92 lines
3.3 KiB
Plaintext
92 lines
3.3 KiB
Plaintext
error[E0277]: the size for values of type `(dyn Foo + Send + 'static)` cannot be known at compilation time
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--> $DIR/not-on-bare-trait-2021.rs:8:8
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LL | fn foo(_x: Foo + Send) {
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| ^^ doesn't have a size known at compile-time
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= help: the trait `Sized` is not implemented for `(dyn Foo + Send + 'static)`
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= help: unsized fn params are gated as an unstable feature
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help: you can use `impl Trait` as the argument type
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LL | fn foo(_x: impl Foo + Send) {
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| ++++
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help: function arguments must have a statically known size, borrowed types always have a known size
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LL | fn foo(_x: &(dyn Foo + Send)) {
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| +++++ +
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error[E0277]: the size for values of type `(dyn Foo + 'static)` cannot be known at compilation time
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--> $DIR/not-on-bare-trait-2021.rs:12:8
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LL | fn bar(x: Foo) -> Foo {
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| ^ doesn't have a size known at compile-time
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= help: the trait `Sized` is not implemented for `(dyn Foo + 'static)`
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= help: unsized fn params are gated as an unstable feature
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help: you can use `impl Trait` as the argument type
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LL | fn bar(x: impl Foo) -> Foo {
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| ++++
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help: function arguments must have a statically known size, borrowed types always have a known size
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LL | fn bar(x: &dyn Foo) -> Foo {
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| ++++
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error[E0782]: trait objects must include the `dyn` keyword
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--> $DIR/not-on-bare-trait-2021.rs:8:12
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LL | fn foo(_x: Foo + Send) {
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| ^^^^^^^^^^
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help: use a new generic type parameter, constrained by `Foo + Send`
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LL | fn foo<T: Foo + Send>(_x: T) {
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| +++++++++++++++ ~
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help: you can also use an opaque type, but users won't be able to specify the type parameter when calling the `fn`, having to rely exclusively on type inference
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LL | fn foo(_x: impl Foo + Send) {
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| ++++
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help: alternatively, use a trait object to accept any type that implements `Foo + Send`, accessing its methods at runtime using dynamic dispatch
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LL | fn foo(_x: &(dyn Foo + Send)) {
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| +++++ +
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error[E0782]: trait objects must include the `dyn` keyword
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--> $DIR/not-on-bare-trait-2021.rs:12:11
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LL | fn bar(x: Foo) -> Foo {
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| ^^^
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help: use a new generic type parameter, constrained by `Foo`
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LL | fn bar<T: Foo>(x: T) -> Foo {
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| ++++++++ ~
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help: you can also use an opaque type, but users won't be able to specify the type parameter when calling the `fn`, having to rely exclusively on type inference
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LL | fn bar(x: impl Foo) -> Foo {
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| ++++
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help: alternatively, use a trait object to accept any type that implements `Foo`, accessing its methods at runtime using dynamic dispatch
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LL | fn bar(x: &dyn Foo) -> Foo {
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| ++++
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error[E0782]: trait objects must include the `dyn` keyword
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--> $DIR/not-on-bare-trait-2021.rs:12:19
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LL | fn bar(x: Foo) -> Foo {
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| ^^^
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help: use `impl Foo` to return an opaque type, as long as you return a single underlying type
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LL | fn bar(x: Foo) -> impl Foo {
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| ++++
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help: alternatively, you can return an owned trait object
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LL | fn bar(x: Foo) -> Box<dyn Foo> {
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| +++++++ +
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error: aborting due to 5 previous errors
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Some errors have detailed explanations: E0277, E0782.
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For more information about an error, try `rustc --explain E0277`.
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