# `trait_upcasting`
-The tracking issue for this feature is: [#31436]
+The tracking issue for this feature is: [#65991]
[#65991]: https://github.com/rust-lang/rust/issues/65991
------------------------
-The `trait_upcasting` feature adds support for trait upcasting. This allows a
-trait object of type `dyn Foo` to be cast to a trait object of type `dyn Bar`
-so long as `Foo: Bar`.
+The `trait_upcasting` feature adds support for trait upcasting coercion. This allows a
+trait object of type `dyn Bar` to be cast to a trait object of type `dyn Foo`
+so long as `Bar: Foo`.
```rust,edition2018
#![feature(trait_upcasting)]
+#![allow(incomplete_features)]
trait Foo {}
impl<T: Foo + ?Sized> Bar for T {}
-let foo: &dyn Foo = &123;
-let bar: &dyn Bar = foo;
+let bar: &dyn Bar = &123;
+let foo: &dyn Foo = bar;
```
// run-pass
#![feature(trait_upcasting)]
+#![allow(incomplete_features)]
trait Foo: PartialEq<i32> + std::fmt::Debug + Send + Sync {
- fn a(&self) -> i32 { 10 }
+ fn a(&self) -> i32 {
+ 10
+ }
- fn z(&self) -> i32 { 11 }
+ fn z(&self) -> i32 {
+ 11
+ }
- fn y(&self) -> i32 { 12 }
+ fn y(&self) -> i32 {
+ 12
+ }
}
trait Bar: Foo {
- fn b(&self) -> i32 { 20 }
+ fn b(&self) -> i32 {
+ 20
+ }
- fn w(&self) -> i32 { 21 }
+ fn w(&self) -> i32 {
+ 21
+ }
}
trait Baz: Bar {
- fn c(&self) -> i32 { 30 }
+ fn c(&self) -> i32 {
+ 30
+ }
}
impl Foo for i32 {
- fn a(&self) -> i32 { 100 }
+ fn a(&self) -> i32 {
+ 100
+ }
}
impl Bar for i32 {
- fn b(&self) -> i32 { 200 }
+ fn b(&self) -> i32 {
+ 200
+ }
}
impl Baz for i32 {
- fn c(&self) -> i32 { 300 }
+ fn c(&self) -> i32 {
+ 300
+ }
}
fn main() {
let baz: &dyn Baz = &1;
let _: &dyn std::fmt::Debug = baz;
- let _: &(dyn Send + Sync) = baz;
- let _: &dyn Send = baz;
- let _: &dyn Sync = baz;
assert_eq!(*baz, 1);
assert_eq!(baz.a(), 100);
assert_eq!(baz.b(), 200);
let bar: &dyn Bar = baz;
let _: &dyn std::fmt::Debug = bar;
- let _: &(dyn Send + Sync) = bar;
- let _: &dyn Send = bar;
- let _: &dyn Sync = bar;
assert_eq!(*bar, 1);
assert_eq!(bar.a(), 100);
assert_eq!(bar.b(), 200);
let foo: &dyn Foo = baz;
let _: &dyn std::fmt::Debug = foo;
- let _: &(dyn Send + Sync) = foo;
- let _: &dyn Send = foo;
- let _: &dyn Sync = foo;
assert_eq!(*foo, 1);
assert_eq!(foo.a(), 100);
assert_eq!(foo.z(), 11);
let foo: &dyn Foo = bar;
let _: &dyn std::fmt::Debug = foo;
- let _: &(dyn Send + Sync) = foo;
- let _: &dyn Send = foo;
- let _: &dyn Sync = foo;
assert_eq!(*foo, 1);
assert_eq!(foo.a(), 100);
assert_eq!(foo.z(), 11);
trait A: B + A {}
-//~^ ERROR cycle detected when computing the supertraits of `A` [E0391]
+//~^ ERROR cycle detected when computing the super predicates of `A` [E0391]
trait B {}
-error[E0391]: cycle detected when computing the supertraits of `A`
+error[E0391]: cycle detected when computing the super predicates of `A`
+ --> $DIR/cyclic-trait-resolution.rs:1:1
+ |
+LL | trait A: B + A {}
+ | ^^^^^^^^^^^^^^
+ |
+note: ...which requires computing the super traits of `A`...
