| error[E0308]: `if` and `else` have incompatible types |
| --> $DIR/box-instead-of-dyn-fn.rs:10:9 |
| | |
| LL | / if a % 2 == 0 { |
| LL | | move || println!("{a}") |
| | | ----------------------- |
| | | | |
| | | the expected closure |
| | | expected because of this |
| LL | | } else { |
| LL | | Box::new(move || println!("{}", b)) |
| | | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected closure, found `Box<[closure@box-instead-of-dyn-fn.rs:10:18]>` |
| LL | | |
| LL | | } |
| | |_____- `if` and `else` have incompatible types |
| | |
| = note: expected closure `[closure@$DIR/box-instead-of-dyn-fn.rs:8:9: 8:16]` |
| found struct `Box<[closure@$DIR/box-instead-of-dyn-fn.rs:10:18: 10:25]>` |
| |
| error[E0746]: return type cannot have an unboxed trait object |
| --> $DIR/box-instead-of-dyn-fn.rs:5:56 |
| | |
| LL | fn print_on_or_the_other<'a>(a: i32, b: &'a String) -> dyn Fn() + 'a { |
| | ^^^^^^^^^^^^^ doesn't have a size known at compile-time |
| | |
| = note: for information on trait objects, see <https://doc.rust-lang.org/book/ch17-02-trait-objects.html#using-trait-objects-that-allow-for-values-of-different-types> |
| = note: if all the returned values were of the same type you could use `impl Fn() + 'a` as the return type |
| = note: for information on `impl Trait`, see <https://doc.rust-lang.org/book/ch10-02-traits.html#returning-types-that-implement-traits> |
| = note: you can create a new `enum` with a variant for each returned type |
| help: return a boxed trait object instead |
| | |
| LL | fn print_on_or_the_other<'a>(a: i32, b: &'a String) -> Box<dyn Fn() + 'a> { |
| | ++++ + |
| help: ... and box this value |
| | |
| LL | Box::new(move || println!("{a}")) |
| | +++++++++ + |
| |
| error: aborting due to 2 previous errors |
| |
| Some errors have detailed explanations: E0308, E0746. |
| For more information about an error, try `rustc --explain E0308`. |