llvm-project/clang/test/SemaCXX/noexcept-destroying-delete.cpp
Aaron Ballman 5ff7f479a1
[C++20] Destroying delete and deleted destructors (#118800)
When a destroying delete overload is selected, the destructor is not
automatically called. Therefore, the destructor can be deleted without
causing the program to be ill-formed.

Fixes #46818
2025-01-09 08:29:19 -05:00

49 lines
1.6 KiB
C++

// RUN: %clang_cc1 -fsyntax-only -verify -fcxx-exceptions -Wno-unevaluated-expression -std=c++20 %s
namespace std {
struct destroying_delete_t {
explicit destroying_delete_t() = default;
};
inline constexpr destroying_delete_t destroying_delete{};
}
struct Explicit {
~Explicit() noexcept(false) {}
void operator delete(Explicit*, std::destroying_delete_t) noexcept {
}
};
Explicit *qn = nullptr;
// This assertion used to fail, see GH118660
static_assert(noexcept(delete(qn)));
struct ThrowingDestroyingDelete {
~ThrowingDestroyingDelete() noexcept(false) {}
void operator delete(ThrowingDestroyingDelete*, std::destroying_delete_t) noexcept(false) {
}
};
ThrowingDestroyingDelete *pn = nullptr;
// noexcept should return false here because the destroying delete itself is a
// potentially throwing function.
static_assert(!noexcept(delete(pn)));
struct A {
virtual ~A(); // implicitly noexcept
};
struct B : A {
void operator delete(B *p, std::destroying_delete_t) { throw "oh no"; } // expected-warning {{'operator delete' has a non-throwing exception specification but can still throw}} \
expected-note {{deallocator has a implicit non-throwing exception specification}}
};
A *p = new B;
// Because the destructor for A is virtual, it is the only thing we consider
// when determining whether the delete expression can throw or not, despite the
// fact that the selected operator delete is a destroying delete. For virtual
// destructors, it's the dynamic type that matters.
static_assert(noexcept(delete p));