cxx1z-copy-omission.cpp
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// RUN: %clang_cc1 -std=c++1z -verify %s
struct Noncopyable {
Noncopyable();
Noncopyable(const Noncopyable &) = delete; // expected-note 1+{{deleted}} expected-note 1+ {{not viable}}
virtual ~Noncopyable();
};
struct Derived : Noncopyable {};
struct NoncopyableAggr { // expected-note 3{{candidate}}
Noncopyable nc;
};
struct Indestructible {
Indestructible();
~Indestructible() = delete; // expected-note 1+{{deleted}}
};
struct Incomplete; // expected-note 1+{{declar}}
Noncopyable make(int kind = 0) {
switch (kind) {
case 0: return {};
case 1: return Noncopyable();
case 2: return Noncopyable{};
case 3: return make();
}
__builtin_unreachable();
}
Indestructible make_indestructible();
Incomplete make_incomplete(); // expected-note 1+{{here}}
void take(Noncopyable nc) {}
Noncopyable nrvo() {
Noncopyable nrvo;
return nrvo; // expected-error {{deleted constructor}}
}
Noncopyable nc1 = make();
Noncopyable nc2 = Noncopyable();
Noncopyable nc3 = Derived(); // expected-error {{deleted constructor}}
Noncopyable nc4((Noncopyable()));
Noncopyable nc5 = {Noncopyable()};
Noncopyable nc6{Noncopyable()};
NoncopyableAggr nca1 = NoncopyableAggr{};
NoncopyableAggr nca2 = NoncopyableAggr{{}};
NoncopyableAggr nca3 = NoncopyableAggr{NoncopyableAggr{Noncopyable()}};
template<typename T> struct Convert { operator T(); }; // expected-note 1+{{candidate}}
Noncopyable conv1 = Convert<Noncopyable>();
Noncopyable conv2((Convert<Noncopyable>()));
Noncopyable conv3 = {Convert<Noncopyable>()};
Noncopyable conv4{Convert<Noncopyable>()};
Noncopyable ref_conv1 = Convert<Noncopyable&>(); // expected-error {{deleted constructor}}
Noncopyable ref_conv2((Convert<Noncopyable&>())); // expected-error {{deleted constructor}}
Noncopyable ref_conv3 = {Convert<Noncopyable&>()}; // expected-error {{deleted constructor}}
Noncopyable ref_conv4{Convert<Noncopyable&>()}; // expected-error {{deleted constructor}}
Noncopyable derived_conv1 = Convert<Derived>(); // expected-error {{deleted constructor}}
Noncopyable derived_conv2((Convert<Derived>())); // expected-error {{deleted constructor}}
Noncopyable derived_conv3 = {Convert<Derived>()}; // expected-error {{deleted constructor}}
Noncopyable derived_conv4{Convert<Derived>()}; // expected-error {{deleted constructor}}
NoncopyableAggr nc_aggr1 = Convert<NoncopyableAggr>();
NoncopyableAggr nc_aggr2((Convert<NoncopyableAggr>()));
NoncopyableAggr nc_aggr3 = {Convert<NoncopyableAggr>()}; // expected-error {{no viable conversion}}
NoncopyableAggr nc_aggr4{Convert<NoncopyableAggr>()}; // expected-error {{no viable conversion}}
NoncopyableAggr nc_aggr5 = Convert<Noncopyable>(); // expected-error {{no viable}}
NoncopyableAggr nc_aggr6((Convert<Noncopyable>())); // expected-error {{no matching constructor}}
NoncopyableAggr nc_aggr7 = {Convert<Noncopyable>()};
NoncopyableAggr nc_aggr8{Convert<Noncopyable>()};
void test_expressions(bool b) {
auto lambda = [a = make()] {};
take({});
take(Noncopyable());
take(Noncopyable{});
take(make());
Noncopyable &&dc1 = dynamic_cast<Noncopyable&&>(Noncopyable());
Noncopyable &&dc2 = dynamic_cast<Noncopyable&&>(nc1);
Noncopyable &&dc3 = dynamic_cast<Noncopyable&&>(Derived());
Noncopyable sc1 = static_cast<Noncopyable>(Noncopyable());
Noncopyable sc2 = static_cast<Noncopyable>(nc1); // expected-error {{deleted}}
Noncopyable sc3 = static_cast<Noncopyable&&>(Noncopyable()); // expected-error {{deleted}}
Noncopyable sc4 = static_cast<Noncopyable>(static_cast<Noncopyable&&>(Noncopyable())); // expected-error {{deleted}}
Noncopyable cc1 = (Noncopyable)Noncopyable();
Noncopyable cc2 = (Noncopyable)Derived(); // expected-error {{deleted}}
Noncopyable fc1 = Noncopyable(Noncopyable());
Noncopyable fc2 = Noncopyable(Derived()); // expected-error {{deleted}}
// We must check for a complete type for every materialized temporary. (Note
// that in the special case of the top level of a decltype, no temporary is
// materialized.)
