error[E0609]: no field `field` on type `impl Future<Output = S>`
  --> $DIR/field-in-sync.rs:10:11
   |
LL |     foo().field;
   |           ^^^^^ field not available in `impl Future`, but it is available in its `Output`
   |
note: this implements `Future` and its output type has the field, but the future cannot be awaited in a synchronous function
  --> $DIR/field-in-sync.rs:10:5
   |
LL | fn main() -> Result<(), ()> {
   | --------------------------- this is not `async`
LL |     foo().field;
   |     ^^^^^

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0609`.