diff options
Diffstat (limited to 'tests/ui/generic-associated-types/bugs/issue-91762.rs')
-rw-r--r-- | tests/ui/generic-associated-types/bugs/issue-91762.rs | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/tests/ui/generic-associated-types/bugs/issue-91762.rs b/tests/ui/generic-associated-types/bugs/issue-91762.rs new file mode 100644 index 000000000..8f2cc4550 --- /dev/null +++ b/tests/ui/generic-associated-types/bugs/issue-91762.rs @@ -0,0 +1,28 @@ +// check-fail +// known-bug: unknown + +// We almost certainly want this to pass, but +// it's particularly difficult currently, because we need a way of specifying +// that `<Self::Base as Functor>::With<T> = Self` without using that when we have +// a `U`. See `https://github.com/rust-lang/rust/pull/92728` for a (hacky) +// solution. This might be better to just wait for Chalk. + +pub trait Functor { + type With<T>; + + fn fmap<T, U>(this: Self::With<T>) -> Self::With<U>; +} + +pub trait FunctorExt<T>: Sized { + type Base: Functor<With<T> = Self>; + + fn fmap<U>(self) { + let arg: <Self::Base as Functor>::With<T>; + let ret: <Self::Base as Functor>::With<U>; + + arg = self; + ret = <Self::Base as Functor>::fmap(arg); + } +} + +fn main() {} |