llvm-project/clang/test/CXX/drs/dr18xx.cpp

// RUN: %clang_cc1 -std=c++98 -triple x86_64-unknown-unknown %s -verify -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++11 -triple x86_64-unknown-unknown %s -verify -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++14 -triple x86_64-unknown-unknown %s -verify -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++17 -triple x86_64-unknown-unknown %s -verify -fexceptions -fcxx-exceptions -pedantic-errors
// RUN: %clang_cc1 -std=c++2a -triple x86_64-unknown-unknown %s -verify -fexceptions -fcxx-exceptions -pedantic-errors

#if __cplusplus < 201103L
// expected-error@+1 {{variadic macro}}
#define static_assert(...) __extension__ _Static_assert(__VA_ARGS__)
#endif

namespace dr1813 { // dr1813: 7
  struct B { int i; };
  struct C : B {};
  struct D : C {};
  struct E : D { char : 4; };

  static_assert(__is_standard_layout(B), "");
  static_assert(__is_standard_layout(C), "");
  static_assert(__is_standard_layout(D), "");
  static_assert(!__is_standard_layout(E), "");

  struct Q {};
  struct S : Q {};
  struct T : Q {};
  struct U : S, T {};

  static_assert(__is_standard_layout(Q), "");
  static_assert(__is_standard_layout(S), "");
  static_assert(__is_standard_layout(T), "");
  static_assert(!__is_standard_layout(U), "");
}

namespace dr1815 { // dr1815: no
#if __cplusplus >= 201402L
  // FIXME: needs codegen test
  struct A { int &&r = 0; }; // expected-note {{default member init}}
  A a = {}; // FIXME expected-warning {{not supported}}

  struct B { int &&r = 0; }; // expected-error {{binds to a temporary}} expected-note {{default member init}}
  B b; // expected-note {{here}}
#endif
}

namespace dr1872 { // dr1872: 9
#if __cplusplus >= 201103L
  template<typename T> struct A : T {
    constexpr int f() const { return 0; }
  };
  struct X {};
  struct Y { virtual int f() const; };
  struct Z : virtual X {};

  constexpr int x = A<X>().f();
  constexpr int y = A<Y>().f();
#if __cplusplus <= 201703L
  // expected-error@-2 {{constant expression}} expected-note@-2 {{call to virtual function}}
#else
  static_assert(y == 0);
#endif
  // Note, this is invalid even though it would not use virtual dispatch.
  constexpr int y2 = A<Y>().A<Y>::f();
#if __cplusplus <= 201703L
  // expected-error@-2 {{constant expression}} expected-note@-2 {{call to virtual function}}
#else
  static_assert(y == 0);
#endif
  constexpr int z = A<Z>().f(); // expected-error {{constant expression}} expected-note {{non-literal type}}
#endif
}

namespace dr1881 { // dr1881: 7
  struct A { int a : 4; };
  struct B : A { int b : 3; };
  static_assert(__is_standard_layout(A), "");
  static_assert(!__is_standard_layout(B), "");

  struct C { int : 0; };
  struct D : C { int : 0; };
  static_assert(__is_standard_layout(C), "");
  static_assert(!__is_standard_layout(D), "");
}

void dr1891() { // dr1891: 4
#if __cplusplus >= 201103L
  int n;
  auto a = []{}; // expected-note 0-4{{}}
  auto b = [=]{ return n; }; // expected-note 0-4{{}}
  typedef decltype(a) A;
  typedef decltype(b) B;

  static_assert(!__has_trivial_constructor(A), "");
#if __cplusplus > 201703L
  // expected-error@-2 {{failed}}
#endif
  static_assert(!__has_trivial_constructor(B), "");

  // C++20 allows default construction for non-capturing lambdas (P0624R2).
  A x;
#if __cplusplus <= 201703L
  // expected-error@-2 {{no matching constructor}}
#endif
  B y; // expected-error {{no matching constructor}}

  // C++20 allows assignment for non-capturing lambdas (P0624R2).
  a = a;
  a = static_cast<A&&>(a);
#if __cplusplus <= 201703L
  // expected-error@-3 {{copy assignment operator is implicitly deleted}}
  // expected-error@-3 {{copy assignment operator is implicitly deleted}}
#endif
  b = b; // expected-error {{copy assignment operator is implicitly deleted}}
  b = static_cast<B&&>(b); // expected-error {{copy assignment operator is implicitly deleted}}
#endif
}