24 lines
558 B
Rust
24 lines
558 B
Rust
//! This test checks that opaque types get unsized instead of
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//! constraining their hidden type to a trait object.
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//@ revisions: next old
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//@[next] compile-flags: -Znext-solver
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#![feature(trait_upcasting)]
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trait Trait {}
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impl Trait for u32 {}
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fn hello() -> Box<impl Trait + ?Sized> {
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if true {
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let x = hello();
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let y: Box<dyn Send> = x as Box<dyn Trait + Send>;
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//[old]~^ ERROR: the size for values of type `impl Trait + ?Sized` cannot be know
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//~^^ ERROR: mismatched types
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}
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Box::new(1u32)
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}
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fn main() {}
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