make_incomplete(); // expected-error {{incomplete}}
make_incomplete().a; // expected-error {{incomplete}}
make_incomplete().*(int Incomplete::*)nullptr; // expected-error {{incomplete}}
dynamic_cast<Incomplete&&>(make_incomplete()); // expected-error {{incomplete}}
const_cast<Incomplete&&>(make_incomplete()); // expected-error {{incomplete}}
sizeof(Indestructible{}); // expected-error {{deleted}}
sizeof(make_indestructible()); // expected-error {{deleted}}
sizeof(make_incomplete()); // expected-error {{incomplete}}
typeid(Indestructible{}); // expected-error {{deleted}}
typeid(make_indestructible()); // expected-error {{deleted}}
typeid(make_incomplete()); // expected-error {{incomplete}}
// FIXME: The first two cases here are now also valid in C++17 onwards.
using I = decltype(Indestructible()); // expected-error {{deleted}}
using I = decltype(Indestructible{}); // expected-error {{deleted}}
using I = decltype(make_indestructible());
using J = decltype(make_incomplete());
Noncopyable cond1 = b ? Noncopyable() : make();
Noncopyable cond2 = b ? Noncopyable() : Derived(); // expected-error {{incompatible}}
Noncopyable cond3 = b ? Derived() : Noncopyable(); // expected-error {{incompatible}}
Noncopyable cond4 = b ? Noncopyable() : nc1; // expected-error {{deleted}}
Noncopyable cond5 = b ? nc1 : Noncopyable(); // expected-error {{deleted}}
// Could convert both to an xvalue of type Noncopyable here, but we're not
// permitted to consider that.
Noncopyable &&cond6 = b ? Noncopyable() : Derived(); // expected-error {{incompatible}}
Noncopyable &&cond7 = b ? Derived() : Noncopyable(); // expected-error {{incompatible}}
// Could convert both to a const lvalue of type Noncopyable here, but we're
// not permitted to consider that, either.
const Noncopyable cnc;
const Noncopyable &cond8 = b ? cnc : Derived(); // expected-error {{incompatible}}
const Noncopyable &cond9 = b ? Derived() : cnc; // expected-error {{incompatible}}
extern const volatile Noncopyable make_cv();
Noncopyable cv_difference1 = make_cv();
const volatile Noncopyable cv_difference2 = make();
}
template<typename T> struct ConversionFunction { operator T(); };
Noncopyable cf1 = ConversionFunction<Noncopyable>();
Noncopyable cf2 = ConversionFunction<Noncopyable&&>(); // expected-error {{deleted}}
Noncopyable cf3 = ConversionFunction<const volatile Noncopyable>();
const volatile Noncopyable cf4 = ConversionFunction<Noncopyable>();
Noncopyable cf5 = ConversionFunction<Derived>(); // expected-error {{deleted}}
struct AsMember {
Noncopyable member;
AsMember() : member(make()) {}
};
// FIXME: DR (no number yet): we still get a copy for base or delegating construction.
struct AsBase : Noncopyable {
AsBase() : Noncopyable(make()) {} // expected-error {{deleted}}
};
struct AsDelegating final {
AsDelegating(const AsDelegating &) = delete; // expected-note {{deleted}}
static AsDelegating make(int);
// The base constructor version of this is problematic; the complete object
// version would be OK. Perhaps we could allow copy omission here for final
// classes?
AsDelegating(int n) : AsDelegating(make(n)) {} // expected-error {{deleted}}
};
namespace CtorTemplateBeatsNonTemplateConversionFn {
struct Foo { template <typename Derived> Foo(const Derived &); };
template <typename Derived> struct Base { operator Foo() const = delete; }; // expected-note {{deleted}}
struct Derived : Base<Derived> {};
Foo f(Derived d) { return d; } // expected-error {{invokes a deleted function}}
Foo g(Derived d) { return Foo(d); } // ok, calls constructor
}