error[E0277]: `*const ()` cannot be sent between threads safely
   --> tests/ui/send-sync-ub.rs:17:5
    |
17  |     thread::spawn(|| {
    |     ^^^^^^^^^^^^^ -- within this `[closure@$DIR/tests/ui/send-sync-ub.rs:17:19: 17:21]`
    |     |
    |     `*const ()` cannot be sent between threads safely
    |
    = help: within `[closure@$DIR/tests/ui/send-sync-ub.rs:17:19: 17:21]`, the trait `std::marker::Send` is not implemented for `*const ()`
    = note: required because it appears within the type `PhantomData<*const ()>`
    = note: required because it appears within the type `Markers<false, false, false>`
note: required because it appears within the type `_foo_impl::Foo<'_>`
   --> tests/ui/send-sync-ub.rs:7:11
    |
7   | #[name_it(Foo)]
    |           ^^^
    = note: required because it appears within the type `Named<_foo_impl::Foo<'_>>`
note: required because it's used within this closure
   --> tests/ui/send-sync-ub.rs:17:19
    |
17  |     thread::spawn(|| {
    |                   ^^
note: required by a bound in `std::thread::spawn`
   --> $RUST/std/src/thread/mod.rs
    |
    |     F: Send + 'static,
    |        ^^^^ required by this bound in `std::thread::spawn`