--> $DIR/cyclic-trait-resolution.rs:1:14
|
LL | trait A: B + A {}
| ^
- |
- = note: ...which again requires computing the supertraits of `A`, completing the cycle
+ = note: ...which again requires computing the super predicates of `A`, completing the cycle
note: cycle used when collecting item types in top-level module
--> $DIR/cyclic-trait-resolution.rs:1:1
|
// run-pass
#![feature(trait_upcasting)]
+#![allow(incomplete_features)]
trait Foo: PartialEq<i32> + std::fmt::Debug + Send + Sync {
- fn a(&self) -> i32 { 10 }
+ fn a(&self) -> i32 {
+ 10
+ }
- fn z(&self) -> i32 { 11 }
+ fn z(&self) -> i32 {
+ 11
+ }
- fn y(&self) -> i32 { 12 }
+ fn y(&self) -> i32 {
+ 12
+ }
}
trait Bar1: Foo {
- fn b(&self) -> i32 { 20 }
+ fn b(&self) -> i32 {
+ 20
+ }
- fn w(&self) -> i32 { 21 }
+ fn w(&self) -> i32 {
+ 21
+ }
}
trait Bar2: Foo {
- fn c(&self) -> i32 { 30 }
+ fn c(&self) -> i32 {
+ 30
+ }
- fn v(&self) -> i32 { 31 }
+ fn v(&self) -> i32 {
+ 31
+ }
}
trait Baz: Bar1 + Bar2 {
- fn d(&self) -> i32 { 40 }
+ fn d(&self) -> i32 {
+ 40
+ }
}
impl Foo for i32 {
- fn a(&self) -> i32 { 100 }
+ fn a(&self) -> i32 {
+ 100
+ }
}
impl Bar1 for i32 {
- fn b(&self) -> i32 { 200 }
+ fn b(&self) -> i32 {
+ 200
+ }
}
impl Bar2 for i32 {
- fn c(&self) -> i32 { 300 }
+ fn c(&self) -> i32 {
+ 300
+ }
}
impl Baz for i32 {
- fn d(&self) -> i32 { 400 }
+ fn d(&self) -> i32 {
+ 400
+ }
}
fn main() {
let baz: &dyn Baz = &1;
let _: &dyn std::fmt::Debug = baz;
- let _: &(dyn Send + Sync) = baz;
- let _: &dyn Send = baz;
- let _: &dyn Sync = baz;
assert_eq!(*baz, 1);
assert_eq!(baz.a(), 100);
assert_eq!(baz.b(), 200);
let bar1: &dyn Bar1 = baz;
let _: &dyn std::fmt::Debug = bar1;
- let _: &(dyn Send + Sync) = bar1;
- let _: &dyn Send = bar1;
- let _: &dyn Sync = bar1;
assert_eq!(*bar1, 1);
assert_eq!(bar1.a(), 100);
assert_eq!(bar1.b(), 200);
let bar2: &dyn Bar2 = baz;
let _: &dyn std::fmt::Debug = bar2;
- let _: &(dyn Send + Sync) = bar2;
- let _: &dyn Send = bar2;
- let _: &dyn Sync = bar2;
assert_eq!(*bar2, 1);
assert_eq!(bar2.a(), 100);
assert_eq!(bar2.c(), 300);
let foo: &dyn Foo = baz;
let _: &dyn std::fmt::Debug = foo;
- let _: &(dyn Send + Sync) = foo;
- let _: &dyn Send = foo;
- let _: &dyn Sync = foo;
assert_eq!(*foo, 1);
assert_eq!(foo.a(), 100);
let foo: &dyn Foo = bar1;
let _: &dyn std::fmt::Debug = foo;
- let _: &(dyn Send + Sync) = foo;
- let _: &dyn Send = foo;
- let _: &dyn Sync = foo;
assert_eq!(*foo, 1);
assert_eq!(foo.a(), 100);
let foo: &dyn Foo = bar2;
let _: &dyn std::fmt::Debug = foo;
- let _: &(dyn Send + Sync) = foo;
- let _: &dyn Send = foo;
- let _: &dyn Sync = foo;
assert_eq!(*foo, 1);
assert_eq!(foo.a(), 100);
}
#![feature(trait_upcasting)]
+#![allow(incomplete_features)]
trait Foo {
- fn a(&self) -> i32 { 10 }
+ fn a(&self) -> i32 {
+ 10
+ }
- fn z(&self) -> i32 { 11 }
