error[E0658]: cannot borrow here, since the borrowed element may contain interior mutability
  --> $DIR/const-promoted-opaque.rs:29:25
   |
LL |     let _: &'static _ = &FOO;
   |                         ^^^^
   |
   = note: see issue #80384 <https://github.com/rust-lang/rust/issues/80384> for more information
   = help: add `#![feature(const_refs_to_cell)]` to the crate attributes to enable
   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date

error[E0493]: destructor of `helper::Foo` cannot be evaluated at compile-time
  --> $DIR/const-promoted-opaque.rs:29:26
   |
LL |     let _: &'static _ = &FOO;
   |                          ^^^ the destructor for this type cannot be evaluated in constants
...
LL | };
   | - value is dropped here

error[E0492]: constants cannot refer to interior mutable data
  --> $DIR/const-promoted-opaque.rs:34:19
   |
LL | const BAZ: &Foo = &FOO;
   |                   ^^^^ this borrow of an interior mutable value may end up in the final value

error[E0716]: temporary value dropped while borrowed
  --> $DIR/const-promoted-opaque.rs:38:26
   |
LL |     let _: &'static _ = &FOO;
   |            ----------    ^^^ creates a temporary value which is freed while still in use
   |            |
   |            type annotation requires that borrow lasts for `'static`
LL |
LL | }
   | - temporary value is freed at the end of this statement

error[E0391]: cycle detected when computing type of opaque `helper::Foo::{opaque#0}`
  --> $DIR/const-promoted-opaque.rs:14:20
   |
LL |     pub type Foo = impl Sized;
   |                    ^^^^^^^^^^
   |
note: ...which requires borrow-checking `helper::FOO`...
  --> $DIR/const-promoted-opaque.rs:21:5
   |
LL |     pub const FOO: Foo = std::sync::atomic::AtomicU8::new(42);
   |     ^^^^^^^^^^^^^^^^^^
note: ...which requires promoting constants in MIR for `helper::FOO`...
  --> $DIR/const-promoted-opaque.rs:21:5
   |
LL |     pub const FOO: Foo = std::sync::atomic::AtomicU8::new(42);
   |     ^^^^^^^^^^^^^^^^^^
note: ...which requires const checking `helper::FOO`...
  --> $DIR/const-promoted-opaque.rs:21:5
   |
LL |     pub const FOO: Foo = std::sync::atomic::AtomicU8::new(42);
   |     ^^^^^^^^^^^^^^^^^^
   = note: ...which requires computing whether `helper::Foo` is freeze...
   = note: ...which requires evaluating trait selection obligation `helper::Foo: core::marker::Freeze`...
   = note: ...which again requires computing type of opaque `helper::Foo::{opaque#0}`, completing the cycle
note: cycle used when computing type of `helper::Foo::{opaque#0}`
  --> $DIR/const-promoted-opaque.rs:14:20
   |
LL |     pub type Foo = impl Sized;
   |                    ^^^^^^^^^^
   = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information

error: aborting due to 5 previous errors

Some errors have detailed explanations: E0391, E0492, E0493, E0658, E0716.
For more information about an error, try `rustc --explain E0391`.