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