[ Varna 2023-06-12; EWG discussed the issue again ]

EWG consensus: "Send LWG2432 back to LWG to encourage them to either add a note for their implementer to issue a warning as QoI, or to use the tools (explicit convertible_to operator=) at their disposal to accomplish their goal"

The operator= suggestion refers to:

initializer_list& operator=(convertible_to<initializer_list> auto&& rhs) { /* ... */ }
initializer_list& operator=(initializer_list const&) requires false = default;