45 lines
1.0 KiB
Rust
45 lines
1.0 KiB
Rust
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// compile-flags: -Ztrait-solver=next
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// check-pass
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#![feature(trivial_bounds, marker_trait_attr)]
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#![allow(trivial_bounds)]
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// This previously triggered a bug in the provisional cache.
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//
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// This has the proof tree
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// - `Root: Trait` proven via impl
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// - `MultipleCandidates: Trait`
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// - candidate: overflow-impl
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// - `Root: Trait` (inductive cycle ~> OVERFLOW)
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// - candidate: trivial-impl ~> YES
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// - merge respones ~> YES
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// - `MultipleCandidates: Trait` (in provisional cache ~> OVERFLOW)
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//
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// We previously incorrectly treated the `MultipleCandidates: Trait` as
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// overflow because it was in the cache and reached via an inductive cycle.
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// It should be `YES`.
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struct Root;
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struct MultipleCandidates;
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#[marker]
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trait Trait {}
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impl Trait for Root
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where
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MultipleCandidates: Trait,
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MultipleCandidates: Trait,
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{}
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// overflow-impl
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impl Trait for MultipleCandidates
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where
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Root: Trait,
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{}
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// trivial-impl
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impl Trait for MultipleCandidates {}
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fn impls_trait<T: Trait>() {}
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fn main() {
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impls_trait::<Root>();
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}
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