34 lines
857 B
Rust
34 lines
857 B
Rust
// Nested impl-traits can impose different member constraints on the same region variable.
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// check-fail
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trait Cap<'a> {}
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impl<T> Cap<'_> for T {}
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// Assuming the hidden type is `[&'_#15r u8; 1]`, we have two distinct member constraints:
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// - '_#15r member ['static, 'a, 'b] // from outer impl-trait
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// - '_#15r member ['static, 'a, 'b] // from inner impl-trait
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// To satisfy both we can choose 'a or 'b, so it's a failure due to ambiguity.
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fn fail_early_bound<'s, 'a, 'b>(a: &'s u8) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>>
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where
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's: 'a,
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's: 'b,
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{
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[a]
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//~^ E0700
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//~| E0700
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}
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// Same as the above but with late-bound regions.
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fn fail_late_bound<'s, 'a, 'b>(
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a: &'s u8,
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_: &'a &'s u8,
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_: &'b &'s u8,
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) -> impl IntoIterator<Item = impl Cap<'a> + Cap<'b>> {
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[a]
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//~^ E0700
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//~| E0700
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}
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fn main() {}
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