diff options
Diffstat (limited to 'tests/ui/inference/issue-80816.rs')
-rw-r--r-- | tests/ui/inference/issue-80816.rs | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/tests/ui/inference/issue-80816.rs b/tests/ui/inference/issue-80816.rs new file mode 100644 index 000000000..4d319b449 --- /dev/null +++ b/tests/ui/inference/issue-80816.rs @@ -0,0 +1,55 @@ +#![allow(unreachable_code)] + +use std::marker::PhantomData; +use std::ops::Deref; +use std::sync::Arc; + +pub struct Guard<T> { + _phantom: PhantomData<T>, +} +impl<T> Deref for Guard<T> { + type Target = T; + fn deref(&self) -> &T { + unimplemented!() + } +} + +pub struct DirectDeref<T>(T); +impl<T> Deref for DirectDeref<Arc<T>> { + type Target = T; + fn deref(&self) -> &T { + unimplemented!() + } +} + +pub trait Access<T> { + type Guard: Deref<Target = T>; + fn load(&self) -> Self::Guard { + unimplemented!() + } +} +impl<T, A: Access<T>, P: Deref<Target = A>> Access<T> for P { + //~^ NOTE: required for `Arc<ArcSwapAny<Arc<usize>>>` to implement `Access<_>` + //~| NOTE unsatisfied trait bound introduced here + type Guard = A::Guard; +} +impl<T> Access<T> for ArcSwapAny<T> { + //~^ NOTE: multiple `impl`s satisfying `ArcSwapAny<Arc<usize>>: Access<_>` found + type Guard = Guard<T>; +} +impl<T> Access<T> for ArcSwapAny<Arc<T>> { + type Guard = DirectDeref<Arc<T>>; +} + +pub struct ArcSwapAny<T> { + _phantom_arc: PhantomData<T>, +} + +pub fn foo() { + let s: Arc<ArcSwapAny<Arc<usize>>> = unimplemented!(); + let guard: Guard<Arc<usize>> = s.load(); + //~^ ERROR: type annotations needed + //~| HELP: try using a fully qualified path to specify the expected types +} + +fn main() {} |