mirror of
https://github.com/rust-lang/rust
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33 lines
862 B
Rust
33 lines
862 B
Rust
//@ compile-flags: -Znext-solver
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//@ check-pass
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trait Eq<'a, 'b, T> {}
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trait Ambig {}
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impl Ambig for () {}
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impl<'a, T> Eq<'a, 'a, T> for () where T: Ambig {}
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fn eq<'a, 'b, T>(t: T)
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where
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(): Eq<'a, 'b, T>,
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{
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}
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fn test<'r>() {
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let mut x = Default::default();
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// When we evaluate `(): Eq<'r, 'r, ?0>` we uniquify the regions.
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// That leads us to evaluate `(): Eq<'?0, '?1, ?0>`. The response of this
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// will be ambiguous (because `?0: Ambig` is ambig) and also not an "identity"
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// response, since the region constraints will contain `'?0 == '?1` (so
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// `is_changed` will return true). Since it's both ambig and changed,
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// fulfillment will both re-register the goal AND loop again. This hits the
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// overflow limit. This should neither be considered overflow, nor ICE.
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eq::<'r, 'r, _>(x);
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x = ();
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}
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fn main() {}
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