture each 'ts', use it.
f([&ts] { return ts; } ()...);
// Capture all 'ts', use all of them.
f([&ts...] { return (int)f(ts...); } ());
// Capture each 'ts', use all of them. Ill-formed. In more detail:
//
// We instantiate two lambdas here; the first captures ts$0, the second
// captures ts$1. Both of them reference both ts parameters, so both are
// ill-formed because ts can't be implicitly captured.
//
// FIXME: This diagnostic does not explain what's happening. We should
// specify which 'ts' we're referring to in its diagnostic name. We should
// also say which slice of the pack expansion is being performed in the
// instantiation backtrace.
f([&ts] { return (int)f(ts...); } ()...); // \
// expected-error 2{{'ts' cannot be implicitly captured}} \
// expected-note 2{{lambda expression begins here}}
}
template void nested2(int); // ok
template void nested2(int, int); // expected-note {{in instantiation of}}
}
namespace PR13860 {
void foo() {
auto x = PR13860UndeclaredIdentifier(); // expected-error {{use of undeclared identifier 'PR13860UndeclaredIdentifier'}}
auto y = [x]() { };
static_assert(sizeof(y), "");
}
}
namespace PR13854 {
auto l = [](void){};
}
namespace PR14518 {
auto f = [](void) { return __func__; }; // no-warning
}
namespace PR16708 {
auto L = []() {
auto ret = 0;
return ret;
return 0;
};
}
namespace TypeDeduction {
struct S {};
void f() {
const S s {};
S &&t = [&] { return s; } ();
#if __cplusplus > 201103L
S &&u = [&] () -> auto { return s; } ();
#endif
}
}
namespace lambdas_in_NSDMIs {
template<class T>
struct L {
T t{};
T t2 = ([](int a) { return [](int b) { return b; };})(t)(t);
};
L<int> l;
namespace non_template {
struct L {
int t = 0;
int t2 = ([](int a) { return [](int b) { return b; };})(t)(t);
};
L l;
}
}
// PR18477: don't try to capture 'this' from an NSDMI encountered while parsing
// a lambda.
namespace NSDMIs_in_lambdas {
template<typename T> struct S { int a = 0; int b = a; };
void f() { []() { S<int> s; }; }
auto x = []{ struct S { int n, m = n; }; };
auto y = [&]{ struct S { int n, m = n; }; }; // expected-error {{non-local lambda expression cannot have a capture-default}}
void g() { auto z = [&]{ struct S { int n, m = n; }; }; }
}
namespace CaptureIncomplete {
struct Incomplete; // expected-note 2{{forward decl}}
void g(const Incomplete &a);
void f(Incomplete &a) {
(void) [a] {}; // expected-error {{incomplete}}
(void) [&a] {};
(void) [=] { g(a); }; // expected-error {{incomplete}}
(void) [&] { f(a); };
}
}
namespace CaptureAbstract {
struct S {
virtual void f() = 0; // expected-note {{unimplemented}}
int n = 0;
};
struct T : S {
constexpr T() {}
void f();
};
void f() {
constexpr T t = T();
S &s = const_cast<T&>(t);
// FIXME: Once we properly compute odr-use per DR712, this should be
// accepted (and should not capture 's').
[=] { return s.n; }; // expected-error {{abstract}}
}
}
namespace PR18128 {
auto l = [=]{}; // expected-error {{non-local lambda expression cannot have a capture-default}}
struct S {
int n;
int (*f())[true ? 1 : ([=]{ return n; }(), 0)];
// expected-error@-1 {{non-local lambda expression cannot have a capture-default}}
// expected-error@-2 {{invalid use of non-static data member 'n'}}
// expected-error@-3 {{a lambda expression may not appear inside of a constant expression}}
int g(int k = ([=]{ return n; }(), 0));
// expected-error@-1 {{non-local lambda expression cannot have a capture-default}}
// expected-error@-2 {{invalid use of non-static data member 'n'}}
int a = [=]{ return n; }(); // ok
int b = [=]{ return [=]{ return n; }(); }(); // ok
int c = []{ int k = 0; return [=]{ return k; }(); }(); // ok
int d = []{ return [=]{ return n; }(); }(); // expected-error {{'this' cannot be implicitly captured in this context}}
};
}
namespace PR18473 {
template<typename T> void f() {
T t(0);
(void) [=]{ int n = t; }; // expected-error {{deleted}}
}
template void f<int>();
struct NoCopy {
NoCopy(int);
NoCopy(const NoCopy &) = delete; // expected-note {{deleted}}
operator int() const;
};
template void f<NoCopy>(); // expected-note {{instantiation}}
}
void PR19249() {
auto x = [&x]{}; // expected-error {{cannot appear in its own init}}
}
namespace PR20731 {
template <class L, int X = sizeof(L)>
void Job(L l);
template <typename... Args>
void Logger(Args &&... args) {
auto len = Invalid_Function((args)...);
// expected-error@-1 {{use of undeclared identifier 'Invalid_Function'}}
Job([len]() {});
}
void GetMethod() {
Logger();
// expected-note@-1 {{in instantiation of function template specialization 'PR20731::Logger<>' requested here}}
}
