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Use smaller example for issue-71659
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JohnTitor committed Oct 17, 2020
1 parent 59cc9de commit d80f93d
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Showing 2 changed files with 15 additions and 77 deletions.
84 changes: 11 additions & 73 deletions src/test/ui/unsized/issue-71659.rs
@@ -1,94 +1,32 @@
#![feature(unsize)]

use std::marker::Unsize;
use std::rc::Rc;
use std::sync::Arc;

pub trait CastTo<T: ?Sized>: Unsize<T> {
fn cast_to(&self) -> &T;
fn cast_mut_to(&mut self) -> &mut T;
fn into_cast_to(self: Box<Self>) -> Box<T>;
fn cast_rc_to(self: Rc<Self>) -> Rc<T>;
fn cast_arc_to(self: Arc<Self>) -> Arc<T>;
}

impl<T: ?Sized> Cast for T {}
pub trait Cast {
fn cast<T: ?Sized>(&self) -> &T
where
Self: CastTo<T>,
{
impl<T: ?Sized, U: ?Sized + Unsize<T>> CastTo<T> for U {
fn cast_to(&self) -> &T {
self
}
}

fn cast_mut<T>(&mut self) -> &mut T
where
Self: CastTo<T>,
{
self.cast_mut_to()
}

fn into_cast<T>(self: Box<Self>) -> Box<T>
where
Self: CastTo<T>,
{
self.into_cast_to()
}

fn cast_rc<T>(self: Rc<Self>) -> Rc<T>
where
Self: CastTo<T>,
{
self.cast_rc_to()
}

fn cast_arc<T>(self: Arc<Self>) -> Arc<T>
impl<T: ?Sized> Cast for T {}
pub trait Cast {
fn cast<T: ?Sized>(&self) -> &T
where
Self: CastTo<T>,
{
self.cast_arc_to()
}
}
impl<T: ?Sized, U: ?Sized + Unsize<T>> CastTo<T> for U {
fn cast_to(&self) -> &T {
self
}

fn cast_mut_to(&mut self) -> &mut T {
self
}

fn into_cast_to(self: Box<Self>) -> Box<T> {
self
}

fn cast_rc_to(self: Rc<Self>) -> Rc<T> {
self
}

fn cast_arc_to(self: Arc<Self>) -> Arc<T> {
self
}
}

pub trait Foo {
fn foo(&self) {
println!("Foo({})", core::any::type_name::<Self>());
}
}

pub trait Bar: CastTo<dyn Foo> + CastTo<dyn core::fmt::Debug> + CastTo<[i32]> {
fn bar(&self) {
println!("Bar({})", core::any::type_name::<Self>());
}
}

impl Foo for [i32; 10] {}
impl Bar for [i32; 10] {}
pub trait Foo: CastTo<[i32]> {}
impl Foo for [i32; 0] {}

fn main() {
let x = [0; 10];
let x: Box<dyn Bar> = Box::new(x);
let x = (*x).cast::<[i32]>();
//~^ ERROR: the trait bound `dyn Bar: CastTo<[i32]>` is not satisfied
let x: &dyn Foo = &[];
let x = x.cast::<[i32]>();
//~^ ERROR: the trait bound `dyn Foo: CastTo<[i32]>` is not satisfied
}
8 changes: 4 additions & 4 deletions src/test/ui/unsized/issue-71659.stderr
@@ -1,8 +1,8 @@
error[E0277]: the trait bound `dyn Bar: CastTo<[i32]>` is not satisfied
--> $DIR/issue-71659.rs:92:18
error[E0277]: the trait bound `dyn Foo: CastTo<[i32]>` is not satisfied
--> $DIR/issue-71659.rs:30:15
|
LL | let x = (*x).cast::<[i32]>();
| ^^^^ the trait `CastTo<[i32]>` is not implemented for `dyn Bar`
LL | let x = x.cast::<[i32]>();
| ^^^^ the trait `CastTo<[i32]>` is not implemented for `dyn Foo`

error: aborting due to previous error

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