error[E0277]: `PhantomPinned` cannot be unpinned
  --> tests/ui/pin_project/overlapping_unpin_struct.rs:20:16
   |
20 |     is_unpin::<S<PhantomPinned>>(); //~ ERROR E0277
   |                ^^^^^^^^^^^^^^^^ within `_::__S<'_, PhantomPinned>`, the trait `Unpin` is not implemented for `PhantomPinned`, which is required by `S<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 `_::__S<'_, PhantomPinned>`
  --> tests/ui/pin_project/overlapping_unpin_struct.rs:8:8
   |
8  | struct S<T> {
   |        ^
note: required for `S<PhantomPinned>` to implement `Unpin`
  --> tests/ui/pin_project/overlapping_unpin_struct.rs:7:1
   |
7  | #[pin_project]
   | ^^^^^^^^^^^^^^ unsatisfied trait bound introduced in this `derive` macro
8  | struct S<T> {
   |        ^^^^
note: required by a bound in `is_unpin`
  --> tests/ui/pin_project/overlapping_unpin_struct.rs:17:16
   |
17 | fn is_unpin<T: Unpin>() {}
   |                ^^^^^ required by this bound in `is_unpin`
   = note: this error originates in the derive macro `::pin_project::__private::__PinProjectInternalDerive` (in Nightly builds, run with -Z macro-backtrace for more info)