1 files changed, 16 insertions, 0 deletions
diff --git a/tests/ui/traits/issue-38604.rs b/tests/ui/traits/issue-38604.rs
new file mode 100644
index 00000000000..002a3c43fcb
--- /dev/null
+++ b/tests/ui/traits/issue-38604.rs
@@ -0,0 +1,16 @@
+trait Q<T:?Sized> {}
+trait Foo where u32: Q<Self> {
+    fn foo(&self);
+}
+
+impl Q<()> for u32 {}
+impl Foo for () {
+    fn foo(&self) {
+        println!("foo!");
+    }
+}
+
+fn main() {
+    let _f: Box<dyn Foo> = //~ ERROR `Foo` cannot be made into an object
+        Box::new(()); //~ ERROR `Foo` cannot be made into an object
+}