1 error[E0308]: mismatched types
2 --> $DIR/issue-102206.rs:6:27
4 LL | std::mem::size_of_val(foo());
5 | --------------------- ^^^^^
7 | | expected reference, found opaque type
8 | | help: consider borrowing here: `&foo()`
9 | arguments to this function are incorrect
11 note: while checking the return type of the `async fn`
12 --> $DIR/issue-102206.rs:3:16
14 LL | async fn foo() {}
15 | ^ checked the `Output` of this `async fn`, found opaque type
16 = note: expected reference `&_`
17 found opaque type `impl Future<Output = ()>`
18 note: function defined here
19 --> $SRC_DIR/core/src/mem/mod.rs:LL:COL
21 error: aborting due to previous error
23 For more information about this error, try `rustc --explain E0308`.