Weird error when implementing Send with a nonexisting type param

[lcnr]

struct Foo<T>(T, *const ());

unsafe impl Send for Foo<T> {}

results in

error[E0412]: cannot find type `T` in this scope
 --> src/lib.rs:3:26
  |
3 | unsafe impl Send for Foo<T> {}
  |                          ^ not found in this scope

error[E0277]: `*const ()` cannot be sent between threads safely
  --> src/lib.rs:3:13
   |
3  |   unsafe impl Send for Foo<T> {}
   |               ^^^^ `*const ()` cannot be sent between threads safely
   |
   = help: within `Foo<[type error]>`, the trait `std::marker::Send` is not implemented for `*const ()`
   = note: required because it appears within the type `Foo<[type error]>`

The second error is incorrect and quite confusing.