b04445d4a8
C++20 isn't final quite yet, but all that remains is formalities, so let's go ahead and change all the references. I think for the next C++ standard we can just call it C++23 rather than C++2b, since the committee has been consistent about time-based releases rather than feature-based. gcc/c-family/ChangeLog 2020-05-13 Jason Merrill <jason@redhat.com> * c.opt (std=c++20): Make c++2a the alias. (std=gnu++20): Likewise. * c-common.h (cxx_dialect): Change cxx2a to cxx20. * c-opts.c: Adjust. * c-cppbuiltin.c: Adjust. * c-ubsan.c: Adjust. * c-warn.c: Adjust. gcc/cp/ChangeLog 2020-05-13 Jason Merrill <jason@redhat.com> * call.c, class.c, constexpr.c, constraint.cc, decl.c, init.c, lambda.c, lex.c, method.c, name-lookup.c, parser.c, pt.c, tree.c, typeck2.c: Change cxx2a to cxx20. libcpp/ChangeLog 2020-05-13 Jason Merrill <jason@redhat.com> * include/cpplib.h (enum c_lang): Change CXX2A to CXX20. * init.c, lex.c: Adjust.
87 lines
2.4 KiB
C
87 lines
2.4 KiB
C
// PR c++/88337 - Implement P1327R1: Allow dynamic_cast/typeid in constexpr.
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// { dg-do compile { target c++20 } }
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// Adopted from g++.old-deja/g++.other/dyncast1.C.
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// 1. downcast
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// 1.1. single inheritance case
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struct A { virtual void a(); };
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struct AA : A {};
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struct B : A {};
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struct BB : B {};
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class C : B {};
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struct D : C {};
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struct CC : B {};
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class DD : CC {};
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class CCC : protected B {};
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class DDD : protected CCC {};
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constexpr D d;
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static_assert (dynamic_cast<D*> ((A*)&d) == nullptr);
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static_assert (dynamic_cast<D*> ((B*)&d) == nullptr);
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static_assert (&d == dynamic_cast<D*> ((C*)&d));
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static_assert (dynamic_cast<C*> ((B*)&d) == nullptr);
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constexpr DD dd;
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static_assert (dynamic_cast<DD*> ((A*)&dd) == nullptr);
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static_assert (dynamic_cast<DD*> ((B*)&dd) == nullptr);
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constexpr DDD ddd;
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static_assert (dynamic_cast<DDD*> ((A*)&ddd) == nullptr);
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static_assert (dynamic_cast<DDD*> ((B*)&ddd) == nullptr);
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static_assert (dynamic_cast<CCC*> ((B*)&ddd) == nullptr);
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// 1.2. multiple inheritance case
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// 1.2.1. all bases are public
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struct E : D, CC {};
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struct EE : CC, D {}; //Will search in reverse order.
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constexpr E e;
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static_assert (dynamic_cast<E*> ((A*)(D*)&e) == nullptr);
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static_assert (dynamic_cast<E*> ((B*)(D*)&e) == nullptr);
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static_assert (&e == dynamic_cast<E*> ((C*)(D*)&e));
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static_assert (&e == dynamic_cast<E*> ((B*)(CC*)&e));
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static_assert ((CC*)&e == dynamic_cast<CC*> ((B*)(CC*)&e));
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constexpr EE ee;
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static_assert (dynamic_cast<EE*> ((A*)(D*)&ee) == nullptr);
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static_assert (dynamic_cast<EE*> ((B*)(D*)&ee) == nullptr);
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static_assert (&ee == dynamic_cast<EE*> ((C*)(D*)&ee));
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static_assert (&ee == dynamic_cast<EE*> ((B*)(CC*)&ee));
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static_assert ((CC*)&ee == dynamic_cast<CC*> ((B*)(CC*)&ee));
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// 1.2.2 one or more branches are nonpublic
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struct X : private BB, E {};
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struct Y : AA, private B {};
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class XX : BB, E {};
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constexpr X x;
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static_assert (&x == dynamic_cast<X*>((B*)(CC*)(E*)&x));
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constexpr XX xx;
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static_assert (dynamic_cast<XX*>((B*)(CC*)(E*)&xx) == nullptr);
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constexpr Y y;
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static_assert (dynamic_cast<Y*>((B*)&y) == nullptr);
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static_assert (dynamic_cast<Y*>((A*)(B*)&y) == nullptr);
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// 2. crosscast
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struct J { virtual void j(); };
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struct K : CC, private J {};
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class KK : J, CC{};
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static_assert (dynamic_cast<CC*> ((B*)(D*)&e) == nullptr);
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static_assert ((CC*)&e == dynamic_cast<CC*> ((C*)(D*)&e));
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constexpr K k;
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static_assert (dynamic_cast<J*> ((B*)&k) == nullptr);
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constexpr KK kk;
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static_assert (dynamic_cast<J*> ((CC*)&kk) == nullptr);
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