error[E0425]: cannot find value `Foo` in this scope --> $DIR/layout-error.rs:21:17 | LL | let a = Foo; | ^^^ not found in this scope error: cannot check whether the hidden type of `layout_error[b009]::main::F::{opaque#0}` satisfies auto traits --> $DIR/layout-error.rs:26:18 | LL | static POOL: Task = Task::new(); | ^^^^^^^ | note: opaque type is declared here --> $DIR/layout-error.rs:24:14 | LL | type F = impl Future; | ^^^^^^^^^^^ note: required because it appears within the type `Task` --> $DIR/layout-error.rs:9:12 | LL | pub struct Task(F); | ^^^^ = note: shared static variables must have a type that implements `Sync` error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0425`.