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| author | Albert Larsan <74931857+albertlarsan68@users.noreply.github.com> | 2023-01-05 09:13:28 +0100 |
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| committer | Albert Larsan <74931857+albertlarsan68@users.noreply.github.com> | 2023-01-11 09:32:08 +0000 |
| commit | cf2dff2b1e3fa55fa5415d524200070d0d7aacfe (patch) | |
| tree | 40a88d9a46aaf3e8870676eb2538378b75a263eb /tests/ui/closures/supertrait-hint-cycle.rs | |
| parent | ca855e6e42787ecd062d81d53336fe6788ef51a9 (diff) | |
| download | rust-cf2dff2b1e3fa55fa5415d524200070d0d7aacfe.tar.gz rust-cf2dff2b1e3fa55fa5415d524200070d0d7aacfe.zip | |
Move /src/test to /tests
Diffstat (limited to 'tests/ui/closures/supertrait-hint-cycle.rs')
| -rw-r--r-- | tests/ui/closures/supertrait-hint-cycle.rs | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/tests/ui/closures/supertrait-hint-cycle.rs b/tests/ui/closures/supertrait-hint-cycle.rs new file mode 100644 index 00000000000..dbb06b2ef7a --- /dev/null +++ b/tests/ui/closures/supertrait-hint-cycle.rs @@ -0,0 +1,65 @@ +// edition:2021 +// check-pass + +#![feature(type_alias_impl_trait)] +#![feature(closure_lifetime_binder)] + +use std::future::Future; + +trait AsyncFn<I, R>: FnMut(I) -> Self::Fut { + type Fut: Future<Output = R>; +} + +impl<F, I, R, Fut> AsyncFn<I, R> for F +where + Fut: Future<Output = R>, + F: FnMut(I) -> Fut, +{ + type Fut = Fut; +} + +async fn call<C, R, F>(mut ctx: C, mut f: F) -> Result<R, ()> +where + F: for<'a> AsyncFn<&'a mut C, Result<R, ()>>, +{ + loop { + match f(&mut ctx).await { + Ok(val) => return Ok(val), + Err(_) => continue, + } + } +} + +trait Cap<'a> {} +impl<T> Cap<'_> for T {} + +fn works(ctx: &mut usize) { + let mut inner = 0; + + type Ret<'a, 'b: 'a> = impl Future<Output = Result<usize, ()>> + 'a + Cap<'b>; + + let callback = for<'a, 'b> |c: &'a mut &'b mut usize| -> Ret<'a, 'b> { + inner += 1; + async move { + let _c = c; + Ok(1usize) + } + }; + call(ctx, callback); +} + +fn doesnt_work_but_should(ctx: &mut usize) { + let mut inner = 0; + + type Ret<'a, 'b: 'a> = impl Future<Output = Result<usize, ()>> + 'a + Cap<'b>; + + call(ctx, for<'a, 'b> |c: &'a mut &'b mut usize| -> Ret<'a, 'b> { + inner += 1; + async move { + let _c = c; + Ok(1usize) + } + }); +} + +fn main() {} |