+ fn z(&self) -> i32 {
+ 11
+ }
- fn y(&self) -> i32 { 12 }
+ fn y(&self) -> i32 {
+ 12
+ }
}
trait Bar {
- fn b(&self) -> i32 { 20 }
+ fn b(&self) -> i32 {
+ 20
+ }
- fn w(&self) -> i32 { 21 }
+ fn w(&self) -> i32 {
+ 21
+ }
}
trait Baz {
- fn c(&self) -> i32 { 30 }
+ fn c(&self) -> i32 {
+ 30
+ }
}
impl Foo for i32 {
- fn a(&self) -> i32 { 100 }
+ fn a(&self) -> i32 {
+ 100
+ }
}
impl Bar for i32 {
- fn b(&self) -> i32 { 200 }
+ fn b(&self) -> i32 {
+ 200
+ }
}
impl Baz for i32 {
- fn c(&self) -> i32 { 300 }
+ fn c(&self) -> i32 {
+ 300
+ }
}
fn main() {
let baz: &dyn Baz = &1;
let _: &dyn std::fmt::Debug = baz;
- //~^ ERROR `dyn Baz` doesn't implement `std::fmt::Debug` [E0277]
+ //~^ ERROR mismatched types [E0308]
let _: &dyn Send = baz;
- //~^ ERROR `dyn Baz` cannot be sent between threads safely [E0277]
+ //~^ ERROR mismatched types [E0308]
let _: &dyn Sync = baz;
- //~^ ERROR `dyn Baz` cannot be shared between threads safely [E0277]
+ //~^ ERROR mismatched types [E0308]
let bar: &dyn Bar = baz;
- //~^ ERROR the trait bound `dyn Baz: Bar` is not satisfied [E0277]
+ //~^ ERROR mismatched types [E0308]
let _: &dyn std::fmt::Debug = bar;
- //~^ ERROR `dyn Bar` doesn't implement `std::fmt::Debug` [E0277]
+ //~^ ERROR mismatched types [E0308]
let _: &dyn Send = bar;
- //~^ ERROR `dyn Bar` cannot be sent between threads safely [E0277]
+ //~^ ERROR mismatched types [E0308]
let _: &dyn Sync = bar;
- //~^ ERROR `dyn Bar` cannot be shared between threads safely [E0277]
+ //~^ ERROR mismatched types [E0308]
let foo: &dyn Foo = baz;
- //~^ ERROR the trait bound `dyn Baz: Foo` is not satisfied [E0277]
+ //~^ ERROR mismatched types [E0308]
let _: &dyn std::fmt::Debug = foo;
- //~^ ERROR `dyn Foo` doesn't implement `std::fmt::Debug` [E0277]
+ //~^ ERROR mismatched types [E0308]
let _: &dyn Send = foo;
- //~^ ERROR `dyn Foo` cannot be sent between threads safely [E0277]
+ //~^ ERROR mismatched types [E0308]
let _: &dyn Sync = foo;
- //~^ ERROR `dyn Foo` cannot be shared between threads safely [E0277]
+ //~^ ERROR mismatched types [E0308]
let foo: &dyn Foo = bar;
- //~^ ERROR the trait bound `dyn Bar: Foo` is not satisfied [E0277]
+ //~^ ERROR mismatched types [E0308]
let _: &dyn std::fmt::Debug = foo;
- //~^ ERROR `dyn Foo` doesn't implement `std::fmt::Debug` [E0277]
+ //~^ ERROR mismatched types [E0308]
let _: &dyn Send = foo;
- //~^ ERROR `dyn Foo` cannot be sent between threads safely [E0277]
+ //~^ ERROR mismatched types [E0308]
let _: &dyn Sync = foo;
- //~^ ERROR `dyn Foo` cannot be shared between threads safely [E0277]
+ //~^ ERROR mismatched types [E0308]
}
-error[E0277]: `dyn Baz` doesn't implement `std::fmt::Debug`
- --> $DIR/invalid-upcast.rs:35:35
+error[E0308]: mismatched types
+ --> $DIR/invalid-upcast.rs:54:35
|
LL | let _: &dyn std::fmt::Debug = baz;
