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.
37 lines
1.1 KiB
C
37 lines
1.1 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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// { dg-additional-options "-fdelete-null-pointer-checks" }
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// dynamic_cast in a constructor.
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// [class.cdtor]#6: "If the operand of the dynamic_cast refers to the object
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// under construction or destruction and the static type of the operand is not
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// a pointer to or object of the constructor or destructor's own class or one
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// of its bases, the dynamic_cast results in undefined behavior.
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struct V {
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virtual void f();
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};
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struct A : V { };
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struct B : V {
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constexpr B(V*, A*);
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};
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struct D : A, B {
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constexpr D() : B((A*)this, this) { } // { dg-message "in 'constexpr' expansion of" }
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};
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constexpr B::B(V* v, A* a)
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{
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// well-defined: v of type V*, V base of B results in B*
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B* b = dynamic_cast<B*>(v);
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if (b != nullptr)
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__builtin_abort ();
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B& br = dynamic_cast<B&>(*v); // { dg-error "reference .dynamic_cast. failed" }
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// { dg-message "dynamic type .A. of its operand does not have an unambiguous public base class .B." "" { target *-*-* } .-1 }
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}
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constexpr D d; // { dg-message "in 'constexpr' expansion of" }
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