Proposed resolution:

This wording is relative to N4988.

1. Modify [unique.ptr.single.observers] as indicated:

   constexpr add_lvalue_reference_t<T> operator*() const noexcept(noexcept(*declval<pointer>()));
   

   -?- Mandates: reference_converts_from_temporary_v<add_lvalue_reference_t<T>, decltype(*declval<pointer>())> is `false`.

   -1- Preconditions: `get() != nullptr` is `true`.

   -2- Returns: `*get()`.

[ Wrocław 2024-11-23; Status changed: Voting → WP. ]

[ 2024-09-18; Reflector poll ]

Set status to Tentatively Ready after seven votes in favour during reflector poll.

If unique_ptr<T,D>::element_type* and D::pointer are not the same type, it's possible for `operator*()` to return a dangling reference that has undefined behaviour.

  struct deleter {
    using pointer = long*;
    void operator()(pointer) const {}
  };
  long l = 0;
  std::unique_ptr<const int, deleter> p(&l);
  int i = *p; // undefined

We should make this case ill-formed.