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Commit | Line | Data |
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04454e1e FG |
1 | error[E0308]: `if` and `else` have incompatible types |
2 | --> $DIR/box-instead-of-dyn-fn.rs:10:9 | |
3 | | | |
4 | LL | / if a % 2 == 0 { | |
5 | LL | | move || println!("{a}") | |
6 | | | ----------------------- | |
7 | | | | | |
8 | | | the expected closure | |
9 | | | expected because of this | |
10 | LL | | } else { | |
11 | LL | | Box::new(move || println!("{}", b)) | |
12 | | | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected closure, found struct `Box` | |
13 | LL | | | |
14 | LL | | } | |
15 | | |_____- `if` and `else` have incompatible types | |
16 | | | |
064997fb FG |
17 | = note: expected closure `[closure@$DIR/box-instead-of-dyn-fn.rs:8:9: 8:16]` |
18 | found struct `Box<[closure@$DIR/box-instead-of-dyn-fn.rs:10:18: 10:25]>` | |
04454e1e FG |
19 | |
20 | error[E0746]: return type cannot have an unboxed trait object | |
21 | --> $DIR/box-instead-of-dyn-fn.rs:5:56 | |
22 | | | |
23 | LL | fn print_on_or_the_other<'a>(a: i32, b: &'a String) -> dyn Fn() + 'a { | |
24 | | ^^^^^^^^^^^^^ doesn't have a size known at compile-time | |
25 | | | |
26 | = 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> | |
27 | = note: if all the returned values were of the same type you could use `impl Fn() + 'a` as the return type | |
28 | = note: for information on `impl Trait`, see <https://doc.rust-lang.org/book/ch10-02-traits.html#returning-types-that-implement-traits> | |
29 | = note: you can create a new `enum` with a variant for each returned type | |
30 | help: return a boxed trait object instead | |
31 | | | |
32 | LL | fn print_on_or_the_other<'a>(a: i32, b: &'a String) -> Box<dyn Fn() + 'a> { | |
33 | | ++++ + | |
34 | help: ... and box this value | |
35 | | | |
36 | LL | Box::new(move || println!("{a}")) | |
37 | | +++++++++ + | |
38 | ||
39 | error: aborting due to 2 previous errors | |
40 | ||
41 | Some errors have detailed explanations: E0308, E0746. | |
42 | For more information about an error, try `rustc --explain E0308`. |