1 files changed, 20 insertions, 0 deletions
diff --git a/src/test/ui/specialization/issue-43037.rs b/src/test/ui/specialization/issue-43037.rs
new file mode 100644
index 000000000..c49119f9c
--- /dev/null
+++ b/src/test/ui/specialization/issue-43037.rs
@@ -0,0 +1,20 @@
+#![feature(specialization)]
+#![allow(incomplete_features)]
+
+trait X {}
+trait Y: X {}
+trait Z {
+    type Assoc: Y;
+}
+struct A<T>(T);
+
+impl<T> Y for T where T: X {}
+impl<T: X> Z for A<T> {
+    type Assoc = T;
+}
+
+// this impl is invalid, but causes an ICE anyway
+impl<T> From<<A<T> as Z>::Assoc> for T {}
+//~^ ERROR type parameter `T` must be used as the type parameter for some local type (e.g., `MyStruct<T>`)
+
+fn main() {}