// RUN: %clang_cc1 -std=c++20 %s -Wno-c++23-extensions -verify
// RUN: %clang_cc1 -std=c++23 %s -verify
template <auto> struct Nothing {};
Nothing<[]() { return 0; }()> nothing;
template <typename> struct NothingT {};
Nothing<[]() { return 0; }> nothingT;
template <typename T>
concept True = [] { return true; }();
static_assert(True<int>);
static_assert(sizeof([] { return 0; }));
static_assert(sizeof([] { return 0; }()));
void f() noexcept(noexcept([] { return 0; }()));
using a = decltype([] { return 0; });
using b = decltype([] { return 0; }());
using c = decltype([]() noexcept(noexcept([] { return 0; }())) { return 0; });
using d = decltype(sizeof([] { return 0; }));
template <auto T>
int unique_test1();
static_assert(&unique_test1<[](){}> != &unique_test1<[](){}>);
template <class T>
auto g(T) -> decltype([]() { T::invalid; } ());
auto e = g(0); // expected-error@-1{{type 'int' cannot be used prior to '::'}}
// expected-note@-1{{while substituting deduced template}}
// expected-note@-3{{while substituting into a lambda}}
// expected-error@-3 {{no matching function for call to 'g'}}
// expected-note@-5 {{substitution failure}}
template <typename T>
auto foo(decltype([] {
return [] { return T(); }();
})) {}
void test() {
foo<int>({});
}
template <typename T>
struct C {
template <typename U>
auto foo(decltype([] {
return [] { return T(); }();
})) {}
};
void test2() {
C<int>{}.foo<long>({});
}
namespace PR52073 {
// OK, these are distinct functions not redefinitions.
template<typename> void f(decltype([]{})) {} // expected-note {{candidate}}
template<typename> void f(decltype([]{})) {} // expected-note {{candidate}}
void use_f() { f<int>({}); } // expected-error {{ambiguous}}
// Same.
template<int N> void g(const char (*)[([]{ return N; })()]) {} // expected-note {{candidate}}
template<int N> void g(const char (*)[([]{ return N; })()]) {} // expected-note {{candidate}}
void use_g() { g<6>(&"hello"); } // expected-error {{ambiguous}}
}
namespace GH51416 {
template <class T>
struct A { // #defined-here-A
void spam(decltype([] {}));
};
template <class T>
void A<T>::spam(decltype([] {})) // expected-error{{out-of-line definition of 'spam' does not match}}
// expected-note@#defined-here-A{{defined here}}
{}
struct B { // #defined-here-B
template <class T>
void spam(decltype([] {}));
};
template <class T>
void B::spam(decltype([] {})) {} // expected-error{{out-of-line definition of 'spam' does not match}}
// expected-note@#defined-here-B{{defined here}}
} // namespace GH51416
namespace GH50376 {
template <typename T, typename Fn>
struct foo_t { // expected-note 2{{candidate constructor}}
foo_t(T ptr) {} // expected-note{{candidate constructor}}
};
template <typename T>
using alias = foo_t<T, decltype([](int) { return 0; })>;
template <typename T>
auto fun(T const &t) -> alias<T> {
return alias<T>{t}; // expected-error{{no viable conversion from returned value of type 'alias<...>'}}
}
void f() {
int i;
auto const error = fun(i); // expected-note{{in instantiation}}
}
} // namespace GH50376
namespace GH51414 {
template <class T> void spam(decltype([] {}) (*s)[sizeof(T)] = nullptr) {}
void foo() {
spam<int>();
}
} // namespace GH51414
namespace GH51641 {
template <class T>
void foo(decltype(+[](T) {}) lambda, T param);
static_assert(!__is_same(decltype(foo<int>), void));
} // namespace GH51641
namespace StaticLambdas {
template <auto> struct Nothing {};
Nothing<[]() static { return 0; }()> nothing;
template <typename> struct NothingT {};
Nothing<[]() static { return 0; }> nothingT;
template <typename T>
concept True = [] static { return true; }();
static_assert(True<int>);
static_assert(sizeof([] static { return 0; }));
static_assert(sizeof([] static { return 0; }()));
void f() noexcept(noexcept([] static { return 0; }()));
using a = decltype([] static { return 0; });
using b = decltype([] static { return 0; }());
using c = decltype([]() static noexcept(noexcept([] { return 0; }())) { return 0; });
using d = decltype(sizeof([] static { return 0; }));
}
namespace lambda_in_trailing_decltype {
auto x = ([](auto) -> decltype([] {}()) {}(0), 2);
}
namespace lambda_in_constraints {
struct WithFoo { static void foo(); };
template <class T>