- | ^^^ `dyn Baz` cannot be formatted using `{:?}` because it doesn't implement `std::fmt::Debug`
+ | -------------------- ^^^ expected trait `Debug`, found trait `Baz`
+ | |
+ | expected due to this
|
- = help: the trait `std::fmt::Debug` is not implemented for `dyn Baz`
- = note: required for the cast to the object type `dyn std::fmt::Debug`
+ = note: expected reference `&dyn Debug`
+ found reference `&dyn Baz`
-error[E0277]: `dyn Baz` cannot be sent between threads safely
- --> $DIR/invalid-upcast.rs:37:24
+error[E0308]: mismatched types
+ --> $DIR/invalid-upcast.rs:56:24
|
LL | let _: &dyn Send = baz;
- | ^^^ `dyn Baz` cannot be sent between threads safely
+ | --------- ^^^ expected trait `Send`, found trait `Baz`
+ | |
+ | expected due to this
|
- = help: the trait `std::marker::Send` is not implemented for `dyn Baz`
- = note: required for the cast to the object type `dyn std::marker::Send`
+ = note: expected reference `&dyn Send`
+ found reference `&dyn Baz`
-error[E0277]: `dyn Baz` cannot be shared between threads safely
- --> $DIR/invalid-upcast.rs:39:24
+error[E0308]: mismatched types
+ --> $DIR/invalid-upcast.rs:58:24
|
LL | let _: &dyn Sync = baz;
- | ^^^ `dyn Baz` cannot be shared between threads safely
+ | --------- ^^^ expected trait `Sync`, found trait `Baz`
+ | |
+ | expected due to this
|
- = help: the trait `std::marker::Sync` is not implemented for `dyn Baz`
- = note: required for the cast to the object type `dyn std::marker::Sync`
+ = note: expected reference `&dyn Sync`
+ found reference `&dyn Baz`
-error[E0277]: the trait bound `dyn Baz: Bar` is not satisfied
- --> $DIR/invalid-upcast.rs:42:25
+error[E0308]: mismatched types
+ --> $DIR/invalid-upcast.rs:61:25
|
LL | let bar: &dyn Bar = baz;
- | ^^^ the trait `Bar` is not implemented for `dyn Baz`
+ | -------- ^^^ expected trait `Bar`, found trait `Baz`
+ | |
+ | expected due to this
|
- = note: required for the cast to the object type `dyn Bar`
+ = note: expected reference `&dyn Bar`
+ found reference `&dyn Baz`
-error[E0277]: `dyn Bar` doesn't implement `std::fmt::Debug`
- --> $DIR/invalid-upcast.rs:44:35
+error[E0308]: mismatched types
+ --> $DIR/invalid-upcast.rs:63:35
|
LL | let _: &dyn std::fmt::Debug = bar;
- | ^^^ `dyn Bar` cannot be formatted using `{:?}` because it doesn't implement `std::fmt::Debug`
+ | -------------------- ^^^ expected trait `Debug`, found trait `Bar`
+ | |
+ | expected due to this
|
- = help: the trait `std::fmt::Debug` is not implemented for `dyn Bar`
- = note: required for the cast to the object type `dyn std::fmt::Debug`
+ = note: expected reference `&dyn Debug`
+ found reference `&dyn Bar`
-error[E0277]: `dyn Bar` cannot be sent between threads safely
- --> $DIR/invalid-upcast.rs:46:24
+error[E0308]: mismatched types
+ --> $DIR/invalid-upcast.rs:65:24
