1 files changed, 37 insertions, 0 deletions
diff --git a/tests/ui/coherence/occurs-check/opaques.rs b/tests/ui/coherence/occurs-check/opaques.rs
new file mode 100644
index 000000000..2fa9dcebf
--- /dev/null
+++ b/tests/ui/coherence/occurs-check/opaques.rs
@@ -0,0 +1,37 @@
+//revisions: old next
+//[next] compile-flags: -Znext-solver
+
+// A regression test for #105787
+
+//[old] known-bug: #105787
+//[old] check-pass
+#![feature(type_alias_impl_trait)]
+mod defining_scope {
+    use super::*;
+    pub type Alias<T> = impl Sized;
+
+    pub fn cast<T>(x: Container<Alias<T>, T>) -> Container<T, T> {
+        x
+    }
+}
+
+struct Container<T: Trait<U>, U> {
+    x: <T as Trait<U>>::Assoc,
+}
+
+trait Trait<T> {
+    type Assoc;
+}
+
+impl<T> Trait<T> for T {
+    type Assoc = Box<u32>;
+}
+impl<T> Trait<T> for defining_scope::Alias<T> {
+    //[next]~^ ERROR conflicting implementations of trait
+    type Assoc = usize;
+}
+
+fn main() {
+    let x: Box<u32> = defining_scope::cast::<()>(Container { x: 0 }).x;
+    println!("{}", *x);
+}