| error[E0308]: mismatched types | |
| --> $DIR/existential-printing.rs:7:13 | |
| | | |
| LL | fn f() -> impl FnOnce<()> { || () } | |
| | --------------- the expected opaque type | |
| LL | | |
| LL | fn main() { () = f(); } | |
| | ^^ --- this expression has type `impl FnOnce<()>` | |
| | | | |
| | expected opaque type, found `()` | |
| | | |
| = note: expected opaque type `impl FnOnce<()>` | |
| found unit type `()` | |
| error: aborting due to 1 previous error | |
| For more information about this error, try `rustc --explain E0308`. |