|
LL | let _: &dyn Send = bar;
- | ^^^ `dyn Bar` cannot be sent between threads safely
+ | --------- ^^^ expected trait `Send`, found trait `Bar`
+ | |
+ | expected due to this
|
- = help: the trait `std::marker::Send` is not implemented for `dyn Bar`
- = note: required for the cast to the object type `dyn std::marker::Send`
+ = note: expected reference `&dyn Send`
+ found reference `&dyn Bar`
-error[E0277]: `dyn Bar` cannot be shared between threads safely
- --> $DIR/invalid-upcast.rs:48:24
+error[E0308]: mismatched types
+ --> $DIR/invalid-upcast.rs:67:24
|
LL | let _: &dyn Sync = bar;
- | ^^^ `dyn Bar` cannot be shared between threads safely
+ | --------- ^^^ expected trait `Sync`, found trait `Bar`
+ | |
+ | expected due to this
|
- = help: the trait `std::marker::Sync` is not implemented for `dyn Bar`
- = note: required for the cast to the object type `dyn std::marker::Sync`
+ = note: expected reference `&dyn Sync`
+ found reference `&dyn Bar`
-error[E0277]: the trait bound `dyn Baz: Foo` is not satisfied
- --> $DIR/invalid-upcast.rs:51:25
+error[E0308]: mismatched types
+ --> $DIR/invalid-upcast.rs:70:25
|
LL | let foo: &dyn Foo = baz;
- | ^^^ the trait `Foo` is not implemented for `dyn Baz`
+ | -------- ^^^ expected trait `Foo`, found trait `Baz`
+ | |
+ | expected due to this
|
- = note: required for the cast to the object type `dyn Foo`
+ = note: expected reference `&dyn Foo`
+ found reference `&dyn Baz`
-error[E0277]: `dyn Foo` doesn't implement `std::fmt::Debug`
- --> $DIR/invalid-upcast.rs:53:35
+error[E0308]: mismatched types
+ --> $DIR/invalid-upcast.rs:72:35
|
LL | let _: &dyn std::fmt::Debug = foo;
- | ^^^ `dyn Foo` cannot be formatted using `{:?}` because it doesn't implement `std::fmt::Debug`
+ | -------------------- ^^^ expected trait `Debug`, found trait `Foo`
+ | |
+ | expected due to this
|
- = help: the trait `std::fmt::Debug` is not implemented for `dyn Foo`
- = note: required for the cast to the object type `dyn std::fmt::Debug`
+ = note: expected reference `&dyn Debug`
+ found reference `&dyn Foo`
-error[E0277]: `dyn Foo` cannot be sent between threads safely
- --> $DIR/invalid-upcast.rs:55:24
+error[E0308]: mismatched types
+ --> $DIR/invalid-upcast.rs:74:24
|
LL | let _: &dyn Send = foo;
- | ^^^ `dyn Foo` cannot be sent between threads safely
+ | --------- ^^^ expected trait `Send`, found trait `Foo`
+ | |
+ | expected due to this
|
- = help: the trait `std::marker::Send` is not implemented for `dyn Foo`
- = note: required for the cast to the object type `dyn std::marker::Send`
+ = note: expected reference `&dyn Send`
+ found reference `&dyn Foo`
-error[E0277]: `dyn Foo` cannot be shared between threads safely
- --> $DIR/invalid-upcast.rs:57:24
+error[E0308]: mismatched types
+ --> $DIR/invalid-upcast.rs:76:24
