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36 lines
1.0 KiB
Rust
36 lines
1.0 KiB
Rust
// compile-flags: -Ztrait-solver=next
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// check-pass
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#![feature(type_alias_impl_trait)]
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type Tait = impl Iterator<Item = impl Sized>;
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/*
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Consider the goal - AliasRelate(Tait, <[i32; 32] as IntoIterator>::IntoIter)
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which is registered on the line above.
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A. SubstRelate - fails (of course).
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B. NormalizesToRhs - Tait normalizes-to <[i32; 32] as IntoIterator>::IntoIter
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* infer definition - Tait := <[i32; 32] as IntoIterator>::IntoIter
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C. NormalizesToLhs - <[i32; 32] as IntoIterator>::IntoIter normalizes-to Tait
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* Find impl candidate, after substitute - std::array::IntoIter<i32, 32>
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* Equate std::array::IntoIter<i32, 32> and Tait
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* infer definition - Tait := std::array::IntoIter<i32, 32>
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B and C are not equal, but they are equivalent modulo normalization.
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We get around this by evaluating both the NormalizesToRhs and NormalizesToLhs
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goals together. Essentially:
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A alias-relate B if A normalizes-to B and B normalizes-to A.
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*/
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fn a(_: Tait) {
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let _: Tait = IntoIterator::into_iter([0i32; 32]);
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}
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fn main() {}
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