template <typename T>
struct A {
T t;
// expected-error@-1 {{field has incomplete type 'void'}}
};
template <typename F>
void g(F f) {
auto a = A<decltype(f())>{};
// expected-note@-1 {{in instantiation of template class 'PR20731::A<void>' requested here}}
auto xf = [a, f]() {};
int x = sizeof(xf);
};
void f() {
g([] {});
// expected-note-re@-1 {{in instantiation of function template specialization 'PR20731::g<(lambda at {{.*}}>' requested here}}
}
template <class _Rp> struct function {
template <class _Fp>
function(_Fp) {
static_assert(sizeof(_Fp) > 0, "Type must be complete.");
}
};
template <typename T> void p(T t) {
auto l = some_undefined_function(t);
// expected-error@-1 {{use of undeclared identifier 'some_undefined_function'}}
function<void()>(([l]() {}));
}
void q() { p(0); }
// expected-note@-1 {{in instantiation of function template specialization 'PR20731::p<int>' requested here}}
}
namespace lambda_in_default_mem_init {
template<typename T> void f() {
struct S { int n = []{ return 0; }(); };
}
template void f<int>();
template<typename T> void g() {
struct S { int n = [](int n){ return n; }(0); };
}
template void g<int>();
}
namespace error_in_transform_prototype {
template<class T>
void f(T t) {
// expected-error@+2 {{type 'int' cannot be used prior to '::' because it has no members}}
// expected-error@+1 {{no member named 'ns' in 'error_in_transform_prototype::S'}}
auto x = [](typename T::ns::type &k) {};
}
class S {};
void foo() {
f(5); // expected-note {{requested here}}
f(S()); // expected-note {{requested here}}
}
}
namespace PR21857 {
template<typename Fn> struct fun : Fn {
fun() = default;
using Fn::operator();
};
template<typename Fn> fun<Fn> wrap(Fn fn);
auto x = wrap([](){});
}
namespace PR13987 {
class Enclosing {
void Method(char c = []()->char {
int d = []()->int {
struct LocalClass {
int Method() { return 0; }
};
return 0;
}();
return d; }()
);
};
}
namespace PR23860 {
template <class> struct A {
void f(int x = []() {
struct B {
void g() {}
};
return 0;
}());
};
int main() {
}
A<int> a;
}
// rdar://22032373
namespace rdar22032373 {
void foo() {
auto blk = [](bool b) {
if (b)
return undeclared_error; // expected-error {{use of undeclared identifier}}
return 0;
};
}
}
namespace nested_lambda {
template <int N>
class S {};
void foo() {
const int num = 18;
auto outer = []() {
auto inner = [](S<num> &X) {};
};
}
}
namespace PR27994 {
struct A { template <class T> A(T); };
template <class T>
struct B {
int x;
A a = [&] { int y = x; };
A b = [&] { [&] { [&] { int y = x; }; }; };
A d = [&](auto param) { int y = x; };
A e = [&](auto param) { [&] { [&](auto param2) { int y = x; }; }; };
};
B<int> b;
template <class T> struct C {
struct D {
int x;
A f = [&] { int y = x; };
};
};
int func() {
C<int> a;
decltype(a)::D b;
}
}
namespace PR30566 {
int name1; // expected-note {{'name1' declared here}}
struct S1 {
template<class T>
S1(T t) { s = sizeof(t); }
int s;
};
void foo1() {
auto s0 = S1{[name=]() {}}; // expected-error 2 {{expected expression}}
auto s1 = S1{[name=name]() {}}; // expected-error {{use of undeclared identifier 'name'; did you mean 'name1'?}}
}
}
namespace PR25627_dont_odr_use_local_consts {
template<int> struct X {};
void foo() {
const int N = 10;
(void) [] { X<N> x; };
}
}
namespace ConversionOperatorDoesNotHaveDeducedReturnType {
auto x = [](int){};
auto y = [](auto &v) -> void { v.n = 0; };
using T = decltype(x);
using U = decltype(y);
using ExpectedTypeT = void (*)(int);
template<typename T>
using ExpectedTypeU = void (*)(T&);
struct X {
friend auto T::operator()(int) const;
friend T::operator ExpectedTypeT() const;
// FIXME: The first of these should match. The second should not.
template<typename T>
friend void U::operator()(T&) const; // expected-error {{does not match}}
template<typename T>
friend U::operator ExpectedTypeU<T>() const; // expected-error {{does not match}}
private:
int n;
};
// Should be OK: lambda's call operator is a friend.
void use(X &x) { y(x); }
// This used to crash in return type deduction for the conversion opreator.
struct A { int n; void f() { +[](decltype(n)) {}; } };
}
namespace TypoCorrection {
template <typename T> struct X {};
// expected-note@-1 {{template parameter is declared here}}
template <typename T>
void Run(const int& points) {
// expected-note@-1 {{'points' declared here}}
auto outer_lambda = []() {
auto inner_lambda = [](const X<Points>&) {};
// expected-error@-1 {{use of undeclared identifier 'Points'; did you mean 'points'?}}
// expected-error@-2 {{template argument for template type parameter must be a type}}
};
}
}