|
LL | let _: &dyn Sync = foo;
- | ^^^ `dyn Foo` cannot be shared between threads safely
+ | --------- ^^^ expected trait `Sync`, found trait `Foo`
+ | |
+ | expected due to this
|
- = help: the trait `std::marker::Sync` is not implemented for `dyn Foo`
- = note: required for the cast to the object type `dyn std::marker::Sync`
+ = note: expected reference `&dyn Sync`
+ found reference `&dyn Foo`
-error[E0277]: the trait bound `dyn Bar: Foo` is not satisfied
- --> $DIR/invalid-upcast.rs:60:25
+error[E0308]: mismatched types
+ --> $DIR/invalid-upcast.rs:79:25
|
LL | let foo: &dyn Foo = bar;
- | ^^^ the trait `Foo` is not implemented for `dyn Bar`
+ | -------- ^^^ expected trait `Foo`, found trait `Bar`
+ | |
+ | expected due to this
|
- = note: required for the cast to the object type `dyn Foo`
+ = note: expected reference `&dyn Foo`
+ found reference `&dyn Bar`
-error[E0277]: `dyn Foo` doesn't implement `std::fmt::Debug`
- --> $DIR/invalid-upcast.rs:62:35
+error[E0308]: mismatched types
+ --> $DIR/invalid-upcast.rs:81:35
|
LL | let _: &dyn std::fmt::Debug = foo;
- | ^^^ `dyn Foo` cannot be formatted using `{:?}` because it doesn't implement `std::fmt::Debug`
+ | -------------------- ^^^ expected trait `Debug`, found trait `Foo`
+ | |
+ | expected due to this
|
- = help: the trait `std::fmt::Debug` is not implemented for `dyn Foo`
- = note: required for the cast to the object type `dyn std::fmt::Debug`
+ = note: expected reference `&dyn Debug`
+ found reference `&dyn Foo`
-error[E0277]: `dyn Foo` cannot be sent between threads safely
- --> $DIR/invalid-upcast.rs:64:24
+error[E0308]: mismatched types
+ --> $DIR/invalid-upcast.rs:83:24
|
LL | let _: &dyn Send = foo;
- | ^^^ `dyn Foo` cannot be sent between threads safely
+ | --------- ^^^ expected trait `Send`, found trait `Foo`
+ | |
+ | expected due to this
|
- = help: the trait `std::marker::Send` is not implemented for `dyn Foo`
- = note: required for the cast to the object type `dyn std::marker::Send`
+ = note: expected reference `&dyn Send`
+ found reference `&dyn Foo`
-error[E0277]: `dyn Foo` cannot be shared between threads safely
- --> $DIR/invalid-upcast.rs:66:24
+error[E0308]: mismatched types
+ --> $DIR/invalid-upcast.rs:85:24
|
LL | let _: &dyn Sync = foo;
- | ^^^ `dyn Foo` cannot be shared between threads safely
+ | --------- ^^^ expected trait `Sync`, found trait `Foo`
+ | |
+ | expected due to this
|
- = help: the trait `std::marker::Sync` is not implemented for `dyn Foo`
- = note: required for the cast to the object type `dyn std::marker::Sync`
+ = note: expected reference `&dyn Sync`
+ found reference `&dyn Foo`
error: aborting due to 15 previous errors
-For more information about this error, try `rustc --explain E0277`.
+For more information about this error, try `rustc --explain E0308`.
