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Diffstat (limited to 'tests/ui/unsized/box-instead-of-dyn-fn.stderr')
-rw-r--r-- | tests/ui/unsized/box-instead-of-dyn-fn.stderr | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/tests/ui/unsized/box-instead-of-dyn-fn.stderr b/tests/ui/unsized/box-instead-of-dyn-fn.stderr new file mode 100644 index 000000000..c96c59afc --- /dev/null +++ b/tests/ui/unsized/box-instead-of-dyn-fn.stderr @@ -0,0 +1,42 @@ +error[E0308]: `if` and `else` have incompatible types + --> $DIR/box-instead-of-dyn-fn.rs:10:9 + | +LL | / if a % 2 == 0 { +LL | | move || println!("{a}") + | | ----------------------- + | | | + | | the expected closure + | | expected because of this +LL | | } else { +LL | | Box::new(move || println!("{}", b)) + | | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected closure, found struct `Box` +LL | | +LL | | } + | |_____- `if` and `else` have incompatible types + | + = note: expected closure `[closure@$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`. |