[Clang] Fix constexpr-ness on implicitly deleted destructors (#116359)

In C++20, a defaulted but implicitly deleted destructor is constexpr if
and only if the class has no virtual base class. This hasn't been
changed in C++23 by P2448R2.

Constexpr-ness on a deleted destructor affects almost nothing. The
`__is_literal` intrinsic is related, while the corresponding
`std::is_literal_type(_v)` utility has been removed in C++20. A recently
added example in `test/AST/ByteCode/cxx23.cpp` will become valid, and
the example is already accepted by GCC.

Clang currently behaves correctly in C++23 mode, because the
constexpr-ness on defaulted destructor is relaxed by P2448R2. But we
should make similar relaxation for an implicitly deleted destructor.

Fixes #85550.

0 files changed, 0 insertions, 0 deletions