// run-pass
+// ignore-compare-mode-nll
#![feature(trait_upcasting)]
+#![allow(incomplete_features)]
trait Foo: PartialEq<i32> + std::fmt::Debug + Send + Sync {
- fn a(&self) -> i32 { 10 }
+ fn a(&self) -> i32 {
+ 10
+ }
- fn z(&self) -> i32 { 11 }
+ fn z(&self) -> i32 {
+ 11
+ }
- fn y(&self) -> i32 { 12 }
+ fn y(&self) -> i32 {
+ 12
+ }
}
trait Bar: Foo {
- fn b(&self) -> i32 { 20 }
+ fn b(&self) -> i32 {
+ 20
+ }
- fn w(&self) -> i32 { 21 }
+ fn w(&self) -> i32 {
+ 21
+ }
}
trait Baz: Bar {
- fn c(&self) -> i32 { 30 }
+ fn c(&self) -> i32 {
+ 30
+ }
}
impl Foo for i32 {
- fn a(&self) -> i32 { 100 }
+ fn a(&self) -> i32 {
+ 100
+ }
}
impl Bar for i32 {
- fn b(&self) -> i32 { 200 }
+ fn b(&self) -> i32 {
+ 200
+ }
}
impl Baz for i32 {
- fn c(&self) -> i32 { 300 }
+ fn c(&self) -> i32 {
+ 300
+ }
}
// Note: upcast lifetime means a shorter lifetime.
-fn upcast_baz<'a: 'b, 'b, T>(v: Box<dyn Baz + 'a>, _l: &'b T) -> Box<dyn Baz + 'b> { v }
-fn upcast_bar<'a: 'b, 'b, T>(v: Box<dyn Bar + 'a>, _l: &'b T) -> Box<dyn Bar + 'b> { v }
-fn upcast_foo<'a: 'b, 'b, T>(v: Box<dyn Foo + 'a>, _l: &'b T) -> Box<dyn Foo + 'b> { v }
+fn upcast_baz<'a: 'b, 'b, T>(v: Box<dyn Baz + 'a>, _l: &'b T) -> Box<dyn Baz + 'b> {
+ v
+}
+fn upcast_bar<'a: 'b, 'b, T>(v: Box<dyn Bar + 'a>, _l: &'b T) -> Box<dyn Bar + 'b> {
+ v
+}
+fn upcast_foo<'a: 'b, 'b, T>(v: Box<dyn Foo + 'a>, _l: &'b T) -> Box<dyn Foo + 'b> {
+ v
+}
fn main() {
let v = Box::new(1);
// run-pass
#![feature(trait_upcasting)]
+#![allow(incomplete_features)]
use std::rc::Rc;
use std::sync::Arc;
trait Foo: PartialEq<i32> + std::fmt::Debug + Send + Sync {
- fn a(&self) -> i32 { 10 }
+ fn a(&self) -> i32 {
+ 10
+ }
- fn z(&self) -> i32 { 11 }
+ fn z(&self) -> i32 {
+ 11
+ }
- fn y(&self) -> i32 { 12 }
+ fn y(&self) -> i32 {
+ 12
+ }
}
trait Bar: Foo {
- fn b(&self) -> i32 { 20 }
+ fn b(&self) -> i32 {
+ 20
+ }
- fn w(&self) -> i32 { 21 }
+ fn w(&self) -> i32 {
+ 21
+ }
}
trait Baz: Bar {
- fn c(&self) -> i32 { 30 }
+ fn c(&self) -> i32 {
+ 30
+ }
}
impl Foo for i32 {
- fn a(&self) -> i32 { 100 }
+ fn a(&self) -> i32 {
+ 100
+ }
}
impl Bar for i32 {
- fn b(&self) -> i32 { 200 }
+ fn b(&self) -> i32 {
+ 200
+ }
}
impl Baz for i32 {
- fn c(&self) -> i32 { 300 }
+ fn c(&self) -> i32 {
+ 300
+ }
}
fn test_box() {
#![feature(trait_upcasting)]
+#![allow(incomplete_features)]
trait Foo: PartialEq<i32> + std::fmt::Debug + Send + Sync {
- fn a(&self) -> i32 { 10 }
+ fn a(&self) -> i32 {
+ 10
+ }
- fn z(&self) -> i32 { 11 }
+ fn z(&self) -> i32 {
+ 11
+ }
- fn y(&self) -> i32 { 12 }
+ fn y(&self) -> i32 {
+ 12
+ }
}
trait Bar: Foo {
- fn b(&self) -> i32 { 20 }
+ fn b(&self) -> i32 {
+ 20
+ }
- fn w(&self) -> i32 { 21 }
+ fn w(&self) -> i32 {
+ 21
+ }
}
trait Baz: Bar {
- fn c(&self) -> i32 { 30 }
+ fn c(&self) -> i32 {
+ 30
+ }
}
impl Foo for i32 {
