Add test for issue-48010

Author: JohnTitor

src/test/ui/associated-types/issue-48010.rs

@@ -0,0 +1,23 @@
+// check-pass
+
+#![crate_type = "lib"]
+
+pub struct Foo;
+
+pub struct Path<T: Bar> {
+    _inner: T::Slice,
+}
+
+pub trait Bar: Sized {
+    type Slice: ?Sized;
+
+    fn open(_: &Path<Self>);
+}
+
+impl Bar for Foo {
+    type Slice = [u8];
+
+    fn open(_: &Path<Self>) {
+        unimplemented!()
+    }
+}