26 lines
627 B
Rust
26 lines
627 B
Rust
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// check-pass
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// issue: 114035
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// revisions: current next
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//[next] compile-flags: -Ztrait-solver=next
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#![feature(trait_upcasting)]
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trait A: B {
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type Assoc;
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}
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trait B {}
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fn upcast(a: &dyn A<Assoc = i32>) -> &dyn B {
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a
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}
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// Make sure that we can drop the existential projection `A::Assoc = i32`
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// when upcasting `dyn A<Assoc = i32>` to `dyn B`. Before, we used some
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// complicated algorithm which required rebuilding a new object type with
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// different bounds in order to test that an upcast was valid, but this
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// didn't allow upcasting to t that have fewer associated types
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// than the source type.
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fn main() {}
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