- fn a(&self) -> i32 { 100 }
+ fn a(&self) -> i32 {
+ 100
+ }
}
impl Bar for i32 {
- fn b(&self) -> i32 { 200 }
+ fn b(&self) -> i32 {
+ 200
+ }
}
impl Baz for i32 {
- fn c(&self) -> i32 { 300 }
+ fn c(&self) -> i32 {
+ 300
+ }
}
fn main() {
error[E0599]: no method named `c` found for reference `&dyn Bar` in the current scope
- --> $DIR/subtrait-method.rs:37:9
+ --> $DIR/subtrait-method.rs:56:9
|
LL | bar.c();
| ^ help: there is an associated function with a similar name: `a`
|
= help: items from traits can only be used if the trait is implemented and in scope
note: `Baz` defines an item `c`, perhaps you need to implement it
- --> $DIR/subtrait-method.rs:17:1
+ --> $DIR/subtrait-method.rs:28:1
|
LL | trait Baz: Bar {
| ^^^^^^^^^^^^^^
error[E0599]: no method named `b` found for reference `&dyn Foo` in the current scope
- --> $DIR/subtrait-method.rs:41:9
+ --> $DIR/subtrait-method.rs:60:9
|
LL | foo.b();
| ^ help: there is an associated function with a similar name: `a`
|
= help: items from traits can only be used if the trait is implemented and in scope
note: `Bar` defines an item `b`, perhaps you need to implement it
- --> $DIR/subtrait-method.rs:11:1
+ --> $DIR/subtrait-method.rs:18:1
|
LL | trait Bar: Foo {
| ^^^^^^^^^^^^^^
error[E0599]: no method named `c` found for reference `&dyn Foo` in the current scope
- --> $DIR/subtrait-method.rs:43:9
+ --> $DIR/subtrait-method.rs:62:9
|
LL | foo.c();
| ^ help: there is an associated function with a similar name: `a`
|
= help: items from traits can only be used if the trait is implemented and in scope
note: `Baz` defines an item `c`, perhaps you need to implement it
- --> $DIR/subtrait-method.rs:17:1
+ --> $DIR/subtrait-method.rs:28:1
|
LL | trait Baz: Bar {
| ^^^^^^^^^^^^^^
error[E0599]: no method named `b` found for reference `&dyn Foo` in the current scope
- --> $DIR/subtrait-method.rs:47:9
+ --> $DIR/subtrait-method.rs:66:9
|
LL | foo.b();
| ^ help: there is an associated function with a similar name: `a`
|
= help: items from traits can only be used if the trait is implemented and in scope
note: `Bar` defines an item `b`, perhaps you need to implement it
- --> $DIR/subtrait-method.rs:11:1
+ --> $DIR/subtrait-method.rs:18:1
|
LL | trait Bar: Foo {
| ^^^^^^^^^^^^^^
error[E0599]: no method named `c` found for reference `&dyn Foo` in the current scope
- --> $DIR/subtrait-method.rs:49:9
+ --> $DIR/subtrait-method.rs:68:9
|
LL | foo.c();
| ^ help: there is an associated function with a similar name: `a`
|
= help: items from traits can only be used if the trait is implemented and in scope
note: `Baz` defines an item `c`, perhaps you need to implement it
- --> $DIR/subtrait-method.rs:17:1
+ --> $DIR/subtrait-method.rs:28:1
|
LL | trait Baz: Bar {
| ^^^^^^^^^^^^^^
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