error[E0277]: `[(); _]` is not a future
  --> $DIR/unresolved-ct-var.rs:6:45
   |
LL |         let s = std::array::from_fn(|_| ()).await;
   |                 --------------------------- ^^^^^ `[(); _]` is not a future
   |                 |
   |                 this call returns `[(); _]`
   |
   = help: the trait `Future` is not implemented for `[(); _]`
   = note: [(); _] must be a future or must implement `IntoFuture` to be awaited
   = note: required for `[(); _]` to implement `IntoFuture`
help: remove the `.await`
   |
LL -         let s = std::array::from_fn(|_| ()).await;
LL +         let s = std::array::from_fn(|_| ());
   |

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0277`.