| error[E0658]: parenthetical notation is only stable when used with `Fn`-family traits |
| --> $DIR/unboxed-closure-feature-gate.rs:13:20 |
| | |
| LL | let x: Box<dyn Foo(isize)>; |
| | ^^^^^^^^^^ |
| | |
| = note: see issue #29625 <https://github.com/rust-lang/rust/issues/29625> for more information |
| = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable |
| = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date |
| |
| error: aborting due to 1 previous error |
| |
| For more information about this error, try `rustc --explain E0658`. |
