| //@ revisions: current next |
| //@[next] compile-flags: -Znext-solver |
| //@ ignore-compare-mode-next-solver (explicit revisions) |
| //@ check-pass |
| |
| fn prove_proj<R>(_: impl FnOnce() -> R) {} |
| fn recur<'a>() -> impl Sized + 'a { |
| // The closure has the signature `fn() -> opaque<'1>`. `prove_proj` |
| // requires us to prove `<closure as FnOnce<()>>::Output = opaque<'2>`. |
| // The old solver uses `replace_opaque_types_with_infer` during normalization |
| // to replace `opaque<'2>` with its hidden type. If that hidden type is still an |
| // inference variable at this point, we unify it with `opaque<'1>` and |
| // end up ignoring that defining use as the hidden type is equal to its key. |
| prove_proj(|| recur()); |
| } |
| |
| fn main() {} |
