rust/tests/ui/error-codes/E0746.stderr

error[E0746]: return type cannot have an unboxed trait object
  --> $DIR/E0746.rs:8:13
   |
LL | fn foo() -> dyn Trait { Struct }
   |             ^^^^^^^^^ doesn't have a size known at compile-time
   |
   = note: for information on `impl Trait`, see <https://doc.rust-lang.org/book/ch10-02-traits.html#returning-types-that-implement-traits>
help: use `impl Trait` as the return type, as all return paths are of type `Struct`, which implements `Trait`
   |
LL | fn foo() -> impl Trait { Struct }
   |             ~~~~~~~~~~

error[E0746]: return type cannot have an unboxed trait object
  --> $DIR/E0746.rs:11:13
   |
LL | fn bar() -> dyn Trait {
   |             ^^^^^^^^^ doesn't have a size known at compile-time
   |
   = note: for information on `impl Trait`, see <https://doc.rust-lang.org/book/ch10-02-traits.html#returning-types-that-implement-traits>
help: use `impl Trait` as the return type, as all return paths are of type `{integer}`, which implements `Trait`
   |
LL | fn bar() -> impl Trait {
   |             ~~~~~~~~~~

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0746`.
review comments 2020-01-14 21:18:06 +00:00			`error[E0746]: return type cannot have an unboxed trait object`
Make `impl Trait` suggestion in E0746 `MachineApplicable` 2020-01-14 00:13:51 +00:00			`--> $DIR/E0746.rs:8:13`
Specific error for unsized `dyn Trait` return type Suggest `impl Trait` when possible, and `Box<dyn Trait>` otherwise. 2020-01-13 21:13:12 +00:00			`\|`
			`LL \| fn foo() -> dyn Trait { Struct }`
			`\| ^^^^^^^^^ doesn't have a size known at compile-time`
			`\|`
			= note: for information on `impl Trait`, see <https://doc.rust-lang.org/book/ch10-02-traits.html#returning-types-that-implement-traits>
Suggest `-> impl Trait` and `-> Box<dyn Trait>` on fn that doesn't return During development, a function could have a return type set that is a bare trait object by accident. We already suggest using either a boxed trait object or `impl Trait` if the return paths will allow it. We now do so too when there are no return paths or they all resolve to `!`. We still don't handle cases where the trait object is not the entirety of the return type gracefully. 2020-04-10 17:19:47 +00:00			help: use `impl Trait` as the return type, as all return paths are of type `Struct`, which implements `Trait`
Specific error for unsized `dyn Trait` return type Suggest `impl Trait` when possible, and `Box<dyn Trait>` otherwise. 2020-01-13 21:13:12 +00:00			`\|`
			`LL \| fn foo() -> impl Trait { Struct }`
Modify structured suggestion output * On suggestions that include deletions, use a diff inspired output format * When suggesting addition, use `+` as underline * Color highlight modified span 2021-06-22 02:07:19 +00:00			`\| ~~~~~~~~~~`
Specific error for unsized `dyn Trait` return type Suggest `impl Trait` when possible, and `Box<dyn Trait>` otherwise. 2020-01-13 21:13:12 +00:00
review comments 2020-01-14 21:18:06 +00:00			`error[E0746]: return type cannot have an unboxed trait object`
Make `impl Trait` suggestion in E0746 `MachineApplicable` 2020-01-14 00:13:51 +00:00			`--> $DIR/E0746.rs:11:13`
Specific error for unsized `dyn Trait` return type Suggest `impl Trait` when possible, and `Box<dyn Trait>` otherwise. 2020-01-13 21:13:12 +00:00			`\|`
			`LL \| fn bar() -> dyn Trait {`
			`\| ^^^^^^^^^ doesn't have a size known at compile-time`
			`\|`
			= note: for information on `impl Trait`, see <https://doc.rust-lang.org/book/ch10-02-traits.html#returning-types-that-implement-traits>
Suggest `-> impl Trait` and `-> Box<dyn Trait>` on fn that doesn't return During development, a function could have a return type set that is a bare trait object by accident. We already suggest using either a boxed trait object or `impl Trait` if the return paths will allow it. We now do so too when there are no return paths or they all resolve to `!`. We still don't handle cases where the trait object is not the entirety of the return type gracefully. 2020-04-10 17:19:47 +00:00			help: use `impl Trait` as the return type, as all return paths are of type `{integer}`, which implements `Trait`
Specific error for unsized `dyn Trait` return type Suggest `impl Trait` when possible, and `Box<dyn Trait>` otherwise. 2020-01-13 21:13:12 +00:00			`\|`
			`LL \| fn bar() -> impl Trait {`
Modify structured suggestion output * On suggestions that include deletions, use a diff inspired output format * When suggesting addition, use `+` as underline * Color highlight modified span 2021-06-22 02:07:19 +00:00			`\| ~~~~~~~~~~`
Specific error for unsized `dyn Trait` return type Suggest `impl Trait` when possible, and `Box<dyn Trait>` otherwise. 2020-01-13 21:13:12 +00:00
Elide E0308 errors in favor of E0746 When a type error involves a `dyn Trait` as the return type, do not emit the type error, as the "return type is not `Sized`" error will provide enough information to the user. 2020-01-14 00:12:44 +00:00			`error: aborting due to 2 previous errors`
Specific error for unsized `dyn Trait` return type Suggest `impl Trait` when possible, and `Box<dyn Trait>` otherwise. 2020-01-13 21:13:12 +00:00
Add E0746 explanation to the index 2020-01-14 01:21:31 +00:00			For more information about this error, try `rustc --explain E0746`.