https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97665
--- Comment #5 from Luke Dalessandro <ldalessandro at gmail dot com> --- Ugh... replying to myself. > You can do Foo foo = Foo(); and it compiles. >> 1. I can't do `Foo foo = Foo();` because the purpose of the union is to >> allocate uninitialized storage for the `Foo` during `constexpr` execution >> when `Foo` has no default constructor. I realize now I meant to write >> `constexpr Foo() = delete;`. This means to say "trivial default constructor," not just "default constructor". The empty default constructor was an adequate test case for this, but is misleading. The `= delete` should be more effective as an example. The context for the use is to create an array that provides uninitialized vector storage during `constexpr` evaluation in the same way a `std::byte[T*sizeof(T)]` array combined with `reinterptret_cast<T*>` might be used during normal execution.
