error[E0277]: `PhantomPinned` cannot be unpinned
  --> tests/ui/pin_project/overlapping_unpin_struct.rs:21:16
   |
21 |     is_unpin::<Foo<PhantomPinned>>(); //~ ERROR E0277
   |                ^^^^^^^^^^^^^^^^^^ within `_::__Origin<'_, PhantomPinned>`, the trait `Unpin` is not implemented for `PhantomPinned`, which is required by `Foo<PhantomPinned>: Unpin`
   |
   = note: consider using the `pin!` macro
           consider using `Box::pin` if you need to access the pinned value outside of the current scope
note: required because it appears within the type `_::__Origin<'_, PhantomPinned>`
  --> tests/ui/pin_project/overlapping_unpin_struct.rs:7:1
   |
7  | / pin_project! {
8  | |     struct Foo<T> {
9  | |         #[pin]
10 | |         inner: T,
11 | |     }
12 | | }
   | |_^
note: required for `Foo<PhantomPinned>` to implement `Unpin`
  --> tests/ui/pin_project/overlapping_unpin_struct.rs:7:1
   |
7  | / pin_project! {
8  | |     struct Foo<T> {
9  | |         #[pin]
10 | |         inner: T,
11 | |     }
12 | | }
   | |_^ unsatisfied trait bound introduced here
note: required by a bound in `is_unpin`
  --> tests/ui/pin_project/overlapping_unpin_struct.rs:18:16
   |
18 | fn is_unpin<T: Unpin>() {}
   |                ^^^^^ required by this bound in `is_unpin`
   = note: this error originates in the macro `$crate::__pin_project_make_unpin_impl` which comes from the expansion of the macro `pin_project` (in Nightly builds, run with -Z macro-backtrace for more info)