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#![crate_type = "lib"] | ||
#![feature(specialization)] | ||
#![feature(unsize, coerce_unsized)] | ||
#![allow(incomplete_features)] | ||
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use std::ops::CoerceUnsized; | ||
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pub struct SmartassPtr<A: Smartass+?Sized>(A::Data); | ||
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pub trait Smartass { | ||
type Data; | ||
type Data2: CoerceUnsized<*const [u8]>; | ||
} | ||
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pub trait MaybeObjectSafe {} | ||
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impl MaybeObjectSafe for () {} | ||
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impl<T> Smartass for T { | ||
type Data = <Self as Smartass>::Data2; | ||
default type Data2 = (); | ||
//~^ ERROR: the trait bound `(): std::ops::CoerceUnsized<*const [u8]>` is not satisfied | ||
} | ||
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impl Smartass for () { | ||
type Data2 = *const [u8; 1]; | ||
} | ||
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impl Smartass for dyn MaybeObjectSafe { | ||
type Data = *const [u8]; | ||
type Data2 = *const [u8; 0]; | ||
} | ||
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impl<U: Smartass+?Sized, T: Smartass+?Sized> CoerceUnsized<SmartassPtr<T>> for SmartassPtr<U> | ||
where <U as Smartass>::Data: std::ops::CoerceUnsized<<T as Smartass>::Data> | ||
{} | ||
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pub fn conv(s: SmartassPtr<()>) -> SmartassPtr<dyn MaybeObjectSafe> { | ||
s | ||
} |
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error[E0277]: the trait bound `(): std::ops::CoerceUnsized<*const [u8]>` is not satisfied | ||
--> $DIR/issue-44861.rs:21:5 | ||
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LL | type Data2: CoerceUnsized<*const [u8]>; | ||
| --------------------------------------- required by `Smartass::Data2` | ||
... | ||
LL | default type Data2 = (); | ||
| ^^^^^^^^^^^^^^^^^^^^^^^^ the trait `std::ops::CoerceUnsized<*const [u8]>` is not implemented for `()` | ||
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error: aborting due to previous error | ||
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For more information about this error, try `rustc --explain E0277`. |