[ub:basic.stc.alloc.dealloc.constraint] Irrelevant UB example

[BlowingWind314]

Currently it says

void operator delete(void* ptr) noexcept {
    throw 0;                // undefined behavior, terminates by throwing an exception
}

[basic.stc.dynamic.deallocation]/3 merely says

... A deallocation function shall not have a potentially throwing exception specification. ...

The "throwing an exception in a noexcept function" example is irrelevant for this UB.

[frederick-vs-ja]

Seems like missed deletion in #9178.

[eisenwave]

Yeah I think you're right. The UB would be caused by https://eel.is/c++draft/basic.stc.dynamic#general-3:

If the behavior of an allocation or deallocation function does not satisfy the semantic constraints specified in [basic.stc.dynamic.allocation] and [basic.stc.dynamic.deallocation], the behavior is undefined ([ub:basic.stc.alloc.dealloc.constraint]).

However, it seems like any restrictions on the behavior in https://eel.is/c++draft/basic.stc.dynamic.deallocation are for standard-library operator delete only. If the user wants to, they can call std::terminate() in their operator delete, and it's not UB. And we don't need to threaten the implementers with UB; we can just state what the behavior of standard-library functions is.

But that also makes [basic.stc.dynamic.general] p3 nonsensical, and that makes this issue non-editorial.

[eisenwave]

CC @jensmaurer @notadragon @AlisdairM opinion?

[BlowingWind314]

But that also makes [basic.stc.dynamic.general] p3 nonsensical, and that makes this issue non-editorial.

See my issue