concept lambda_works = requires {
[]() { T::foo(); }; // expected-error{{type 'int' cannot be used prior to '::'}}
// expected-note@-1{{while substituting into a lambda expression here}}
// expected-note@-2{{in instantiation of requirement here}}
// expected-note@-4{{while substituting template arguments into constraint expression here}}
};
static_assert(!lambda_works<int>); // expected-note {{while checking the satisfaction of concept 'lambda_works<int>' requested here}}
static_assert(lambda_works<WithFoo>);
template <class T>
int* func(T) requires requires { []() { T::foo(); }; }; // expected-error{{type 'int' cannot be used prior to '::'}}
// expected-note@-1{{while substituting into a lambda expression here}}
// expected-note@-2{{in instantiation of requirement here}}
// expected-note@-3{{while substituting template arguments into constraint expression here}}
double* func(...);
static_assert(__is_same(decltype(func(0)), double*)); // expected-note {{while checking constraint satisfaction for template 'func<int>' required here}}
// expected-note@-1 {{in instantiation of function template specialization 'lambda_in_constraints::func<int>'}}
static_assert(__is_same(decltype(func(WithFoo())), int*));
template <class T>
auto direct_lambda(T) -> decltype([] { T::foo(); }) {}
void direct_lambda(...) {}
void recursive() {
direct_lambda(0); // expected-error@-4 {{type 'int' cannot be used prior to '::'}}
// expected-note@-1 {{while substituting deduced template arguments}}
// expected-note@-6 {{while substituting into a lambda}}
bool x = requires { direct_lambda(0); }; // expected-error@-7 {{type 'int' cannot be used prior to '::'}}
// expected-note@-1 {{while substituting deduced template arguments}}
// expected-note@-9 {{while substituting into a lambda}}
}
}
// GH63845: Test if we have skipped past RequiresExprBodyDecls in tryCaptureVariable().
namespace GH63845 {
template <bool> struct A {};
struct true_type {
constexpr operator bool() noexcept { return true; }
};
constexpr bool foo() {
true_type x{};
return requires { typename A<x>; };
}
static_assert(foo());
} // namespace GH63845
// GH69307: Test if we can correctly handle param decls that have yet to get into the function scope.
namespace GH69307 {
constexpr auto ICE() {
constexpr auto b = 1;
return [=](auto c) -> int
requires requires { b + c; }
{ return 1; };
};
constexpr auto Ret = ICE()(1);
} // namespace GH69307
// GH88081: Test if we evaluate the requires expression with lambda captures properly.
namespace GH88081 {
// Test that ActOnLambdaClosureQualifiers() is called only once.
void foo(auto value)
requires requires { [&] -> decltype(value) {}; }
// expected-error@-1 {{non-local lambda expression cannot have a capture-default}}
{}
struct S { //#S
S(auto value) //#S-ctor
requires requires { [&] -> decltype(value) { return 2; }; } {} // #S-requires
static auto foo(auto value) -> decltype([&]() -> decltype(value) {}()) { return {}; } // #S-foo
// FIXME: 'value' does not constitute an ODR use here. Add a diagnostic for it.
static auto bar(auto value) -> decltype([&] { return value; }()) {
return "a"; // #bar-body
}
};
S s("a"); // #use
// expected-error@#S-requires {{cannot initialize return object of type 'decltype(value)' (aka 'const char *') with an rvalue of type 'int'}}
// expected-error@#use {{no matching constructor}}
// expected-note@#S-requires {{substituting into a lambda expression here}}
// expected-note@#S-requires {{substituting template arguments into constraint expression here}}
// expected-note@#S-requires {{in instantiation of requirement here}}
// expected-note@#use {{checking constraint satisfaction for template 'S<const char *>' required here}}
// expected-note@#use {{requested here}}
// expected-note-re@#S 2{{candidate constructor {{.*}} not viable}}
// expected-note@#S-ctor {{constraints not satisfied}}
// expected-note-re@#S-requires {{because {{.*}} would be invalid}}
void func() {
S::foo(42);
S::bar("str");
S::bar(0.618);
// expected-error-re@#bar-body {{cannot initialize return object of type {{.*}} (aka 'double') with an lvalue of type 'const char[2]'}}
// expected-note@-2 {{requested here}}
}
} // namespace GH88081
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