error[E0277]: `[async fn body@$DIR/async.rs:23:29: 25:2]` is not a future --> $DIR/async.rs:23:25 | LL | async fn foo(x: u32) -> u32 { | ^^^ `[async fn body@$DIR/async.rs:23:29: 25:2]` is not a future | = help: the trait `Future` is not implemented for `[async fn body@$DIR/async.rs:23:29: 25:2]` = note: [async fn body@$DIR/async.rs:23:29: 25:2] must be a future or must implement `IntoFuture` to be awaited error: internal compiler error: projection clauses should be implied from elsewhere. obligation: `Obligation(predicate=Binder(ProjectionPredicate(AliasTy { substs: [[async fn body@$DIR/async.rs:23:29: 25:2]], def_id: ... }, Term::Ty(u32)), []), depth=0)` --> $DIR/async.rs:23:25 | LL | async fn foo(x: u32) -> u32 { | ^^^query stack during panic: #0 [typeck] type-checking `foo` #1 [thir_body] building THIR for `foo` #2 [mir_built] building MIR for `foo` #3 [unsafety_check_result] unsafety-checking `foo` #4 [mir_const] preparing `foo` for borrow checking #5 [mir_promoted] processing MIR for `foo` #6 [mir_borrowck] borrow-checking `foo` #7 [type_of] computing type of `foo::{opaque#0}` #8 [check_mod_item_types] checking item types in top-level module #9 [analysis] running analysis passes on this crate end of query stack error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0277`.