error[E0391]: cycle detected when computing type of `Foo::{opaque#0}`
  --> $DIR/reveal_local.rs:5:12
   |
LL | type Foo = impl Debug;
   |            ^^^^^^^^^^
   |
note: ...which requires type-checking `not_good`...
  --> $DIR/reveal_local.rs:13:5
   |
LL |     is_send::<Foo>();
   |     ^^^^^^^^^^^^^^
   = note: ...which requires evaluating trait selection obligation `Foo: core::marker::Send`...
   = note: ...which again requires computing type of `Foo::{opaque#0}`, completing the cycle
note: cycle used when checking item types in top-level module
  --> $DIR/reveal_local.rs:1:1
   |
LL | / #![feature(type_alias_impl_trait)]
LL | |
LL | | use std::fmt::Debug;
LL | |
...  |
LL | |
LL | | fn main() {}
   | |____________^

error: aborting due to previous error

For more information about this error, try `rustc --explain E0391`.